WorldWideScience

Sample records for reduced activation steel

  1. Reduced-activation steels: present status and future development

    International Nuclear Information System (INIS)

    Klueh, R.L.

    2007-01-01

    Full text of publication follows: Reduced-activation steels for fusion reactor applications were developed in the 1980's to replace the commercial elevated- temperature steels first considered. In the United States, this involved replacing Sandvik HT9 and modified 9Cr-1Mo steels. Reduced-activation steels, which were developed for more rapid radioactivity decay following exposure in a fusion neutron environment, were patterned after the commercial steels they were to replace. The objective for the reduced-activation steels was that they have strengths (yield stress and ultimate tensile strength from room temperature to 600 deg. C) and impact toughness (measured in a Charpy test) comparable to or better than the steels they were replacing. That objective was achieved in reduced-activation steels developed in Japan, Europe, and the United States. Since the reduced-activation steels were developed in the 1980's, reactor designers have been interested designs for increased efficiency of future fusion plants. This means reactors will need to operate at higher temperatures-above 550 deg. C, which is the upper-temperature limit for the reduced-activation steels. Although the tensile and impact toughness of the reduced-activation steels exceed those of the commercial steels they were patterned after, their creep-rupture properties are inferior to some of the commercial steels they replaced. furthermore, they are much inferior to commercial steels that have been developed since the 1980's. Reasons for why the creep-rupture properties for the new commercial ferritic/martensitic steels are superior to the earlier commercial steels and the reduced-activation steels were examined. The reasons involve compositional changes that were made in the earlier commercial steels to give the new commercial steels their superior properties. Computational thermodynamics calculations were carried out to compare the expected equilibrium phases. It appears that similar changes in composition

  2. The development of EUROFER reduced activation steel

    Energy Technology Data Exchange (ETDEWEB)

    Schaaf, B. van der E-mail: vanderschaaf@nrg-nl.com; Tavassoli, F.; Fazio, C.; Rigal, E.; Diegele, E.; Lindau, R.; LeMarois, G

    2003-09-01

    Ferritic martensitic steels show limited swelling and susceptibility to helium effects and can be made with low activation chemical compositions. These properties make them the reference steel for the development of breeding blankets in fusion power plants. EUROFER97 is the European implementation of such a steel, where experience gained from an IEA co-operation with Japan and the US is also implemented. Results obtained so far show that EUROFER steel has attractive mechanical properties even after long ageing times. Compatibility tests in water and PbLi17 are in progress. Oxidised aluminium is the most effective protective layer in PbLi17. The displacement damage and helium formation strongly influence the hydrogen transport in the steel. Present experiments should be backed by tests in a more fusion relevant environment, e.g. IFMIF. The 2.5 dpa neutron irradiations at low temperatures result in a higher DBTT. High dose irradiations, up to 80 dpa, are underway. The early results of ODS grades with EUROFER steel composition show potential of these grades for increasing the operating temperature with 100-150 K.

  3. Dynamic mechanical properties of reduced activation ferritic steels

    International Nuclear Information System (INIS)

    Hirose, T.; Kohyama, A.; Tanigawa, H.; Ando, M.; Jitsukawa, S.

    2003-01-01

    A fatigue test method by a miniaturized hourglass-shaped fatigue specimen has been developed for International Fusion Materials Irradiation Facility (IFMIF) and sufficient potential as the alternative to a conventional large specimen was presented. Furthermore, focused ion beam micro- sampling method was successfully applied to microstructural analysis on fracture process. Where, the effects of displacement damage and transmutation helium on the fatigue properties of Reduced Activation Ferritic/Martensitic Steels, RAFs, were investigated. Neutron irradiation and helium-ion-implantation at ambient temperature caused radiation hardening to degrade fatigue lifetime of F82H steel. Microstructural analysis revealed that local brittle fractures occurred at early stage of fatigue tests was the origin of the degradation.. No significant difference in fatigue life degradation was detected with and without implanted helium. This result suggests that 100 appm helium implanted has no impact on fracture life time under neutron irradiation. (author)

  4. Development of ferritic steels for reduced activation: the US program

    International Nuclear Information System (INIS)

    Klueh, R.L.; Gelles, D.S.; Lechtenberg, T.A.

    1986-01-01

    The Cr-Mo ferritic (martensitic) steels are candidates for the structural components of fusion reactors. Irradiation of such steels in a fusion environment produces long-lived radioactive isotopes, which lead to difficult radioactive waste disposal problems once the structure is removed from service. Such problems could be reduced by using steels that contain only elements that produce radioactive isotopes that decay to low levels in a reasonable time (tens of years instead of hundreds or thousands of years). The US Department of Energy has a program to develop steels to meet the criteria for shallow land burial as opposed to deep geologic storage. A review of the alloy development programs indicates that ferritic steels that meet these criteria can be developed

  5. Materials design data for reduced activation martensitic steel type EUROFER

    Energy Technology Data Exchange (ETDEWEB)

    Tavassoli, A.-A.F. E-mail: tavassoli@cea.fr; Alamo, A.; Bedel, L.; Forest, L.; Gentzbittel, J.-M.; Rensman, J.-W.; Diegele, E.; Lindau, R.; Schirra, M.; Schmitt, R.; Schneider, H.C.; Petersen, C.; Lancha, A.-M.; Fernandez, P.; Filacchioni, G.; Maday, M.F.; Mergia, K.; Boukos, N.; Baluc,; Spaetig, P.; Alves, E.; Lucon, E

    2004-08-01

    Materials design limits derived so far from the data generated in Europe for the reduced activation ferritic/martensitic (RAFM) steel type Eurofer are presented. These data address the short-term needs of the ITER Test Blanket Modules and a DEMOnstration fusion reactor. Products tested include plates, bars, tubes, TIG and EB welds, as well as powder consolidated blocks and solid-solid HIP joints. Effects of thermal ageing and low dose neutron irradiation are also included. Results are sorted and screened according to design code requirements before being introduced in reference databases. From the physical properties databases, variations of magnetic properties, modulus of elasticity, density, thermal conductivity, thermal diffusivity, specific heat, mean and instantaneous linear coefficients of thermal expansion versus temperature are derived. From the tensile and creep properties databases design allowable stresses are derived. From the instrumented Charpy impact and fracture toughness databases, ductile to brittle transition temperature, toughness and behavior of materials in different fracture modes are evaluated. From the fatigue database, total strain range versus number of cycles to failure curves are plotted and used to derive fatigue design curves. Cyclic curves are also derived and compared with monotonic hardening curves. Finally, irradiated and aged materials data are compared to ensure that the safety margins incorporated in unirradiated design limits are not exceeded.

  6. Recent progress of R and D activities on reduced activation ferritic/martensitic steels

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Q., E-mail: qunying.huang@fds.org.cn [Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, P.O. Box 1135, Hefei, Anhui 230031 (China); Baluc, N. [CRPP-EPFL, ODGA C110 5232 Villigen PSI (Switzerland); Dai, Y. [LNM, PSI, 5232 Villigen PSI (Switzerland); Jitsukawa, S. [JAEA, 2-4 Shirakata, Tokai-Mura, Ibaraki-Ken 319-1195 (Japan); Kimura, A. [IAE, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Konys, J. [KIT, P.O. Box 3640, 76021 Karlsruhe (Germany); Kurtz, R.J. [PNNL, Richland, WA 99352 (United States); Lindau, R. [KIT, P.O. Box 3640, 76021 Karlsruhe (Germany); Muroga, T. [NIFS, Oroshi, Toki, Gifu 509-5292 (Japan); Odette, G.R. [UCSB, Santa Barbara, CA (United States); Raj, B. [IGCAR, Kalpakkam 603 102 (India); Stoller, R.E.; Tan, L. [ORNL, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Tanigawa, H. [JAEA, Naka, Ibaraki 311-0193 (Japan); Tavassoli, A.-A.F. [DMN/Dir, DEN, CEA Saclay, 91191 Gif-sur-Yvette cedex (France); Yamamoto, T. [UCSB, Santa Barbara, CA (United States); Wan, F. [DMPC, USTB, Beijing 100083 (China); Wu, Y. [Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, P.O. Box 1135, Hefei, Anhui 230031 (China)

    2013-11-15

    Several types of reduced activation ferritic/martensitic (RAFM) steel have been developed over the past 30 years in China, Europe, India, Japan, Russia and the USA for application in ITER test blanket modules (TBMs) and future fusion DEMO and power reactors. The progress has been particularly important during the past few years with evaluation of mechanical properties of these steels before and after irradiation and in contact with different cooling media. This paper presents recent RAFM steel results obtained in ITER partner countries in relation to different TBM and DEMO options.

  7. Optimum alloy compositions in reduced-activation martensitic 9Cr steels for fusion reactor

    International Nuclear Information System (INIS)

    Abe, F.; Noda, T.; Okada, M.

    1992-01-01

    In order to obtain potential reduced-activation ferritic steels suitable for fusion reactor structures, the effect of alloying elements W and V on the microstructural evolution, toughness, high-temperature creep and irradiation hardening behavior was investigated for simple 9Cr-W and 9Cr-V steels. The creep strength of the 9Cr-W steels increased but their toughness decreased with increasing W concentration. The 9Cr-V steels exhibited poor creep rupture strength, far below that of a conventional 9Cr-1MoVNb steel and poor toughness after aging at 873 K. It was also found that the Δ-ferrite should be avoided, because it degraded both the roughness and high-temperature creep strength. Based on the results on the simple steels, optimized martensitic 9Cr steels were alloy-designed from a standpoint of enough thoughness and high-temperature creep strength. Two kinds of optimized 9Cr steels with low and high levels of W were obtained; 9Cr-1WVTa and 9Cr-3WVTa. These steels indeed exhibited excellent toughness and creep strength, respectively. The 9Cr-1WVTa steel exhibiting an excellent roughness was shown to be the most promising for relatively low-temperature application below 500deg C, where irradiation embrittlement is significant. The 9Cr-3WVTa steel was the most promising for high temperature application above 500deg C from the standpoint of enough high-temperature strength. (orig.)

  8. Impurity content of reduced-activation ferritic steels and a vanadium alloy

    International Nuclear Information System (INIS)

    Klueh, R.L.; Grossbeck, M.L.; Bloom, E.E.

    1997-01-01

    Inductively coupled plasma mass spectrometry was used to analyze a reduced-activation ferritic/martensitic steel and a vanadium alloy for low-level impurities that would compromise the reduced-activation characteristics of these materials. The ferritic steel was from the 5-ton IEA heat of modified F82H, and the vanadium alloy was from a 500-kg heat of V-4Cr-4Ti. To compare techniques for analysis of low concentrations of impurities, the vanadium alloy was also examined by glow discharge mass spectrometry. Two other reduced-activation steels and two commercial ferritic steels were also analyzed to determine the difference in the level of the detrimental impurities in the IEA heat and steels for which no extra effort was made to restrict some of the tramp impurities. Silver, cobalt, molybdenum, and niobium proved to be the tramp impurities of most importance. The levels observed in these two materials produced with present technology exceeded the limits for low activation for either shallow land burial or recycling. The chemical analyses provide a benchmark for the improvement in production technology required to achieve reduced activation; they also provide a set of concentrations for calculating decay characteristics for reduced-activation materials. The results indicate the progress that has been made and give an indication of what must still be done before the reduced-activation criteria can be achieved

  9. Low-chromium reduced-activation chromium-tungsten steels

    Energy Technology Data Exchange (ETDEWEB)

    Klueh, R.L.; Alexander, D.J.; Maziasz, P.J. [Oak Ridge National Lab., TN (United States)

    1996-10-01

    Bainitic microstructures formed during continuous cooling can differ from classical upper and lower bainite formed during isothermal transformation. Two types of non-classical bainite were observed depending on the cooling rate: carbide-free acicular bainite at rapid cooling rates and granular bainite at slower cooling rates. The Charpy impact toughness of the acicular ferrite was found to be considerably better than for the granular bainite. It was postulated that alloying to improve the hardenability of the steel would promote the formation of acicular bainite, just as increasing the cooling rate does. To test this, chromium and tungsten were added to the 2 1/4Cr-2W and 2 1/4Cr-2WV steel compositions to increase their hardenability, and the microstructures and mechanical properties were examined.

  10. Low-chromium reduced-activation chromium-tungsten steels

    International Nuclear Information System (INIS)

    Klueh, R.L.; Alexander, D.J.; Maziasz, P.J.

    1996-01-01

    Bainitic microstructures formed during continuous cooling can differ from classical upper and lower bainite formed during isothermal transformation. Two types of non-classical bainite were observed depending on the cooling rate: carbide-free acicular bainite at rapid cooling rates and granular bainite at slower cooling rates. The Charpy impact toughness of the acicular ferrite was found to be considerably better than for the granular bainite. It was postulated that alloying to improve the hardenability of the steel would promote the formation of acicular bainite, just as increasing the cooling rate does. To test this, chromium and tungsten were added to the 2 1/4Cr-2W and 2 1/4Cr-2WV steel compositions to increase their hardenability, and the microstructures and mechanical properties were examined

  11. Development of Reduced Activation Ferritic-Martensitic Steels in South Korea

    International Nuclear Information System (INIS)

    Chun, Y. B.; Choi, B. K.; Han, C. H.; Lee, D. W.; Cho, S.; Kim, T. K.; Jeong, Y. H.

    2012-01-01

    In the mid-1980s research programs for development of low activation materials began. This is based on the US Nuclear Regulatory Commission Guidelines (10CFR part 61) that were developed to reduce longlived radioactive isotopes, which allows nuclear reactor waste to be disposed of by shallow land burial when removed from service. Development of low activation materials is also key issue in nuclear fusion systems, as the structural components can became radioactive due to nuclear transmutation caused by exposure to high dose neutron irradiation. Reduced-activation ferritic martensitic (RAFM) steels have been developed in the leading countries in nuclear fusion technology, and are now being considered as candidate structural material for the test blanket module (TBM) in the international thermonuclear experiment reactor (ITER). South Korea joined the ITER program in 2003 and since then extensive effort has been made for developing the helium-cooled solid-breeder (HCSB) TBM which is scheduled to be tested in the ITER program. However, there has been no research activity to develop RAFM steels in South Korea, while all the participants in the ITER program have developed their own RAFM steels. It is recently that the Korea Atomic Energy Research Institute (KAERI) started the Korean RAFM steel research program, aiming at an application for the HCSB-type TBM structure in ITER. In what follows, the current status of RAFM steels and the R and D program led by KAERI to develop Korean RAFM steels are summarized

  12. Current status of reduced-activation ferritic/martensitic steels R and D for fusion energy

    International Nuclear Information System (INIS)

    Kimura, Akihiko

    2005-01-01

    Reduced-activation ferritic/martensitic (RAF/M) steels have been considered to be the prime candidate for the fusion blanket structural material. The irradiation data obtained up to now indicates rather high feasibility of the steels for application to fusion reactors because of their high resistance to degradation of material performance caused by both the irradiation-induced displacement damage and transmutation helium atoms. The martensitic structure of RAF/M steels consists of a large number of lattice defects before the irradiation, which strongly retards the formation of displacement damage through absorption and annihilation of the point defects generated by irradiation. Transmutation helium can be also trapped at those defects in the martensitic structure so that the growth of helium bubbles at grain boundaries is suppressed. The major properties of the steels are well within our knowledge, and processing technologies are mostly developed for fusion application. RAF/M steels are now certainly ready to proceed to the next stage, that is, the construction of International Thermo-nuclear Experimental Reactor Test Blanket Modules (ITER-TBM). Oxide dispersion strengthening (ODS) steels have been developed for higher thermal efficiency of fusion power plants. Recent irradiation experiments indicated that the steels were quite highly resistant to neutron irradiation embrittlement, showing hardening accompanied by no loss of ductility. High-Cr ODS steels whose chromium concentration was in the range from 14 to 19 mass% showed high resistance to corrosion in supercritical pressurized water. It is shown that the 14Cr-ODS steel is susceptible to neither hydrogen nor helium embrittlement. A combined utilization of ODS steels with RAF/M steels will be effective to realize fusion power early at a reasonable thermal efficiency. (author)

  13. TIG of Reduced Activation Ferrite/Martensitic Steel for the Korean ITER-TBM

    International Nuclear Information System (INIS)

    Ku, Duck Young; Ahn, Mu Young; Yu, In Keun; Cho, Seun Gyon; Oh, Seung Jin

    2010-01-01

    Test Blanket Modules (TBM) will be tested in ITER to verify the capability of tritium breeding and recovery and the extraction of thermal energy suitable for the production of electricity. A Helium Cooled Solid Breeder (HCSB) TBM has been developed in Korea to accomplish these goals. Reduced Activation Ferritic/Martensitic (RAFM) steel has been chosen as the primary candidate structural material for Korean TBM. Due to the complexity of the First wall (FW) and Side wall (SW), it is necessary to develop various joining technologies, such as Hot Isostatic Pressing (HIP), Electron Beam Welding (EBW) and Tungsten Inert Gas (TIG) welding, for the successful fabrication of TBM. In this study, the mechanical properties of TIG welded RAFM steel were investigated. Various mechanical tests of TIG-welded RAFM steel were performed to obtain the optimized TIG welding process for RAFM steel

  14. TIG of Reduced Activation Ferrite/Martensitic Steel for the Korean ITER-TBM

    Energy Technology Data Exchange (ETDEWEB)

    Ku, Duck Young; Ahn, Mu Young; Yu, In Keun; Cho, Seun Gyon [ITER Korea, National Fusion Research Institute, Daejeon (Korea, Republic of); Oh, Seung Jin [KHNP, Daejeon (Korea, Republic of)

    2010-10-15

    Test Blanket Modules (TBM) will be tested in ITER to verify the capability of tritium breeding and recovery and the extraction of thermal energy suitable for the production of electricity. A Helium Cooled Solid Breeder (HCSB) TBM has been developed in Korea to accomplish these goals. Reduced Activation Ferritic/Martensitic (RAFM) steel has been chosen as the primary candidate structural material for Korean TBM. Due to the complexity of the First wall (FW) and Side wall (SW), it is necessary to develop various joining technologies, such as Hot Isostatic Pressing (HIP), Electron Beam Welding (EBW) and Tungsten Inert Gas (TIG) welding, for the successful fabrication of TBM. In this study, the mechanical properties of TIG welded RAFM steel were investigated. Various mechanical tests of TIG-welded RAFM steel were performed to obtain the optimized TIG welding process for RAFM steel

  15. Tensile and impact behaviour of BATMAN II steels, Ti-bearing reduced activation martensitic alloys

    Science.gov (United States)

    Filacchioni, G.; Casagrande, E.; De Angelis, U.; De Santis, G.; Ferrara, D.; Pilloni, L.

    Two series of Reduced Activation Ferrous alloys (RAF) have been produced and studied by Casaccia's Laboratories. These martensitic alloys are named BATMAN steels. They are among the few presently developed RAF materials to exploit Ti as a carbide forming and grain size stabilizing element instead of Ta. In this work their mechanical properties are illustrated.

  16. Structural and mechanical properties of welded joints of reduced activation martensitic steels

    International Nuclear Information System (INIS)

    Filacchioni, G.; Montanari, R.; Tata, M.E.; Pilloni, L.

    2002-01-01

    Gas tungsten arc welding and electron beam welding methods were used to realise welding pools on plates of reduced activation martensitic steels. Structural and mechanical features of these simulated joints have been investigated in as-welded and post-welding heat-treated conditions. The research allowed to assess how each welding technique affects the original mechanical properties of materials and to find suitable post-welding heat treatments. This paper reports results from experimental activities on BATMAN II and F82H mod. steels carried out in the frame of the European Blanket Project - Structural Materials Program

  17. Recent results of the reduced activation ferritic/martensitic steel development

    Energy Technology Data Exchange (ETDEWEB)

    Jitsukawa, S. E-mail: jitsukawa@ifmif.tokai.jaeri.go.jp; Kimura, A.; Kohyama, A.; Klueh, R.L.; Tavassoli, A.A.; Schaaf, B. van der; Odette, G.R.; Rensman, J.W.; Victoria, M.; Petersen, C

    2004-08-01

    Significant progress has been achieved in the international research effort on reduced-activation steels. Extensive tensile, fracture toughness, fatigue, and creep properties in unirradiated and irradiated conditions have been performed and evaluated. Since it is not possible to include all work in this limited review, selected areas will be presented to indicate the scope and progress of recent international efforts. These include (1) results from mechanical properties studies that have been combined in databases to determine materials design limits for the preliminary design of an ITER blanket module. (2) Results indicate that the effect of transmutation-produced helium on fracture toughness is smaller than indicated previously. (3) Further efforts to reduce irradiation-induced degradation of fracture toughness. (4) The introduction of a post-irradiation constitutive equation for plastic deformation. (5) The production of ODS steels that have been used to improve high-temperature strength. (6) The method developed to improve fracture toughness of ODS steels.

  18. Thermal and mechanical behaviour of the reduced-activation-ferritic-martensitic steel EUROFER

    International Nuclear Information System (INIS)

    Lindau, R.; Moeslang, A.; Schirra, M.

    2002-01-01

    Reduced activation ferritic/martensitic (RAFM) steels are being considered for structural application in potential fusion energy systems. Based on the substantial experience with RAFM developmental steels of OPTIFER type, an industrial 3.5 tons batch of a 9CrWVTa-RAFM steel, called EUROFER 97 had been specified and ordered. A characterisation programme has been launched to determine the relevant mechanical and physical-metallurgical properties in order to qualify the steel for fusion application. The hardening, tempering and transformation behaviour of EUROFER is in good agreement with that of other RAFM-steels like OPTIFER and the Japanese industrial scale heat F82H mod. Tensile tests, performed between RT and 750 deg. C, show comparable strength and ductility values that are not strongly affected by different heat treatments and ageing at 580 and 600 deg. C up to 3300 h. Impact bending tests indicate a superior ductile to brittle transition temperature (DBTT) of EUROFER in the as-received condition compared with that of F82H mod. Creep tests between 450 and 650 deg. C up to test times of 15000 h reveal a creep strength similar to other RAFM steels like OPTIFER and F82H mod. EUROFER shows a good low-cycle fatigue behaviour with longer lifetimes than F82H mod. The deformation and softening behaviour is similar

  19. Tensile and charpy impact properties of irradiated reduced-activation ferritic steels

    Energy Technology Data Exchange (ETDEWEB)

    Klueh, R.L.; Alexander, D.J. [Oak Ridge National Lab., TN (United States)

    1996-10-01

    Tensile tests were conducted on eight reduced-activation Cr-W steels after irradiation to 15-17 and 26-29 dpa, and Charpy impact tests were conducted on the steels irradiated to 26-29 dpa. Irradiation was in the Fast Flux Test Facility at 365{degrees}C on steels containing 2.25-12% Cr, varying amounts of W, V, and Ta, and 0.1%C. Previously, tensile specimens were irradiated to 6-8 dpa and Charpy specimens to 6-8, 15-17, and 20-24 dpa. Tensile and Charpy specimens were also thermally aged to 20000 h at 365{degrees}C. Thermal aging had little effect on the tensile behavior or the ductile-brittle transition temperature (DBTT), but several steels showed a slight increase in the upper-shelf energy (USE). After {approx}7 dpa, the strength of the steels increased and then remained relatively unchanged through 26-29 dpa (i.e., the strength saturated with fluence). Post-irradiation Charpy impact tests after 26-29 dpa showed that the loss of impact toughness, as measured by an increase in DBTT and a decrease in the USE, remained relatively unchanged from the values after 20-24 dpa, which had been relatively unchanged from the earlier irradiations. As before, the two 9Cr steels were the most irradiation resistant.

  20. Technical issues of fabrication technologies of reduced activation ferritic/martensitic steels

    International Nuclear Information System (INIS)

    Tanigawa, Hiroyasu; Sakasegawa, Hideo; Hirose, Takanori

    2013-01-01

    Highlights: • The key technical issues of RAFM steel fabrication are the control of Ta, and deoxidation of the steel with a limited amount of Al addition. • Addition of Ta with poor deoxidation might results in the agglomeration of inclusions at 1/2t position. • ESR was proved to be effective removing Ta oxide inclusions and avoiding agglomeration of inclusions at 1/2t position, and achieving low oxygen concentration. -- Abstract: The key issue for DEMO application is that Reduced activation ferritic/martensitic (RAFM) steels fabrication technologies has to be highly assured, especially with respect to high availability, reliability and reduced activation capability on the DEMO level fabrication, which requires not a few tons but thousand tons RAFM fabrication. One of the key technical issues of RAFM fabrication is the control of Ta, and deoxidation of the steel with a limited amount of Al addition. The series of F82H (Fe–8Cr–2W–V, Ta) melting revealed that Ta have tendency to form oxide on melting process, and this will have large impact on reliability of the steels. Al is also the key elements, as it is commonly used for deoxidation of steels, and achieving lower oxygen level is essential to obtain good mechanical properties, but the maximum concentration of Al is limited in view of reduced activation capability. These tendency and limitation resulted in the Ta oxide agglomeration in the middle of plate, but the remelting process, ESR (electro slag remelting), was found to be successful on removing those Ta oxides

  1. Report of IEA workshop on reduced activation ferritic/martensitic steels

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    IEA Workshop on Reduced Activation Ferritic/Martensitic Steels under implementing agreement for program of research and development on fusion materials was held at Tokyo Yayoi Kaikan and JAERI headquarter on November 2-3, 2000. The objective of this workshop was a review of the fusion material development programs, the progress of the collaboration and the irradiation effects studies on RAF/M steels in the collaborating parties (Europe, Russia the United States, and Japan). Moreover, the development of plans for future collaboration was discussed. The present report contains viewgraphs presented at the workshop. (author)

  2. Vacuum Plasma Spraying W-coated Reduced Activation Structural Steels for Fusion Plasma Facing Components

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Sanghoon; Kim, Tae Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    Tungsten (W) and its alloys are considered as candidate materials for plasma facing materials of the first wall and diverter components in fusion reactor systems because of high sputtering resistance and low tritium retention in a fusion environment. Therefore, it is considered that the joining between W and reduced activation structural steels, and its evaluation, are critical issues for the development of fusion reactors. However, the joining between these materials is a very challenging process because of significant differences in their physical properties, particularly the mismatch of coefficients of thermal expansion (CTE). For instance, the CTE of pure W is known to be about 4.3Χ10{sup -6}K{sup -1}; however, that of martensitic steels reaches over three times, about 12-14Χ10{sup -6}K{sup -1} at room temperature even up to 373K. Nevertheless, several joining techniques have been developed for joining between W and structural steels, such as a vapor deposition method, brazing and diffusion bonding. Meanwhile, vacuum plasma spraying (VPS) is supposed to be one of the prospective methods to fabricate a sufficient W layer on the steel substrates because of the coating of a large area with a relatively high fabricating rate. In this study, the VPS method of W powders on reduced activation steels was employed, and its microstructure and hardness distribution were investigated. ODS ferritic steels and F82H steel were coated by VPS-W, and the microstructure and hardness distribution were investigated. A microstructure analysis revealed that pure W was successfully coated on steel substrates by the VPS process without an intermediate layer, in spite of a mismatch of the CTE between dissimilar materials. After neutron irradiation, irradiation hardening significantly occurred in the VPSW. However, the hardening of VPS-W was lesser than that of bulk W irradiated HFIR at 773K. Substrate materials, ODS ferritic steels, and F82H steel, did not show irradiation hardening

  3. Influence of Prior Fatigue Cycling on Creep Behavior of Reduced Activation Ferritic-Martensitic Steel

    Science.gov (United States)

    Sarkar, Aritra; Vijayanand, V. D.; Parameswaran, P.; Shankar, Vani; Sandhya, R.; Laha, K.; Mathew, M. D.; Jayakumar, T.; Rajendra Kumar, E.

    2014-06-01

    Creep tests were carried out at 823 K (550 °C) and 210 MPa on Reduced Activation Ferritic-Martensitic (RAFM) steel which was subjected to different extents of prior fatigue exposure at 823 K at a strain amplitude of ±0.6 pct to assess the effect of prior fatigue exposure on creep behavior. Extensive cyclic softening that characterized the fatigue damage was found to be immensely deleterious for creep strength of the tempered martensitic steel. Creep rupture life was reduced to 60 pct of that of the virgin steel when the steel was exposed to as low as 1 pct of fatigue life. However, creep life saturated after fatigue exposure of 40 pct. Increase in minimum creep rate and decrease in creep rupture ductility with a saturating trend were observed with prior fatigue exposures. To substantiate these findings, detailed transmission electron microscopy studies were carried out on the steel. With fatigue exposures, extensive recovery of martensitic-lath structure was distinctly observed which supported the cyclic softening behavior that was introduced due to prior fatigue. Consequently, prior fatigue exposures were considered responsible for decrease in creep ductility and associated reduction in the creep rupture strength.

  4. Damage behavior in helium-irradiated reduced-activation martensitic steels at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Fengfeng [Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Guo, Liping, E-mail: guolp@whu.edu.cn [Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Chen, Jihong; Li, Tiecheng; Zheng, Zhongcheng [Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Yao, Z. [Department of Mechanical and Materials Engineering, Queen’s University, Kingston K7L 3N6, ON (Canada); Suo, Jinping [State Key Laboratory of Mould Technology, Institute of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2014-12-15

    Dislocation loops induced by helium irradiation at elevated temperatures in reduced-activation martensitic steels were investigated using transmission electron microscopy. Steels were irradiated with 100 keV helium ions to 0.8 dpa between 300 K and 723 K. At irradiation temperatures T{sub irr} ⩽ 573 K, small defects with both Burger vectors b = 1/2〈1 1 1〉 and b = 〈1 0 0〉 were observed, while at T{sub irr} ⩾ 623 K, the microstructure was dominated by large convoluted interstitial dislocation loops with b = 〈1 0 0〉. Only small cavities were found in the steels irradiated at 723 K.

  5. Development of Reduced Activation Ferritic-Martensitic Steels and fabrication technologies for Indian test blanket module

    Energy Technology Data Exchange (ETDEWEB)

    Raj, Baldev [Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Jayakumar, T., E-mail: tjk@igcar.gov.in [Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India)

    2011-10-01

    For the development of Reduced Activation Ferritic-Martensitic Steel (RAFMS), for the Indian Test Blanket Module for ITER, a 3-phase programme has been adopted. The first phase consists of melting and detailed characterization of a laboratory scale heat conforming to Eurofer 97 composition, to demonstrate the capability of the Indian industry for producing fusion grade steel. In the second phase which is currently in progress, the chemical composition will be optimized with respect to tungsten and tantalum for better combination of mechanical properties. Characterization of the optimized commercial scale India-specific RAFM steel will be carried out in the third phase. The first phase of the programme has been successfully completed and the tensile, impact and creep properties are comparable with Eurofer 97. Laser and electron beam welding parameters have been optimized and welding consumables were developed for Narrow Gap - Gas Tungsten Arc welding and for laser-hybrid welding.

  6. Microstructural characterization of 5-9% chromium reduced-activation steels

    Energy Technology Data Exchange (ETDEWEB)

    Jayaram, R. [Univ. of Pittsburgh, PA (United States); Klueh, R.L. [Oak Ridge National Lab., TN (United States)

    1997-08-01

    The microstructures of a 9Cr-2W-0.25-0.1C (9Cr-2WV), a 9Cr-2W-0.25V-0.07Ta-0.1C (9Cr-2WVTa), a 7Cr-2W-0.25V-0.07Ta-0.1C (7Cr-2WVTa), and a 5Cr-2W-0.25V-0.07Ta-0.1C (5Cr-2WVTa) steel (all compositions are in weight percent) have been characterized by Analytical Electron Microscopy (AEM) and Atom Probe Field Ion Microscopy (APFIM). The matrix in all four reduced-activation steels was 100% martensite. In the two 9Cr steels, the stable precipitates were blocky M{sub 23}C{sub 6} and small spherical MC. The two lower-chromium steels contained blocky M{sub 7}C{sub 3} and small needle-shaped carbonitrides in addition to M{sub 23}C{sub 6}. AEM and APFIM analysis revealed that in the steels containing tantalum, the majority of the tantalum was in solid solution. The experimental observations were in good agreement with phases and compositions predicted by phase equilibria calculations.

  7. Microstructural characterization of 5-9% chromium reduced-activation steels

    International Nuclear Information System (INIS)

    Jayaram, R.; Klueh, R.L.

    1997-01-01

    The microstructures of a 9Cr-2W-0.25-0.1C (9Cr-2WV), a 9Cr-2W-0.25V-0.07Ta-0.1C (9Cr-2WVTa), a 7Cr-2W-0.25V-0.07Ta-0.1C (7Cr-2WVTa), and a 5Cr-2W-0.25V-0.07Ta-0.1C (5Cr-2WVTa) steel (all compositions are in weight percent) have been characterized by Analytical Electron Microscopy (AEM) and Atom Probe Field Ion Microscopy (APFIM). The matrix in all four reduced-activation steels was 100% martensite. In the two 9Cr steels, the stable precipitates were blocky M 23 C 6 and small spherical MC. The two lower-chromium steels contained blocky M 7 C 3 and small needle-shaped carbonitrides in addition to M 23 C 6 . AEM and APFIM analysis revealed that in the steels containing tantalum, the majority of the tantalum was in solid solution. The experimental observations were in good agreement with phases and compositions predicted by phase equilibria calculations

  8. Chemical compatibility study of lithium titanate with Indian reduced activation ferritic martensitic steel

    International Nuclear Information System (INIS)

    Sonak, Sagar; Jain, Uttam; Haldar, Rumu; Kumar, Sanjay

    2015-01-01

    Highlights: • Chemical compatibility between Li_2TiO_3 and Indian RAFM steel has been studied at ITER operating temperature. • The lithium titanate chemically reacted with ferritic martensitic steel to form a brittle and non-adherent oxide layer. • The layer grew in a parabolic manner as a function of heating time. • Diffusion of oxygen (from Li_2TiO_3) appears to be controlling the oxide layer. - Abstract: Chemical compatibility between lithium titanate and Indian reduced activation ferritic-martensitic steel (In-RAFMS) was studied for the first time under ITER operating temperature. Lithium titanate required for the study was synthesized in-house. Coupons of In-RAFMS were packed inside lithium titanate powder and heated at 550 °C up to 900 h under inert argon atmosphere. The lithium titanate chemically reacted with ferritic martensitic steel to form a brittle and non-adherent oxide layer. The layer grew in a parabolic manner as a function of heating time. Microstructural and phase evolution of this oxide layer was studied using XRD, SEM and EPMA. Iron and chromium enriched zones were found within the oxide layer. Diffusion of oxygen (from Li_2TiO_3) appears to be controlling the oxide layer.

  9. Reduced activation ODS ferritic steel - recent development in high speed hot extrusion processing

    Energy Technology Data Exchange (ETDEWEB)

    Oksiuta, Zbigniew [Faculty of Mechanical Engineering, Bialystok Technical University (Poland); Lewandowska, Malgorzata; Kurzydlowski, Krzysztof [Faculty of Materials Science and Engineering, Warsaw University of Technology (Poland); Baluc, Nadine [Ecole Polytechnique Federale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas, Association Euratom-Confederation Suisse, Villigen PSI (Switzerland)

    2010-05-15

    The paper presents the microstructure and mechanical properties of an oxide dispersion strengthened (ODS), reduced activation, ferritic steel, namely the Fe-14Cr-2W-0.3Ti-0.3Y{sub 2}O{sub 3} alloy, which was fabricated by hot isostatic pressing followed by high speed hydrostatic extrusion (HSHE) and heat treatment HT at 1050 C. Transmission electron microscopy (TEM) observations revealed significant differences in the grain size and dislocation density between the as-HIPped and as-HSHE materials. It was also found that the microstructure of the steel is stable after HT. The HSHE process improves significantly the tensile and Charpy impact properties of the as-HIPped steel. The ultimate tensile strength at room temperature increases from 950 up to 1350 MPa, while the upper shelf energy increases from 3.0 up to 6.0 J. However, the ductile-to-brittle transition temperature (DBTT) remains relatively high (about 75 C).These results indicate that HSHE is a promising method for achieving grain refinement and thus improving the mechanical properties of ODS ferritic steels. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  10. Strain-rate behavior in tension of the tempered martensitic reduced activation steel Eurofer97

    Energy Technology Data Exchange (ETDEWEB)

    Cadoni, Ezio; Dotta, Matteo; Forni, Daniele [University of Applied Sciences of Southern Switzerland, P.O. Box 105, CH-6952 Canobbio (Switzerland); Spaetig, Philippe, E-mail: philippe.spatig@psi.ch [Ecole Polytechnique Federale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas, Association Euratom-Confederation Suisse, CH-5232 Villigen PSI (Switzerland)

    2011-07-31

    The tensile properties of the high-chromium tempered martensitic reduced activation steel Eurofer97 were determined from tests carried out over a wide range of strain-rates on cylindrical specimens. The quasi-static tests were performed with a universal electro-mechanical machine, whereas a hydro-pneumatic machine and a JRC-split Hopkinson tensile bar apparatus were used for medium and high strain-rates respectively. This tempered martensitic stainless steel showed significant strain-rate sensitivity. The constitutive behavior was investigated within a framework of dislocations dynamics model using Kock's approach. The parameters of the model were determined and then used to predict the deformation range of the tensile deformation stability. A very good agreement between the experimental results and predictions of the model was found.

  11. Strain-rate behavior in tension of the tempered martensitic reduced activation steel Eurofer97

    International Nuclear Information System (INIS)

    Cadoni, Ezio; Dotta, Matteo; Forni, Daniele; Spaetig, Philippe

    2011-01-01

    The tensile properties of the high-chromium tempered martensitic reduced activation steel Eurofer97 were determined from tests carried out over a wide range of strain-rates on cylindrical specimens. The quasi-static tests were performed with a universal electro-mechanical machine, whereas a hydro-pneumatic machine and a JRC-split Hopkinson tensile bar apparatus were used for medium and high strain-rates respectively. This tempered martensitic stainless steel showed significant strain-rate sensitivity. The constitutive behavior was investigated within a framework of dislocations dynamics model using Kock's approach. The parameters of the model were determined and then used to predict the deformation range of the tensile deformation stability. A very good agreement between the experimental results and predictions of the model was found.

  12. Multiscale simulation of yield strength in reduced-activation ferritic/martensitic steel

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chen Chong; Zhang, Chi; Yang, Zhigang [Key Laboratory of Advanced Materials of Ministry of Education, School of Materials Science and Engineering, Tsinghua University, Beijing (China); Zhao, Ji Jun [State Key Laboratory of Materials Modification by Laser, Electron, and Ion Beams, School of Physics and Optoelectronic Technology and College of Advanced Science and Technology, Dalian University of Technology, Dalian (China)

    2017-04-15

    One of the important requirements for the application of reduced-activation ferritic/martensitic (RAFM) steel is to retain proper mechanical properties under irradiation and high-temperature conditions. To simulate the yield strength and stress-strain curve of steels during high-temperature and irradiation conditions, a multiscale simulation method consisting of both microstructure and strengthening simulations was established. The simulation results of microstructure parameters were added to a superposition strengthening model, which consisted of constitutive models of different strengthening methods. Based on the simulation results, the strength contribution for different strengthening methods at both room temperature and high-temperature conditions was analyzed. The simulation results of the yield strength in irradiation and high-temperature conditions were mainly consistent with the experimental results. The optimal application field of this multiscale model was 9Cr series (7–9 wt.%Cr) RAFM steels in a condition characterized by 0.1–5 dpa (or 0 dpa) and a temperature range of 25–500°C.

  13. Mechanical characterization of a reduced activation 9 Cr ferritic/martensitic steel of spanish production

    International Nuclear Information System (INIS)

    Rodriguez, D.; Serrano, M.

    2012-01-01

    This paper shows the first results concerning the characterization of two heats of a reduced activation 9 Cr ferritic/martensitic steel (RAFM) made in Spain, called AF1B and AF2A. The results of this characterization are compared with their European counterparts, EUROFER97-2, which was chosen as reference material. All activities described were performed in the Structural Materials Unit of CIEMAT, within the national project TECNO-FUS CONSOLIDER INGENIO.The two Spanish heats have the same production process and heat treatment. Both heats have a similar tensile behaviour similar to EUROFER97-2, but on the other hand impact properties are lower. The microstructure of AF1B reveals large biphasic inclusions that affecting its mechanical properties, especially the impact properties. AF2A casting was free of these inclusions. (Author) 24 refs.

  14. Effect of heat treatment and irradiation temperature on impact behavior of irradiated reduced-activation ferritic steels

    International Nuclear Information System (INIS)

    Klueh, R.L.; Alexander, D.J.

    1998-01-01

    Charpy tests were conducted on eight normalized-and-tempered reduced-activation ferritic steels irradiated in two different normalized conditions. Irradiation was conducted in the Fast Flux Test Facility at 393 C to ∼14 dpa on steels with 2.25, 5, 9, and 12% Cr (0.1% C) with varying amounts of W, V, and Ta. The different normalization treatments involved changing the cooling rate after austenitization. The faster cooling rate produced 100% bainite in the 2.25 Cr steels, compared to duplex structures of bainite and polygonal ferrite for the slower cooling rate. For both cooling rates, martensite formed in the 5 and 9% Cr steels, and martensite with ∼25% δ-ferrite formed in the 12% Cr steel. Irradiation caused an increase in the ductile-brittle transition temperature (DBTT) and a decrease in the upper-shelf energy. The difference in microstructure in the low-chromium steels due to the different heat treatments had little effect on properties. For the high-chromium martensitic steels, only the 5 Cr steel was affected by heat treatment. When the results at 393 C were compared with previous results at 365 C, all but a 5 Cr and a 9 Cr steel showed the expected decrease in the shift in DBTT with increasing temperature

  15. Development of next generation tempered and ODS reduced activation ferritic/martensitic steels for fusion energy applications

    Science.gov (United States)

    Zinkle, S. J.; Boutard, J. L.; Hoelzer, D. T.; Kimura, A.; Lindau, R.; Odette, G. R.; Rieth, M.; Tan, L.; Tanigawa, H.

    2017-09-01

    Reduced activation ferritic/martensitic steels are currently the most technologically mature option for the structural material of proposed fusion energy reactors. Advanced next-generation higher performance steels offer the opportunity for improvements in fusion reactor operational lifetime and reliability, superior neutron radiation damage resistance, higher thermodynamic efficiency, and reduced construction costs. The two main strategies for developing improved steels for fusion energy applications are based on (1) an evolutionary pathway using computational thermodynamics modelling and modified thermomechanical treatments (TMT) to produce higher performance reduced activation ferritic/martensitic (RAFM) steels and (2) a higher risk, potentially higher payoff approach based on powder metallurgy techniques to produce very high strength oxide dispersion strengthened (ODS) steels capable of operation to very high temperatures and with potentially very high resistance to fusion neutron-induced property degradation. The current development status of these next-generation high performance steels is summarized, and research and development challenges for the successful development of these materials are outlined. Material properties including temperature-dependent uniaxial yield strengths, tensile elongations, high-temperature thermal creep, Charpy impact ductile to brittle transient temperature (DBTT) and fracture toughness behaviour, and neutron irradiation-induced low-temperature hardening and embrittlement and intermediate-temperature volumetric void swelling (including effects associated with fusion-relevant helium and hydrogen generation) are described for research heats of the new steels.

  16. Metallurgical Characterization of Reduced Activation Martensitic Steel F-82H Modified

    International Nuclear Information System (INIS)

    Fernandez, P.; Lapena, J.; Lancha, A.M.; Gomez-Briceno, D.; Schirra, M.

    1999-12-01

    During 1995-1998 within of research and development programs on reduced ferritic/martensitic steels for fusion, metallurgical characterization of 8Cr-2WVTa steel, denominated F-28H modified, have been carried out. The work has focused on studying the microstructural and mechanical (tensile, creep, low cycle fatigue and charpy) characteristics of as-received state and aged material in the temperature range 300 degree centigrade to 600 degree centigrade for periods up to 5000 h. (Author) 45 refs

  17. Development of an extensive database of mechanical properties for Reduced Activation Ferritic/Martensitic Steels

    International Nuclear Information System (INIS)

    Tanigawa, H.; Shiba, K.; Ando, M.; Wakai, E.; Jitsukawa, S.; Hirose, T.; Kasada, R.; Kimura, A.; Kohyama, A.; Kohno, Y.; Klueh, R.L.; Sokolov, M.; Stoller, R.; Zinklek, S.; Yamamoto, T.; Odette, G.; Kurtz, R.J.

    2007-01-01

    Full text of publication follows: Reduced activation ferritic/martensitic steels (RAFMs) are recognized as the primary candidate structural materials for fusion blanket systems, as they have been developed based on massive industrial experience of ferritic/martensitic steel replacing Mo and Nb of high chromium heat resistant martensitic steels (such as modified 9Cr-1Mo) with W and Ta, respectively. F82H (8Cr-2W-0.2V-0.04Ta-0.1C) and JLF-1 (9Cr-2W-0.2V-0.08Ta-0.1C) are RAFMs, which have been developed and studied in Japan and the various effects of irradiation were reported. F82H is designed with emphasis on high temperature property and weldablility, and was provided and evaluated in various countries as a part of the IEA fusion materials development collaboration. The Japan/US collaboration program also has been conducted with the emphasis on heavy irradiation effects of F82H, JLF-1 and ORNL9Cr2WVTa over the past two decades using Fast Flux Testing Facility (FFTF) of PNNL and High Flux Isotope Reactor (HFIR) of ORNL, and the irradiation condition of the irradiation capsules of those reactors were precisely controlled by the well matured capsule designing and instrumentation. Now, among the existing database for RAFMs the most extensive one is that for F82H. The objective of this paper is to review the database status of RAFMs, mainly on F82H, to identify the key issues for the future development of database. Tensile, fracture toughness, creep and fatigue properties and microstructural studies before and after irradiation are summarized. (authors)

  18. Development of an extensive database of mechanical properties for Reduced Activation Ferritic/Martensitic Steels

    Energy Technology Data Exchange (ETDEWEB)

    Tanigawa, H.; Shiba, K.; Ando, M.; Wakai, E.; Jitsukawa, S. [Japan Atomic Energy Agency, Tokai-mura, Naga-gun, Ibaraki-ken (Japan); Hirose, T. [Blanket Engineering Group, Japan Atomic Energy Agency, Naka, Ibaraki (Japan); Kasada, R.; Kimura, A.; Kohyama, A. [Kyoto Univ., lnstitute of Advanced Energy (Japan); Kohno, Y. [Muroran Institute of Technology, Muroran, Hokkaido (Japan); Klueh, R.L. [0ak Ridge Noational Laboratory, TN (United States); Sokolov, M.; Stoller, R.; Zinklek, S. [0ak Ridge Noational Laboratory, Materials Science and Technology Div., TN (United States); Yamamoto, T.; Odette, G. [UCSB, Dept. of Chemical Engineering UCSB, Santa-Barbara (United States); Kurtz, R.J. [Pacifie Northwest National Laboratory, Richland WA (United States)

    2007-07-01

    Full text of publication follows: Reduced activation ferritic/martensitic steels (RAFMs) are recognized as the primary candidate structural materials for fusion blanket systems, as they have been developed based on massive industrial experience of ferritic/martensitic steel replacing Mo and Nb of high chromium heat resistant martensitic steels (such as modified 9Cr-1Mo) with W and Ta, respectively. F82H (8Cr-2W-0.2V-0.04Ta-0.1C) and JLF-1 (9Cr-2W-0.2V-0.08Ta-0.1C) are RAFMs, which have been developed and studied in Japan and the various effects of irradiation were reported. F82H is designed with emphasis on high temperature property and weldablility, and was provided and evaluated in various countries as a part of the IEA fusion materials development collaboration. The Japan/US collaboration program also has been conducted with the emphasis on heavy irradiation effects of F82H, JLF-1 and ORNL9Cr2WVTa over the past two decades using Fast Flux Testing Facility (FFTF) of PNNL and High Flux Isotope Reactor (HFIR) of ORNL, and the irradiation condition of the irradiation capsules of those reactors were precisely controlled by the well matured capsule designing and instrumentation. Now, among the existing database for RAFMs the most extensive one is that for F82H. The objective of this paper is to review the database status of RAFMs, mainly on F82H, to identify the key issues for the future development of database. Tensile, fracture toughness, creep and fatigue properties and microstructural studies before and after irradiation are summarized. (authors)

  19. Delta ferrite in the weld metal of reduced activation ferritic martensitic steel

    Energy Technology Data Exchange (ETDEWEB)

    Sam, Shiju, E-mail: shiju@ipr.res.in [Institute for Plasma Research, Gandhinagar, Gujarat 382 428 (India); Das, C.R.; Ramasubbu, V.; Albert, S.K.; Bhaduri, A.K.; Jayakumar, T. [Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Rajendra Kumar, E. [Institute for Plasma Research, Gandhinagar, Gujarat 382 428 (India)

    2014-12-15

    Formation of delta(δ)-ferrite in the weld metal, during autogenous bead-on-plate welding of Reduced Activation Ferritic Martensitic (RAFM) steel using Gas Tungsten Arc Welding (GTAW) process, has been studied. Composition of the alloy is such that delta-ferrite is not expected in the alloy; but examination of the weld metal revealed presence of delta-ferrite in the weld metal. Volume fraction of delta-ferrite is found to be higher in the weld interface than in the rest of the fusion zone. Decrease in the volume fraction of delta-ferrite, with an increase in preheat temperature or with an increase in heat input, is observed. Results indicate that the cooling rate experienced during welding affects the volume fraction of delta-ferrite retained in the weld metal and variation in the delta-ferrite content with cooling rate is explained with variation in the time that the weld metal spends in various temperature regimes in which delta-ferrite is stable for the alloy during its cooling from the liquid metal to the ambient temperature. This manuscript will discuss the effect of welding parameters on formation of delta-ferrite and its retention in the weld metal of RAFM steel.

  20. Microstructural evolution of reduced-activation martensitic steel under single and sequential ion irradiations

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Fengfeng [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Guo, Liping, E-mail: guolp@whu.edu.cn [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Jin, Shuoxue; Li, Tiecheng; Zheng, Zhongcheng [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Yang, Feng; Xiong, Xuesong; Suo, Jinping [State Key Laboratory of Mould Technology, Institute of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2013-07-15

    Microstructural evolution of super-clean reduced-activation martensitic steels irradiated with single-beam (Fe{sup +}) and sequential-beam (Fe{sup +} plus He{sup +}) at 350 °C and 550 °C was studied. Sequential-beam irradiation induced smaller size and larger number density of precipitates compared to single-beam irradiation at 350 °C. The largest size of cavities was observed after sequential-beam irradiation at 550 °C. The segregation of Cr and W and depletion of Fe in carbides were observed, and the maximum depletion of Fe and enrichment of Cr occurred under irradiation at 350 °C.

  1. Technical issues of reduced activation ferritic/martensitic steels for fabrication of ITER test blanket modules

    International Nuclear Information System (INIS)

    Tanigawa, H.; Hirose, T.; Shiba, K.; Kasada, R.; Wakai, E.; Serizawa, H.; Kawahito, Y.; Jitsukawa, S.; Kimura, A.; Kohno, Y.; Kohyama, A.; Katayama, S.; Mori, H.; Nishimoto, K.; Klueh, R.L.; Sokolov, M.A.; Stoller, R.E.; Zinkle, S.J.

    2008-01-01

    Reduced activation ferritic/martensitic steels (RAFMs) are recognized as the primary candidate structural materials for fusion blanket systems. The RAFM F82H was developed in Japan with emphasis on high-temperature properties and weldability. Extensive irradiation studies have conducted on F82H, and it has the most extensive available database of irradiated and unirradiated properties of all RAFMs. The objective of this paper is to review the R and D status of F82H and to identify the key technical issues for the fabrication of an ITER test blanket module (TBM) suggested from the recent research achievements in Japan. This work clarified that the primary issues with F82H involve welding techniques and the mechanical properties of weld joints. This is the result of the distinctive nature of the joint caused by the phase transformation that occurs in the weld joint during cooling, and its impact on the design of a TBM will be discussed

  2. Thermo-mechanical fatigue behavior of reduced activation ferrite/martensite stainless steels

    International Nuclear Information System (INIS)

    Petersen, C.; Rodrian, D.

    2002-01-01

    The thermo-mechanical cycling fatigue (TMCF) behavior of reduced activation ferrite/martensite stainless steels is examined. The test rig consists of a stiff load frame, which is directly heated by the digitally controlled ohmic heating device. Cylindrical specimens are used with a wall thickness of 0.4 mm. Variable strain rates are applied at TMCF test mode, due to the constant heating rate of 5.8 K/s and variable temperature changes. TMCF results of as received EUROFER 97 in the temperature range between 100 and 500-600 deg. C show a reduction in life time (a factor of 2) compared to F82H mod. and OPTIFER IV. TMCF-experiments with hold times of 100 and 1000 s show dramatic reduction in life time for all three materials

  3. Radiation effects on low cycle fatigue properties of reduced activation ferritic/martensitic steels

    International Nuclear Information System (INIS)

    Hirose, T.; Tanigawa, H.; Ando, M.; Kohyama, A.; Katoh, Y.; Narui, M.

    2002-01-01

    The reduced activation ferritic/martensitic steel, RAFs F82H IEA heat has been fatigue-tested at ambient temperature under diametral strain controlled conditions. In order to evaluate the effects of radiation damage and transmutation damage on fatigue characteristics, post-neutron irradiation and post-helium ion implantation fatigue tests were carried out. Fracture surfaces and fatigue crack initiation on the specimen surface were observed by SEM. Low-temperature irradiation caused an increase in stress amplitude and a reduction in fatigue lifetime corresponding to radiation hardening and loss of ductility. Neutron irradiated samples showed brittle fracture surface, and it was significant for large strain tests. On the other hand, helium implantation caused delay of cyclic softening. However, brittle crack initiation and propagation did not depend on the helium concentration profiles

  4. Diffusion bonding of reduced activation ferritic steel F82H for demo blanket application

    International Nuclear Information System (INIS)

    Kurasawa, T.; Tamura, M.

    1996-01-01

    A reduced activation ferritic steel, a grade F82H developed by JAERI, is a promising candidate structural material for the blanket and the first wall of DEMO reactors. In the present study, diffusion bonding of F82H has been investigated to develop the fabrication procedures of the blanket box and the first wall panel with cooling channels embedded by F82H. The parameters examined are the bonding temperature (810-1050 C), bonding pressure (2-10 MPa) and roughness of the bonding surface (0.5-12.8 μR max ), and metallurgical examination and mechanical tests of the diffusion bonded joints have been conducted. From the tests, sufficient bonding was obtained under the temperatures of 840-1 050 C (compressive stress of 3-12 MPa), and it was found that heat treatment following diffusion bonding is essential to obtain the mechanical properties similar to that of the base metal. (orig.)

  5. Interfacial properties of HIP joint between beryllium and reduced activation ferritic/martensitic steel

    International Nuclear Information System (INIS)

    Hirose, T.; Ogiwara, H.; Enoeda, M.; Akiba, M.

    2007-01-01

    Full text of publication follows: ITER test blanket module is the most important components to validate energy production and fuel breeding process for future demonstration reactor. Reduced activation ferritic / martensitic steel is recognized as a promising structural material for breeding blanket systems. And Beryllium must be used as plasma facing materials for ITER in vessel components. In this work, interfacial properties of beryllium/reduced activation ferritic/martensitic steel (RAF/Ms) joint were investigated for a first wall of ITER test blanket module (TBM). The starting materials were ITER grade Beryllium, S65C and a Japanese RAF/M, F82H. The joint was produced by solid state hot isostatic pressing (HIP) method. Chromium layer with the thickness of 1 μm and 10 μm were formed by plasma vapor deposition on the beryllium surface as a diffusion barrier. The HIP was carried out at 1023 K and 1233 K which are determined by standard normalizing and tempering temperature of F82H. The joint made at 1233 K was followed by tempering at 1033 K. The bonding interface was characterized by electron probe microanalysis (EPMA). The bonding strength was also investigated by isometric four point bending tests at ambient temperature. EPMA showed chromium layer effectively worked as a diffusion barrier at 1023 K. However, the beryllium rich layer was formed in F82H after HIP at 1233 K followed by tempering. Bending tests revealed that thin chromium layer and low temperature HIP is preferable. The high temperature HIP introduce brittle BeFe inter metallic compounds along bonding interface. On the other hand, joint with thick chromium layer suffer from brittleness of chromium itself. (authors)

  6. Interfacial properties of HIP joint between beryllium and reduced activation ferritic/martensitic steel

    Energy Technology Data Exchange (ETDEWEB)

    Hirose, T. [Blanket Engineering Group, Japan Atomic Energy Agency, Naka, Ibaraki (Japan); Ogiwara, H. [Japan Atomic Energy Agency, Tokai-mura, Naga-gun, Ibaraki-ken (Japan); Enoeda, M. [Naka Fusion Research Establishment, J.A.E.R.I., Japan Atomic Energy Research Institute, Naka-gun, Ibaraki-ken (Japan); Akiba, M. [Naka Fusion Institute, Japan Atomic Energy Agency, Naka, Ibaraki (Japan)

    2007-07-01

    Full text of publication follows: ITER test blanket module is the most important components to validate energy production and fuel breeding process for future demonstration reactor. Reduced activation ferritic / martensitic steel is recognized as a promising structural material for breeding blanket systems. And Beryllium must be used as plasma facing materials for ITER in vessel components. In this work, interfacial properties of beryllium/reduced activation ferritic/martensitic steel (RAF/Ms) joint were investigated for a first wall of ITER test blanket module (TBM). The starting materials were ITER grade Beryllium, S65C and a Japanese RAF/M, F82H. The joint was produced by solid state hot isostatic pressing (HIP) method. Chromium layer with the thickness of 1 {mu}m and 10 {mu}m were formed by plasma vapor deposition on the beryllium surface as a diffusion barrier. The HIP was carried out at 1023 K and 1233 K which are determined by standard normalizing and tempering temperature of F82H. The joint made at 1233 K was followed by tempering at 1033 K. The bonding interface was characterized by electron probe microanalysis (EPMA). The bonding strength was also investigated by isometric four point bending tests at ambient temperature. EPMA showed chromium layer effectively worked as a diffusion barrier at 1023 K. However, the beryllium rich layer was formed in F82H after HIP at 1233 K followed by tempering. Bending tests revealed that thin chromium layer and low temperature HIP is preferable. The high temperature HIP introduce brittle BeFe inter metallic compounds along bonding interface. On the other hand, joint with thick chromium layer suffer from brittleness of chromium itself. (authors)

  7. Effects of irradiation on low cycle fatigue properties for reduced activation ferritic/martensitic steel

    International Nuclear Information System (INIS)

    Kim, S.W.; Tanigawa, H.; Hirose, T.; Kohyama, A.

    2007-01-01

    Full text of publication follows: In materials life decision for a commercial blanket, thermal fatigue property of materials is a particularly important. The loading of structural materials in fusion reactor is, besides the plasma surface interactions, a combined effect of high heat fluxes and neutron irradiation. Depending on the pulse lengths, the operating conditions, and the thermal conductivity, these oscillating temperature gradients will cause elastic and elastic-plastic cyclic deformation giving rise to (creep-) fatigue in structural first wall and blanket components. Especially, investigation of the fatigue property in Reduced Activation Ferritic/Martensitic (RAF/M) steel and establishment of the evaluation technology are demanded in particular immediately for design/manufacturing of ITER-TBM. And also, fatigue testing after irradiation will be carried out in hot cells with remote control system. Considering limited ability of specimen manipulation in the cells, the specimen and the test method need to be simple for operation. The existing data bases of RAF/M steel provide baseline data set including post-irradiation fatigue data. However, to perform the accurate fatigue lifetime assessment for ITER-TBM and beyond utilizing the existing data base, the mechanical understanding of fatigue fracture is mandatory. It has been previously reported by co-authors that dislocation cell structure was developed on low cycle fatigued RAF/M steel, and led the fatigue crack to develop along prior austenitic grain boundary. In this work, the effects of nuclear irradiation on low cycle fatigue properties for RAF/M steels and its fracture mechanisms were examined based on the flow stress analysis and detailed microstructure analysis. Fracture surfaces and crack initiation site were investigated by scanning electron microscope (SEM). Transmission electron microscopy (TEM) was also applied to clarify the microstructural features of fatigue behavior. It is also important to

  8. Effects of irradiation on low cycle fatigue properties for reduced activation ferritic/martensitic steel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S.W. [Kyoto Univ., Graduate School of Energy Science (Japan); Tanigawa, H. [Japan Atomic Energy Agency, Tokai-mura, Naga-gun, Ibaraki-ken (Japan); Hirose, T. [Blanket Engineering Group, Japan Atomic Energy Agency, Naka, Ibaraki (Japan); Kohyama, A. [Kyoto Univ., lnstitute of Advanced Energy (Japan)

    2007-07-01

    Full text of publication follows: In materials life decision for a commercial blanket, thermal fatigue property of materials is a particularly important. The loading of structural materials in fusion reactor is, besides the plasma surface interactions, a combined effect of high heat fluxes and neutron irradiation. Depending on the pulse lengths, the operating conditions, and the thermal conductivity, these oscillating temperature gradients will cause elastic and elastic-plastic cyclic deformation giving rise to (creep-) fatigue in structural first wall and blanket components. Especially, investigation of the fatigue property in Reduced Activation Ferritic/Martensitic (RAF/M) steel and establishment of the evaluation technology are demanded in particular immediately for design/manufacturing of ITER-TBM. And also, fatigue testing after irradiation will be carried out in hot cells with remote control system. Considering limited ability of specimen manipulation in the cells, the specimen and the test method need to be simple for operation. The existing data bases of RAF/M steel provide baseline data set including post-irradiation fatigue data. However, to perform the accurate fatigue lifetime assessment for ITER-TBM and beyond utilizing the existing data base, the mechanical understanding of fatigue fracture is mandatory. It has been previously reported by co-authors that dislocation cell structure was developed on low cycle fatigued RAF/M steel, and led the fatigue crack to develop along prior austenitic grain boundary. In this work, the effects of nuclear irradiation on low cycle fatigue properties for RAF/M steels and its fracture mechanisms were examined based on the flow stress analysis and detailed microstructure analysis. Fracture surfaces and crack initiation site were investigated by scanning electron microscope (SEM). Transmission electron microscopy (TEM) was also applied to clarify the microstructural features of fatigue behavior. It is also important to

  9. Compatibility of reduced activation ferritic/martensitic steels with liquid breeders

    International Nuclear Information System (INIS)

    Muroga, T.; Nagasaka, T.; Kondo, M.; Sagara, A.; Noda, N.; Suzuki, A.; Terai, T.

    2008-10-01

    The compatibility of Reduced Activation Ferritic/Martensitic Steel (RAFM) with liquid Li and molten-salt Flibe have been characterized and accessed. Static compatibility tests were carried out in which the specimens were immersed into liquid Li or Flibe in isothermal autoclaves. Also carried out were compatibility tests in flowing liquid Li by thermal convection loops. In the case of liquid Li, the corrosion rate increased with temperature significantly. The corrosion was almost one order larger for the loop tests than for the static tests. Chemical analysis showed that the corrosion was enhanced when the level of N in Li is increased. Transformation from martensitic to ferritic phase and the resulting softening were observed in near-surface area of Li-exposed specimens, which were shown to be induced by decarburization. In the case of Flibe, the corrosion loss was much larger in a Ni crucible than in a RAFM crucible. Both fluorides and oxides were observed on the surfaces. Thus, the key corrosion process of Flibe is the competing process of fluoridation and oxidation. Possible mechanism of the enhanced corrosion in Ni crucible is electrochemical circuit effect. It was suggested that the corrosion loss rate of RAFM by liquid Li and Flibe can be reduced by reducing the level of impurity N in Li and avoiding the use of dissimilar materials in Flibe, respectively. (author)

  10. Progress of reduced activation ferritic/martensitic steel development in Japan

    International Nuclear Information System (INIS)

    Jitsukawa, S.; Kimura, A.; Kohyama, A.; Ukai, S.; Sawai, T.; Wakai, E.; Shiba, K.; Miwa, Y.; Furuya, K.; Tanigawa, H.; Ando, M.

    2005-01-01

    Recent accomplishment by the Japanese activity for the reduced activation ferritic/martensitic steel (RAF/M) development has been reviewed. Some of the results obtained in EU and US by international collaborative activities are also introduced. Effect of irradiation on the shift of ductile-to-brittle transition temperature (DBTT) has been evaluated to a dose of 20dpa. Results suggest that RAF/M appears to satisfy the requirement on DBTT-shift for the blanket application in the dose range up to several tens of dpa. Also, enhancement effect of DBTT-shift by transmutation produced helium (He) atoms was revealed to be smaller than has been suggested previously. Preliminary studies about the effect of irradiation on fatigue mechanism, the susceptibility to environmentally assisted cracking in water and flow stress-strain relation have been conducted for the specimens irradiated to several dpa, including the post irradiation tensile property examination of the joints by Hot-isostatic press (HIP) bonding method. The results also indicate that RAF/Ms exhibit suitable properties for ITER test blanket module. (author)

  11. Effect of W and Ta on creep–fatigue interaction behavior of reduced activation ferritic–martensitic (RAFM) steels

    Energy Technology Data Exchange (ETDEWEB)

    Shankar, Vani, E-mail: vani@igcar.gov.in [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Institute for Plasma Research, Ahmedabad 382428 (India); Mariappan, K.; Sandhya, R.; Laha, K.; Jayakumar, T.; Kumar, E. Rajendra [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Institute for Plasma Research, Ahmedabad 382428 (India)

    2015-11-15

    Highlights: • SR correlated with deformation under CFI in RAFM steels. • Stress relaxation directly related to plastic strain accumulated, inversely to CFI life. • Optimum combination of W and Ta best for CFI life. • RAFM steels demonstrated compressive dwell sensitivity. • SR tends toward constant value at long hold. - Abstract: The aim of this work is to understand the effect of varying tungsten and tantalum contents on creep–fatigue interaction (CFI) behavior of reduced activation ferritic–martensitic (RAFM) steels. Increase in W improved CFI life. Effect of changing Ta and W upon the resultant CFI life seems to be interrelated and an optimum combination of both W and Ta works out to be the best for CFI life. Stress relaxation obtained during application of hold can be a useful parameter to relate deformation and damage in the RAFM steels.

  12. Effect of W and Ta on creep–fatigue interaction behavior of reduced activation ferritic–martensitic (RAFM) steels

    International Nuclear Information System (INIS)

    Shankar, Vani; Mariappan, K.; Sandhya, R.; Laha, K.; Jayakumar, T.; Kumar, E. Rajendra

    2015-01-01

    Highlights: • SR correlated with deformation under CFI in RAFM steels. • Stress relaxation directly related to plastic strain accumulated, inversely to CFI life. • Optimum combination of W and Ta best for CFI life. • RAFM steels demonstrated compressive dwell sensitivity. • SR tends toward constant value at long hold. - Abstract: The aim of this work is to understand the effect of varying tungsten and tantalum contents on creep–fatigue interaction (CFI) behavior of reduced activation ferritic–martensitic (RAFM) steels. Increase in W improved CFI life. Effect of changing Ta and W upon the resultant CFI life seems to be interrelated and an optimum combination of both W and Ta works out to be the best for CFI life. Stress relaxation obtained during application of hold can be a useful parameter to relate deformation and damage in the RAFM steels.

  13. Fractographic examination of reduced activation ferritic/martensitic steel charpy specimens irradiated to 30 dpa at 370{degrees}C

    Energy Technology Data Exchange (ETDEWEB)

    Gelles, D.S.; Hamilton, M.L. [Pacific Northwest National Lab., Richland, WA (United States); Schubert, L.E. [Univ. of Missouri, Rolla, MO (United States)

    1996-10-01

    Fractographic examinations are reported for a series of reduced activation ferritic/Martensitic steel Charpy impact specimens tested following irradiation to 30 dpa at 370{degrees}C in FFTF. One-third size specimens of six low activation steels developed for potential application as structural materials in fusion reactors were examined. A shift in brittle fracture appearance from cleavage to grain boundary failure was noted with increasing manganese content. The results are interpreted in light of transmutation induced composition changes in a fusion environment.

  14. Fatigue life assessment based on crack growth behavior in reduced activation ferritic/martensitic steel

    International Nuclear Information System (INIS)

    Nogami, Shuhei; Sato, Yuki; Hasegawa, Akira

    2010-01-01

    Crack growth behavior under low cycle fatigue in reduced activation ferritic/martensitic steel, F82H IEA-heat (Fe-8Cr-2W-0.2V-0.02Ta), was investigated to improve the fatigue life assessment method of fusion reactor structural material. Low cycle fatigue test was carried out at room temperature in air at a total strain range of 0.4-1.5% using an hourglass-type miniature fatigue specimen. The relationship between the surface crack length and life fraction was described using one equation independent of the total strain range. Therefore, the fatigue life and residual life could be estimated using the surface crack length. Moreover, the microcrack initiation life could be estimated using the total strain range if there was a one-to-one correspondence between the total strain range and number of cycles to failure. The crack growth rate could be estimated using the total strain range and surface crack length by introducing the concept of the normalized crack growth rate. (author)

  15. Evaluation of mechanical properties of weldments for reduced activation ferritic/martensitic steel

    Energy Technology Data Exchange (ETDEWEB)

    Nakata, T. [Muroran Institute of Technology, Dept. of Materials Science and Engineeering, Muroran, Hokkaido (Japan); Tanigawa, H.; Ando, M. [Japan Atomic Energy Agency, Naga-gun, Ibaraki-ken (Japan); Komazaki, S.; Kohno, Y. [Muroran Institute of Technology, Muroran (Japan)

    2007-07-01

    Full text of publication follows: Reduced activation ferritic/martensitic steels are the first candidate material for fusion reactor, and will be used as the structural materials of ITER test blanket modules (TBM). TBM will be assembled by welding various parts, it is important to be clearly mechanical properties of weldments to qualify TBM structure. In this paper, unirradiated mechanical properties of weldments, which is consisted of weld metal, heat affected zone (HAZ) and base metal region, obtained from TIG and EB welded F82H IEA-heat were evaluated by tensile, Charpy impact and creep test. Charpy impact test revealed that impact properties of weld metal does not deteriorate compared with that of base metal. The creep tests were carried out at temperatures of 773-873 K and at stress levels of 130-280 MPa, with the specimens which include weld metal and HAZ region in the gage section. In these conditions, rupture time of weldments yield to about 100-1000 hours. In the high-stress range, creep lives of welded joint decreased about 40% of base metal. However, in the low-stress range, creep lives of welded joint decrease about 60 to 70% of base metal. The failure at fine grain HAZ region (Type IV failure) does not occur in these conditions. The mechanism of these properties deterioration will be discussed based on the detailed analyses on microstructure changes. (authors)

  16. Effect of helium on fatigue crack growth and life of reduced activation ferritic/martensitic steel

    International Nuclear Information System (INIS)

    Nogami, Shuhei; Takahashi, Manabu; Hasegawa, Akira; Yamazaki, Masanori

    2013-01-01

    The effects of helium on the fatigue life, micro-crack growth behavior up to final fatigue failure, and fracture mode under fatigue in the reduced activation ferritic/martensitic steel, F82H IEA-heat, were investigated by low cycle fatigue tests at room temperature in air at a total strain range of 0.6–1.5%. Significant reduction of the fatigue life due to helium implantation was observed for a total strain range of 1.0–1.5%, which might be attributable to an increase in the micro-crack propagation rate. However, the reduction of fatigue life due to helium implantation was not significant for a total strain range of 0.6–0.8%. A brittle fracture surface (an original point of micro-crack initiation) and a cleavage fracture surface were observed in the helium-implanted region of fracture surface. A striation pattern was observed in the non-implanted region. These fracture modes of the helium-implanted specimen were independent of the strain range

  17. High Temperature Elastic Properties of Reduced Activation Ferritic-Martensitic (RAFM) Steel Using Impulse Excitation Technique

    Science.gov (United States)

    Tripathy, Haraprasanna; Raju, Subramanian; Hajra, Raj Narayan; Saibaba, Saroja

    2018-03-01

    The polycrystalline elastic constants of an indigenous variant of 9Cr-1W-based reduced activation ferritic-martensitic (RAFM) steel have been determined as a function of temperature from 298 K to 1323 K (25 °C to 1000 °C), using impulse excitation technique (IET). The three elastic constants namely, Young's modulus E, shear modulus G, and bulk modulus B, exhibited significant softening with increasing temperature, in a pronounced non-linear fashion. In addition, clearly marked discontinuities in their temperature variations are noticed in the region, where ferrite + carbides → austenite phase transformation occurred upon heating. Further, the incidence of austenite → martensite transformation upon cooling has also been marked by a step-like jump in both elastic E and shear moduli G. The martensite start M s and M f finish temperatures estimated from this study are, M s = 652 K (379 °C) and M f =580 K (307 °C). Similarly, the measured ferrite + carbide → austenite transformation onset ( Ac 1) and completion ( Ac 3) temperatures are found to be 1126 K and 1143 K (853 °C and 870 °C), respectively. The Poisson ratio μ exhibited distinct discontinuities at phase transformation temperatures; but however, is found to vary in the range 0.27 to 0.29. The room temperature estimates of E, G, and μ for normalized and tempered microstructure are found to be 219 GPa, 86.65 GPa, and 0.27, respectively. For the metastable austenite phase, the corresponding values are: 197 GPa, 76.5 GPa, and 0.29, respectively. The measured elastic properties as well as their temperature dependencies are found to be in good accord with reported estimates for other 9Cr-based ferritic-martensitic steel grades. Estimates of θ D el , the elastic Debye temperature and γ G, the thermal Grüneisen parameter obtained from measured bulk elastic properties are found to be θ D el = 465 K (192 °C) and γ G = 1.57.

  18. Metallurgical characterization of the reduced activation ferritic/martensitic steel Eurofer'97 on as-received condition

    International Nuclear Information System (INIS)

    Fernandez, P.; Lancha, A.M.; Lapena, J.; Hernandez-Mayoral, M.

    2001-01-01

    A new European reduced activation ferrous alloy (denominated Eurofer'97) developed as possible first wall and breeder blanket structural material for fusion applications is being characterized. In this paper, activities specially focussed to investigate the microstructural and mechanical properties of this material on the as-received state (normalized at 980 degree sign C/27' plus tempered at 760 degree sign C/90'/air cooled) are presented. Chemical analyses, a detailed microstructural study, hardness, tensile and Charpy tests have been carried out and are compared to the reduced activation material F-82H modified previously studied. The results show that the Eurofer'97 is a fully martensitic steel free of δ-ferrite with similar tensile and better impact properties than the F-82H modified steel. Two types of carbides have been observed in the Eurofer'97, namely, Cr rich precipitates and Ta/V rich precipitates, tentatively identified as M 23 C 6 type and (Ta,V)C type, respectively

  19. Materials design data for reduced activation martensitic steel type F82H

    Energy Technology Data Exchange (ETDEWEB)

    Tavassoli, A.-A.F. E-mail: tavassoli@cea.fr; Rensman, J.-W.; Schirra, M.; Shiba, K

    2002-11-01

    This paper presents materials data for design of ITER test blanket modules with the reduced activation ferritic martensitic steel type F82H as structural material. From the physical properties databases, variations of modulus of elasticity, density, thermal conductivity, thermal diffusivity, specific heat, mean and instantaneous linear coefficients of thermal expansion versus temperature are derived. Also reported are Poisson's ratio and magnetic properties. From the tension test results, nominal and minimum stress values of S{sub y} and S{sub u} are derived and used for calculation of allowable primary membrane stress intensity S{sub m}. Likewise, uniform and total elongations, as well as reduction of area data, are used for calculation of minimum and true ductility at rupture values. From the instrumented Charpy impact and fracture toughness test data, ductile to brittle transition temperature, toughness and behavior of material in different fracture modes are evaluated. The effect of specimen size and geometry are discussed but preference is given to standard size specimens. From the fatigue data, total strain range versus number of cycles to failure curves are plotted and used to derive fatigue design curves, using a reduction factor of 2 on strain and a reduction factor of 20 on number of cycles to failure. Cyclic hardening curves are also derived and compared with monotonic hardening curves. From the creep data, time dependent allowable stresses S{sub r} and S{sub t} are calculated. Combination of tension and creep results are used to deduce S{sub mt} and isochronus curves. Finally, irradiated and aged materials data are compared to insure that the safety margins incorporated in unirradiated design limits are not exceeded.

  20. Hardening and embrittlement mechanisms of reduced activation ferritic/martensitic steels irradiated at 573 K

    Energy Technology Data Exchange (ETDEWEB)

    Tanigawa, H. [Japan Atomic Energy Agency, Tokai-mura, Naga-gun, Ibaraki-ken (Japan); Klueh, R.L. [Oak Ridge Noational Laboratory, TN (United States); Hashimoto, N. [Hokkaido Univ., Materials Science and Engineering Div., Graduate School of Engineering, Sapporo (Japan); Sokolov, M. [Oak Ridge National Laboratory, Materials Science and Technology Div., TN (United States)

    2007-07-01

    Full text of publication follows: It has been reported that reduced-activation ferritic/martensitic steels (RAFMs), such as F82H, ORNL9Cr-2WVTa, and JLF-1, showed a variety of changes in ductile-brittle transition temperature and yield stress after irradiation at 573 K up to 5 dpa, and those differences could not be interpreted solely by the difference of dislocation microstructure induced by irradiation. To investigate the impact of other microstructural feature, i.e. precipitates, the precipitation behavior of F82H, ORNL 9Cr-2WVTa, and JLF-1 was examined. It was revealed that irradiation-induced precipitation and amorphization of precipitates partly occurred and caused the different precipitation on block, packet and prior austenitic grain boundaries. In addition to these phenomena, irradiation-induced nano-size precipitates were also observed in the matrix. It was also revealed that the chemical compositions of precipitates approached the calculated thermal equilibrium state of M{sub 23}C{sub 6} at an irradiation temperature of 573 K. The calculation also suggests the presence of Laves phase at 573 K, which is usually not observed at this temperature, but the ion irradiation on aged F82H with Laves phase suggests that Laves phase becomes amorphous and could not be stable under irradiation at 573 K. This observation indicates the possibility that the irradiation-induced nano-size precipitation could be the consequence of the conflict between precipitation and amorphization of Laves phase. Over all, these observations suggests that the variety of embrittlement and hardening of RAFMs observed at 573 K irradiation up to 5 dpa might be the consequence of the transition phenomena that occur as the microstructure approaches thermal equilibrium during irradiation at 573 K. (authors)

  1. Influence of strain rate and temperature on tensile properties and flow behaviour of a reduced activation ferritic-martensitic steel

    Energy Technology Data Exchange (ETDEWEB)

    Vanaja, J., E-mail: jvanaja4@gmail.com [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Laha, K. [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Sam, Shiju [Institute for Plasma Research, Gandhinagar, Gujarat (India); Nandagopal, M.; Panneer Selvi, S.; Mathew, M.D.; Jayakumar, T. [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Rajendra Kumar, E. [Institute for Plasma Research, Gandhinagar, Gujarat (India)

    2012-05-15

    Tensile strength and flow behaviour of a Reduced Activation Ferritic-Martensitic (RAFM) steel (9Cr-1W-0.06Ta-0.22V-0.08C) have been investigated over a temperature range of 300-873 K at different strain rates. Tensile strength of the steel decreased with temperature and increased with strain rate except at intermediate temperatures. Negative strain rate sensitivity of flow stress of the steel at intermediate temperatures revealed the occurrence of dynamic strain ageing in the steel, even though no serrated flow was observed. The tensile flow behaviour of the material was well represented by the Voce strain hardening equation for all the test conditions. Temperature and strain rate dependence of the various parameters of Voce equation were interpreted with the possible deformation mechanisms. The equivalence between the saturation stress at a given strain rate in tensile test and steady state deformation rate at a given stress in creep test was found to be satisfied by the RAFM steel.

  2. Effect of tungsten and tantalum on the low cycle fatigue behavior of reduced activation ferritic/martensitic steels

    Energy Technology Data Exchange (ETDEWEB)

    Shankar, Vani, E-mail: vani@igcar.gov.in [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Mariappan, K.; Nagesha, A.; Prasad Reddy, G.V.; Sandhya, R.; Mathew, M.D.; Jayakumar, T. [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India)

    2012-05-15

    Highlights: Black-Right-Pointing-Pointer Effect of tungsten and tantalum on low cycle fatigue behavior of RAFM steels. Black-Right-Pointing-Pointer Both alloying elements W and Ta improved fatigue life. Black-Right-Pointing-Pointer Increase in Ta content improved fatigue life more than W. Black-Right-Pointing-Pointer Optimization of W content at 1.4 wt.%. Black-Right-Pointing-Pointer Softening behavior closely related to W and Ta content. - Abstract: Reduced activation ferritic/martensitic (RAFM) steels are candidate materials for the test blanket modules of International Thermonuclear Experimental Reactor (ITER). Several degradation mechanisms such as thermal fatigue, low cycle fatigue, creep fatigue interaction, creep, irradiation hardening, swelling and phase instability associated irradiation embrittlement must be understood in order to estimate the component lifetime and issues concerning the structural integrity of components. The current work focuses on the effect of tungsten and tantalum on the low cycle fatigue (LCF) behavior of RAFM steels. Both alloying elements tungsten and tantalum improved the fatigue life. Influence of Ta on increasing fatigue life was an order of magnitude higher than the influence of W on improving the fatigue life. Based on the present study, the W content was optimized at 1.4 wt.%. Softening behavior of RAFM steels showed a strong dependence on W and Ta content in RAFM steels.

  3. Influence of strain rate and temperature on tensile properties and flow behaviour of a reduced activation ferritic-martensitic steel

    Science.gov (United States)

    Vanaja, J.; Laha, K.; Sam, Shiju; Nandagopal, M.; Panneer Selvi, S.; Mathew, M. D.; Jayakumar, T.; Rajendra Kumar, E.

    2012-05-01

    Tensile strength and flow behaviour of a Reduced Activation Ferritic-Martensitic (RAFM) steel (9Cr-1W-0.06Ta-0.22V-0.08C) have been investigated over a temperature range of 300-873 K at different strain rates. Tensile strength of the steel decreased with temperature and increased with strain rate except at intermediate temperatures. Negative strain rate sensitivity of flow stress of the steel at intermediate temperatures revealed the occurrence of dynamic strain ageing in the steel, even though no serrated flow was observed. The tensile flow behaviour of the material was well represented by the Voce strain hardening equation for all the test conditions. Temperature and strain rate dependence of the various parameters of Voce equation were interpreted with the possible deformation mechanisms. The equivalence between the saturation stress at a given strain rate in tensile test and steady state deformation rate at a given stress in creep test was found to be satisfied by the RAFM steel.

  4. Influence of strain rate and temperature on tensile properties and flow behaviour of a reduced activation ferritic–martensitic steel

    International Nuclear Information System (INIS)

    Vanaja, J.; Laha, K.; Sam, Shiju; Nandagopal, M.; Panneer Selvi, S.; Mathew, M.D.; Jayakumar, T.; Rajendra Kumar, E.

    2012-01-01

    Tensile strength and flow behaviour of a Reduced Activation Ferritic–Martensitic (RAFM) steel (9Cr–1W–0.06Ta–0.22V–0.08C) have been investigated over a temperature range of 300–873 K at different strain rates. Tensile strength of the steel decreased with temperature and increased with strain rate except at intermediate temperatures. Negative strain rate sensitivity of flow stress of the steel at intermediate temperatures revealed the occurrence of dynamic strain ageing in the steel, even though no serrated flow was observed. The tensile flow behaviour of the material was well represented by the Voce strain hardening equation for all the test conditions. Temperature and strain rate dependence of the various parameters of Voce equation were interpreted with the possible deformation mechanisms. The equivalence between the saturation stress at a given strain rate in tensile test and steady state deformation rate at a given stress in creep test was found to be satisfied by the RAFM steel.

  5. Development of an extensive database of mechanical and physical properties for reduced-activation martensitic steel F82H

    Energy Technology Data Exchange (ETDEWEB)

    Jitsukawa, S. E-mail: jitsukawa@ifmif.tokai.jaeri.go.jp; Tamura, M.; Schaaf, B. van der; Klueh, R.L.; Alamo, A.; Petersen, C.; Schirra, M.; Spaetig, P.; Odette, G.R.; Tavassoli, A.A.; Shiba, K.; Kohyama, A.; Kimura, A

    2002-12-01

    Tensile, fracture toughness, creep and fatigue properties and microstructural studies of the reduced-activation martensitic steel F82H (8Cr-2W-0.04Ta-0.1C) before and after irradiation are reported. The design concept used for the development of this alloy is also introduced. A large number of collaborative test results including those generated under the International Energy Agency (IEA) implementing agreements are collected and are used to evaluate the feasibility of using reduced-activation martensitic steels for fusion reactor structural materials, with F82H as one of the reference alloys. All the specimens used in these tests were prepared from plates obtained from 5-ton heats of F82H supplied to all participating laboratories by JAERI. Many of the results have been entered into relational databases with emphasis on traceability of records on how the specimens were prepared from plates and ingots.

  6. Development of an extensive database of mechanical and physical properties for reduced-activation martensitic steel F82H

    International Nuclear Information System (INIS)

    Jitsukawa, S.; Tamura, M.; Schaaf, B. van der; Klueh, R.L.; Alamo, A.; Petersen, C.; Schirra, M.; Spaetig, P.; Odette, G.R.; Tavassoli, A.A.; Shiba, K.; Kohyama, A.; Kimura, A.

    2002-01-01

    Tensile, fracture toughness, creep and fatigue properties and microstructural studies of the reduced-activation martensitic steel F82H (8Cr-2W-0.04Ta-0.1C) before and after irradiation are reported. The design concept used for the development of this alloy is also introduced. A large number of collaborative test results including those generated under the International Energy Agency (IEA) implementing agreements are collected and are used to evaluate the feasibility of using reduced-activation martensitic steels for fusion reactor structural materials, with F82H as one of the reference alloys. All the specimens used in these tests were prepared from plates obtained from 5-ton heats of F82H supplied to all participating laboratories by JAERI. Many of the results have been entered into relational databases with emphasis on traceability of records on how the specimens were prepared from plates and ingots

  7. Microstructural characterization of weld joints of 9Cr reduced activation ferritic martensitic steel fabricated by different joining methods

    Energy Technology Data Exchange (ETDEWEB)

    Thomas Paul, V.; Saroja, S.; Albert, S.K.; Jayakumar, T.; Rajendra Kumar, E., E-mail: vtp@igcar.gov.in

    2014-10-15

    This paper presents a detailed electron microscopy study on the microstructure of various regions of weldment fabricated by three welding methods namely tungsten inert gas welding, electron beam welding and laser beam welding in an indigenously developed 9Cr reduced activation ferritic/martensitic steel. Electron back scatter diffraction studies showed a random micro-texture in all the three welds. Microstructural changes during thermal exposures were studied and corroborated with hardness and optimized conditions for the post weld heat treatment have been identified for this steel. Hollomon–Jaffe parameter has been used to estimate the extent of tempering. The activation energy for the tempering process has been evaluated and found to be corresponding to interstitial diffusion of carbon in ferrite matrix. The type and microchemistry of secondary phases in different regions of the weldment have been identified by analytical transmission electron microscopy. - Highlights: • Comparison of microstructural parameters in TIG, electron beam and laser welds of RAFM steel • EBSD studies to illustrate the absence of preferred orientation and identification of prior austenite grain size using phase identification map • Optimization of PWHT conditions for indigenous RAFM steel • Study of kinetics of tempering and estimation of apparent activation energy of the process.

  8. Stress Corrosion cracking susceptibility of reduced-activation martensitic steel F82H

    Energy Technology Data Exchange (ETDEWEB)

    Miwa, Y. [Nuclear Energy and Science Directorate, Japan Atomic Energy Agency, Tokai-mura, Ibaraki-ken (Japan); Jitsukawa, S.; Tsukada, T. [Japan Atomic Energy Agency, Tokai-mura, Naga-gun, Ibaraki-ken (Japan)

    2007-07-01

    Full text of publication follows: For fusion power source in near future, supercritical water-cooled type blanket system was planned in Japan Atomic Energy Agency. The blankest system was designed by the present knowledge base and a reasonable extrapolation in material and design technology. Reduced-activation martensitic steel, F82H, is one of the blanket system structural materials. Therefore durability of the F82H for corrosion and stress corrosion cracking (SCC) is one of the concerns for this water-cooling concept of the blanket system. In this paper, SCC susceptibility of F82H was studied after heat treatments simulating post weld heat treatment (PWHT) or neutron-irradiation at 493 K to a dose level of 2.2 dpa. In order to evaluate SCC susceptibility of F82H, slow strain rate testing (SSRT) in high-purity, circulating water was conducted at 513-603 K in an autoclave. The strain rate was 1.0- 2.0x10{sup -7} s{sup -1}. Concentration of dissolved oxygen and hydrogen of the circulating water was controlled by bubbling with these gases. Specimens were heat treated after normalization at 1313 K for 40 min and water quenching. Some of the specimens were tempered at 873-1073 K for 1 h. Since the temperature control during PWHT in vacuum vessel by remote handling will be difficult, it is expected the tempering temperature will be different at place to place. Some specimens after tempering at 1033 K for 1 h were irradiated at 493 K to 2.2 dpa in Japan Research Reactor No.3 at Japan Atomic Energy Agency. The SSRT results showed the as-normalized specimens failed by IGSCC in oxygenated temperature water at 573 K. SSRT results of specimens with other tempering temperature conditions will be presented at conference. In irradiated specimen, IGSCC did not occur in oxygenated water at 5113-603 K. IGSCC also did not occur in hydrogenated water at 573 K. However TGSCC occurred in the irradiated specimen with a round notch (radius= {approx}0.2 mm) in oxygenated water at 573 K

  9. Low cycle fatigue design data for India-specific reduced activation ferritic-martensitic (IN-RAFM) steel

    Energy Technology Data Exchange (ETDEWEB)

    Mariappan, K.; Shankar, Vani, E-mail: vani@igcar.gov.in; Sandhya, R.; Laha, K.

    2016-03-15

    Highlights: • Generation of first set of experimental data related to LCF performance of the commercial heat of IN-RAFM steel. • Analysis of cyclic behavior from the perspective of both design and material characteristics. • Various correction factors to account for various plastic strain accumulations, change in Poisson’s ratio and asymmetry of loadings. • Low cycle fatigue design parameters and correction factor values were comparable with P91 steel as reported in RCC-MR design code. - Abstract: The objective of the present paper is to provide first hand experimental data and analysis on the low cycle fatigue (LCF) performance of a commercial heat of Indian reduced activation ferritic-martensitic (IN-RAFM) steel. Since this material is not yet codified in RCC-MR, cyclic properties were generated for the design of the structural material of the Test Blanket Modules (TBM) made of RAFM steel. Hence, as a part of the material development program, LCF experiments were conducted on IN-RAFM steel obtained in the normalized and tempered condition. Total axial strain controlled experiments were performed in air by employing strain amplitudes ranging from ±0.25 to ±1.0% and at temperatures of 300, 673, 723, 823, and 873 K and a nominal strain rate, 3 × 10{sup −3} s{sup −1}. In the present work, various cyclic parameters that are useful for the design oriented fatigue analysis are derived as per the systematic procedure given in the RCC-MR design code. The physical significance of each design parameter such as elasto-plastic corrections based on Neuber analysis has been explained and correlated with the material behavior such as the cyclic softening nature of the RAFM steel.

  10. Recent status and improvement of reduced-activation ferritic-martensitic steels for high-temperature service

    Energy Technology Data Exchange (ETDEWEB)

    Tan, L., E-mail: tanl@ornl.gov [Oak Ridge National Laboratory, Oak Ridge, TN, 37831 (United States); Katoh, Y. [Oak Ridge National Laboratory, Oak Ridge, TN, 37831 (United States); Tavassoli, A.-A.F.; Henry, J. [DMN/Dir, DEN, CEA Saclay, 91191, Gif-sur-Yvette Cedex (France); Rieth, M. [Karlsruhe Institute of Technology, Karlsruhe, 76021 (Germany); Sakasegawa, H. [National Institutes for Quantum and Radiological Science and Technology, Rokkasho, Aomori, 039-3212 (Japan); Oak Ridge National Laboratory, Oak Ridge, TN, 37831 (United States); Tanigawa, H. [National Institutes for Quantum and Radiological Science and Technology, Rokkasho, Aomori, 039-3212 (Japan); Huang, Q. [Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui, 230031 (China)

    2016-10-15

    Reduced-activation ferritic-martensitic (RAFM) steels, candidate structural materials for fusion reactors, have achieved technological maturity after about three decades of research and development. The recent status of a few developmental aspects of current RAFM steels, such as aging resistance, plate thickness effects, fracture toughness, and fatigue, is updated in this paper, together with ongoing efforts to develop next-generation RAFM steels for superior high-temperature performance. In addition to thermomechanical treatments, including nonstandard heat treatment, alloy chemistry refinements and modifications have demonstrated some improvements in high-temperature performance. Castable nanostructured alloys (CNAs) were developed by significantly increasing the amount of nanoscale MX (M = V/Ta/Ti, X = C/N) precipitates and reducing coarse M{sub 23}C{sub 6} (M = Cr). Preliminary results showed promising improvement in creep resistance and Charpy impact toughness. Limited low-dose neutron irradiation results for one of the CNAs and China low activation martensitic are presented and compared with data for F82H and Eurofer97 irradiated up to ∼70 displacements per atom at ∼300–325 °C.

  11. Material science and manufacturing of heat-resistant reduced-activation ferritic-martensitic steels for fusion

    International Nuclear Information System (INIS)

    Ioltukhovskiy, A.G.; Blokhin, A.I.; Budylkin, N.I.; Chernov, V.M.; Leont'eva-Smirnova, M.V.; Mironova, E.G.; Medvedeva, E.A.; Solonin, M.I.; Porollo, S.I.; Zavyalsky, L.P.

    2000-01-01

    A number of issues regarding the development and use of 10-12% Cr reduced-activation ferritic-martensitic steels (RAFMS) for fusion are considered. These include: (1) problems of manufacturing and modifying their composition and metallurgical condition; (2) the influence on properties of their composition, purity, δ-ferrite concentration and cooling rates in the final stages of manufacturing; and (3) the effects of neutron irradiation at 320-650 deg. C up to 108 dpa on their mechanical properties. In addition, neutron activation and nuclear accumulation of elements in RAFMS with different initial concentrations of alloying and impurity elements for typical fusion reactor (DEMO) irradiation regimes have been calculated

  12. Development of filler wires for welding of reduced activation ferritic martensitic steel for India's test blanket module of ITER

    International Nuclear Information System (INIS)

    Srinivasan, G.; Arivazhagan, B.; Albert, S.K.; Bhaduri, A.K.

    2010-01-01

    Indigenous development of reduced activation ferritic-martensitic (RAFM) steel has become necessary for India as a participant in the International Thermo-nuclear Experimental Reactor (ITER) programme. Optimisation of RAFM steel is in an advanced stage for the fabrication of test blanket module (TBM) components. Simultaneously, development of RAFM steel filler wires has been undertaken since there is no commercial filler wires are available for fabrication of components using RAFM steel. The purpose of this study is to develop filler wires that can be directly used for both gas tungsten arc welding (GTAW) and for narrow-gap gas tungsten arc welding (NG-GTAW) that reduces the deposited weld metal volume and heat affected zone (HAZ) width. Further, the filler wires would also be used for hybrid laser-MIG welding for thick section joints. In view of meeting all the requirements, a detailed specification was prepared for the development of filler wires for welding of RAFM steel. Meanwhile, welding trials have been carried out on 2.5 mm thick plates of the RAFM steel using GTAW process at various heat inputs with a preheat temperature of 250 C followed by various post weld heat treatments (PWHT). The microstructure of the weld metal in most of the cases showed the presence of some amount of delta-ferrite. Filler wires as per specifications have also been developed with minor variations on the chemistry against the specified values. Welding parameters and PWHT parameters were optimized to qualify the filler wires without the presence of delta-ferrite in the weld metal and with optimized mechanical properties. Results showed that the weld metals are free from delta-ferrite. Tensile properties at ambient temperature and at 500 C are well above the specified values, and are much higher than the base metal values. Ductile Brittle Transition Temperature (DBTT) has been evaluated as -81 C based on the 68 J criteria. The present study highlights the basis and methodology

  13. Comparative study of He bubble formation in nanostructured reduced activation steel and its coarsen-grained counterpart

    Science.gov (United States)

    Liu, W. B.; Zhang, J. H.; Ji, Y. Z.; Xia, L. D.; Liu, H. P.; Yun, D.; He, C. H.; Zhang, C.; Yang, Z. G.

    2018-03-01

    High temperature (550 °C) He ions irradiation was performed on nanostructured (NS) and coarsen-grained (CG) reduced activation steel to investigate the effects of GBs/interfaces on the formation of bubbles during irradiation. Experimental results showed that He bubbles were preferentially trapped at dislocations and/or grain boundaries (GBs) for both of the samples. Void denuded zones (VDZs) were observed in the CG samples, while VDZs near GBs were unobvious in NS sample. However, both the average bubble size and the bubble density in peak damage region of the CG sample were significantly larger than that observed in the NS sample, which indicated that GBs play an important role during the irradiation, and the NS steel had better irradiation resistance than its CG counterpart.

  14. Microstructure anisotropy and its effect on mechanical properties of reduced activation ferritic/martensitic steel fabricated by selective laser melting

    Science.gov (United States)

    Huang, Bo; Zhai, Yutao; Liu, Shaojun; Mao, Xiaodong

    2018-03-01

    Selective laser melting (SLM) is a promising way for the fabrication of complex reduced activation ferritic/martensitic steel components. The microstructure of the SLM built China low activation martensitic (CLAM) steel plates was observed and analyzed. The hardness, Charpy impact and tensile testing of the specimens in different orientations were performed at room temperature. The results showed that the difference in the mechanical properties was related to the anisotropy in microstructure. The planer unmelted porosity in the interface of the adjacent layers induced opening/tensile mode when the tensile samples parallel to the build direction were tested whereas the samples vertical to the build direction fractured in the shear mode with the grains being sheared in a slant angle. Moreover, the impact absorbed energy (IAE) of all impact specimens was significantly lower than that of the wrought CLAM steel, and the IAE of the samples vertical to the build direction was higher than that of the samples parallel to the build direction. The impact fracture surfaces revealed that the load parallel to the build layers caused laminated tearing among the layers, and the load vertical to the layers induced intergranular fracture across the layers.

  15. Convoluted dislocation loops induced by helium irradiation in reduced-activation martensitic steel and their impact on mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Fengfeng [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory, School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Yao, Z. [Department of Mechanical and Materials Engineering, Queen' s University, Kingston, ON, Canada K7L 3N6 (Canada); Guo, Liping, E-mail: guolp@whu.edu.cn [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory, School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Suo, Jinping [State Key Laboratory of Mould Technology, Institute of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Wen, Yongming [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory, School of Physics and Technology, Wuhan University, Wuhan 430072 (China)

    2014-06-01

    Helium irradiation induced dislocation loops in reduced-activation martensitic steels were investigated using transmission electron microscopy. The specimens were irradiated with 100 keV helium ions to 0.8 dpa at 350 °C. Unexpectedly, very large dislocation loops were found, significantly larger than that induced by other types of irradiations under the same dose. Moreover, the large loops were convoluted and formed interesting flower-like shape. The large loops were determined as interstitial type. Loops with the Burgers vectors of b=〈100〉 were only observed. Furthermore, irradiation induced hardening caused by these large loops was observed using the nano-indentation technique.

  16. Effects of Ti element on the microstructural stability of 9Cr–WVTiN reduced activation martensitic steel under ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Fengfeng [Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Guo, Liping, E-mail: guolp@whu.edu.cn [Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Jin, Shuoxue; Li, Tiecheng; Chen, Jihong [Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Suo, Jinping; Yang, Feng [State Key Laboratory of Mould Technology, Institute of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Yao, Z. [Department of Mechanical and Materials Engineering, Queen’s University, Kingston K7L 3N6, ON (Canada)

    2014-12-15

    Microstructure of 9Cr–WVTiN reduced-activation martensitic steels with two different Ti concentrations irradiated with Fe{sup +}, He{sup +} and H{sup +} at 300 °C was studied with transmission electron microscopy. Small dislocation loops were observed in the irradiated steels. The mean size and number density of dislocation loops decreased with the increase of Ti concentration. The segregation of Cr and Fe in carbides was observed in both irradiated steels, and the enrichment of Cr and depletion of Fe were more severe in the low Ti-concentration 9Cr–WVTiN steel.

  17. Extraction residue analysis on F82H-BA07 heat and other reduced activation ferritic/martensitic steels

    International Nuclear Information System (INIS)

    Nagasaka, Takuya; Hishinuma, Yoshimitsu; Muroga, Takeo; Li, Yanfen; Watanabe, Hideo; Tanigawa, Hiroyasu; Sakasegawa, Hideo; Ando, Masami

    2011-01-01

    Extraction residue analysis was conducted on reduced activation ferritic/martensitic steels, such as F82H-BA07 heat, F82H-IEA heat, JLF-1 JOYO heat and CLAM steel. M 23 C 6 type precipitates, TaC precipitates and Fe 2 W Laves phase were identified in the present analyses. M 23 C 6 precipitates were coarsened in F82H-BA07 compared with the other steels at as-normalized and tempered (NT) condition. TaC precipitate formation was enhanced in JLF-1 and CLAM compared with F82H-BA07 and F82H-IEA at as-NT condition. Laves phase were detected in F82H-IEA after aging above 550 o C, where solid solution W was significantly decreased. F82H-IEA exhibited hardening after aging at 400 and 500 o C for 100 khr, whereas softening at 600 and 650 o C. This behavior is similar to JLF-1 and CLAM, and can be understood by precipitation of TaC and Laves phase.

  18. Creep strength of reduced activation ferritic/martensitic steel Eurofer'97

    International Nuclear Information System (INIS)

    Fernandez, P.; Lancha, A.M.; Lapena, J.; Lindau, R.; Rieth, M.; Schirra, M.

    2005-01-01

    Creep rupture strength of tempered martensitic steel Eurofer'97 has been investigated. Different products form (plate and bar) have been tested in the temperature range from 450 deg. C to 650 deg. C at different loads. No significant differences in the creep rupture properties have been found between the studied product forms. The Eurofer'97 has shown adequate creep rupture strength levels at short creep rupture tests, similar to those of the F-82 H mod. steel. However, for long testing times (>9000 h) the results available up to now at 500 deg. C and 550 deg. C seem to indicate a change in the creep degradation mechanism

  19. Control of molten salt corrosion of reduced activation steel for fusion applications by metallic beryllium

    International Nuclear Information System (INIS)

    Calderoni, P.; Sharpe, P.; Nishimura, H.; Terai, T.

    2007-01-01

    Full text of publication follows: In 2001 the INL started a research program as a part of the 2. Japan/US Program on Irradiation Tests for Fusion Energy Research (JUPITER-II collaboration) aimed at the characterization of the 2LiF-BeF2 (Flibe) molten salt as a breeder and coolant material for fusion applications. A key objective of the work was to demonstrate chemical compatibility between Flibe and potential fusion structural materials once suitable fluoride potential control methods are established. A series of tests performed at INL demonstrated that this can be achieved by contacting the salt with metallic beryllium, and the results have been published in recent years. A further step was to expose two specimens of low activation ferritic/martensitic steel 9Cr-2W JLF-1 to static corrosion tests that include an active corrosion agent (hydrofluoric gas) and fluoride potential control (metallic Be) at 530 C, and the results of the tests are presented in this paper. The specimen and a beryllium rod were simultaneously immersed in the molten salt through gas tight fittings mounted on risers extending from the top lid of the test vessel; the beryllium rod was extracted after 5 hours, while the sample was left in the salt for 250 hours during which salt samples were withdrawn from the melt at fixed intervals. A diagnostic system based on the measurement of reacting HF through on-line titration was coupled with the analysis of metallic components in the salt samples that were dissolved and analyzed using inductively coupled plasma atomic emission spectroscopy (ICP-AES). Impurity levels of oxygen, nitrogen and carbon were determined from pieces of the solidified melt using Leco analytical systems. The results confirmed the expected correlation of the HF recovery with the concentration of metallic elements dissolved in the salt because of specimen corrosion. The metals concentration falls below the detectable limit when the beryllium rod is inserted and increases when the

  20. Reduced-activation austenitic stainless steels: The Fe--Mn--Cr--C system

    International Nuclear Information System (INIS)

    Klueh, R.L.; Maziasz, P.J.

    1988-01-01

    Nickel-free manganese-stabilized steels are being developed for fusion-reactor applications. As the first part of this effort, the austenite-stable region in the Fe--Mn--Cr--C system was determined. Results indicated that the Schaeffler diagram developed for Fe--Ni--Cr--C alloys cannot be used to predict the constituents expected for high-manganese steels. This is true because manganese is not as strong an austenite stabilizer relative to δ-ferrite formation as predicted by the diagram, but it is a stronger austenite stabilizer relative to martensite than predicted. Therefore, the austenite-stable region for Ne--Mn--Cr--C alloys occurs at lower chromium and hugher combinations of manganese and carbon than predicted by the Schaeffler diagram. Development of a manganese-stabilized stainless steel should be possible in the composition range of 20 to 25% Mn, 10 to 15% Cr, and 0.01 to 0.25%C. Tensile behavior of an Fe--20%Mn--12%Cr--0.25%C alloy was determined. The strength and ductility of this possible base composition was comparable to type 316 stainless steel in both the solution-annealed and cold-worked condition

  1. Low-activation Mn-Cr austenitic stainless steel with further reduced content of long-lived radioactive elements

    Energy Technology Data Exchange (ETDEWEB)

    Onozuka, M.; Saida, T.; Hirai, S. [Mitsubishi Heavy Ind. Ltd., Yokohama (Japan); Kusuhashi, M.; Sato, I.; Hatakeyama, T. [The Japan Steel Works Ltd., Chatsu-machi 4, Muroran 051-8505 (Japan)

    1998-06-01

    Low-activation austenitic stainless steel based on Mn-Cr non-magnetic steels has been developed. The alloying elements of long-life activation, such as Ni, Mo and Co, were eliminated and substituted with Mn along with an addition of N. A Mn-Cr austenitic stainless steel, 24.5Mn-13.5Cr-0.02C-0.2N, has been developed successfully. Examined material properties, including mechanical, thermal and magnetic properties, as well as weldability and characteristics of corrosion resistance, are presented. It was found that the alloy has excellent material properties virtually equivalent to those of 316SS. In this study, the applicability of the Schaeffler, DeLong and Hull constitution diagrams for the stainless steels with low Ni and high Mn contents was also examined. The boundary conditions distinguishing the single austenite phase from the others have been identified for the Mn-Cr steels. (orig.) 22 refs.

  2. Low-activation Mn Cr austenitic stainless steel with further reduced content of long-lived radioactive elements

    Science.gov (United States)

    Onozuka, Masanori; Saida, Tomikane; Hirai, Shouzou; Kusuhashi, Mikio; Sato, Ikuo; Hatakeyama, Tsuyoshi

    1998-06-01

    Low-activation austenitic stainless steel based on Mn-Cr non-magnetic steels has been developed. The alloying elements of long-life activation, such as Ni, Mo and Co, were eliminated and substituted with Mn along with an addition of N. A Mn-Cr austenitic stainless steel, 24.5Mn-13.5Cr-0.02C-0.2N, has been developed successfully. Examined material properties, including mechanical, thermal and magnetic properties, as well as weldability and characteristics of corrosion resistance, are presented. It was found that the alloy has excellent material properties virtually equivalent to those of 316SS. In this study, the applicability of the Schaeffler, DeLong and Hull constitution diagrams for the stainless steels with low Ni and high Mn contents was also examined. The boundary conditions distinguishing the single austenite phase from the others have been identified for the Mn-Cr steels.

  3. Effect of pre-strain on susceptibility of Indian Reduced Activation Ferritic Martensitic Steel to hydrogen embrittlement

    International Nuclear Information System (INIS)

    Sonak, Sagar; Tiwari, Abhishek; Jain, Uttam; Keskar, Nachiket; Kumar, Sanjay; Singh, Ram N.; Dey, Gautam K.

    2015-01-01

    The role of pre-strain on hydrogen embrittlement susceptibility of Indian Reduced Activation Ferritic Martensitic Steel was investigated using constant nominal strain-rate tension test. The samples were pre-strained to different levels of plastic strain and their mechanical behavior and mode of fracture under the influence of hydrogen was studied. The effect of plastic pre-strain in the range of 0.5–2% on the ductility of the samples was prominent. Compared to samples without any pre-straining, effect of hydrogen was more pronounced on pre-strained samples. Prior deformation reduced the material ductility under the influence of hydrogen. Up to 35% reduction in the total strain was observed under the influence of hydrogen in pre-strained samples. Hydrogen charging resulted in increased occurrence of brittle zones on the fracture surface. Hydrogen Enhanced Decohesion (HEDE) was found to be the dominant mechanism of fracture.

  4. Development of filler wires for welding of reduced activation ferritic martenstic steel for India's test blanket module of ITER

    International Nuclear Information System (INIS)

    Srinivasan, G.; Arivazhagan, B.; Albert, S.K.; Bhaduri, A.K.

    2011-01-01

    Highlights: → Weld microstructure produced by RAFMS filler wires are free from delta ferrite. → Cooling rates of by weld thermal cycles influences the presence of delta ferrite. → Weld parameters modified with higher pre heat temperature and high heat input. → PWHT optimized based on correlation of hardness between base and weld metals. → Optimised mechanical properties achieved by proper tempering of the martensite. - Abstract: Indigenous development of reduced activation ferritic martensitic steel (RAFMS) has become mandatory to India to participate in the International Thermo-nuclear Experimental Reactor (ITER) programme. Optimisation of RAFMS is in an advanced stage for the fabrication of test blanket module (TBM) components. Simultaneously, development of RAFMS filler wires has been undertaken since there is no commercial filler wires are available for fabrication of components using RAFMS. Purpose of this study is to develop filler wires that can be directly used for both tungsten inert gas welding (TIG) and narrow gap tungsten inert gas welding (NG-TIG), which reduces the deposited weld metal volume and heat affected zone (HAZ) width. Further, the filler wires would also be used for hybrid laser welding for thick section joints. In view of meeting all the requirements, a detailed specification was prepared for the development of filler wires for welding of RAFM steel. Meanwhile, autogenous welding trials have been carried out on 2.5 mm thick plates of the RAFM steel using TIG process at various heat inputs with a preheat temperature of 250 deg. C followed by various post weld heat treatments (PWHT). The microstructure of the weld metal in most of the cases showed the presence of some delta-ferrite. Filler wires as per specifications have also been developed with minor variations on the chemistry against the specified values. Welding parameters and PWHT parameters were optimised to qualify the filler wires without the presence of delta-ferrite in

  5. Control of substrate oxidation in MOD cerawwwmic coating on low-activation ferritic steel with reduced-pressure atmosphere

    Science.gov (United States)

    Tanaka, Teruya; Muroga, Takeo

    2014-12-01

    An Er2O3 ceramic coating fabricated using the metal-organic decomposition (MOD) method on a Cr2O3-covered low-activation ferritic steel JLF-1 substrate was examined to improve hydrogen permeation barrier performance of the coating. The Cr2O3 layer was obtained before coating by heat treating the substrate at 700 °C under reduced pressures of baking. Preprocessing to obtain a Cr2O3 layer would provide flexibility in the coating process for blanket components and ducts. Moreover, the Cr2O3 layer suppressed hydrogen permeation through the JLF-1 substrate. While further optimization of the coating fabrication process is required, it would be possible to suppress hydrogen permeation significantly by multilayers of Cr2O3 and MOD oxide ceramic.

  6. Behavior of Eurofer97 reduced activation martensitic steel upon heating and continuous cooling

    International Nuclear Information System (INIS)

    Danon, A.; Alamo, A.

    2002-01-01

    The phase transformation behavior of the Eurofer97 steel (Fe9Cr1WVTa) has been investigated. The transformation temperatures upon heating and cooling were determined by dilatometry for different rates in the range 0.0028-100 deg. C/s. The prior austenitic grain size of Eurofer97, measured as a function of the austenitization temperature, does not change appreciably up to 1050 deg. C and then increases with increasing austenite temperature from 1050 up to 1200 deg. C. Continuous cooling transformation diagrams were determined for the austenitization temperatures of 980, 1060 and 1140 deg. C. They show a well-known form with two main phase fields, martensite and ferrite. Values of the critical cooling rates and ferrite start temperatures depend on the austenitization temperature. After thermal cycles samples were further characterized by optical microscopy, scanning electron microscopy and thermoelectric power measurements

  7. Recent progress in reduced activation ferritic steels R and D in Japan

    International Nuclear Information System (INIS)

    Kimura, A.; Kohyama, A.; Sawai, T.; Shiba, K.; Hishinuma, A.; Jitsukawa, S.; Ukai, S.

    2003-01-01

    The Japanese RAFSs R and D road map toward DEMO is shown. Important steps include high-dose irradiation by fission reactors, such as HFIR in ORNL, irradiation tests by 14 MeV neutrons in IFMIF and application to ITER test blanket modules to provide an adequate database of RAFS for the design of DEMO. Current status of RAFS development is also introduced. The major properties of concern are well within our knowledge and process technologies are mostly ready for fusion application. The RAFSs are now certainly ready to proceed to the next stage. Material database is already in hand and further progress is anticipated for the design of ITER test blanket. Oxide Dispersion strengthening (ODS) steels are quite promising for high temperature operation of the blanket system with potential improvements in radiation resistance of mechanical performances and of corrosion. (author)

  8. Microstructure and mechanical properties in the weld heat affected zone of 9Cr-2W-VTa reduced activation ferritic/martensitic steel for fusion

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Joonoh; Lee, Changhoon; Lee, Taeho; Jang, Minho; Park, Mingu [Korea Institute of Materials Science, Changwon (Korea, Republic of); Kim, Hyoung Chan [National Fusion Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    Reduced activation ferritic/martensitic (RAFM) steel demonstrated excellent resistance to the neutron irradiation and mechanical properties. The investigation of weldability in company with the development of RAFM steel is essential for construction of the fusion reactor. Generally, the superior mechanical properties of the RAFM steel can be upset during welding process due to microstructural change by rapid heating and cooling in the weld heat affected zone (HAZ). The phase transformation and mechanical properties in the weld HAZ of RAFM steel were investigated. The base steel consisted of tempered martensite and two carbides. During rapid welding thermal cycle, the microstructure of the base steel was transformed into martensite and δ-ferrite. In addition, the volume fraction of δ-ferrite and grain size increased with increase in the peak temperature and heat input. The strength of the HAZs was higher than that of the base steel due to the formation of martensite, whereas the impact properties of the HAZs deteriorated as compared with the base steel due to the formation of δ-ferrite. The PWHT improved the impact properties of the HAZs, resulting from the formation of tempered martensite.

  9. Impact properties of reduced activation ferritic/martensitic steel, F82H jointed by hot isostatic pressing

    Energy Technology Data Exchange (ETDEWEB)

    Ogiwara, H.; Tanigawa, H. [Japan Atomic Energy Agency, Tokai-mura, Naga-gun, Ibaraki-ken (Japan); Hirose, T. [Blanket Engineering Group, Japan Atomic Energy Agency, Naka, Ibaraki (Japan); Enoeda, M. [Naka Fusion Research Establishment, J.A.E.R.I., Japan Atomic Energy Research Institute, Ibaraki-ken (Japan); Kohyama, A. [Kyoto Univ., lnstitute of Advanced Energy (Japan)

    2007-07-01

    Full text of publication follows: Reduced-activation ferritic/martensitic steels are the leading candidate structural material for the blanket system of fusion reactors. The important issue at the current stage is the finalization of a detailed manufacturing specification for ITER test blanket module. Hot isostatic pressing (HIP) process is one of the most important methods to fabricate the first wall with cooling channels. The objective of this paper is to optimize HIP condition to obtain the excellent joints mechanical properties. The materials used were F82H steels. The joint was produced by solid state HIP method. Before HIP treatments, specimens were heated in vacuum condition to out-gas. This treatment was conducted to decrease oxidation on the surfaces. HIP treatments were carried out for 2 h at 1100 deg. C - 140 MPa. The specimens were normalized at 960 deg. C for 0.5 h and tempered at 750 deg. C for 1.5 h. The bonding interface was characterized by scanning electron microscopy. Charpy impact tests and tensile tests were conducted to evaluate the mechanical properties of the HIP joint. Impact tests revealed that there were no significant differences in the ductile-brittle transition temperatures of HIP jointed specimens and base metal specimens, but the upper-shelf energy (USE) of the HIP joint specimens at room temperature was only about 10% of that of the base metal specimens. SEM observations of the fracture surface of HIP joint specimens revealed that a large number of oxides were formed on the HIP joint. This result indicates that oxides formed on the HIP joint are the dominant factor of the impact properties. Based on these results, the pre-HIP treatment conditions had been optimized to reduce the number of oxides, and USE of HIP joint specimens increased to about 50% of that of the base metal. The detailed analyses on the HIP joint microstructure will be reported. (authors)

  10. Effects of Ti and Ta addition on microstructure stability and tensile properties of reduced activation ferritic/martensitic steel for nuclear fusion reactors

    Science.gov (United States)

    Kim, Han Kyu; Lee, Ji Won; Moon, Joonoh; Lee, Chang Hoon; Hong, Hyun Uk

    2018-03-01

    The effects of Ti and Ta addition on microstructure stability and tensile properties of a reduced activation ferritic/martensitic (RAFM) steel have been investigated. Ti addition of 0.06 wt% to conventional RAFM reference base steel (Fe-9.3Cr-0.93W-0.22V-0.094Ta-0.1C) was intended to promote the precipitation of nano-sized (Ti,W) carbides with a high resistance to coarsening. In addition, the Ti addition was substituted for 0.094 wt% Ta. The Ti-added RAFM steel (Ti-RAFM) exhibited a higher yield strength (ΔYS = 32 MPa) at 600 °C than the reference base steel due to additional precipitation hardening by (Ti,W)-rich MX with an average size of 6.1 nm and the area fraction of 2.39%. However, after thermal exposure at 600 °C for 1000 h, this Ti-RAFM was more susceptible to degradation than the reference base steel; the block width increased by 77.6% in Ti-RAFM after thermal exposure while the reference base steel showed only 9.1% increase. In order to suppress diffusion rate during thermal exposure, the large-sized Ta element with low activation was added to Ti-RAFM. The Ta-added Ti-RAFM steel exhibited good properties with outstanding microstructure stability. Quantitative comparison in microstructures was discussed with a consideration of Ti and Ta addition.

  11. Significant change of local atomic configurations at surface of reduced activation Eurofer steels induced by hydrogenation treatments

    Energy Technology Data Exchange (ETDEWEB)

    Greculeasa, S.G.; Palade, P.; Schinteie, G. [National Institute for Materials Physics, P.O. Box MG-7, 77125, Bucharest-Magurele (Romania); Kuncser, A.; Stanciu, A. [National Institute for Materials Physics, P.O. Box MG-7, 77125, Bucharest-Magurele (Romania); University of Bucharest, Faculty of Physics, 77125, Bucharest-Magurele (Romania); Lungu, G.A. [National Institute for Materials Physics, P.O. Box MG-7, 77125, Bucharest-Magurele (Romania); Porosnicu, C.; Lungu, C.P. [National Institute for Laser, Plasma and Radiation Physics, 77125, Bucharest-Magurele (Romania); Kuncser, V., E-mail: kuncser@infim.ro [National Institute for Materials Physics, P.O. Box MG-7, 77125, Bucharest-Magurele (Romania)

    2017-04-30

    Highlights: • Engineering of Eurofer slab properties by hydrogenation treatments. • Hydrogenation modifies significantly the local atomic configurations at the surface. • Hydrogenation increases the expulsion of the Cr atoms toward the very surface. • Approaching binomial atomic distribution by hydrogenation in the next surface 100 nm. - Abstract: Reduced-activation steels such as Eurofer alloys are candidates for supporting plasma facing components in tokamak-like nuclear fusion reactors. In order to investigate the impact of hydrogen/deuterium insertion in their crystalline lattice, annealing treatments in hydrogen atmosphere have been applied on Eurofer slabs. The resulting samples have been analyzed with respect to local structure and atomic configuration both before and after successive annealing treatments, by X-ray diffractometry (XRD), scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS), X-ray photoelectron spectroscopy (XPS) and conversion electron Mössbauer spectroscopy (CEMS). The corroborated data point out for a bcc type structure of the non-hydrogenated alloy, with an average alloy composition approaching Fe{sub 0.9}Cr{sub 0.1} along a depth of about 100 nm. EDS elemental maps do not indicate surface inhomogeneities in concentration whereas the Mössbauer spectra prove significant deviations from a homogeneous alloying. The hydrogenation increases the expulsion of the Cr atoms toward the surface layer and decreases their oxidation, with considerable influence on the surface properties of the steel. The hydrogenation treatment is therefore proposed as a potential alternative for a convenient engineering of the surface of different Fe-Cr based alloys.

  12. Effects of impurity elements on mechanical properties and microstructures of reduced-activation ferritic/martensitic steels

    Energy Technology Data Exchange (ETDEWEB)

    Sawahata, A. [Ibaraki Univ., Graduate School of Science and Engineering, Hitachi (Japan); Tanigawa, H.; Shiba, K. [Japan Atomic Energy Agency, Naga-gun, Ibaraki-ken (Japan); Enomoto, M. [Ibaraki Univ., Dept. of Materials Science, Faculty of Engineering, Hitachi (Japan)

    2007-07-01

    Full text of publication follows: Reduced activation ferritic/martensitic steels (RAFs), such as F82H (Fe-8Cr-2W-0.2V- 0.04Ta-0.1C, in wt%), are one of the leading candidates for structural materials of fusion reactors. Impact property of F82H can be improved by adjusting the amount of tantalum or titanium concentration. On the other hand, it was reported by microstructure analyses of IEA steel that tantalum has a tendency to form oxides and causes a large dispersion of fracture toughness. In this study, the correlation between titanium or tantalum concentration and the impact property were reported focusing on difference in microstructure. Charpy impact test and microstructure analyses were carried out against modified F82H series of which titanium, nitrogen and tantalum composition were controlled. Charpy impact test results showed that the ductile-brittle transition temperature (DBTT) of T05A (0.05Ta- 0.0014N-steels. The size distribution analyses of oxides indicate that the number density of composite oxides in T05B was higher than in T05A. In addition, EDX analyses showed that composite oxides in T05B had a strong peak of titanium, but the peak were not detected in the oxides in T05A. These results suggest that titanium has a significant influence on the formation of oxides, and affects the impact property. The influence of tantalum concentration on the formation of these oxides and mechanical properties will be reported. (authors)

  13. Control of substrate oxidation in MOD ceramic coating on low-activation ferritic steel with reduced-pressure atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Teruya, E-mail: teru@nifs.ac.jp; Muroga, Takeo

    2014-12-15

    Highlights: • A Cr{sub 2}O{sub 3} layer was produced on a ferritic steel substrate with a reduced-pressure. • The Cr{sub 2}O{sub 3} layer prevents further substrate oxidation in following coating process. • The Cr{sub 2}O{sub 3} layer has a function as a hydrogen permeation barrier. • A smooth MOD Er{sub 2}O{sub 3} coating was successfully made on the Cr{sub 2}O{sub 3} layer by dip coating. • The Cr{sub 2}O{sub 3} layer would enhance flexibility in MOD coating process and performances. - Abstract: An Er{sub 2}O{sub 3} ceramic coating fabricated using the metal–organic decomposition (MOD) method on a Cr{sub 2}O{sub 3}-covered low-activation ferritic steel JLF-1 substrate was examined to improve hydrogen permeation barrier performance of the coating. The Cr{sub 2}O{sub 3} layer was obtained before coating by heat treating the substrate at 700 °C under reduced pressures of <5 × 10{sup −3} Pa and 5 Pa. The Cr{sub 2}O{sub 3} layer was significantly stable even with heat treatment at 700 °C in air. This layer prevented further production of Fe{sub 2}O{sub 3}, which has been considered to degrade coating performance. An MOD Er{sub 2}O{sub 3} coating with a smooth surface was successfully obtained on a Cr{sub 2}O{sub 3}-covered JLF-1 substrate by dip coating followed by drying and baking. Preprocessing to obtain a Cr{sub 2}O{sub 3} layer would provide flexibility in the coating process for blanket components and ducts. Moreover, the Cr{sub 2}O{sub 3} layer suppressed hydrogen permeation through the JLF-1 substrate. While further optimization of the coating fabrication process is required, it would be possible to suppress hydrogen permeation significantly by multilayers of Cr{sub 2}O{sub 3} and MOD oxide ceramic.

  14. Mechanical properties of 9Cr–1W reduced activation ferritic martensitic steel weldment prepared by electron beam welding process

    Energy Technology Data Exchange (ETDEWEB)

    Das, C.R., E-mail: chitta@igcar.gov.in [Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India); Albert, S.K. [Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India); Sam, Shiju [Institute for Plasma Research, Gandhinagar (India); Mastanaiah, P. [Defense Research and Development Laboratory, Hyderabad (India); Chaitanya, G.M.S.K.; Bhaduri, A.K.; Jayakumar, T. [Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India); Murthy, C.V.S. [Defense Research and Development Laboratory, Hyderabad (India); Kumar, E. Rajendra [Institute for Plasma Research, Gandhinagar (India)

    2014-11-15

    Highlights: • Width of HAZ is smaller in the 9Cr–1W RAFM weldment prepared by EB process compared to that reported for TIG weldments in literature. • Weld joint is stronger than that of the base metal. • Toughness of weld metal prepared by EB welding process is comparable to that (in PWHT condition) prepared by TIG process. • DBTT of as-welded 9Cr–1W RAFM weldment prepared by EB process is comparable to that reported for TIG weld metal in PWHT condition. - Abstract: Microstructure and mechanical properties of the weldments prepared from 9Cr–1W reduced activation ferritic martensitic (RAFM) steel using electron beam welding (EBW) process were studied. Microstructure consists of tempered lath martensite where precipitates decorating the boundaries in post weld heat treated (PWHT) condition. Lath and precipitate sizes were found to be finer in the weld metal than in base metal. Accordingly, hardness of the weld metal was found to be higher than the base metal. Tensile strength of the cross weldment specimen was 684 MPa, which was comparable with the base metal tensile strength of 670 MPa. On the other hand, DBTT of 9Cr–1W weld metal in as-welded condition is similar to that reported for TIG weld metal in PWHT condition.

  15. Mechanical properties of 9Cr–1W reduced activation ferritic martensitic steel weldment prepared by electron beam welding process

    International Nuclear Information System (INIS)

    Das, C.R.; Albert, S.K.; Sam, Shiju; Mastanaiah, P.; Chaitanya, G.M.S.K.; Bhaduri, A.K.; Jayakumar, T.; Murthy, C.V.S.; Kumar, E. Rajendra

    2014-01-01

    Highlights: • Width of HAZ is smaller in the 9Cr–1W RAFM weldment prepared by EB process compared to that reported for TIG weldments in literature. • Weld joint is stronger than that of the base metal. • Toughness of weld metal prepared by EB welding process is comparable to that (in PWHT condition) prepared by TIG process. • DBTT of as-welded 9Cr–1W RAFM weldment prepared by EB process is comparable to that reported for TIG weld metal in PWHT condition. - Abstract: Microstructure and mechanical properties of the weldments prepared from 9Cr–1W reduced activation ferritic martensitic (RAFM) steel using electron beam welding (EBW) process were studied. Microstructure consists of tempered lath martensite where precipitates decorating the boundaries in post weld heat treated (PWHT) condition. Lath and precipitate sizes were found to be finer in the weld metal than in base metal. Accordingly, hardness of the weld metal was found to be higher than the base metal. Tensile strength of the cross weldment specimen was 684 MPa, which was comparable with the base metal tensile strength of 670 MPa. On the other hand, DBTT of 9Cr–1W weld metal in as-welded condition is similar to that reported for TIG weld metal in PWHT condition

  16. The influence of inclusions on the low cycle fatigue properties of reduced activation ferritic/martensitic steel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, D.H.; Kima, S.W. [Kyoto Univ., Graduate School of Energy Science (Japan); Tanigawa, H. [Japan Atomic Energy Agency, Tokai-mura, Naga-gun, Ibaraki-ken (Japan); Hirose, T. [Blanket Engineering Group, Japan Atomic Energy Agency, Naka, Ibaraki (Japan); Kohyama, A. [Kyoto Univ., lnstitute of Advanced Energy (Japan)

    2007-07-01

    Full text of publication follows: Reduced activation ferritic/martensitic (RAFM) steels, such as F82H, are the primary near-term candidate for the blanket structural material of nuclear fusion reactors. During operation, blanket structural materials will be subjected to cyclic loading caused by start-up and shut-down procedure or plasma disruption. Therefore, investigation of fatigue property is essential to reactor design. It is considered that fatigue properties depend on the material factor such as the inclusion distribution, surface morphology and so on. Especially, many experimental results show that inclusions become the fracture origin in a given volume of material subjected to cyclic stress, and fracture failure is most likely to initiate at the largest inclusion in the volume. Therefore, the prediction of the size of maximum inclusion and its impact on fatigue properties would be essential to the fusion reactor materials development and application. This paper examines the possible relation between fatigue life and inclusion parameters such as size, shape, distribution and composition. The low cycle fatigue behavior of F82H steel at room temperature in air condition under fully reversed push-pull triangular wave was studied using miniaturized hourglass-type specimens with 1.25 mm in diameter. Total strain range is selected from 0.8% to 2.4%, and the strain rate was 0.04%/s. To examine the size and composition of the inclusions, fracture surfaces and crack initiation region were investigated by a scanning electron microscope (SEM) and EDS. The inclusions such as TaO{sub x}, TaO{sub x}- Al{sub 2}O{sub 3} and Al{sub 2}O{sub 3} with the size below 10 {mu}m are observed on specimen surface. The surface observation of the specimen which discontinued testing at 20 and 500 cycle tested at the strain range of 1.4% revealed that fatigue loading induced separation of inclusions from the matrix in initial stage, then micro-crack induced around the inclusions

  17. Development of HIP bonding procedure and mechanical properties of HIP bonded joints for reduced activation ferritic steel F-82H

    International Nuclear Information System (INIS)

    Oda, Masahiro; Kurasawa, Toshimasa; Kuroda, Toshimasa; Hatano, Toshihisa; Takatsu, Hideyuki

    1997-03-01

    Structural materials of blanket components in fusion DEMO reactors will receive a neutron wall load more than 3-5MW/m 2 as well as exposed by surface heat flux more than 0.5MW/m 2 . A reduced activation ferritic steel F-82H has been developed by JAERI in collaboration with NKK from viewpoints of resistance for high temperature and neutron loads and lower radioactivity. This study intends to obtain basic performance of F-82H to establish the fabrication procedure of the first wall and blanket box by using Hot Isostatic Pressing (HIP) bonding. Before HIP bonding tests, effects of heat treatment temperature and surface roughness on mechanical properties of joints were investigated in the heat treatment tests and diffusion bonding tests, respectively. From these results, the optimum HIP bonding conditions and the post heat treatment were selected. Using these conditions, the HIP bonding tests were carried out to evaluate HIP bondability and to obtain mechanical properties of the joints. Sufficient HIP bonding performance was obtained under the temperature of 1040degC, the compressive stress of 150MPa, the holding time of 2h, and the surface roughness ∼μ m. Mechanical properties of HIP bonded joints with these conditions were similar to those of as-received base metal. An oxide formation on the surface to be bonded would need to be avoided for sufficient bonding. The bonding ratio, Charpy impact value and fatigue performance of the joints strongly depended on the HIP conditions, especially temperature, while micro-structure, Vickers hardness and tensile properties had little dependence on the HIP temperature. The surface roughness strongly affected the bonding ratio and would be required to be in the level of a few μ m. In the HIP bonding test of the welded material, the once-melted surface could be jointed by the HIP bonding under the above-mentioned procedure. (J.P.N.)

  18. Hydrogen permeation measurement of the reduced activation ferritic steel F82H by the vacuum thermo-balance method

    International Nuclear Information System (INIS)

    Yoshida, Hajime; Enoeda, Mikio; Abe, Tetsuya; Akiba, Masato

    2005-03-01

    Hydrogen permeation fluxes of the reduced activation ferritic steel F82H were quantitatively measured by a newly proposed method, vacuum thermo-balance method, for a precise estimation of tritium leakage in a fusion reactor. We prepared sample capsules made of F82H, which enclosed hydrogen gas. The hydrogen in the capsules permeated through the capsule wall, and subsequently desorbed from the capsule surface during isothermal heating. The vacuum thermo-balance method allows simultaneous measurement of the hydrogen permeation flux by two independent methods, namely, the net weight reduction of the sample capsule and exhaust gas analysis. Thus the simultaneous measurements by two independent methods increase the reliability of the permeability measurement. When the gas pressure of enclosed hydrogen was 0.8 atm at the sample temperature of 673 K, the hydrogen permeation flux of F82H obtained by the net weight reduction and the exhaust gas analysis was 0.75x10 18 (H 2 /m 2 s) and 2.2x10 18 (H 2 /m 2 s), respectively. The ratio of the hydrogen permeation fluxes obtained by the net weight reduction to that measured by the exhaust gas analysis was in the range from 1/4 to 1/1 in this experiment. The temperature dependence of the estimated permeation flux was similar in both methods. Taking the uncertainties of both measurements into consideration, both results are supposed to be consistent. The enhancement of hydrogen permeation flux was observed from the sample of which outer surface was mechanically polished. Through the present experiments, it has been demonstrated that the vacuum thermo-balance method is effective for the measurement of hydrogen permeation rate of F82H. (author)

  19. Microstructural Variations Across a Dissimilar 316L Austenitic: 9Cr Reduced Activation Ferritic Martensitic Steel Weld Joint

    Science.gov (United States)

    Thomas Paul, V.; Karthikeyan, T.; Dasgupta, Arup; Sudha, C.; Hajra, R. N.; Albert, S. K.; Saroja, S.; Jayakumar, T.

    2016-03-01

    This paper discuss the microstructural variations across a dissimilar weld joint between SS316 and 9Cr-RAFM steel and its modifications on post weld heat treatments (PWHT). Detailed characterization showed a mixed microstructure of austenite and martensite in the weld which is in agreement with the phases predicted using Schaeffler diagram based on composition measurements. The presence of very low volume fraction of δ-ferrite in SS316L has been identified employing state of the art electron back-scattered diffraction technique. PWHT of the ferritic steel did not reduce the hardness in the weld metal. Thermal exposure at 973 K (700 °C) showed a progressive reduction in hardness of weld joint with duration of treatment except in austenitic base metal. However, diffusion annealing at 1073 K (800 °C) for 100 hours resulted in an unexpected increase in hardness of weld metal, which is a manifestation of the dilution effects and enrichment of Ni on the transformation characteristics of the weld zone. Migration of carbon from ferritic steel aided the precipitation of fine carbides in the austenitic base metal on annealing at 973 K (700 °C); but enhanced diffusion at 1073 K (880 °C) resulted in coarsening of carbides and thereby reduction of hardness.

  20. Precipitation sensitivity to alloy composition in Fe-Cr-Mn austenitic steels developed for reduced activation for fusion application

    International Nuclear Information System (INIS)

    Maziasz, P.J.; Klueh, R.L.

    1988-01-01

    Special austenitic steels are being designed in which alloying elements like Mo, Nb, and Ni are replaced with Mn, W, V, Ti, and/or Ta to reduce the long-term radioactivity induced by fusion reactor irradiation. However, the new steels still need to have properties otherwise similar to commercial steels like type 316. Precipitation strongly affects strength and radiation-resistance in austenitic steels during irradiation at 400--600/degree/C, and precipitation is also usually quite sensitive to alloy composition. The initial stage of development was to define a base Fe-Cr-Mn-C composition that formed stable austenite after annealing and cold-working, and resisted recovery or excessive formation of coarse carbide and intermetallic phases during elevated temperature annealing. These studies produced a Fe-12Cr-20Mn-0.25C base alloy. The next stage was to add the minor alloying elements W, Ti, V, P, and B for more strength and radiation-resistance. One of the goals was to produce fine MC precipitation behavior similar to the Ti-modified Fe-Cr-Ni prime candidate alloy (PCA). Additions of Ti+V+P+B produced fine MC precipitation along network dislocations and recovery/recrystallization resistance in 20% cold worked material aged at 800/degree/C for 166h, whereas W, Ti, W+Ti, or Ti+P+B additions did not. Addition of W+Ti+V+P+B also produced fine MC, but caused some σ phase formation and more recrystallization as well. 29 refs., 14 figs., 9 tabs

  1. Effects of helium on ductile brittle transition behavior of reduced activation ferritic steels after high concentration he implantation at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, A.; Ejiri, M.; Nogami, S.; Ishiga, M.; Abe, K. [Tohoku Univ., Dept. of Quantum Science and Energy Engr, Sendai (Japan); Kasada, R.; Kimura, A. [Kyoto Univ., Institute of Advanced Energy (Japan); Jitsukawa, S. [Japan Atomic Energy Agency, Tokai-mura, Naga-gun, Ibaraki-ken (Japan)

    2007-07-01

    Full text of publication follows: Influence of Helium (He) on fracture behavior of reduced activation ferritic/martensitic steels including Oxide Dispersion Strengthening (ODS) steels and F82H were examined. To study the He effects on fracture behavior of these steels after He bubble formation conditions, higher concentration of He implantation at around 550 C were performed and examined the relationship between microstructure evolution and fracture behavior of the steels. The 1.5CVN mini size Charpy specimens were used to evaluate impact test behavior. Reduced activation ferritic ODS steels, 9Cr-ODS and 12Cr-ODS steels were examine. F82H was also examined as reference material. Helium implantation was performed by a cyclotron of Tohoku University with a beam of 50 MeV {alpha}-particles at temperature around 550 C. A tandem-type energy degrader system was used to implant He into the specimen from the irradiated surface to the range of 50 MeV {alpha}-particles, that was about 380 {mu}m in iron. Implanted He concentration were about 1000 appm. Charpy impact test was performed using a instrumented impact test apparatus in Oarai branch of IMR, Tohoku University. Analyses of absorbed energy change and fracture surface were carried out. Vickers hardness test was also carried out on He implanted area of the 1.5CVN specimen to estimate irradiation hardening. Microstructural observation was performed by TEM. In the case of F82H, DBTT increased by the 1000 appm He implantation condition was about 80 C and grain boundary fracture surface was only observed in the He implanted area of all the ruptured specimens in brittle manner. On the other hand, DBTT shift and fracture mode change of He implanted 9Cr-ODS steel was not observed after He implantation. Microstructural observation showed that He bubble formation on the lath boundaries and grain boundaries were significant in F82H, but the bubble segregation on grain boundary in ODS steel was not apparent. The bubble formation

  2. Phase transformation and impact properties in the experimentally simulated weld heat-affected zone of a reduced activation ferritic/martensitic steel

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Joonoh, E-mail: mjo99@kims.re.kr [Ferrous Alloy Department, Advanced Metallic Materials Division, Korea Institute of Materials Science, 797 Changwondaero, Seongsangu, Changwon, Gyeongnam 642-831 (Korea, Republic of); Lee, Chang-Hoon; Lee, Tae-Ho [Ferrous Alloy Department, Advanced Metallic Materials Division, Korea Institute of Materials Science, 797 Changwondaero, Seongsangu, Changwon, Gyeongnam 642-831 (Korea, Republic of); Jang, Min-Ho [Ferrous Alloy Department, Advanced Metallic Materials Division, Korea Institute of Materials Science, 797 Changwondaero, Seongsangu, Changwon, Gyeongnam 642-831 (Korea, Republic of); Division of Materials Science and Engineering, Hanyang University, Seongdong-ku, Seoul 133-791 (Korea, Republic of); Park, Min-Gu [Ferrous Alloy Department, Advanced Metallic Materials Division, Korea Institute of Materials Science, 797 Changwondaero, Seongsangu, Changwon, Gyeongnam 642-831 (Korea, Republic of); Department of Material Science and Engineering, Pusan National University, 30 Jangjeon-Dong, Geumjeong-gu, Pusan 609-735 (Korea, Republic of); Han, Heung Nam [Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-742 (Korea, Republic of)

    2014-12-15

    In this work, the phase transformation and impact properties in the weld heat-affected zone (HAZ) of a reduced activation ferritic/martensitic (RAFM) steel are investigated. The HAZs were experimentally simulated using a Gleeble simulator. The base steel consisted of tempered martensite through normalizing at 1000 °C and tempering at 750 °C, while the HAZs consisted of martensite, δ-ferrite and a small volume of autotempered martensite. The impact properties using a Charpy V-notch impact test revealed that the HAZs showed poor impact properties due to the formation of martensite and δ-ferrite as compared with the base steel. In addition, the impact properties of the HAZs further deteriorated with an increase in the δ-ferrite fraction caused by increasing the peak temperature. The impact properties of the HAZs could be improved through the formation of tempered martensite after post weld heat treatment (PWHT), but they remained lower than that of the base steel because the δ-ferrite remained in the tempered HAZs.

  3. Reduced Activation Ferritic/Martensitic Steel Eurofer 97 as Possible Structural Material for Fusion Devices. Metallurgical Characterization on As-Received Condition and after Simulated Services Conditions

    International Nuclear Information System (INIS)

    Fernandez, P.; Lancha, A. M.; Lapena, J.; Serrano, M.; Hernandez-Mayoral, M.

    2004-01-01

    Metallurgical Characterization of the reduced activation ferritic/martensitic steel Eurofer'97, on as-received condition and after thermal ageing treatment in the temperature range from 400 degree centigree to 600 degree centigree for periods up to 10.000 h, was carried out. The microstructure of the steel remained stable (tempered martensite with M 2 3 C 6 and MX precipitates) after the thermal ageing treatments studied in this work. In general, this stability was also observed in the mechanical properties. The Eurofer'97 steel exhibited similar values of hardness, ultimate tensile stress, 0,2% proof stress, USE and T 0 3 regardless of the investigated material condition. However, ageing at 600 degree centigree for 10.000 ha caused a slight increase in the DBTT, of approximately 23 . In terms of creep properties, the steel shows in general adequate creep rupture strength levels for short rupture times. However, the results obtained up to now for long time creep rupture tests at 500 degree centigree suggests a change in the deformation mechanisms. (Author) 62 refs

  4. Development of filler wires for welding of reduced activation ferritic martensitic steel for India's test blanket module of ITER

    Energy Technology Data Exchange (ETDEWEB)

    Srinivasan, G.; Arivazhagan, B.; Albert, S.K.; Bhaduri, A.K. [Indira Gandhi Centre for Atomic Research, Kalpakkam (India)

    2010-07-01

    Indigenous development of reduced activation ferritic-martensitic (RAFM) steel has become necessary for India as a participant in the International Thermo-nuclear Experimental Reactor (ITER) programme. Optimisation of RAFM steel is in an advanced stage for the fabrication of test blanket module (TBM) components. Simultaneously, development of RAFM steel filler wires has been undertaken since there is no commercial filler wires are available for fabrication of components using RAFM steel. The purpose of this study is to develop filler wires that can be directly used for both gas tungsten arc welding (GTAW) and for narrow-gap gas tungsten arc welding (NG-GTAW) that reduces the deposited weld metal volume and heat affected zone (HAZ) width. Further, the filler wires would also be used for hybrid laser-MIG welding for thick section joints. In view of meeting all the requirements, a detailed specification was prepared for the development of filler wires for welding of RAFM steel. Meanwhile, welding trials have been carried out on 2.5 mm thick plates of the RAFM steel using GTAW process at various heat inputs with a preheat temperature of 250 C followed by various post weld heat treatments (PWHT). The microstructure of the weld metal in most of the cases showed the presence of some amount of delta-ferrite. Filler wires as per specifications have also been developed with minor variations on the chemistry against the specified values. Welding parameters and PWHT parameters were optimized to qualify the filler wires without the presence of delta-ferrite in the weld metal and with optimized mechanical properties. Results showed that the weld metals are free from delta-ferrite. Tensile properties at ambient temperature and at 500 C are well above the specified values, and are much higher than the base metal values. Ductile Brittle Transition Temperature (DBTT) has been evaluated as -81 C based on the 68 J criteria. The present study highlights the basis and methodology

  5. A comparison of low-chromium and high-chromium reduced-activation steels for fusion applications

    International Nuclear Information System (INIS)

    Klueh, R.L.; Maziasz, P.J.; Alexander, D.J.

    1996-01-01

    Ferritic steels have been considered candidate structural materials for first wall and blanket structures for fusion power plants since the late 1970s. The first steels considered in the United States were the conventional Cr-Mo steels Sandvik HT9 (nominally 12Cr-1Mo-0.25V-0.5W-0.5Ni-0.2C, here designated l2Cr-1MoVW), modified 9Cr-1Mo steel (9Cr-1Mo-0.2V-0.06Nb-0. IC, designated 9Cr-1MoVNb) and, to a lesser extent, 2 1/4Cr-1Mo steel (2.25Cr-Mo-0.1C). All compositions are in wt. %. The normalized-and-tempered 9 and 12Cr steels had a tempered martensite microstructure, and the normalized-and-tempered 2 1/4 Cr steel had a tempered bainite microstructure. This report describes chromium steels tested in normalized and tempered conditions. Miniature tensile and Charpy specimens were tested

  6. Synergistic effect of helium and hydrogen for bubble swelling in reduced-activation ferritic/martensitic steel under sequential helium and hydrogen irradiation at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Wenhui [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Guo, Liping, E-mail: guolp@whu.edu.cn [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Chen, Jihong; Luo, Fengfeng; Li, Tiecheng [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Ren, Yaoyao [Center for Electron Microscopy, Wuhan University, Wuhan 430072 (China); Suo, Jinping; Yang, Feng [State Key Laboratory of Mould Technology, Institute of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2014-04-15

    Highlights: • Helium/hydrogen synergistic effect can increase irradiation swelling of RAFM steel. • Hydrogen can be trapped to the outer surface of helium bubbles. • Too large a helium bubble can become movable. • Point defects would become mobile and annihilate at dislocations at high temperature. • The peak swelling temperature for RAFM steel is 450 °C. - Abstract: In order to investigate the synergistic effect of helium and hydrogen on swelling in reduced-activation ferritic/martensitic (RAFM) steel, specimens were separately irradiated by single He{sup +} beam and sequential He{sup +} and H{sup +} beams at different temperatures from 250 to 650 °C. Transmission electron microscope observation showed that implantation of hydrogen into the specimens pre-irradiated by helium can result in obvious enhancement of bubble size and swelling rate which can be regarded as a consequence of hydrogen being trapped by helium bubbles. But when temperature increased, Ostwald ripening mechanism would become dominant, besides, too large a bubble could become mobile and swallow many tiny bubbles on their way moving, reducing bubble number density. And these effects were most remarkable at 450 °C which was the peak bubble swelling temperature for RAMF steel. When temperature was high enough, say above 450, point defects would become mobile and annihilate at dislocations or surface. As a consequence, helium could no longer effectively diffuse and clustering in materials and bubble formation was suppressed. When temperature was above 500, helium bubbles would become unstable and decompose or migrate out of surface. Finally no bubble was observed at 650 °C.

  7. Synergistic effect of helium and hydrogen for bubble swelling in reduced-activation ferritic/martensitic steel under sequential helium and hydrogen irradiation at different temperatures

    International Nuclear Information System (INIS)

    Hu, Wenhui; Guo, Liping; Chen, Jihong; Luo, Fengfeng; Li, Tiecheng; Ren, Yaoyao; Suo, Jinping; Yang, Feng

    2014-01-01

    Highlights: • Helium/hydrogen synergistic effect can increase irradiation swelling of RAFM steel. • Hydrogen can be trapped to the outer surface of helium bubbles. • Too large a helium bubble can become movable. • Point defects would become mobile and annihilate at dislocations at high temperature. • The peak swelling temperature for RAFM steel is 450 °C. - Abstract: In order to investigate the synergistic effect of helium and hydrogen on swelling in reduced-activation ferritic/martensitic (RAFM) steel, specimens were separately irradiated by single He + beam and sequential He + and H + beams at different temperatures from 250 to 650 °C. Transmission electron microscope observation showed that implantation of hydrogen into the specimens pre-irradiated by helium can result in obvious enhancement of bubble size and swelling rate which can be regarded as a consequence of hydrogen being trapped by helium bubbles. But when temperature increased, Ostwald ripening mechanism would become dominant, besides, too large a bubble could become mobile and swallow many tiny bubbles on their way moving, reducing bubble number density. And these effects were most remarkable at 450 °C which was the peak bubble swelling temperature for RAMF steel. When temperature was high enough, say above 450, point defects would become mobile and annihilate at dislocations or surface. As a consequence, helium could no longer effectively diffuse and clustering in materials and bubble formation was suppressed. When temperature was above 500, helium bubbles would become unstable and decompose or migrate out of surface. Finally no bubble was observed at 650 °C

  8. Effect of Microstructures and Tempering Heat Treatment on the Mechanical Properties of 9Cr-2W Reduced-Activation Ferritic-Martensitic Steel

    International Nuclear Information System (INIS)

    Park, Min-Gu; Kang, Nam Hyun; Moon, Joonoh; Lee, Tae-Ho; Lee, Chang-Hoon; Kim, Hyoung Chan

    2015-01-01

    The aim of this study was to investigate the effect of microstructures (martensite, ferrite, or mixed ferrite and martensite) on the mechanical properties. Of particular interest was the Charpy impact results for 9Cr-2W reduced-activation ferritic-martensitic (RAFM) steels. Under normalized conditions, steel with martensitic microstructure showed superior tensile strength and Charpy impact results. This may result from auto-tempering during the transformation of martensite. On the other hand, both ferrite, and ferrite mixed with martensite, showed unusually poor Charpy impact results. This is because the ferrite phases, and coarse M_23C_6 carbides at the ferrite-grain boundaries acted as cleavage crack propagation paths, and as preferential initiation sites for cleavage cracks, respectively. After the tempering heat treatment, although tensile strength decreased, the energy absorbed during the Charpy impact test drastically increased for martensite, and ferrite mixed with martensite. This was due to the tempered martensite. On the other hand, there were no distinctive differences in tensile and Charpy impact properties of steel with ferrite microstructure, when comparing normalized and tempered conditions.

  9. Investigation on microstructure and properties of narrow-gap laser welding on reduced activation ferritic/martensitic steel CLF-1 with a thickness of 35 mm

    Science.gov (United States)

    Wu, Shikai; Zhang, Jianchao; Yang, Jiaoxi; Lu, Junxia; Liao, Hongbin; Wang, Xiaoyu

    2018-05-01

    Reduced activation ferritic martensitic (RAFM) steel is chosen as a structural material for test blanket modules (TBMs) to be constructed in International Thermonuclear Experimental Reactor (ITER) and China Fusion Engineering Test Reactor (CFETR). Chinese specific RAFM steel named with CLF-1 has been developed for CFETR. In this paper, a narrow-gap groove laser multi-pass welding of CLF-1 steel with thickness of 35 mm is conduced by YLS-15000 fiber laser. Further, the microstructures of different regions in the weld joint were characterized, and tensile impact and micro-hardness tests were carried out for evaluating the mecharical properties. The results show that the butt weld joint of CLF-1 steel with a thickness of 35 mm was well-formed using the optimal narrow-gap laser filler wire welding and no obvious defects was found such as incomplete fusion cracks and pores. The microstructures of backing layer is dominated by lath martensites and the Heat-Affected Zone (HAZ) was mainly filled with two-phase hybrid structures of secondary-tempering sorbites and martensites. The filler layer is similar to the backing layer in microstructures. In tensile tests, the tensile samples from different parts of the joint all fractured at base metal (BM). The micro-hardness of weld metal (WM) was found to be higher than that of BM and the Heat-Affected Zone (HAZ) exhibited no obvious softening. After post weld heat treatment (PWHT), it can be observed that the fusion zone of the autogenous welding bead and the upper filling beads mainly consist of lath martensites which caused the lower impact absorbing energy. The HAZ mainly included two-phase hybrid structures of secondary-tempering sorbites and martensites and exhibited favorable impact toughness.

  10. Metallurgical properties of reduced activation martensitic steel Eurofer'97 in the as-received condition and after thermal ageing

    International Nuclear Information System (INIS)

    Fernandez, P.; Lancha, A.M.; Lapena, J.; Serrano, M.; Hernandez-Mayoral, M.

    2002-01-01

    This paper describes the microstructural studies and the mechanical testing (hardness, tensile and charpy tests) performed on the Eurofer'97 steel in the as-received condition and after thermal ageing treatments up to 600 deg. C. In addition, fracture toughness tests on the as-received condition have been carried out in order to determine the Master Curve. During the thermal ageing treatments studied (500 deg. C/5000 h and 600 deg. C/1000 h) the general microstructure of the steel (tempered martensite with M 23 C 6 and MX precipitates) remained stable. Only a slight growth of the particles has been observed. In terms of mechanical properties, the Eurofer'97 steel exhibited similar values of tensile properties (tensile and yield strength) and ductile-brittle transition temperature regardless of the material condition studied.

  11. Development of filler wires for welding of reduced activation ferritic martenstic steel for India's test blanket module of ITER

    Energy Technology Data Exchange (ETDEWEB)

    Srinivasan, G., E-mail: gsrini@igcar.gov.in [Materials Technology Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamilnadu (India); Arivazhagan, B.; Albert, S.K.; Bhaduri, A.K. [Materials Technology Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamilnadu (India)

    2011-06-15

    Highlights: > Weld microstructure produced by RAFMS filler wires are free from delta ferrite. > Cooling rates of by weld thermal cycles influences the presence of delta ferrite. > Weld parameters modified with higher pre heat temperature and high heat input. > PWHT optimized based on correlation of hardness between base and weld metals. > Optimised mechanical properties achieved by proper tempering of the martensite. - Abstract: Indigenous development of reduced activation ferritic martensitic steel (RAFMS) has become mandatory to India to participate in the International Thermo-nuclear Experimental Reactor (ITER) programme. Optimisation of RAFMS is in an advanced stage for the fabrication of test blanket module (TBM) components. Simultaneously, development of RAFMS filler wires has been undertaken since there is no commercial filler wires are available for fabrication of components using RAFMS. Purpose of this study is to develop filler wires that can be directly used for both tungsten inert gas welding (TIG) and narrow gap tungsten inert gas welding (NG-TIG), which reduces the deposited weld metal volume and heat affected zone (HAZ) width. Further, the filler wires would also be used for hybrid laser welding for thick section joints. In view of meeting all the requirements, a detailed specification was prepared for the development of filler wires for welding of RAFM steel. Meanwhile, autogenous welding trials have been carried out on 2.5 mm thick plates of the RAFM steel using TIG process at various heat inputs with a preheat temperature of 250 deg. C followed by various post weld heat treatments (PWHT). The microstructure of the weld metal in most of the cases showed the presence of some delta-ferrite. Filler wires as per specifications have also been developed with minor variations on the chemistry against the specified values. Welding parameters and PWHT parameters were optimised to qualify the filler wires without the presence of delta-ferrite in the weld

  12. Creep deformation and rupture behaviour of 9Cr–1W–0.2V–0.06Ta Reduced Activation Ferritic–Martensitic steel

    International Nuclear Information System (INIS)

    Vanaja, J.; Laha, K.; Mythili, R.; Chandravathi, K.S.; Saroja, S.; Mathew, M.D.

    2012-01-01

    Highlights: ► Creep tests on broad temperature and stress ranges were carried out. ► Microstructural instability on creep and thermal exposures were studied using TEM. ► Creep damage tolerance factor of the material was estimated. - Abstract: This paper presents the creep deformation and rupture behaviour of indigenously produced 9Cr–1W–0.2V–0.06Ta Reduced Activation Ferritic–Martensitic (RAFM) steel for fusion reactor application. Creep studies were carried out at 773, 823 and 873 K over a stress range of 100–300 MPa. The creep deformation of the steel was found to proceed with relatively shorter primary regime followed by an extended tertiary regime with virtually no secondary regime. The variation of minimum creep rate of the material with applied stress followed a power law relation, ε m = Aσ n , with stress exponent value ‘n’ decreasing with increase in temperature. The product of minimum creep rate and creep rupture life was found to obey the modified Monkman–Grant relation. The time to onset of tertiary stage of deformation was directly proportional to rupture life. TEM studies revealed relatively large changes in martensitic sub-structure and coarsening of precipitates in the steel on creep exposure as compared to thermal exposure. Microstructural degradation was considered as the prime cause of extended tertiary stage of creep deformation, which was also reflected in the damage tolerance factor λ with a value more than 2.5. In view of the microstructural instability of the material on creep exposure, the variation of minimum creep rate with stress and temperature did not obey Dorn's equation modified by invoking Lagneborg and Bergman's concepts of back stress.

  13. A study on influence of heat input variation on microstructure of reduced activation ferritic martensitic steel weld metal produced by GTAW process

    International Nuclear Information System (INIS)

    Arivazhagan, B.; Srinivasan, G.; Albert, S.K.; Bhaduri, A.K.

    2011-01-01

    Reduced activation ferritic martensitic (RAFM) steel is a major structural material for test blanket module (TBM) to be incorporated in International Thermonuclear Experimental Reactor (ITER) programme to study the breeding of tritium in fusion reactors. This material has been mainly developed to achieve significant reduction in the induced radioactivity from the structural material used. Fabrication of TBM involves extensive welding, and gas tungsten arc welding (GTAW) process is one of the welding processes being considered for this purpose. In the present work, the effect of heat input on microstructure of indigenously developed RAFM steel weld metal produced by GTAW process has been studied. Autogenous bead-on-plate welding, autogenous butt-welding, butt-welding with filler wire addition, and pulsed welding on RAFMS have been carried out using GTAW process respectively. The weld metal is found to contain δ-ferrite and its volume fraction increased with increase in heat input. This fact suggests that δ-ferrite content in the weld metal is influenced by the cooling rate during welding. It was also observed that the hardness of the weld metal decreased with increase in δ-ferrite content. This paper highlights the effect of heat input and PWHT duration on microstructure and hardness of welds.

  14. Cyclic softening as a parameter for prediction of remnant creep rupture life of a Indian reduced activation ferritic–martensitic (IN-RAFM) steel subjected to fatigue exposures

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, Aritra, E-mail: aritra@igcar.gov.in [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, Tamil Nadu (India); Vijayanand, V.D.; Shankar, Vani; Parameswaran, P.; Sandhya, R.; Laha, K.; Mathew, M.D.; Jayakumar, T. [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, Tamil Nadu (India); Rajendrakumar, E. [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat (India)

    2014-12-15

    Sequential fatigue-creep tests were conducted on Indian reduced activation ferritic–martensitic steel at 823 K leading to sharp decrease in residual creep life with increase in prior fatigue exposures. Extensive recovery of martensitic-lath structure taking place during fatigue deformation, manifested as cyclic softening in the cyclic stress response, shortens the residual creep life. Based on the experimental results, cyclic softening occurring during fatigue stage can be correlated with residual creep life, evolving in an empirical model which predicts residual creep life as a function of cyclic softening. Predicted creep lives for specimens pre-cycled at various strain amplitudes are explained on the basis of mechanism of cyclic softening.

  15. Effect of microstructural evolution by isothermal aging on the mechanical properties of 9Cr-1WVTa reduced activation ferritic/martensitic steels

    Energy Technology Data Exchange (ETDEWEB)

    Park, Min-Gu [Korea Institute of Materials Science, Changwon 642-831 (Korea, Republic of); Lee, Chang-Hoon, E-mail: lee1626@kims.re.kr [Korea Institute of Materials Science, Changwon 642-831 (Korea, Republic of); Moon, Joonoh; Park, Jun Young; Lee, Tae-Ho [Korea Institute of Materials Science, Changwon 642-831 (Korea, Republic of); Kang, Namhyun [Pusan National University, Busan 609-735 (Korea, Republic of); Chan Kim, Hyoung [National Fusion Research Institute, Daejeon 305-806 (Korea, Republic of)

    2017-03-15

    The influence of microstructural changes caused by aging condition on tensile and Charpy impact properties was investigated for reduced activation ferritic-martensitic (RAFM) 9Cr-1WVTa steels having single martensite and a mixed microstructure of martensite and ferrite. For the mixed microstructure of martensite and ferrite, the Charpy impact properties deteriorated in both as-normalized and tempered conditions due to the ferrite and the accompanying M{sub 23}C{sub 6} carbides at the ferrite grain boundaries which act as path and initiation sites for cleavage cracks, respectively. However, aging at 550 °C for 20–100 h recovered gradually the Charpy impact toughness without any distinct drop in strength, as a result of the spheroidization of the coarse M{sub 23}C{sub 6} carbides at the ferrite grain boundaries, which makes crack initiation more difficult.

  16. Viscoplastic equations incorporated into a finite element model to predict deformation behavior of irradiated reduced activation ferritic/martensitic steel

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yuanyuan, E-mail: 630wyy@163.com [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), Dalian University of Technology, Dalian 116024 (China); Zhao, Jijun, E-mail: zhaojj@dlut.edu.cn [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), Dalian University of Technology, Dalian 116024 (China); Zhang, Chi [Key Laboratory of Advanced Materials of Ministry of Education, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2017-05-15

    Highlights: • The initial internal variable in the Anand model is modified by considering both temperature and irradiation dose. • The tensile stress-strain response is examined and analyzed under different temperatures and irradiation doses. • Yield strengths are predicted as functions of strain rate, temperature and irradiation dose. - Abstract: The viscoplastic equations with a modified initial internal variable are implemented into the finite element code to investigate stress-strain response and irradiation hardening of the materials under increased temperature and at different levels of irradiated dose. We applied this model to Mod 9Cr-1Mo steel. The predicted results are validated by the experimentally measured data. Furthermore, they show good agreement with the previous data from a constitutive crystal plasticity model in account of dislocation and interstitial loops. Three previous hardening models for predicting the yield strength of the material are discussed and compared with our simulation results.

  17. Surface nanocrystallization of stainless steel for reduced biofilm adherence

    International Nuclear Information System (INIS)

    Yu Bin; Li, D Y; Davis, Elisabeth M; Irvin, Randall T; Hodges, Robert S

    2008-01-01

    Stainless steel is one of the most common metallic biomedical materials. For medical applications, its resistance to the adherence of biofilms is of importance to the elimination or minimization of bacterial infections. In this study, we demonstrate the effectiveness of a process combining surface nanocrystallization and thermal oxidation (or a recovery heat treatment in air) for reducing the biofilm's adherence to stainless steel. During this treatment, a target surface was sandblasted and the resultant dislocation cells in the surface layer were turned into nanosized grains by a subsequent recovery treatment in air. This process generated a more protective oxide film that blocked the electron exchange or reduced the surface activity more effectively. As a result, the biofilm's adherence to the treated surface was markedly minimized. A synthetic peptide was utilized as a substitute of biofilms to evaluate the adhesion between a treated steel surface and biofilms using an atomic force microscope (AFM) through measuring the adhesive force between the target surface and a peptide-coated AFM tip. It was shown that the adhesive force decreased with a decrease in the grain size of the steel. The corresponding surface electron work function (EWF) of the steel was also measured, which showed a trend of variation in EWF with the grain size, consistent with corresponding changes in the adhesive force

  18. Evaluation of mechanically alloyed Cu-based powders as filler alloy for brazing tungsten to a reduced activation ferritic-martensitic steel

    Science.gov (United States)

    de Prado, J.; Sánchez, M.; Ureña, A.

    2017-07-01

    80Cu-20Ti powders were evaluated for their use as filler alloy for high temperature brazing of tungsten to a reduced activation ferritic/martensitic steel (Eurofer), and its application for the first wall of the DEMO fusion reactor. The use of alloyed powders has not been widely considered for brazing purposes and could improve the operational brazeability of the studied system due to its narrower melting range, determined by DTA analysis, which enhances the spreading capabilities of the filler. Ti contained in the filler composition acts as an activator element, reacting and forming several interfacial layers at the Eurofer-braze, which enhances the wettability properties and chemical interaction at the brazing interface. Brazing thermal cycle also activated the diffusion phenomena, which mainly affected to the Eurofer alloying elements causing in it a softening band of approximately 400 μm of thickness. However, this softening effect did not degrade the shear strength of the brazed joints (94 ± 23 MPa), because failure during testing was always located at the tungsten-braze interface.

  19. Evaluation of mechanically alloyed Cu-based powders as filler alloy for brazing tungsten to a reduced activation ferritic-martensitic steel

    Energy Technology Data Exchange (ETDEWEB)

    Prado, J. de, E-mail: javier.deprado@urjc.es; Sánchez, M.; Ureña, A.

    2017-07-15

    80Cu-20Ti powders were evaluated for their use as filler alloy for high temperature brazing of tungsten to a reduced activation ferritic/martensitic steel (Eurofer), and its application for the first wall of the DEMO fusion reactor. The use of alloyed powders has not been widely considered for brazing purposes and could improve the operational brazeability of the studied system due to its narrower melting range, determined by DTA analysis, which enhances the spreading capabilities of the filler. Ti contained in the filler composition acts as an activator element, reacting and forming several interfacial layers at the Eurofer-braze, which enhances the wettability properties and chemical interaction at the brazing interface. Brazing thermal cycle also activated the diffusion phenomena, which mainly affected to the Eurofer alloying elements causing in it a softening band of approximately 400 μm of thickness. However, this softening effect did not degrade the shear strength of the brazed joints (94 ± 23 MPa), because failure during testing was always located at the tungsten-braze interface. - Highlights: •W-Eurofer brazed joints, manufactured using Cu-based mechanically alloyed powders as filler is proposed. •The benefits derivate from the alloyed composition could improve the operational brazeability of the studied system. •Tested pre-alloyed fillers have a more homogeneous melting stage which enhances its spreading and flowing capabilities. •This behaviour could lead to work with higher heating rates and lower brazing temperatures.

  20. Synergistic effects on dislocation loops in reduced-activation martensitic steel investigated by single and sequential hydrogen/helium ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Weiping [Hubei Nuclear Solid Physics Key Laboratory, Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Luo, Fengfeng [Hubei Nuclear Solid Physics Key Laboratory, Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Institute of Applied Physics, Jiangxi Academy of Sciences, Nanchang 330029 (China); Yu, Yanxia; Zheng, Zhongcheng; Shen, Zhenyu [Hubei Nuclear Solid Physics Key Laboratory, Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Guo, Liping, E-mail: guolp@whu.edu.cn [Hubei Nuclear Solid Physics Key Laboratory, Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Ren, Yaoyao [Center for Electron Microscopy, Wuhan University, Wuhan 430072 (China); Suo, Jinping [State Key Laboratory of Mould Technology, Institute of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2016-10-15

    Single-beam and sequential-beam irradiations were performed to investigate the H/He synergistic effect on dislocation loops in reduced-activation ferritic/martensitic (RAFM) steels. The irradiations were carried out with 10 keV H{sup +}, 18 keV He{sup +} and 160 keV Ar{sup +}, alone and in combination at 723 K. He{sup +} single-beam irradiation induced much larger dislocation loops than that induced by both H{sup +} and Ar{sup +} single-beam irradiation. H{sup +} post-irradiation after He{sup +} irradiation further increased the size of dislocation loops, whilst He{sup +} post-irradiation or Ar{sup +} post-irradiation following H{sup +} irradiation only slightly increased the size of dislocation loops. The experiment results indicate that pre-implanted H{sup +} can drastically inhibit the growth while post-implanted H{sup +} can significantly enhance the growth of dislocation loops induced by He{sup +} irradiation. The mechanisms behind the complex synergistic phenomena between H and He and the different roles that H and He played in the growth of dislocation loops are discussed.

  1. Properties of Hooked Steel Fibers Reinforced Alkali Activated Material Concrete

    Directory of Open Access Journals (Sweden)

    Faris M. A.

    2016-01-01

    Full Text Available In this study, alkali activated material was produced by using Class F fly ash from Manjung power station, Lumut, Perak, Malaysia. Fly ash then was activated by alkaline activator which is consisting of sodium silicate (Na2SiO3 and sodium hydroxide (NaOH. Hooked end steel fibers were added into the alkali activated material system with percentage vary from 0 % – 5 %. Chemical compositions of fly ash were first analyzed by using x-ray fluorescence (XRF. All hardened alkali activated material samples were tested for density, workability, and compression after 28 days. Results show a slight increase of density with the addition of steel fibers. However, the workability was reduced with the addition of steel fibers content. Meanwhile, the addition of steel fibers shows the improvement of compressive strength which is about 19 % obtained at 3 % of steel fibers addition.

  2. Influence of Tool Rotational Speed and Post-Weld Heat Treatments on Friction Stir Welded Reduced Activation Ferritic-Martensitic Steel

    Science.gov (United States)

    Manugula, Vijaya L.; Rajulapati, Koteswararao V.; Reddy, G. Madhusudhan; Mythili, R.; Bhanu Sankara Rao, K.

    2017-08-01

    The effects of tool rotational speed (200 and 700 rpm) on evolving microstructure during friction stir welding (FSW) of a reduced activation ferritic-martensitic steel (RAFMS) in the stir zone (SZ), thermo-mechanically affected zone (TMAZ), and heat-affected zone (HAZ) have been explored in detail. The influence of post-weld direct tempering (PWDT: 1033 K (760 °C)/ 90 minutes + air cooling) and post-weld normalizing and tempering (PWNT: 1253 K (980 °C)/30 minutes + air cooling + tempering 1033 K (760 °C)/90 minutes + air cooling) treatments on microstructure and mechanical properties has also been assessed. The base metal (BM) microstructure was tempered martensite comprising Cr-rich M23C6 on prior austenite grain and lath boundaries with intra-lath precipitation of V- and Ta-rich MC precipitates. The tool rotational speed exerted profound influence on evolving microstructure in SZ, TMAZ, and HAZ in the as-welded and post-weld heat-treated states. Very high proportion of prior austenitic grains and martensite lath boundaries in SZ and TMAZ in the as-welded state showed lack of strengthening precipitates, though very high hardness was recorded in SZ irrespective of the tool speed. Very fine-needle-like Fe3C precipitates were found at both the rotational speeds in SZ. The Fe3C was dissolved and fresh precipitation of strengthening precipitates occurred on both prior austenite grain and sub-grain boundaries in SZ during PWNT and PWDT. The post-weld direct tempering caused coarsening and coalescence of strengthening precipitates, in both matrix and grain boundary regions of TMAZ and HAZ, which led to inhomogeneous distribution of hardness across the weld joint. The PWNT heat treatment has shown fresh precipitation of M23C6 on lath and grain boundaries and very fine V-rich MC precipitates in the intragranular regions, which is very much similar to that prevailed in BM prior to FSW. Both the PWDT and PWNT treatments caused considerable reduction in the hardness of SZ

  3. Pressure Vessel Steel Research: Belgian Activities

    International Nuclear Information System (INIS)

    Van Walle, E.; Fabry, A.; Ait Abderrahim, H.; Chaouadi, R.; D'hondt, P.; Puzzolante, J.L.; Van de Velde, J.; Van Ransbeeck, T.; Gerard, R.

    1994-03-01

    A review of the Belgian research activities on Nuclear Reactor Pressure Vessel Steels (RPVS) and on related Neutron Dosimetry Aspects is presented. Born out of the surveillance programmes of the Belgian nuclear power plants, this research has lead to the development of material saving techniques, like reconstitution and miniaturization, and to improved neutron dosimetry techniques. A physically- justified RPVS fracture toughness indexation methodology, supported by micro-mechanistic modelling, is based on the elaborate use of the instrumented Charpy impact signal. Computational tools for neutron dosimetry allow to reduce the uncertainties on surveillance capsule fluences significantly

  4. Pressure Vessel Steel Research: Belgian Activities

    Energy Technology Data Exchange (ETDEWEB)

    Van Walle, E; Fabry, A; Ait Abderrahim, H; Chaouadi, R; D` hondt, P; Puzzolante, J L; Van de Velde, J; Van Ransbeeck, T [Centre d` Etude de l` Energie Nucleaire, Mol (Belgium); Gerard, R [TRACTEBEL, Brussels (Belgium)

    1994-03-01

    A review of the Belgian research activities on Nuclear Reactor Pressure Vessel Steels (RPVS) and on related Neutron Dosimetry Aspects is presented. Born out of the surveillance programmes of the Belgian nuclear power plants, this research has lead to the development of material saving techniques, like reconstitution and miniaturization, and to improved neutron dosimetry techniques. A physically- justified RPVS fracture toughness indexation methodology, supported by micro-mechanistic modelling, is based on the elaborate use of the instrumented Charpy impact signal. Computational tools for neutron dosimetry allow to reduce the uncertainties on surveillance capsule fluences significantly.

  5. Inhibition of Bio corrosion of steel coupon by sulphate reducing ...

    African Journals Online (AJOL)

    ADOWIE PERE

    Inhibition of Bio corrosion of steel coupon by sulphate reducing bacteria and Iron oxidizing bacteria using .... Ethanol for 24 h. The extract was ... with distilled water to get a zero reading from the meter before .... Ethanol extract of musa species peels as a green corrosion ... Eco friendly extract of banana peel as corrosion ...

  6. Microbial corrosion of carbon steel by sulfate-reducing bacteria:

    DEFF Research Database (Denmark)

    Nielsen, Lars Vendelbo; Hilbert, Lisbeth Rischel

    1997-01-01

    Electrochemical measurements (EIS and DC-polarisation curves) have been conducted on carbon steel coupons exposed in SRB-active environments. Results from EIS measurements show that very large interfacial capacities are found in such systems, and consequently high capacitive currents are to be ex...

  7. Mechanical characterization of a reduced activation 9 Cr ferritic/martensitic steel of spanish production; Caracterizacion mecanica de un acero ferritico/martenitico de activacion reducida de produccion espanola

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, D.; Serrano, M.

    2012-07-01

    This paper shows the first results concerning the characterization of two heats of a reduced activation 9 Cr ferritic/martensitic steel (RAFM) made in Spain, called AF1B and AF2A. The results of this characterization are compared with their European counterparts, EUROFER97-2, which was chosen as reference material. All activities described were performed in the Structural Materials Unit of CIEMAT, within the national project TECNO-FUS CONSOLIDER INGENIO.The two Spanish heats have the same production process and heat treatment. Both heats have a similar tensile behaviour similar to EUROFER97-2, but on the other hand impact properties are lower. The microstructure of AF1B reveals large biphasic inclusions that affecting its mechanical properties, especially the impact properties. AF2A casting was free of these inclusions. (Author) 24 refs.

  8. Effect of machining on the deformability of steel in surface-active medium at lower temperatures

    International Nuclear Information System (INIS)

    Gusti, E.Ya.; Babej, Yu.I.

    1977-01-01

    The effect of some machining methods of carbon steel, chromium steel, and chromium nickel steel, and that of low temperatures on the principle characteristics of formability during impact bending in air and a surface-active environment have been studied. The temperature decrease from the ambient to -80 deg is shown to reduce steel formability as evaluated by deflection (f) and to increase the forming force. The variation of these characteristics with lowering temperature, however, is greatly affected by machining process conditions. The FRHT (Friction-Hardening Treatment) on the white layer assures minimum ductility losses, and increases steel strength at low temperatures both in air and in the surface-active environment

  9. Thermal expansion characteristics of Fe–9Cr–0.12C–0.56Mn–0.24V–1.38W–0.06Ta (wt.%) reduced activation ferritic–martensitic steel

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, Raju, E-mail: sraju@igcar.gov.in [Metallurgy & Materials Group, Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam 603102 (India); Tripathy, Haraprasanna; Rai, Arun Kumar; Hajra, Raj Narayan; Saibaba, Saroja; Jayakumar, Tammana [Metallurgy & Materials Group, Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam 603102 (India); Rajendra Kumar, Ellappan [TBM Division, Institute for Plasma Research (IPR), Gandhi Nagar (India)

    2015-04-15

    Highlights: • Lattice & bulk thermal expansion of RAFM steel characterized by HTXRD and dilatometry. • Mean thermal expansion of α-ferrite is 1.48 × 10{sup −5} K{sup −1}; that of γ-austenite, 2.4 × 10{sup −5} K{sup −1}. • Magnetism makes a small negative contribution to overall thermal expansion. - Abstract: The lattice and bulk thermal expansion behavior of an Indian version of reduced activation ferritic–martensitic (INRAFM) steel has been quantified using high temperature X-ray diffraction and dilatometry. The lattice parameter of tempered α-ferrite phase exhibited a smooth quadratic increase with temperature, while that of γ-austenite remained fairly linear up to 1273 K. The results suggest that α-ferrite + Carbides → γ-austenite transformation occurs upon continuous heating in the temperature range, 1146 ⩽ T ⩽ 1173 K. Further, this transformation is found to be accompanied by a reduction in average atomic volume. The mean linear thermal expansion coefficients of tempered α-ferrite and γ-austenite phases are estimated to be about 1.48 × 10{sup −5} and 2.4 × 10{sup −5} K{sup −1} respectively. The magnetic contribution to relative thermal dilatation (Δl/l{sub 298}){sub mag} is found to be small and negative, as compared to phonon contribution.

  10. Does carbonation of steel slag particles reduce their toxicity? An in vitro approach.

    Science.gov (United States)

    Ibouraadaten, Saloua; van den Brule, Sybille; Lison, Dominique

    2015-06-01

    Mineral carbonation can stabilize industrial residues and, in the steel industry, may contribute to simultaneously valorize CO2 emissions and slag. We hypothesized that, by restricting the leaching of metals of toxicological concern such as Cr and V, carbonation can suppress the toxicity of these materials. The cytotoxic activity (WST1 assay) of slag dusts collected from a stainless and a Linz-Donawitz (LD) steel plant, before and after carbonation, was examined in J774 macrophages. The release of Cr, V, Fe, Mn and Ni was measured after incubation in artificial lung fluids mimicking the extracellular and phagolysosomal milieu to which particles are confronted after inhalation. LD slag had the higher Fe, Mn and V content, and was more cytotoxic than stainless steel slag. The cytotoxic activity of LD but not of stainless dusts was reduced after carbonation. The cytotoxic activity of the dusts toward J774 macrophages necessitated a direct contact with the cells and was reduced in the presence of inhibitors of phagocytosis (cytochalasin D) or phagolysosome acidification (bafilomycin), pointing to a key role of metallic constituents released in phagolysosomes. This in vitro study supports a limited reduction of the cytotoxic activity of LD, but not of stainless, steel dusts upon carbonation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Activation volume of martensitic ODS steel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, D. W.; Noh, S.; Kim, T. K. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    Apparent activation volume as a function of temperature is 86b{sup 3}-42b{sup 3}. Activation volume decreases with increasing temperature. Activation volume changes scarcely with decreasing strain rate. Strain rate sensitivity increases with increasing temperature and decreasing strain rate. Nano-sized oxide dispersion strengthened (ODS) martensitic steel has a high strength, low thermal expansion coefficient, high thermal conductivity, and a good swelling resistance. Martensitic ODS steel is a candidate material for fuel cladding of sodium cooled fast breeder reactor (SFR). The plastic flow stress is determined through the interaction of dislocations with the obstacles encountered inside lattice. Dislocation movement through the lattice or past an obstacle requires surmounting of the energy barrier by a combination of applied stress and thermal activation. The plastic deformation of materials is a thermally activated process dependent upon time, temperature, and strain rate. Characterization of the rate controlling mechanism for plastic deformation due to dislocation motion in crystalline materials is done by the assessment of activation volume based on thermal activation analysis.

  12. R and D status of China low activation martensitic steel

    International Nuclear Information System (INIS)

    Huang Qunying; Li Chunjing; Li Yanfen; Liu Shaojun; Wu Yican; Li Jiangang; Shan Yiyin; Yu Jinnan; Zhu Shengyun; Zhang Pinyuan; Yang Jianfeng; Han Fusheng; Kong Mingguang; Li Heqin; Muroga, T.; Nagasaka, T.

    2007-01-01

    The Reduced Activation Ferritic/Martensitic (RAFM) steel is considered as the primary candidate structural material for DEMO and the first fusion plant, and widely studied in the world. China low activation martensitic steel (CLAM) is being developed in Institute of Plasma Physics, Chinese Academy of Sciences, under wide collaboration with many other domestic and foreign institutes and universities. This paper summarized the main R and D progress on CLAM, which covered composition optimization of the CLAM, smelting and processing techniques, physical and mechanical property test and evaluation before and after irradiation, compatibility with liquid LiPb, welding techniques etc. Finally, further research and development, and the prospects on its application were stated. (authors)

  13. Thermal expansion characteristics of Fe-9Cr-0.12C-0.56Mn-0.24V-1.38W-0.06Ta (wt.%) reduced activation ferritic-martensitic steel

    Science.gov (United States)

    Subramanian, Raju; Tripathy, Haraprasanna; Rai, Arun Kumar; Hajra, Raj Narayan; Saibaba, Saroja; Jayakumar, Tammana; Rajendra Kumar, Ellappan

    2015-04-01

    The lattice and bulk thermal expansion behavior of an Indian version of reduced activation ferritic-martensitic (INRAFM) steel has been quantified using high temperature X-ray diffraction and dilatometry. The lattice parameter of tempered α-ferrite phase exhibited a smooth quadratic increase with temperature, while that of γ-austenite remained fairly linear up to 1273 K. The results suggest that α-ferrite + Carbides → γ-austenite transformation occurs upon continuous heating in the temperature range, 1146 ⩽ T ⩽ 1173 K. Further, this transformation is found to be accompanied by a reduction in average atomic volume. The mean linear thermal expansion coefficients of tempered α-ferrite and γ-austenite phases are estimated to be about 1.48 × 10-5 and 2.4 × 10-5 K-1 respectively. The magnetic contribution to relative thermal dilatation (Δl/l298)mag is found to be small and negative, as compared to phonon contribution.

  14. Alternatives to reduce corrosion of carbon steel storage drums

    International Nuclear Information System (INIS)

    Zirker, L.R.; Beitel, G.A.

    1995-11-01

    The major tasks of this research were (a) pollution prevention opportunity assessments on the overpacking operations for failed or corroded drums, (b) research on existing container corrosion data, (c) investigation of the storage environment of the new Resource Conservation and Recovery Act Type II storage modules, (d) identification of waste streams that demonstrate deleterious corrosion affects on drum storage life, and (e) corrosion test cell program development. Twenty-one waste streams from five US Department of Energy (DOE) sites within the DOE Complex were identified to demonstrate a deleterious effect to steel storage drums. The major components of these waste streams include acids, salts, and solvent liquids, sludges, and still bottoms. The solvent-based waste streams typically had the shortest time to failure: 0.5 to 2 years. The results of this research support the position that pollution prevention evaluations at the front end of a project or process will reduce pollution on the back end

  15. Fundamental Studies on the Electrochemical Behaviour of Carbon Steel Exposed in Sulphide and Sulphate-Reducing Environments

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    The aim of the report is to give a fundamental understanding of the response of different electrochemical techniques on carbon steel in a sulphide environment as well as in a biologically active sulphate-reducing environment (SRB). This will form the basis for further studies and for recommendati......The aim of the report is to give a fundamental understanding of the response of different electrochemical techniques on carbon steel in a sulphide environment as well as in a biologically active sulphate-reducing environment (SRB). This will form the basis for further studies...

  16. Achieving reduced fouling of cooling water exchangers with stainless steel tubes

    International Nuclear Information System (INIS)

    Iftikhar, A.; Mir, N.

    2010-01-01

    Good performance of cooling water heat exchangers plays a vital role in the over all energy efficiency of a chemical plant. Heavy fouling on carbon steel tubes of the cooling water exchangers was causing poor performance and frequent cleaning requirement. The carbon steel tubes were replaced with stainless steel tubes. Improved performance was achieved and cleaning frequency reduced. The paper covers the details of study and methodology applied for the above changes along with summary of results. (author)

  17. Impact of a nickel-reduced stainless steel implant on striated muscle microcirculation: a comparative in vivo study.

    Science.gov (United States)

    Kraft, C N; Burian, B; Perlick, L; Wimmer, M A; Wallny, T; Schmitt, O; Diedrich, O

    2001-12-05

    The impairment of skeletal muscle microcirculation by a biomaterial may have profound consequences. With moderately good physical and corrosion characteristics, implant-quality stainless steel is particularly popular in orthopedic surgery. However, due to the presence of a considerable amount of nickel in the alloy, concern has been voiced in respect to local tissue responses. More recently a stainless steel alloy with a significant reduction of nickel has become commercially available. We, therefore, studied in vivo nutritive perfusion and leukocytic response of striated muscle to this nickel-reduced alloy, and compared these results with those of the materials conventional stainless steel and titanium. Using the hamster dorsal skinfold chamber preparation and intravital microscopy, we could demonstrate that reduction of the nickel quantity in a stainless steel implant has a positive effect on local microvascular parameters. Although the implantation of a conventional stainless steel sample led to a distinct and persistent activation of leukocytes combined with disruption of the microvascular endothelial integrity, marked leukocyte extravasation, and considerable venular dilation, animals with a nickel-reduced stainless steel implant showed only a moderate increase of these parameters, with a clear tendency of recuperation. Titanium implants merely caused a transient increase of leukocyte-endothelial cell interaction within the first 120 min, and no significant change in macromolecular leakage, leukocyte extravasation, or venular diameter. Pending biomechanical and corrosion testing, nickel-reduced stainless steel may be a viable alternative to conventional implant-quality stainless steel for biomedical applications. Concerning tolerance by the local vascular system, titanium currently remains unsurpassed. Copyright 2001 John Wiley & Sons, Inc. J Biomed Mater Res 57: 404-412, 2001

  18. System for actively reducing sound

    NARCIS (Netherlands)

    Berkhoff, Arthur P.

    2005-01-01

    A system for actively reducing sound from a primary noise source, such as traffic noise, comprising: a loudspeaker connector for connecting to at least one loudspeaker for generating anti-sound for reducing said noisy sound; a microphone connector for connecting to at least a first microphone placed

  19. RESEARCH OF SYNERGETIC RELIABILITY OF PEARLITE-REDUCED STRUCTURAL STEEL 09G2FB

    Directory of Open Access Journals (Sweden)

    Gustov Yuriy Ivanovich

    2012-10-01

    Full Text Available The primary objective of the research is the synergetic reliability of perlite-reduced structural steel 09G2FB exposed to various thermal and mechanical treatments. In the aftermath of the above exposure, the steel in question has proved to assume a set of strength-related and plastic mechanical properties (σσδ and ψ.

  20. Alkali activated slag mortars provide high resistance to chloride-induced corrosion of steel

    Science.gov (United States)

    Criado, Maria; Provis, John L.

    2018-06-01

    The pore solutions of alkali-activated slag cements and Portland-based cements are very different in terms of their chemical and redox characteristics, particularly due to the high alkalinity and high sulfide content of alkali-activated slag cement. Therefore, differences in corrosion mechanisms of steel elements embedded in these cements could be expected, with important implications for the durability of reinforced concrete elements. This study assesses the corrosion behaviour of steel embedded in alkali-activated blast furnace slag (BFS) mortars exposed to alkaline solution, alkaline chloride-rich solution, water, and standard laboratory conditions, using electrochemical techniques. White Portland cement (WPC) mortars and blended cement mortars (white Portland cement and blast furnace slag) were also tested for comparative purposes. The steel elements embedded in immersed alkali-activated slag mortars presented very negative redox potentials and high apparent corrosion current values; the presence of sulfide reduced the redox potential, and the oxidation of the reduced sulfur-containing species within the cement itself gave an electrochemical signal that classical electrochemical tests for reinforced concrete durability would interpret as being due to steel corrosion processes. However, the actual observed resistance to chloride-induced corrosion was very high, as measured by extraction and characterisation of the steel at the end of a 9-month exposure period, whereas the steel embedded in white Portland cement mortars was significantly damaged under the same conditions.

  1. The microstructural stability and mechanical properties of two low activation martensitic steels

    International Nuclear Information System (INIS)

    Victoria, M.; Marmy, P.; Batawi, E.; Peters, J.; Briguet, C.; Rezai-Aria, F.; Gavillet, D.

    1996-01-01

    A desirable feature of future magnetically confined fusion reactors is the prospect of producing low level radioactive waste. In order to minimize the volume of radioactive material, in particular from the first wall and blanket structures, reduced long term activation alloys are being developed. Here, a low activation composition of a martensitic 9% Cr steel has been studied, based on the DIN (Deutsches Inst. fuer Normung) 1.4914 composition (MANET) but replacing Ni, Mo and Nb by the low activation elements W, V and Ta. Two casts were produced from high purity components, in which the effects of controlled additions of Mn (0.58 and 0.055 wt. %) and N (7 and 290 wt. ppm) were studied, so that the final compositions resulted in one cast with high Mn and low N (steel A) and the other with the opposite conditions (steel B). The two steels were evaluated in terms of structural stability and mechanical properties under tensile, fatigue and fracture toughness tests. It has been found that both alloys have a DBTT below room temperature, which in the case of the steel A is 70 K below that of MANET. Although the tensile strength is somewhat below that of the parent steel, both steels have longer fatigue life

  2. Study of sulphate-reducing bacteria corrosion in the weld joint for API X-70 steel

    Energy Technology Data Exchange (ETDEWEB)

    Flores, J. E.; Patino-Carachure, C.; Alfonso, I.; Rodriguez, J. A.; Rosas, G.

    2012-11-01

    The corrosion behavior originated by sulfate-reducing bacteria (SRB) was studied in two regions of welded API X-70 steel pipeline. The studies were focused on base material (BM) and heat affected zone (HAZ), from the internal region of the pipe. SRB were extracted from oil and grown in a Postgate medium. Corrosion was evaluated at 60 degree centigrade for times between 5 and 64 days. Potentiodynamic polarization curves, obtained by electrochemical techniques, indicated surface activation at short times. Structural and morphological characterizations were carried out by scanning electron microscopy (SEM) and optical microscopy (OM). H{sub 2}S concentration and pH were also measured. Results showed an important increase in the corrosion damage up to 20 days, influenced by the SRB activity, which lead to a maximum of H{sub 2}S (pH minimum). It was found a localized corrosion attack in the HAZ in a higher quantity compared to BM; and the formation of a thin film on the steel surface, originated by corrosion products and bacterial activity. (Author) 15 refs.

  3. Pushover Analysis of Steel Seismic Resistant Frames with Reduced Web Section and Reduced Beam Section Connections

    Directory of Open Access Journals (Sweden)

    Daniel Tomas Naughton

    2017-10-01

    Full Text Available The widespread brittle failure of welded beam-to-column connections caused by the 1994 Northridge and 1995 Kobe earthquakes highlighted the need for retrofitting measures effective in reducing the strength demand imposed on connections under cyclic loading. Researchers presented the reduced beam section (RBS as a viable option to create a weak zone away from the connection, aiding the prevention of brittle failure at the connection weld. More recently, an alternative connection known as a reduced web section (RWS has been developed as a potential replacement, and initial studies show ideal performance in terms of rotational capacity and ductility. This study performs a series of non-linear static pushover analyses using a modal load case on three steel moment-resisting frames of 4-, 8-, and 16-storeys. The frames are studied with three different connection arrangements; fully fixed moment connections, RBSs and RWSs, in order to compare the differences in capacity curves, inter-storey drifts, and plastic hinge formation. The seismic-resistant connections have been modeled as non-linear hinges in ETABS, and their behavior has been defined by moment-rotation curves presented in previous recent research studies. The frames are displacement controlled to the maximum displacement anticipated in an earthquake with ground motions having a 2% probability of being exceeded in 50 years. The study concludes that RWSs perform satisfactorily when compared with frames with fully fixed moment connections in terms of providing consistent inter-storey drifts without drastic changes in drift between adjacent storeys in low- to mid-rise frames, without significantly compromising the overall strength capacity of the frames. The use of RWSs in taller frames causes an increase in inter-storey drifts in the lower storeys, as well as causing a large reduction in strength capacity (33%. Frames with RWSs behave comparably to frames with RBSs and are deemed a suitable

  4. Effect of heat treatment and irradiation temperature on mechanical properties and structure of reduced-activation Cr-W-V steels of bainitic, martensitic, and martensitic-ferritic classes

    International Nuclear Information System (INIS)

    Gorynin, I.V.; Rybin, V.V.; Kursevich, I.P.; Lapin, A.N.; Nesterova, E.V.; Klepikov, E.Yu.

    2000-01-01

    Effects of molybdenum replacement by tungsten in steels of the bainitic, martensitic, and martensitic-ferritic classes containing 2.5%, 8% and 11% Cr, respectively, were investigated. The phase composition and structure of the bainitic steels were varied by changing the cooling rates from the austenitization temperature (from values typical for normalization up to V=3.3 x 10 -2 deg. C/s) and then tempering. The steels were irradiated to a fluence of 4x10 23 n/m 2 (≥0.5 MeV) at 270 deg. C and to fluences of 1.3x10 23 and 1.2x10 24 n/m 2 (≥0.5 MeV) at 70 deg. C. The 2.5Cr-1.4WV and 8Cr-1.5WV steels have shown lower values of the shifts in ductile-brittle transition temperature (DBTT) under irradiation in comparison with corresponding Cr-Mo steels. Radiation embrittlement at elevated irradiation temperature was lowest in bainitic 2.5Cr-1.4WV steel and martensitic-ferritic 11Cr-1.5WV steel. The positive effect of molybdenum replacement by tungsten at irradiation temperature ∼300 deg. C is reversed at T irr =70 deg. C

  5. Microstructure and mechanical properties of unirradiated low activation ferritic steel

    International Nuclear Information System (INIS)

    Hsu, C.Y.; Lechtenberg, T.A.

    1986-01-01

    Transmission electron micrographs of normalized and tempered 9Cr-2.5W-0.3V-0.15C low activation ferritic steel showed tempered lath-type martensite with precipitation of rod and plate-like carbides at lath and grain boundaries. X-ray diffraction analysis of the extracted replicas revealed nearly 100% M 23 C 6 carbides (a=1.064 nm), with no indication of Fe 2 W-type Laves phase even after thermal aging at 600 0 C/1000 h. Thermal aging increased the number density of rod-like M 23 C 6 along prior austenite grain boundaries and martensite lath boundaries. The elevated-temperature tensile strengths of this steel are about 10% higher than the average strengths of commercial heats of 9Cr-1Mo and modified 9Cr-1Mo steels up to 650 0 C, with equivalent uniform elongation and ∝50% decrease in total elongation. The DBTT was determined to be -25 0 C which is similar to other 9Cr-1Mo steels. Fractographic examination of tensile tested specimens shows a mixed mode of equiaxed and elongated dimples at test temperatures above 400 0 C. Modification of the Ga3X alloy composition for opimization of materials properties is discussed. However, the proposed low activation ferritic steel shows the promise of improved mechanical properties over 9Cr-1Mo steels. (orig.)

  6. Inhibition of bio corrosion of steel coupon by sulphate reducing ...

    African Journals Online (AJOL)

    SRB) and Iron oxidizing bacteria (IOB) using Aloe vera (Aloe barbadensis) extract was tested. The water sample revealed a heterotrophic bacterial count of 1.7x103 cfu/ml for the sulphate reducing bacteria and 4.1x103 cfu/ml for the Iron oxidizing ...

  7. Food-safe modification of stainless steel food processing surfaces to reduce bacterial biofilms.

    Science.gov (United States)

    Awad, Tarek Samir; Asker, Dalal; Hatton, Benjamin D

    2018-06-11

    Biofilm formation on stainless steel (SS) surfaces of food processing plants, leading to foodborne illness outbreaks, is enabled by the attachment and confinement within microscale cavities of surface roughness (grooves, scratches). We report Foodsafe Oil-based Slippery Coatings (FOSCs) for food processing surfaces that suppress bacterial adherence and biofilm formation by trapping residual oil lubricant within these surface cavities to block microbial growth. SS surfaces were chemically functionalized with alkylphosphonic acid to preferentially wet a layer of food grade oil. FOSCs reduced the effective surface roughness, the adhesion of organic food residue, and bacteria. FOSCs significantly reduced Pseudomonas aeruginosa biofilm formation on standard roughness SS-316 by 5 log CFU cm-2, and by 3 log CFU cm-2 for mirror-finished SS. FOSCs also enhanced surface cleanability, which we measured by bacterial counts after conventional detergent cleaning. Importantly, both SS grades maintained their anti-biofilm activity after erosion of the oil layer by surface wear with glass beads, which suggests there is a residual volume of oil that remains to block surface cavity defects. These results indicate the potential of such low-cost, scalable approaches to enhance the cleanability of SS food processing surfaces and improve food safety by reducing biofilm growth.

  8. Reducing Staphylococcus aureus biofilm formation on stainless steel 316L using functionalized self-assembled monolayers.

    Science.gov (United States)

    Kruszewski, Kristen M; Nistico, Laura; Longwell, Mark J; Hynes, Matthew J; Maurer, Joshua A; Hall-Stoodley, Luanne; Gawalt, Ellen S

    2013-05-01

    Stainless steel 316L (SS316L) is a common material used in orthopedic implants. Bacterial colonization of the surface and subsequent biofilm development can lead to refractory infection of the implant. Since the greatest risk of infection occurs perioperatively, strategies that reduce bacterial adhesion during this time are important. As a strategy to limit bacterial adhesion and biofilm formation on SS316L, self-assembled monolayers (SAMs) were used to modify the SS316L surface. SAMs with long alkyl chains terminated with hydrophobic (-CH3) or hydrophilic (oligoethylene glycol) tail groups were used to form coatings and in an orthogonal approach, SAMs were used to immobilize gentamicin or vancomycin on SS316L for the first time to form an "active" antimicrobial coating to inhibit early biofilm development. Modified SS316L surfaces were characterized using surface infrared spectroscopy, contact angles, MALDI-TOF mass spectrometry and atomic force microscopy. The ability of SAM-modified SS316L to retard biofilm development by Staphylococcus aureus was functionally tested using confocal scanning laser microscopy with COMSTAT image analysis, scanning electron microscopy and colony forming unit analysis. Neither hydrophobic nor hydrophilic SAMs reduced biofilm development. However, gentamicin-linked and vancomycin-linked SAMs significantly reduced S. aureus biofilm formation for up to 24 and 48 h, respectively. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Sulfate-reducing bacteria inhabiting natural corrosion depostis from marine steel structures

    NARCIS (Netherlands)

    Païssé, S.; Ghiglione, J.-F.; Marty, F.; Abbas, B.; Gueuné, H.; Sanchez Amaya, J.; Muyzer, G.; Quillet, L.

    2013-01-01

    In the present study, investigations were conducted on natural corrosion deposits to better understand the role of sulfate-reducing bacteria (SRB) in the accelerated corrosion process of carbon steel sheet piles in port environments. We describe the abundance and diversity of total and metabolically

  10. Influence of calcareous deposit on corrosion behavior of Q235 carbon steel with sulfate-reducing bacteria

    Science.gov (United States)

    Zhang, Jie; Li, Xiaolong; Wang, Jiangwei; Xu, Weichen; Duan, Jizhou; Chen, Shougang; Hou, Baorong

    2017-12-01

    Cathodic protection is a very effective method to protect metals, which can form calcareous deposits on metal surface. Research on the interrelationship between fouling organism and calcareous deposits is very important but very limited, especially sulfate-reducing bacteria (SRB). SRB is a kind of very important fouling organism that causes microbial corrosion of metals. A study of the influence of calcareous deposit on corrosion behavior of Q235 carbon steel in SRB-containing culture medium was carried out using electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and surface spectroscopy (EDS). The calcareous deposit was formed with good crystallinity and smooth surface under the gradient current density of -30 μA cm-2 in natural seawater for 72 h. Our results can help elucidate the formation of calcareous deposits and reveal the interrelationship between SRB and calcareous deposits under cathodic protection. The results indicate that the corrosion tendency of carbon steel was obviously affected by Sulfate-reducing Bacteria (SRB) metabolic activity and the calcareous deposit formed on the surface of carbon steel under cathodic protection was favourable to reduce the corrosion rate. Calcareous deposits can promote bacterial adhesion before biofilm formation. The results revealed the interaction between biofouling and calcareous deposits, and the anti-corrosion ability was enhanced by a kind of inorganic and organic composite membranes formed by biofilm and calcareous deposits.

  11. Detection of Interfacial Debonding in a Rubber-Steel-Layered Structure Using Active Sensing Enabled by Embedded Piezoceramic Transducers.

    Science.gov (United States)

    Feng, Qian; Kong, Qingzhao; Jiang, Jian; Liang, Yabin; Song, Gangbing

    2017-09-01

    Rubber-steel-layered structures are used in many engineering applications. Laminated rubber-steel bearing, as a type of seismic isolation device, is one of the most important applications of the rubber-steel-layered structures. Interfacial debonding in rubber-steel-layered structures is a typical failure mode, which can severely reduce their load-bearing capacity. In this paper, the authors developed a simple but effective active sensing approach using embedded piezoceramic transducers to provide an in-situ detection of the interfacial debonding between the rubber layers and steel plates. A sandwiched rubber-steel-layered specimen, consisting of one rubber layer and two steel plates, was fabricated as the test specimen. A novel installation technique, which allows the piezoceramic transducers to be fully embedded into the steel plates without changing the geometry and the surface conditions of the plates, was also developed in this research. The active sensing approach, in which designed stress waves can propagate between a pair of the embedded piezoceramic transducers (one as an actuator and the other one as a sensor), was employed to detect the steel-rubber debonding. When the rubber-steel debonding occurs, the debonded interfaces will attenuate the propagating stress wave, so that the amplitude of the received signal will decrease. The rubber-steel debonding was generated by pulling the two steel plates in opposite directions in a material-testing machine. The changes of the received signal before and after the debonding were characterized in a time domain and further quantified by using a wavelet packet-based energy index. Experiments on the healthy rubber-steel-layered specimen reveal that the piezoceramic-induced stress wave can propagate through the rubber layer. The destructive test on the specimen demonstrates that the piezoceramic-based active sensing approach can effectively detect the rubber-steel debonding failure in real time. The active sensing

  12. Steel

    International Nuclear Information System (INIS)

    Zorev, N.N.; Astafiev, A.A.; Loboda, A.S.; Savukov, V.P.; Runov, A.E.; Belov, V.A.; Sobolev, J.V.; Sobolev, V.V.; Pavlov, N.M.; Paton, B.E.

    1977-01-01

    Steels also containing Al, N and arsenic, are suitable for the construction of large components for high-power nuclear reactors due to their good mechanical properties such as good through-hardening, sufficiently low brittleness conversion temperature and slight displacement of the latter with neutron irradiation. Defined steels and their properties are described. (IHOE) [de

  13. Microbiologically influenced corrosion of carbon steel in the presence of sulphate reducing bacteria

    International Nuclear Information System (INIS)

    Tunaru, M.; Velciu, L.; Mihalache, M.; Laurentiu, P.

    2016-01-01

    Sulphate-reducing bacteria (SRB) are the most important organisms in microbiologically induced corrosion. In this context, the paper presents an assessment (by experimental tests) of the behaviour of carbon steel samples (SA106gr.B) in SRB media. Some of samples were immersed in microbial environment in order microbiological analysis of their surface and another part was used to perform accelerated electrochemical tests to determine electrochemical parameters for the system carbon steel / microbial medium (corrosion rate, the polarization resistance of the surface, susceptibility to pitting corrosion). The surfaces of the tested samples were analyzed using the optical and electronic microscope, and emphasized the role of bacteria in the development of biofilms under which appeared characteristics of corrosion attack. The correlation of all results confirmed that SRB accelerated the localized corrosion of the surfaces of SA 106gr.B carbon steel. (authors)

  14. Properties of Hooked Steel Fibers Reinforced Alkali Activated Material Concrete

    OpenAIRE

    Faris M. A.; Abdullah Mohd Mustafa Al Bakri; Ismail Khairul Nizar; Muniandy Ratnasamy; Mahmad Nor Aiman; Putra Jaya Ramadhansyah; Waried Wazien A. Z.

    2016-01-01

    In this study, alkali activated material was produced by using Class F fly ash from Manjung power station, Lumut, Perak, Malaysia. Fly ash then was activated by alkaline activator which is consisting of sodium silicate (Na2SiO3) and sodium hydroxide (NaOH). Hooked end steel fibers were added into the alkali activated material system with percentage vary from 0 % – 5 %. Chemical compositions of fly ash were first analyzed by using x-ray fluorescence (XRF). All hardened alkali activated materia...

  15. A XPS Study of the Passivity of Stainless Steels Influenced by Sulfate-Reducing Bacteria.

    Science.gov (United States)

    Chen, Guocun

    The influence of sulfate-reducing bacteria (SRB) on the passivity of type 304 and 317L stainless steels (SS) was investigated by x-ray photoelectron spectroscopy (XPS), microbiological and electrochemical techniques. Samples were exposed to SRB, and then the resultant surfaces were analyzed by XPS, and the corrosion resistance by potentiodynamic polarization in deaerated 0.1 M HCl. To further understand their passivity, the SRB-exposed samples were analyzed by XPS after potentiostatic polarization at a passive potential in the hydrochloric solution. The characterization was performed under two surface conditions: unrinsed and rinsed by deaerated alcohol and deionized water. Comparisons were made with control samples immersed in uninoculated medium. SRB caused a severe loss of the passivity of 304 SS through sulfide formation and possible additional activation to form hexavalent chromium. The sulfides included FeS, FeS_2, Cr_2S _3, NiS and possibly Fe_ {rm 1-x}S. The interaction took place nonuniformly, resulting in undercutting of the passive film and preferential hydration of inner surface layers. The bacterial activation of the Cr^{6+ }^ecies was magnified by subsequent potentiostatic polarization. In contrast, 317L SS exhibited a limited passivity. The sulfides were formed mainly in the outer layers. Although Cr^{6+}^ecies were observed after the exposure, they were dissolved upon polarization. Since 317L SS has a higher Mo content, its higher passivity was ascribed to Mo existing as molybdate on the surface and Mo^{5+} species in the biofilm. Consequently, the interaction of SRB with Mo was studied. It was observed that molybdate could be retained on the surfaces of Mo coupons by corrosion products. In the presence of SRB, however, a considerable portion of the molybdate interacted with intermediate sulfur -containing proteins, forming Mo(V)-S complexes and reducing bacterial growth and sulfate reduction. The limited insolubility of the Mo(V)-S complexes in 0

  16. Both sulfate-reducing bacteria and Enterobacteriaceae take part in marine biocorrosion of carbon steel.

    Science.gov (United States)

    Bermont-Bouis, D; Janvier, M; Grimont, P A D; Dupont, I; Vallaeys, T

    2007-01-01

    In order to evaluate the part played in biocorrosion by microbial groups other than sulfate-reducing bacteria (SRB), we characterized the phylogenetic diversity of a corrosive marine biofilm attached to a harbour pile structure as well as to carbon steel surfaces (coupons) immersed in seawater for increasing time periods (1 and 8 months). We thus experimentally checked corroding abilities of defined species mixtures. Microbial community analysis was performed using both traditional cultivation techniques and polymerase chain reaction cloning-sequencing of 16S rRNA genes. Community structure of biofilms developing with time on immersed coupons tended to reach after 8 months, a steady state similar to the one observed on a harbour pile structure. Phylogenetic affiliations of isolates and cloned 16S rRNA genes (rrs) indicated that native biofilms (developing after 1-month immersion) were mainly colonized by gamma-proteobacteria. Among these, Vibrio species were detected in majority with molecular methods while cultivation techniques revealed dominance of Enterobacteriaceae such as Citrobacter, Klebsiella and Proteus species. Conversely, in mature biofilms (8-month immersion and pile structure), SRB, and to a lesser extent, spirochaetes were dominant. Corroding activity detection assays confirmed that Enterobacteriaceae (members of the gamma-proteobacteria) were involved in biocorrosion of metallic material in marine conditions. In marine biofilms, metal corrosion may be initiated by Enterobacteriaceae.

  17. Cathodic protection of XL 52 steel under the influence of sulfate reducing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Esquivel, R. Garcia [Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas No. 152, Col. San Bartolo Atepehuacan, Mexico, D.F. 07730 (Mexico); Departamento de lngenieria Metalurgica, Facultad de Quimica, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, 04510 Mexico, D.F. (Mexico); Olivares, G. Zavala; Gayosso, M.J. Hernandez; Trejo, A. Gayosso [Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas No. 152, Col. San Bartolo Atepehuacan, Mexico, D.F. 07730 (Mexico)

    2011-01-15

    The effect of sulfate reducing bacteria (SRB) upon the cathodic protection of XL 52 steel was determined, in order to identify if the potential value of -0.950 V versus copper/copper sulfate electrode is good enough to protect the metal surface. During the experiments, different operational parameters were monitored: hydrogen sulfide production, iron concentration, electrolyte alkalinity, microorganisms' population, as well as the metal surface damage. At the same time, the corrosion rate was determined using two electrochemical techniques: polarization resistance (PR) and electrochemical impedance spectroscopy (EIS). According to the results, it was observed that the protection potential of -0.950 V versus copper/copper sulfate electrode is not enough to control the microbiologically induced corrosion. This situation is reinforced by the fact that significant iron concentration was found in the electrolyte. The microbiological activity is not affected by the protection potential. On the contrary, the population growth is slightly strengthened. The alkalinity generated by the applied potential did not stop the SRB growth. A type of localized corrosion was developed during the experiments with microorganisms, even when the protection potential was applied to the system. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Electrodeposited Reduced Graphene Oxide Films on Stainless Steel, Copper, and Aluminum for Corrosion Protection Enhancement

    OpenAIRE

    Abdulkareem Mohammed Ali Al-Sammarraie; Mazin Hasan Raheema

    2017-01-01

    The enhancement of corrosion protection of metals and alloys by coating with simple, low cost, and highly adhered layer is still a main goal of many workers. In this research graphite flakes converted into graphene oxide using modified Hammers method and then reduced graphene oxide was electrodeposited on stainless steel 316, copper, and aluminum for corrosion protection application in seawater at four temperatures, namely, 20, 30, 40, and 50°C. All corrosion measurements, kinetics, and therm...

  19. Production and qualification for fusion applications, a steel of low activity ferritic-martensitic ASTURFER; Produccion y cualificacion, para aplicaciones de fusion, de un acero de baja actividad ferritico-martensitico, ASTURFER

    Energy Technology Data Exchange (ETDEWEB)

    Moran, A.; Belzunce, J.; Artimez, J. M.

    2011-07-01

    This article details the work carried out in the design and development pilot plant scale of a steel ferritic-martensitic of reduced activity, Asturfer, with a chemical composition and metallurgical properties similar to steel Eurofer. We describe the different stages of steel production and the results of the characterizations made in the context of an extensive test program.

  20. Open Circuit Potential Study of Stainless Steel in Environment Containing Marine Sulphate-Reducing Bacteria

    International Nuclear Information System (INIS)

    Fathul Karim Sahrani; Madzlan Abd. Aziz; Zaharah Ibrahim; Adibah Yahya

    2008-01-01

    The corrosion potential of AISI 304 stainless steel coupons influenced by sulphate-reducing bacteria (SRB) has been studied. Pure colony of SRB was isolated from the Malaysia Marine and Heavy Engineering, Pasir Gudang, Johor. Open circuit potential measurements were carried out in variable types of culturing solutions with SRB1, SRB2, combination of SRB1 and SRB2 and without SRBs inoculated. Results showed that the corrosion potential, E oc increased in the presence of SRBs (in pure and mixed culture) compared to that of control. EDS analysis showed the strong peak of sulphur in coupon containing SRB cultures compared to the control. ESEM data showed that the high density cell of SRBs were associated with corroding sections of surface steel comparing with non-corroding sections for coupons immersed in VMNI medium containing SRBs. (author)

  1. Carbon steel corrosion induced by sulphate-reducing bacteria in artificial seawater: electrochemical and morphological characterizations

    Energy Technology Data Exchange (ETDEWEB)

    Paula, Mariana Silva de; Goncalves, Marcia Monteiro Machado; Rola, Monick Alves da Cruz; Maciel, Diana Jose; Senna, Lilian Ferreira de; Lago, Dalva Cristina Baptista do, E-mail: sdp.mari@gmail.com, E-mail: marciamg@uerj.br, E-mail: monickcruz@yahoo.com.br, E-mail: dijmaciel@gmail.com, E-mail: lsenna@uerj.br, E-mail: dalva@uerj.br [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil). Instituto de Quimica

    2016-10-15

    In this work, the corrosion behavior of carbon steel AISI 1020 was evaluated in artificial seawater in the presence of mixed sulfate-reducing bacteria (SRB) culture isolated from the rust of a pipeline. The corrosion evaluation was performed by electrochemical techniques (open circuit potential (E{sub ocp}), polarization curves and electrochemical impedance spectroscopy (EIS)), while the formation of a biofilm and corrosion products were observed by scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDS). The presence of SRB in the medium shifted the open circuit potential to more positive values and increased the corrosion rate of the steel. Electrochemical and morphological techniques confirmed the presence of a biofilm on the steel surface. EDS spectra data showed the presence of sulfur in the corrosion products. After removing the biofilm, localized corrosion was observed on the surface, confirming that localized corrosion had occurred. The biogenic sulfide may lead to the formation of galvanic cells and contributes to cathodic depolarization. (author)

  2. Growth characteristics of thermophile sulfate-reducing bacteria and its effect on carbon steel

    Energy Technology Data Exchange (ETDEWEB)

    Liu, T.; Liu, H.; Hu, Y.; Zhou, L.; Zheng, B. [Department of Chemistry and Engineering, Huazhong University of Science and Technology, Wuhan (China)

    2009-03-15

    Sulfate-reducing bacteria (SRB) have been identified as the main corrosive microorganisms causing unpredictable failure of materials. In this present work, a strain of thermophile SRB isolated from Bohai oilfield of China has been characterized and preliminarily identified. Furthermore, its effects on carbon steel at 60 C in SRB culture media were studied by electrochemical methods such as potentiodynamic polarization and electrochemical impedance spectroscopy (EIS), and weight loss measurements. The results show that the bacteria belong to Desulfotomaculum. The optimum growth temperature and pH of the bacteria were 60 C and 7.0, respectively. Weight loss measurements suggested that the corrosion rate of carbon steel in the culture media inoculated with thermophile SRB at 60 C was 2.2 times less than that at 37 C. At 60 C, SRB shifted the freely corroding potential of carbon steel toward a more positive value in the first 10 days, which later change to a negative value. Results obtained from potentiodynamic polarization and EIS were in good agreement. The changes in biofilm structure with increase in bacteria supply offers some kind of protection to the base material in the early culture days at 60 C. Subsequently, it accelerated corrosion. Energy dispersive spectrometry (EDS) and X-ray diffraction (XRD) methods indicate that corrosion products such as iron sulfides (FeS{sub x}) in biofilm play an important role in the biocorrosion process. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  3. Carbon steel corrosion induced by sulphate-reducing bacteria in artificial seawater: electrochemical and morphological characterizations

    International Nuclear Information System (INIS)

    Paula, Mariana Silva de; Goncalves, Marcia Monteiro Machado; Rola, Monick Alves da Cruz; Maciel, Diana Jose; Senna, Lilian Ferreira de; Lago, Dalva Cristina Baptista do

    2016-01-01

    In this work, the corrosion behavior of carbon steel AISI 1020 was evaluated in artificial seawater in the presence of mixed sulfate-reducing bacteria (SRB) culture isolated from the rust of a pipeline. The corrosion evaluation was performed by electrochemical techniques (open circuit potential (E_o_c_p), polarization curves and electrochemical impedance spectroscopy (EIS)), while the formation of a biofilm and corrosion products were observed by scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDS). The presence of SRB in the medium shifted the open circuit potential to more positive values and increased the corrosion rate of the steel. Electrochemical and morphological techniques confirmed the presence of a biofilm on the steel surface. EDS spectra data showed the presence of sulfur in the corrosion products. After removing the biofilm, localized corrosion was observed on the surface, confirming that localized corrosion had occurred. The biogenic sulfide may lead to the formation of galvanic cells and contributes to cathodic depolarization. (author)

  4. Study of sulphate-reducing bacteria corrosion in the weld joint for API X-70 steel

    Directory of Open Access Journals (Sweden)

    Flores, J. E.

    2012-10-01

    Full Text Available The corrosion behavior originated by sulfate-reducing bacteria (SRB was studied in two regions of welded API X-70 steel pipeline. The studies were focused on base material (BM and heat affected zone (HAZ, from the internal region of the pipe. SRB were extracted from oil and grown in a Postgate medium. Corrosion was evaluated at 60 °C for times between 5 and 64 days. Potentiodynamic polarization curves, obtained by electrochemical techniques, indicated surface activation at short times. Structural and morphological characterizations were carried out by scanning electron microscopy (SEM and optical microscopy (OM. H2S concentration and pH were also measured. Results showed an important increase in the corrosion damage up to 20 days, influenced by the SRB activity, which lead to a maximum of H2S (pH minimum. It was found a localized corrosion attack in the HAZ in a higher quantity compared to BM; and the formation of a thin film on the steel surface, originated by corrosion products and bacterial activity.

    El comportamiento ante la corrosión, originada por bacterias sulfato-reductoras (SRB, fue estudiado en dos regiones de un tubo de acero soldado API X-70. Los estudios se enfocaron en el material base (BM y la zona afectada térmicamente (HAZ, en la parte interna del tubo. Las SRB fueron extraídas del petróleo y cultivadas en un medio Postgate. El comportamiento a la corrosión fue evaluado a una temperatura de 60 °C, por periodos comprendidos entre 5 y 64 días. El análisis de las curvas de polarización potenciodinámicas, obtenidas por técnicas electroquímicas, indicó la activación de la superficie para tiempos cortos. La superficie fue caracterizada estructural y morfológicamente mediante microscopia electrónica de barrido (SEM, así como mediante microscopía óptica (OM. La concentración de H2S y el pH también fueron medidos. Los resultados mostraron un aumento importante de la corrosi

  5. Steel passive state stability in activated fly ash mortars

    Directory of Open Access Journals (Sweden)

    Fernández-Jiménez, A.

    2010-12-01

    Full Text Available The present study explores the behaviour of structural steel embedded in Portland cement (OPC mortars and NaOH- and NaOH-waterglass-activated fly ash, in the presence and absence of 2 % Cl- (CaCl2. Variations were determined in the corrosion potential (Ecorr, linear polarization resistance (Rp and corrosion current density (icorr under different environmental conditions (90 days at 95 % relative humidity (RH, 30 days at ≈ 30 % RH, 760 days at ≈ 95 % RH. In the absence of Cl-, fly ash mortars were able to passivate steel reinforcement, although the stability of the passive state in changing environmental conditions was found to depend heavily on the activating solution used. Steel corrosion in the presence of 2 % Cl- was observed to be similar to the corrosion reported for the material in OPC mortars.

    En el presente trabajo se estudia el comportamiento del acero estructural embebido en morteros de cemento Pórtland (OPC y de cenizas volantes activadas con NaOH y una mezcla de NaOH y waterglass, en ausencia y en presencia de un 2% de Cl- (CaCl2. Se determino la evolución del potencial de corrosión (Ecorr, la resistencia de polarización lineal (Rp y la intensidad de corrosión (icorr, variando las condiciones ambientales (90 días al 95% de humedad relativa (HR-30 días a ≈ 30% HR- 760 días a ≈ 95% HR. En ausencia de Cl- los morteros de cenizas volantes activadas pueden pasivar los refuerzos de acero, si bien la estabilidad del estado pasivo ante cambios en las condiciones ambientales parece mostrar una fuerte dependencia de la solución activadora empleada. En presencia de un 2% de Cl- los aceros se corroen mostrando en comportamiento similar al observado en morteros en base OPC.

  6. Determination of biocorrosion of low alloy steel by sulfate-reducing Desulfotomaculum sp. isolated from crude oil field

    Energy Technology Data Exchange (ETDEWEB)

    Cetin, D.; Doenmez, G. [Faculty of Science, Department of Biology, Ankara University, Tandogan, 06100, Ankara (Turkey); Bilgic, S. [Faculty of Science, Department of Chemistry, Ankara University, Tandogan, 06100, Ankara (Turkey); Doenmez, S. [Faculty of Engineering, Department of Food Engineering, Ankara University, Diskapi, 06110 Ankara (Turkey)

    2007-11-15

    In this study corrosion behavior of low alloy steel, in the presence of anaerobic sulfate-reducing Desulfotomaculum sp. which was isolated from an oil production well, was investigated. In order to determine corrosion rates and mechanisms, mass loss measurements and electrochemical polarization studies were performed without and with bacteria in the culture medium. Scanning electron microscopic observations and energy dispersive X-ray spectra (EDS) analysis were made on steel coupons. The effect of iron concentration on corrosion behavior was determined by Tafel extrapolation method. In a sterile culture medium, as the FeSO{sub 4} . 7H{sub 2}O concentration increased, corrosion potential (E{sub cor}) values shifted towards more anodic potentials and corrosion current density (I{sub cor}) values increased considerably. After inoculation of sulfate-reducing bacteria (SRB), E{sub cor} shifted towards cathodic values. I{sub cor} values increased with increasing incubation time for 10 and 100 mg/L concentrations of FeSO{sub 4} . 7H{sub 2}O. Results have shown that the corrosion activity changed due to several factors such as bacterial metabolites, ferrous sulfide, hydrogen sulfide, iron phosphide, and cathodic depolarization effect. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  7. A shallow land buriable low-activation austenitic stainless steel for fusion applications

    International Nuclear Information System (INIS)

    Zucchetti, M.

    1990-01-01

    First-wall components are the most activated materials in fusion reactors, but their activity can be reduced by material selection. The development of new alloys with good mechanical and physical properties and with low activation characteristics is needed. The PCA is one of the reference austenitic stainless steels for fusion structural applications in the United States. In this paper, the authors analyze the induced radioactivity in the PCA in connection with the shallow land burial (SLB) waste disposal concept. The most proper elemental substitutions is suggested for reducing the activity in the PCA. A low-activity version of the PCA is proposed. Since recycling is not possible, shallow land burial is the best achievable goal for a low-activation steel for the first wall. The PCA cannot be accepted for SLB, mainly due to the presence of molybdenum, niobium, and certain impurities. With limited elemental substitutions and impurity limitations, a new alloy (PCA-la) can be obtained. The PCA-la meets requirements for SLB. The properties of PCA-la should be comparable to those of the PCA. Fabrication and testing of specimens to check its main properties will be the next step of this work

  8. The effect of reduced oxygen content powder on the impact toughness of 316 steel powder joined to 316 steel by low temperature HIP

    International Nuclear Information System (INIS)

    Lind, Anders; Sundstroem, Johan; Peacock, Alan

    2005-01-01

    During the manufacture of the blanket modules, 316L steel powder is simultaneously consolidated and joined to tubes and blocks of 316L materials by hot isostatic pressing (HIP). The high processing temperature can detrimentally increase the grain size of the water-cooling tubes in the structure and the blocks reducing their strength. It is well known [L. Arnberg, A. Karlsson, Influence of powder surface oxidation on some properties of a HIPed martensitic chromium steel, Int. J. Powder Metall. 24 (2) (1988) 107-112] that surface oxides on the powder particles negatively influence the impact toughness of material and joints consolidated in this way. At a high HIP temperature, the oxides are at least partly transformed, thereby improving the impact toughness [L. Nyborg, I. Olefjord, Surface analysis of PM martensitic steel before and after consolidation. Part 2. Surface analysis of compacted material, Powder Metall. 31 (1) (1988) 40-44]. In order to get acceptable mechanical properties of materials produced at a low HIP temperature, the oxygen content on the powder surfaces needs to be reduced. In order to study the effect of reducing the powder oxygen content, it was reduced and the results were compared to those of specimens with ordinary oxygen content. The effect on the impact toughness and the tensile strength of low temperature (1020 and 1060 deg. C) HIP joints between steel blocks and powder consolidated material with low and ordinary oxygen content was measured

  9. Study of the characteristics of duplex stainless steel activated tungsten inert gas welds

    International Nuclear Information System (INIS)

    Chern, Tsann-Shyi; Tseng, Kuang-Hung; Tsai, Hsien-Lung

    2011-01-01

    The purpose of this study is to investigate the effects of the specific fluxes used in the tungsten inert gas (TIG) process on surface appearance, weld morphology, angular distortion, mechanical properties, and microstructures when welding 6 mm thick duplex stainless steel. This study applies a novel variant of the autogenous TIG welding, using oxide powders (TiO 2 , MnO 2 , SiO 2 , MoO 3 , and Cr 2 O 3 ), to grade 2205 stainless steel through a thin layer of the flux to produce a bead-on-plate joint. Experimental results indicate that using SiO 2 , MoO 3 , and Cr 2 O 3 fluxes leads to a significant increase in the penetration capability of TIG welds. The activated TIG process can increase the joint penetration and the weld depth-to-width ratio, and tends to reduce the angular distortion of grade 2205 stainless steel weldment. The welded joint also exhibited greater mechanical strength. These results suggest that the plasma column and the anode root are a mechanism for determining the morphology of activated TIG welds.

  10. Combined geochemical and electrochemical methodology to quantify corrosion of carbon steel by bacterial activity

    International Nuclear Information System (INIS)

    Schutz, Marta K.; Moreira, Rebeca; Tribollet, Bernard; Vivier, Vincent; Bildstein, Olivier; Lartigue, Jean-Eric; Libert, Marie; Schlegel, Michel L.

    2014-01-01

    The availability of respiratory substrates, such as H 2 and Fe(II,III) solid corrosion products within nuclear waste repository, will sustain the activities of hydrogen-oxidizing bacteria (HOB) and iron-reducing bacteria (IRB). This may have a direct effect on the rate of carbon steel corrosion. This study investigates the effects of Shewanella oneidensis (an HOB and IRB model organism) on the corrosion rate by looking at carbon steel dissolution in the presence of H 2 as the sole electron donor. Bacterial effect is evaluated by means of geochemical and electrochemical techniques. Both showed that the corrosion rate is enhanced by a factor of 2-3 in the presence of bacteria. The geochemical experiments indicated that the composition and crystallinity of the solid corrosion products (magnetite and vivianite) are modified by bacteria. Moreover, the electrochemical experiments evidenced that the bacterial activity can be stimulated when H 2 is generated in a small confinement volume. In this case, a higher corrosion rate and mineralization (vivianite) on the carbon steel surface were observed. The results suggest that the mechanism likely to influence the corrosion rate is the bioreduction of Fe(III) from magnetite coupled to the H 2 oxidation. (authors)

  11. Paying the full price of steel – Perspectives on the cost of reducing carbon dioxide emissions from the steel industry

    International Nuclear Information System (INIS)

    Rootzén, Johan; Johnsson, Filip

    2016-01-01

    This study examines the impacts felt downstream of carbon pricing and investments made in CO_2 abatement within the steel industry. Using the supply of steel to a passenger car as a case study, the effects of a steel price increase on cost structures and price at each step of the supply chain were assessed. Since the prices of emission allowances under the European Union Emissions Trading System fall well below those required to unlock investments in low-CO_2 production processes in the integrated steelmaking industry this paper seeks to pave the way for a discussion on complementary policy options. The results of the analysis suggest that passing on the compliance costs of the steel industry would have only marginal impacts on costs and prices for the end-use sectors (e.g., on the production cost or selling price of the passenger car). Under the assumptions made herein, at a carbon price of 100 €/tCO_2, the retail price of a mid-sized European passenger car would have to be increased by approximately 100–125 €/car (<0.5%) to cover the projected increases in steel production costs. - Highlights: • Examines impacts downstream of investments in CO_2 abatement in the steel industry. • Show how investing in low-CO_2 processes have marginal impacts in end-user stage. • Increase in the retail price of a mid-sized passenger car would be well below 1%. • Open up for complementary policies, financing mechanisms or new business models.

  12. Effect of activation cross-section uncertainties in selecting steels for the HYLIFE-II chamber to successful waste management

    International Nuclear Information System (INIS)

    Sanz, J.; Cabellos, O.; Reyes, S.

    2005-01-01

    We perform the waste management assessment of the different types of steels proposed as structural material for the inertial fusion energy (IFE) HYLIFE-II concept. Both recycling options, hands-on (HoR) and remote (RR), are unacceptable. Regarding shallow land burial (SLB), 304SS has a very good performance, and both Cr-W ferritic steels (FS) and oxide-dispersion-strengthened (ODS) FS are very likely to be acceptable. The only two impurity elements that question the possibility of obtaining reduced activation (RA) steels for SLB are niobium and molybdenum. The effect of activation cross-section uncertainties on SLB assessments is proved to be important. The necessary improvement of some tungsten and niobium cross-sections is justified

  13. Biocorrosion of carbon steel alloys by an hydrogenotrophic sulfate-reducing bacterium Desulfovibrio capillatus isolated from a Mexican oil field separator

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, E. [IRD, Institut de Recherche pour le Developement, Universites de Provence et de la Mediterranee, ESIL Case 925, 163 Avenue de Luminy, F-13288 Marseille, Cedex 09 (France); Bethencourt, M. [Departamento de Ciencia de los Materiales e Ingenieria Metalurgica y Quimica Inorganica, CASEM, Universidad de Cadiz, Poligono Rio San Pedro s/n, 11510 Puerto Real (Spain)]. E-mail: manuel.bethencourt@uca.es; Botana, F.J. [Departamento de Ciencia de los Materiales e Ingenieria Metalurgica y Quimica Inorganica, CASEM, Universidad de Cadiz, Poligono Rio San Pedro s/n, 11510 Puerto Real (Spain); Cano, M.J. [Departamento de Ciencia de los Materiales e Ingenieria Metalurgica y Quimica Inorganica, CASEM, Universidad de Cadiz, Poligono Rio San Pedro s/n, 11510 Puerto Real (Spain); Sanchez-Amaya, J.M. [Departamento de Ciencia de los Materiales e Ingenieria Metalurgica y Quimica Inorganica, CASEM, Universidad de Cadiz, Poligono Rio San Pedro s/n, 11510 Puerto Real (Spain); Corzo, A. [Departamento de Biologia, CASEM, Universidad de Cadiz, Poligono Rio San Pedro s/n, 11510 Puerto Real (Spain); Garcia de Lomas, J. [Departamento de Biologia, CASEM, Universidad de Cadiz, Poligono Rio San Pedro s/n, 11510 Puerto Real (Spain); Fardeau, M.L. [IRD, Institut de Recherche pour le Developement, Universites de Provence et de la Mediterranee, ESIL Case 925, 163 Avenue de Luminy, F-13288 Marseille, Cedex 09 (France); Ollivier, B. [IRD, Institut de Recherche pour le Developement, Universites de Provence et de la Mediterranee, ESIL Case 925, 163 Avenue de Luminy, F-13288 Marseille, Cedex 09 (France)

    2006-09-15

    The hydrogenotrophic sulfate-reducing bacterium (SRB) Desulfovibrio capillatus (DSM14982{sup T}) was isolated from an oil field separator with serious corrosion problems; this is the study of its role in the corrosion of carbon steels under anaerobic conditions. Immersion tests with two steel alloys, St-35.8 (typical carbon steel employed in European naval industry), and API-5XL52 (weathering alloy steel employed in Mexican oil industries) were performed. Total exposure was 45 days and different concentrations of thiosulfate as electron acceptor for bacterial growth were employed. The samples immersed in media with SRB undergo fast activation and numerous active sites form on the surface. Microscopic observations were made by environmental scanning electron microscopy (ESEM). Weight loss and electrochemical testing included open circuit potential (E {sub corr}), polarization resistance (R {sub p}), electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN) were measured with and without bacteria in the culture medium in order to determine corrosion rates and mechanisms. All electrochemical techniques have shown that after the end of the exponential phase the corrosion activity notably increased due to the high concentration of bacterial metabolites. Finally, the corrosion behavior of API-5XL52 was worse than St-35.8.

  14. Biocorrosion of carbon steel alloys by an hydrogenotrophic sulfate-reducing bacterium Desulfovibrio capillatus isolated from a Mexican oil field separator

    International Nuclear Information System (INIS)

    Miranda, E.; Bethencourt, M.; Botana, F.J.; Cano, M.J.; Sanchez-Amaya, J.M.; Corzo, A.; Garcia de Lomas, J.; Fardeau, M.L.; Ollivier, B.

    2006-01-01

    The hydrogenotrophic sulfate-reducing bacterium (SRB) Desulfovibrio capillatus (DSM14982 T ) was isolated from an oil field separator with serious corrosion problems; this is the study of its role in the corrosion of carbon steels under anaerobic conditions. Immersion tests with two steel alloys, St-35.8 (typical carbon steel employed in European naval industry), and API-5XL52 (weathering alloy steel employed in Mexican oil industries) were performed. Total exposure was 45 days and different concentrations of thiosulfate as electron acceptor for bacterial growth were employed. The samples immersed in media with SRB undergo fast activation and numerous active sites form on the surface. Microscopic observations were made by environmental scanning electron microscopy (ESEM). Weight loss and electrochemical testing included open circuit potential (E corr ), polarization resistance (R p ), electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN) were measured with and without bacteria in the culture medium in order to determine corrosion rates and mechanisms. All electrochemical techniques have shown that after the end of the exponential phase the corrosion activity notably increased due to the high concentration of bacterial metabolites. Finally, the corrosion behavior of API-5XL52 was worse than St-35.8

  15. Chemical and electrochemical aspects of the corrosion of stainless steels in the presence of sulphate reducing bacteria

    International Nuclear Information System (INIS)

    Feron, D.

    1990-01-01

    The corrosion behaviour of austenitic and ferritic stainless steels (316 L and 430Ti) in the presence of sulfate reducing bacteria, was investigated by several electrochemical techniques which were coupled with corrosion measurements on coupons and chemical analyses. Experiments were performed with 'Desulfovibrio vulgaris' and 'Desulfovibrio gigas' in three growth media containing lactate and sulfate. The decreases in corrosion potentials were correlated to the increase in sulphide content. The polarization curves showed also the major influence of sulphides on the passivity of stainless steels. Electrochemical impedance measurements were used to provide information in understanding the interactions between growth media or bacteria and stainless steels surfaces. The behaviour of the tested stainless steels in these conditions was mainly dependent on sulphide concentrations. (Author). 7 refs., 8 figs., 4 tabs

  16. Electrodeposited Reduced Graphene Oxide Films on Stainless Steel, Copper, and Aluminum for Corrosion Protection Enhancement

    Directory of Open Access Journals (Sweden)

    Abdulkareem Mohammed Ali Al-Sammarraie

    2017-01-01

    Full Text Available The enhancement of corrosion protection of metals and alloys by coating with simple, low cost, and highly adhered layer is still a main goal of many workers. In this research graphite flakes converted into graphene oxide using modified Hammers method and then reduced graphene oxide was electrodeposited on stainless steel 316, copper, and aluminum for corrosion protection application in seawater at four temperatures, namely, 20, 30, 40, and 50°C. All corrosion measurements, kinetics, and thermodynamics parameters were established from Tafel plots using three-electrode potentiostat. The deposited films were examined by FTIR, Raman, XRD, SEM, and AFM techniques; they revealed high percentages of conversion to the few layers of graphene with confirmed defects.

  17. Corrosion of 2205 Duplex Stainless Steel Weldment in Chloride Medium Containing Sulfate-Reducing Bacteria

    Science.gov (United States)

    Antony, P. J.; Singh Raman, R. K.; Kumar, Pradeep; Raman, R.

    2008-11-01

    Influence of changes in microstructure caused due to welding on microbiologically influenced corrosion of a duplex stainless steel was studied by exposing the weldment and parent metal to chloride medium containing sulfate-reducing bacteria (SRB). Identically prepared coupons (same area and surface finish) exposed to sterile medium were used as the control. Etching-type attack was observed in the presence of SRB, which was predominant in the heat-affected zone (HAZ) of the weldment. The anodic polarization studies indicated an increase in current density for coupon exposed to SRB-containing medium as compared to that obtained for coupon exposed to sterile medium. The scanning electron microscopy (SEM) observations after anodic polarization revealed that the attack was preferentially in the ferrite phase of HAZ of the weldment, whereas it was restricted to the austenite phase of the parent metal.

  18. A discussion on improving hydration activity of steel slag by altering its mineral compositions.

    Science.gov (United States)

    Wang, Qiang; Yan, Peiyu; Feng, Jianwen

    2011-02-28

    This study aims to investigate the ways to improve the cementitious properties of steel slag. The results show that the cementitious phase of steel slag is composed of silicate and aluminate, but the large particles of these phases make a very small contribution to the cementitious properties of steel slag. RO phase (CaO-FeO-MnO-MgO solid solution), Fe(3)O(4), C(2)F and f-CaO make no contribution to the cementitious properties of steel slag. A new kind of steel slag with more cementitious phase and less RO phase can be obtained by removing some large particles. This new steel slag possesses better cementitious properties than the original steel slag. The large particles can be used as fine aggregates for concrete. Adding regulating agent high in CaO and SiO(2) during manufacturing process of steel slag to increase the cementitious phase to inert phase ratio is another way to improve its cementitious properties. The regulating agent should be selected to adapt to the specific steel slag and the alkalinity should be increased as high as possible on the premise that the f-CaO content does not increase. The cooling rate should be enhanced to improve the hydration activity of the cementitious phase at the early ages and the grindability of steel slag. Copyright © 2010 Elsevier B.V. All rights reserved.

  19. Behavior of helium gas atoms and bubbles in low activation 9Cr martensitic steels

    Science.gov (United States)

    Hasegawa, Akira; Shiraishi, Haruki; Matsui, Hideki; Abe, Katsunori

    1994-09-01

    The behavior of helium-gas release from helium-implanted 9Cr martensitic steels (500 appm implanted at 873 K) during tensile testing at 873 K was studied. Modified 9Cr-1Mo, low-activation 9Cr-2W and 9Cr-0.5V were investigated. Cold-worked AISI 316 austenitic stainless steel was also investigated as a reference which was susceptible helium embrittlement at high temperature. A helium release peak was observed at the moment of rupture in all the specimens. The total quantity of helium released from these 9Cr steels was in the same range but smaller than that of 316CW steel. Helium gas in the 9Cr steels should be considered to remain in the matrix at their lath-packets even if deformed at 873 K. This is the reason why the martensitic steels have high resistance to helium embrittlement.

  20. Behavior of helium gas atoms and bubbles in low activation 9Cr martensitic steels

    International Nuclear Information System (INIS)

    Hasegawa, Akira; Shiraishi, Haruki; Matsui, Hideki; Abe, Katsunori

    1994-01-01

    The behavior of helium-gas release from helium-implanted 9Cr martensitic steels (500 appm implanted at 873 K) during tensile testing at 873 K was studied. Modified 9Cr-1Mo, low-activation 9Cr-2W and 9Cr-0.5V were investigated. Cold-worked AISI 316 austenitic stainless steel was also investigated as a reference which was susceptible helium embrittlement at high temperature. A helium release peak was observed at the moment of rupture in all the specimens. The total quantity of helium released from these 9Cr steels was in the same range but smaller than that of 316CW steel. Helium gas in the 9Cr steels should be considered to remain in the matrix at their lath-packets even if deformed at 873 K. This is the reason why the martensitic steels have high resistance to helium embrittlement. ((orig.))

  1. Evaluation of properties of low activation Mn-Cr steel. 3. Evaluation of corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Shigeru [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Fukaya, Kiyoshi [Nihon Advanced Technology Co., Ltd., Tokai, Ibaraki (Japan); Ishiyama, Shintaro [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Sato, Ikuo; Kusuhashi, Mikio; Hatakeyama, Takeshi [Japan Steel Works Ltd., Muroran, Hokkaido (Japan). Muroran Plant; Takahashi, Heishichiro [Hokkaido Univ., Sapporo, Hokkaido (Japan); Kikuchi, Mitsuru [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

    2002-05-01

    JAERI and the Japan Steel Works LTD. (JSW) have developed new Mn-Cr steels as low induced activation material. Until now, chemical composition and metallurgical processes were optimized and some steels named VC-series were selected. The properties of the steels have been evaluated and reported elsewhere. In this study, corrosion resistance of VC-series was studied. Corrosion tests for stainless steels were performed to investigate a relationship between corrosion rate and chemical composition or sensitization. Furthermore, corrosion tests under actual environment for the vacuum vessel of the reinforced JT-60 were done for non-magnetic steels. As a result, almost no weight change was observed for uniform and gap corrosion tests, No crack was shown for double U-bend corrosion tests. (author)

  2. Reduced-activation materials for fusion reactors: An overview of the proceedings

    International Nuclear Information System (INIS)

    Klueh, R.L.; Packan, N.H.; Gelles, D.S.; Okada, M.

    1988-01-01

    Some of the most serious safety and environmental concerns for future fusion reactors involve induced radioactivity in the first wall and blanket structures. One problem caused by the induced radioactivity in a reactor constructed from the conventional austenitic and ferritic steels presently being considered as structural materials would be the disposal of the highly radioactive structures after their service lifetimes. To simplify the waste-disposal process, ''low-activation'' or ''reduced-activation'' alloys are being developed. The objective for such materials is that they qualify for shallow land burial, as opposed to the much more expensive deep geologic disposal. This paper reviews these classes of materials for this purpose: austenitic stainless steels, ferritic steels, and vanadium alloys

  3. High-throughput design of low-activation, high-strength creep-resistant steels for nuclear-reactor applications

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Qi; Zwaag, Sybrand van der [Novel Aerospace Materials Group, Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2629 HS, Delft (Netherlands); Xu, Wei, E-mail: xuwei@ral.neu.edu.cn [State Key Laboratory of Rolling and Automation, Northeastern University, 110819, Shenyang (China); Novel Aerospace Materials Group, Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2629 HS, Delft (Netherlands)

    2016-02-15

    Reduced-activation ferritic/martensitic steels are prime candidate materials for structural applications in nuclear power reactors. However, their creep strength is much lower than that of creep-resistant steel developed for conventional fossil-fired power plants as alloying elements with a high neutron activation cannot be used. To improve the creep strength and to maintain a low activation, a high-throughput computational alloy design model coupling thermodynamics, precipitate-coarsening kinetics and an optimization genetic algorithm, is developed. Twelve relevant alloying elements with either low or high activation are considered simultaneously. The activity levels at 0–10 year after the end of irradiation are taken as optimization parameter. The creep-strength values (after exposure for 10 years at 650 °C) are estimated on the basis of the solid-solution strengthening and the precipitation hardening (taking into account precipitate coarsening). Potential alloy compositions leading to a high austenite fraction or a high percentage of undesirable second phase particles are rejected automatically in the optimization cycle. The newly identified alloys have a much higher precipitation hardening and solid-solution strengthening at the same activity level as existing reduced-activation ferritic/martensitic steels.

  4. Activating Attachments Reduces Memories of Traumatic Images.

    Directory of Open Access Journals (Sweden)

    Richard A Bryant

    Full Text Available Emotional memories, and especially intrusive memories, are a common feature of many psychological disorders, and are overconsolidated by stress. Attachment theory posits that activation of mental representations of attachment figures can reduce stress and boost coping. This study tested the proposition that attachment activation would reduce consolidation of emotional and intrusive memories. Sixty-seven undergraduate students viewed subliminal presentations of traumatic and neutral images, which were preceded by subliminal presentations of either attachment-related images or non-attachment-related images; free recall and intrusive memories were assessed two days later. Participants with low avoidant attachment tendencies who received the attachment primes recalled fewer memories and reported fewer intrusions than those who received the non-attachment primes. Unexpectedly, those with high anxious attachment tendencies reported fewer memories. These findings generally accord with attachment theory, and suggest that consolidation of emotional memories can be moderated by activation of attachment representations.

  5. Reducing Staphylococcus aureus biofilm formation on stainless steel 316L using functionalized self-assembled monolayers

    International Nuclear Information System (INIS)

    Kruszewski, Kristen M.; Nistico, Laura; Longwell, Mark J.; Hynes, Matthew J.; Maurer, Joshua A.; Hall-Stoodley, Luanne; Gawalt, Ellen S.

    2013-01-01

    Stainless steel 316L (SS316L) is a common material used in orthopedic implants. Bacterial colonization of the surface and subsequent biofilm development can lead to refractory infection of the implant. Since the greatest risk of infection occurs perioperatively, strategies that reduce bacterial adhesion during this time are important. As a strategy to limit bacterial adhesion and biofilm formation on SS316L, self-assembled monolayers (SAMs) were used to modify the SS316L surface. SAMs with long alkyl chains terminated with hydrophobic (− CH 3 ) or hydrophilic (oligoethylene glycol) tail groups were used to form coatings and in an orthogonal approach, SAMs were used to immobilize gentamicin or vancomycin on SS316L for the first time to form an “active” antimicrobial coating to inhibit early biofilm development. Modified SS316L surfaces were characterized using surface infrared spectroscopy, contact angles, MALDI-TOF mass spectrometry and atomic force microscopy. The ability of SAM-modified SS316L to retard biofilm development by Staphylococcus aureus was functionally tested using confocal scanning laser microscopy with COMSTAT image analysis, scanning electron microscopy and colony forming unit analysis. Neither hydrophobic nor hydrophilic SAMs reduced biofilm development. However, gentamicin-linked and vancomycin-linked SAMs significantly reduced S. aureus biofilm formation for up to 24 and 48 h, respectively. - Highlights: ► SS316L was modified with glycol terminated SAMs in order to reduce biofilm growth. ► Antibiotics gentamicin and vancomycin were immobilized on SS316L via SAMs. ► Only the antibiotic modifications reduced biofilm development on SS316L

  6. Reducing Staphylococcus aureus biofilm formation on stainless steel 316L using functionalized self-assembled monolayers

    Energy Technology Data Exchange (ETDEWEB)

    Kruszewski, Kristen M., E-mail: kruszewskik@duq.edu [Duquesne University, Department of Chemistry and Biochemistry, 600 Forbes Avenue, Pittsburgh, PA 15282 (United States); Nistico, Laura, E-mail: lnistico@wpahs.org [Allegheny General Hospital, Center for Genomic Sciences, Allegheny-Singer Research Institute, 320 East North Avenue, 11th floor, South Tower, Pittsburgh, PA 15212 (United States); Longwell, Mark J., E-mail: mlongwel@wpahs.org [Allegheny General Hospital, Center for Genomic Sciences, Allegheny-Singer Research Institute, 320 East North Avenue, 11th floor, South Tower, Pittsburgh, PA 15212 (United States); Hynes, Matthew J., E-mail: mjhynes@go.wustl.edu [Washington University in St. Louis, Department of Chemistry, One Brookings Drive, St. Louis, MO 63130 (United States); Maurer, Joshua A., E-mail: maurer@wustl.edu [Washington University in St. Louis, Department of Chemistry, One Brookings Drive, St. Louis, MO 63130 (United States); Hall-Stoodley, Luanne, E-mail: L.Hall-Stoodley@soton.ac.uk [Southampton Wellcome Trust Clinical Research Facility/NIHR Respiratory BRU, University of Southampton Faculty of Medicine, Southampton General Hospital, Tremona Road, Southampton, Hampshire SO16 6YD (United Kingdom); Gawalt, Ellen S., E-mail: gawalte@duq.edu [Duquesne University, Department of Chemistry and Biochemistry, McGowan Institute for Regenerative Medicine, 600 Forbes Avenue, Pittsburgh, PA 15282 (United States)

    2013-05-01

    Stainless steel 316L (SS316L) is a common material used in orthopedic implants. Bacterial colonization of the surface and subsequent biofilm development can lead to refractory infection of the implant. Since the greatest risk of infection occurs perioperatively, strategies that reduce bacterial adhesion during this time are important. As a strategy to limit bacterial adhesion and biofilm formation on SS316L, self-assembled monolayers (SAMs) were used to modify the SS316L surface. SAMs with long alkyl chains terminated with hydrophobic (− CH{sub 3}) or hydrophilic (oligoethylene glycol) tail groups were used to form coatings and in an orthogonal approach, SAMs were used to immobilize gentamicin or vancomycin on SS316L for the first time to form an “active” antimicrobial coating to inhibit early biofilm development. Modified SS316L surfaces were characterized using surface infrared spectroscopy, contact angles, MALDI-TOF mass spectrometry and atomic force microscopy. The ability of SAM-modified SS316L to retard biofilm development by Staphylococcus aureus was functionally tested using confocal scanning laser microscopy with COMSTAT image analysis, scanning electron microscopy and colony forming unit analysis. Neither hydrophobic nor hydrophilic SAMs reduced biofilm development. However, gentamicin-linked and vancomycin-linked SAMs significantly reduced S. aureus biofilm formation for up to 24 and 48 h, respectively. - Highlights: ► SS316L was modified with glycol terminated SAMs in order to reduce biofilm growth. ► Antibiotics gentamicin and vancomycin were immobilized on SS316L via SAMs. ► Only the antibiotic modifications reduced biofilm development on SS316L.

  7. Efficiency of inhibitor for biocorrosion influenced by consortium sulfate reducing bacteria on carbon steel

    Energy Technology Data Exchange (ETDEWEB)

    Mahat, Nur Akma; Othman, Norinsan Kamil [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Sahrani, Fathul Karim [School of Environment and Natural Resources Science, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

    2015-09-25

    The inhibition efficiency of benzalkonium chloride (BKC) in controlling biocorrosion on the carbon steel surfaces has been investigated. The carbon steel coupons were incubated in the presence of consortium SRB (C-SRB) with and without BKC for the difference medium concentration. The corrosion rate and inhibition efficiency have been evaluated by a weight loss method. The morphology of biofilm C-SRB on the steel surfaces were characterized with variable pressure scanning electron microscopy (VPSEM). The results revealed that BKC exhibits a low corrosion rate, minimizing the cell growth and biofilm development on the carbon steel surfaces.

  8. Efficiency of inhibitor for biocorrosion influenced by consortium sulfate reducing bacteria on carbon steel

    International Nuclear Information System (INIS)

    Mahat, Nur Akma; Othman, Norinsan Kamil; Sahrani, Fathul Karim

    2015-01-01

    The inhibition efficiency of benzalkonium chloride (BKC) in controlling biocorrosion on the carbon steel surfaces has been investigated. The carbon steel coupons were incubated in the presence of consortium SRB (C-SRB) with and without BKC for the difference medium concentration. The corrosion rate and inhibition efficiency have been evaluated by a weight loss method. The morphology of biofilm C-SRB on the steel surfaces were characterized with variable pressure scanning electron microscopy (VPSEM). The results revealed that BKC exhibits a low corrosion rate, minimizing the cell growth and biofilm development on the carbon steel surfaces

  9. Efficiency of inhibitor for biocorrosion influenced by consortium sulfate reducing bacteria on carbon steel

    Science.gov (United States)

    Mahat, Nur Akma; Othman, Norinsan Kamil; Sahrani, Fathul Karim

    2015-09-01

    The inhibition efficiency of benzalkonium chloride (BKC) in controlling biocorrosion on the carbon steel surfaces has been investigated. The carbon steel coupons were incubated in the presence of consortium SRB (C-SRB) with and without BKC for the difference medium concentration. The corrosion rate and inhibition efficiency have been evaluated by a weight loss method. The morphology of biofilm C-SRB on the steel surfaces were characterized with variable pressure scanning electron microscopy (VPSEM). The results revealed that BKC exhibits a low corrosion rate, minimizing the cell growth and biofilm development on the carbon steel surfaces.

  10. Future directions for ferritic/martensitic steels for nuclear applications

    International Nuclear Information System (INIS)

    Klueh, R.L.; Swindeman, R.W.

    2000-01-01

    High-chromium (7-12% Cr) ferritic/martensitic steels are being considered for nuclear applications for both fission and fusion reactors. Conventional 9-12Cr Cr-Mo steels were the first candidates for these applications. For fusion reactors, reduced-activation steels were developed that were patterned on the conventional steels but with molybdenum replaced by tungsten and niobium replaced by tantalum. Both the conventional and reduced-activation steels are considered to have an upper operating temperature limit of about 550degC. For improved reactor efficiency, higher operating temperatures are required. For ferritic/martensitic steels that could meet such requirements, oxide dispersion-strengthened (ODS) steels are being considered. In this paper, the ferritic/martensitic steels that are candidate steels for nuclear applications will be reviewed, the prospect for ODS steel development and the development of steels produced by conventional processes will be discussed. (author)

  11. Strengthening effect of reduced graphene oxide in steel clad copper rod

    Science.gov (United States)

    Gao, Haitao; Liu, Xianghua; Ai, Zhengrong; Zhang, Shilong; Liu, Lizhong

    2016-11-01

    Reduced graphene oxide has been extensively used as reinforcing agent owing to their high mechanical properties. In this work, an attempt is made to synthesize steel clad copper rod reinforced with reduced graphene oxide (RGO) by the combination of powder-in-tube and intermediate annealing (IA). Experiments show that the Fe/RGO/Cu composites manifest better mechanical properties than Fe/Cu composites. In the process of groove rolling, RGO acts as effective binder, which can greatly improve the adhesive strength of copper scrap and two metals. Moreover, the strengthening effect of RGO is tightly related to its dispersion state. The RGO diffuses much more uniformly on the metallic substrate under the IA temperature of 1100 °C than 800 °C, which can be characterized by less deformation twins appearing at the interface of core copper and the formation of Fe-RGO-Cu transition belt at the bonding interface. In this case, the peak hardness, tensile strength and shear strength of Fe/RGO/Cu composites are 52 HV, 125 and 41 MPa higher than those of the Fe/Cu composites, respectively. The difference of strengthening effect and mechanisms of RGO under 800 and 1100 °C of IA are systematically discussed by referring to experimental results.

  12. Comparative study in the induced corrosion by sulfate reducing microorganisms, in a stainless steel 304L sensitized and a carbon steel API X65

    International Nuclear Information System (INIS)

    Diaz S, A.; Gonzalez F, E.; Arganis J, C.; Luna C, P.; Carapia M, L.

    2004-01-01

    In spite of the operational experience related with the presence of the phenomenon of microbiological corrosion (MIC) in industrial components, it was not but until the decade of the 80 s when the nuclear industry recognized its influence in some systems of Nuclear Generating Power plants. At the moment, diverse studies that have tried to explain the generation mechanism of this phenomenon exist; however, they are even important queries that to solve, especially those related with the particularities of the affected metallic substrates. Presently work, the electrochemical behavior of samples of stainless steel AISI 304L sensitized is evaluated and the carbon steel APIX65, before the action of sulfate reducing microorganisms low the same experimental conditions; found that for the APIX65 the presence of this type of bacteria promoted the formation of a stable biofilm that allowed the maintenance of the microorganisms that damaged the material in isolated places where stings were generated; while in the AISI 304L, it was not detected damage associated to the inoculated media. The techniques of Resistance to the Polarization and Tafel Extrapolation, allowed the calculation of the speed of uniform corrosion, parameter that doesn't seem to be influenced by the presence of the microorganisms; while that noise electrochemical it distinguished in real time, the effect of the sulfate reducing in the steel APIX65. (Author)

  13. Determination of oxygen content in steel using activation analysis with 14 MeV neutron

    International Nuclear Information System (INIS)

    Calado, C.E.

    1978-01-01

    In the quantitative analysis of oxygen in steel by fast neutron activation analysis the oxygen content is evaluated from the measured activity of 16 N produced. Steel s mples are irradiated in 14 MeV neutron flux. After irradiation the samples are pneumatically transfered to the counting terminal where activity is measured. Oxygen concentrations, are obtained by comparison with standards of specified oxygen content [pt

  14. Reduced Antivation Ferritic/Martensitic Steel Eurofer 97 as Possible Structural Material for Fusion Devices. Metallurgical Characterization on As-Received Condition and after Simulated Services Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, P.; Lancha, A. M.; Lapena, J.; Serrano, M.; Hernandez-Mayoral, M.

    2004-07-01

    Metallurgical Characterization of the reduced activation ferritic/martensitic steel Eurofer'97, on as-received condition and after thermal ageing treatment in the temperature range from 400 degree centigree to 600 degree centigree for periods up to 10.000 h, was carried out. The microstructure of the steel remained stable (tempered martensite with M{sub 2}3 C{sub 6} and MX precipitates) after the thermal ageing treatments studied in this work. In general, this stability was also observed in the mechanical properties. The Eurofer'97 steel exhibited similar values of hardness, ultimate tensile stress, 0,2% proof stress, USE and T{sub 0}3 regardless of the investigated material condition. However, ageing at 600 degree centigree for 10.000 ha caused a slight increase in the DBTT, of approximately 23. In terms of creep properties, the steel shows in general adequate creep rupture strength levels for short rupture times. However, the results obtained up to now for long time creep rupture tests at 500 degree centigree suggests a change in the deformation mechanisms. (Author) 62 refs.

  15. Assessment of Effectiveness of Cool Coat in Reducing Heat Strain among Workers in Steel Industry.

    Science.gov (United States)

    Parameswarappa, S B; Narayana, J

    2017-01-01

    A research study was conducted to assess the effectiveness of cool coat in reducing heat strain among workers exposed to heat in a steel plant located in south India. The study consists of assessing heat strain of workers exposed to heat in a steel plant by measuring physiological reactions of workers such as pulse rate and core body temperature with and without cool coat. The coal coat taken for this study was procured from M/s Yamuna Industries, Noida. Out of 140 employees exposed to heat hazard, 101 employees were examined in this study. Study was done in important production units in steel plant having heat hazard. Workers were interviewed and examined and information regarding thermal comfort was collected. First, the heat strain was assessed when the workers were not using cool coats. The air temperature was measured at all hot zone workplaces and found in the range of 34 0 C to 39.4 0 C (Mean: 36.54 0 C & S.D: 1.54). Physiological response such as core body temperature, pulse rate and blood pressure of workers exposed to heat hazard were measured before & after work to know the heat strain sustained by workers when they were working. Maximum core body temperature after work was found to be 39.3 0 C (Mean; 38.52 & S.D; 0.7). Maximum pulse rate of workers after work was found to be 120 beats/minute (Mean; 94.96 beats/minute, S.D: 13.11). The study indicate core body temperature of workers was found more than the permissible exposure limit prescribed by ACGIH, indicating the heat strain sustained by workers is significant, whereas the pulse rate and blood pressure was found normal & not exceeded the limits. Second, with cool coat, the heat strain was assessed among 10 workers selected from the 101 employees. Core body temperature was measured before and soon after work, The core body temperature recorded soon after work was in the range of 35.5 - 37.20C (Mean 36.36, SD= 0.52), indicating a drop in the core body temperature. In this study, a core body

  16. Active compressor engine silencer reduces exhaust noise

    International Nuclear Information System (INIS)

    Denenberg, J.N.; Miller, S.K.; Jay, M.A.

    1994-01-01

    An active industrial silencer on a compressor engine at a Tenneco Gas station has reduced low-frequency 'rumbling' noise by 8 dB during trials while lowering backpressure about 90$. This 8 dB reduction of the piston firing frequency corresponds to a more than 80% decrease in emitted acoustic power. The silencing unit, installed on one of six engines at the station near Eden, N.Y., continues in operation. Based on the results, the manufacturer is identifying additional compressor sites for further tests. This paper reviews this project

  17. The effect of variations in carbon activity on the carburization of austenitic steels in sodium

    International Nuclear Information System (INIS)

    Gwyther, J.R.; Hobdell, M.R.; Hooper, A.J.

    1978-07-01

    Experience has shown that the liquid sodium coolant of fast breeder reactors is an effective carbon-transport medium; the resulting carburization of thin austenitic stainless steel components (eg IHX and fuel cladding) could adversely affect their mechanical integrity. The degree and nature of steel carburization depend, inter alia, on the carbon activity of the sodium environment. Exploratory tests are described in which specimens of austenitic stainless steel were carburized in sodium, the carbon activity of which was continuously monitored by a BNL electrochemical carbon meter. The sodium carbon activity was initially high, but decreased with time, simulating conditions equivalent to plant start-up or coolant clean-up following accidental oil ingress. The extent and nature of steel carburization was identified by metallography, electron microscopy, X-ray crystallography and chemical analysis. (author)

  18. Steel framing strategies for highly skewed bridges to reduce/eliminate distortion near skewed supports.

    Science.gov (United States)

    2014-05-01

    Different problems in straight skewed steel I-girder bridges are often associated with the methods used for detailing the cross-frames. Use of theoretical terms to describe these detailing methods and absence of complete and simplified design approac...

  19. Activation energy of time-dependent martensite formation in steel

    DEFF Research Database (Denmark)

    Villa, Matteo; Somers, Marcel A. J.

    2018-01-01

    The kinetics of {557}γ lath martensite formation in (wt%) 17Cr-7Ni-1Al-0.09C and 15Cr-7Ni-2Mo-1Al-0.08C steels was assessed with magnetometry at sub-zero Celsius temperatures. Samples were cooled to 77 K by immersion in boiling nitrogen to suppress martensite formation. Thereafter, thermally...... applied to evaluate the data available in the literature. The overall analysis showed that EA varies in the range 2–27 kJ mol−1 and increases logarithmically with the total fraction of interstitials in the steel....

  20. The effect of reduced oxygen content powder on the impact toughness of 316 steel powder joined to 316 steel by low temperature HIP

    International Nuclear Information System (INIS)

    Lind, Anders; Sundstroem, Johan

    2004-11-01

    During the manufacture of the blanket modules, 316L steel powder is simultaneously consolidated and joined to tubes and blocks of 316L materials by Hot Isostatic Pressing (HIP). The high processing temperature can detrimentally increase the grain size of the water cooling tubes in the structure and the blocks reducing their strength. It is well known that surface oxides on the powder particles negatively influence the impact toughness of material and joints consolidated in this way. By increasing the consolidation temperature the metallurgical bonding is improved, due to a redistribution of oxygen within the oxide layer towards more discrete oxide particles. In order to get acceptable mechanical properties of materials produced at a low HIP temperature the oxygen content on the powder surfaces needs to be reduced. The aim of this new techniques to reduce the oxygen content of the metal powder. The influence on Charpy impact energy and tensile strength were demonstrated

  1. Low activation steels welding with PWHT and coating for ITER test blanket modules and DEMO

    International Nuclear Information System (INIS)

    Aubert, P.; Tavassoli, F.; Rieth, M.; Diegele, E.; Poitevin, Y.

    2011-01-01

    EUROFER weldability is investigated in support of the European material properties database and TBM manufacturing. Electron Beam, Hybrid, laser and narrow gap TIG processes have been carried out on the EUROFER-97 steel (thickness up to 40 mm), a reduced activation ferritic-martensitic steel developed in Europe. These welding processes produce similar welding results with high joint coefficients and are well adapted for minimizing residual distortions. The fusion zones are typically composed of martensite laths, with small grain sizes. In the heat-affected zones, martensite grains contain carbide precipitates. High hardness values are measured in all these zones that if not tempered would degrade toughness and creep resistance. PWHT developments have driven to a one-step PWHT (750 o C/3 h), successfully applied to joints restoring good material performances. It will produce less distortion levels than a full austenitization PWHT process, not really applicable to a complex welded structure such as the TBM. Different tungsten coatings have been successfully processed on EUROFER material. It has shown no really effect on the EUROFER base material microstructure.

  2. Low activation steels welding with PWHT and coating for ITER test blanket modules and DEMO

    Science.gov (United States)

    Aubert, P.; Tavassoli, F.; Rieth, M.; Diegele, E.; Poitevin, Y.

    2011-02-01

    EUROFER weldability is investigated in support of the European material properties database and TBM manufacturing. Electron Beam, Hybrid, laser and narrow gap TIG processes have been carried out on the EUROFER-97 steel (thickness up to 40 mm), a reduced activation ferritic-martensitic steel developed in Europe. These welding processes produce similar welding results with high joint coefficients and are well adapted for minimizing residual distortions. The fusion zones are typically composed of martensite laths, with small grain sizes. In the heat-affected zones, martensite grains contain carbide precipitates. High hardness values are measured in all these zones that if not tempered would degrade toughness and creep resistance. PWHT developments have driven to a one-step PWHT (750 °C/3 h), successfully applied to joints restoring good material performances. It will produce less distortion levels than a full austenitization PWHT process, not really applicable to a complex welded structure such as the TBM. Different tungsten coatings have been successfully processed on EUROFER material. It has shown no really effect on the EUROFER base material microstructure.

  3. Low activation steels welding with PWHT and coating for ITER test blanket modules and DEMO

    Energy Technology Data Exchange (ETDEWEB)

    Aubert, P., E-mail: Philippe.aubert@cea.fr [CEA Saclay, DEN/DM2S, F-91191 Gif sur Yvette (France); Tavassoli, F. [CEA Saclay, DEN/DMN, F-91191 Gif sur Yvette (France); Rieth, M. [KIT, IMF I, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany); Diegele, E.; Poitevin, Y. [Fusion for Energy (F4E), C/Josep Pla 2 - Ed. B3, 08019 Barcelona (Spain)

    2011-02-15

    EUROFER weldability is investigated in support of the European material properties database and TBM manufacturing. Electron Beam, Hybrid, laser and narrow gap TIG processes have been carried out on the EUROFER-97 steel (thickness up to 40 mm), a reduced activation ferritic-martensitic steel developed in Europe. These welding processes produce similar welding results with high joint coefficients and are well adapted for minimizing residual distortions. The fusion zones are typically composed of martensite laths, with small grain sizes. In the heat-affected zones, martensite grains contain carbide precipitates. High hardness values are measured in all these zones that if not tempered would degrade toughness and creep resistance. PWHT developments have driven to a one-step PWHT (750 {sup o}C/3 h), successfully applied to joints restoring good material performances. It will produce less distortion levels than a full austenitization PWHT process, not really applicable to a complex welded structure such as the TBM. Different tungsten coatings have been successfully processed on EUROFER material. It has shown no really effect on the EUROFER base material microstructure.

  4. Attenuation capability of low activation-modified high manganese austenitic stainless steel for fusion reactor system

    Energy Technology Data Exchange (ETDEWEB)

    Eissa, M.M. [Steel Technology Department, Central Metallurgical Research and Development Institute (CMRDI), Helwan (Egypt); El-kameesy, S.U.; El-Fiki, S.A. [Physics Department, Faculty of Science, Ain Shams University, Cairo (Egypt); Ghali, S.N. [Steel Technology Department, Central Metallurgical Research and Development Institute (CMRDI), Helwan (Egypt); El Shazly, R.M. [Physics Department, Faculty of Science, Al-Azhar University, Cairo (Egypt); Saeed, Aly, E-mail: aly_8h@yahoo.com [Nuclear Power station Department, Faculty of Engineering, Egyptian-Russian University, Cairo (Egypt)

    2016-11-15

    Highlights: • Improvement stainless steel alloys to be used in fusion reactors. • Structural, mechanical, attenuation properties of investigated alloys were studied. • Good agreement between experimental and calculated results has been achieved. • The developed alloys could be considered as candidate materials for fusion reactors. - Abstract: Low nickel-high manganese austenitic stainless steel alloys, SSMn9Ni and SSMn10Ni, were developed to use as a shielding material in fusion reactor system. A standard austenitic stainless steel SS316L was prepared and studied as a reference sample. The microstructure properties of the present stainless steel alloys were investigated using Schaeffler diagram, optical microscopy, and X-ray diffraction pattern. Mainly, an austenite phase was observed for the prepared stainless steel alloys. Additionally, a small ferrite phase was observed in SS316L and SSMn10Ni samples. The mechanical properties of the prepared alloys were studied using Vickers hardness and tensile tests at room temperature. The studied manganese stainless steel alloys showed higher hardness, yield strength, and ultimate tensile strength than SS316L. On the other hand, the manganese stainless steel elongation had relatively lower values than the standard SS316L. The removal cross section for both slow and total slow (primary and those slowed down in sample) neutrons were carried out using {sup 241}Am-Be neutron source. Gamma ray attenuation parameters were carried out for different gamma ray energy lines which emitted from {sup 60}Co and {sup 232}Th radioactive sources. The developed manganese stainless steel alloys had a higher total slow removal cross section than SS316L. While the slow neutron and gamma rays were nearly the same for all studied stainless steel alloys. From the obtained results, the developed manganese stainless steel alloys could be considered as candidate materials for fusion reactor system with low activation based on the short life

  5. Hydrogen behaviour in the aged low activation martensitic steel F82H for fusion reactor applications

    International Nuclear Information System (INIS)

    Benamati, G.

    1997-10-01

    A time dependent permeation method is used to measure the permeability, diffusivity and solubility of hydrogen in the low activation martensitic steel F82H aged for 2000 h under vacuum at 773 K. The measurements cover the temperature range from 373 to 723 K which includes the onset of hydrogen trapping effects on diffusivity and solubility. The results are interpreted using a trapping model. The number of trap sites and their average energies for hydrogen in the aged F82H steel are determined. These data are compared with those obtained for deuterium in F82H steel

  6. Control of activation levels to simplify waste management of fusion reactor ferritic steel components

    International Nuclear Information System (INIS)

    Wiffen, F.W.; Santoro, R.T.

    1984-01-01

    The objective of this work is to examine the restrictions placed on the composition of steels to allow simplified waste management after service in a fusion reactor first wall. Decay of steel activity within tens of years could simplify waste disposal or even permit recycle. For material recycle, N, Al, Ni, Cu, Nb, and Mo must be excluded. For shallow land burial, initial concentration limits include (in at. ppM) Ni, <20,000; Mo, <3650; N, <3650; Cu, <2400; and Nb, <1.0. Other constituents of steels will not be limited

  7. Carbon-14 speciation during anoxic corrosion of activated steel in a repository environment

    Energy Technology Data Exchange (ETDEWEB)

    Wieland, E.; Cvetkovic, B.Z.; Kunz, D. [Paul Scherrer Institute, Villigen (Switzerland). Lab. for Waste Management; Salazar, G.; Szidat, S. [Bern Univ. (Switzerland). Dept. of Chemistry and Biochemistry and Oeschger Centre for Climate Change Research

    2018-01-15

    Radioactive waste contains significant amounts of {sup 14}C which has been identified a key radionuclide in safety assessments. In Switzerland, the {sup 14}C inventory of a cement-based repository for low- and intermediate-level radioactive waste (L/ILW) is mainly associated with activated steel (∝85 %). {sup 14}C is produced by {sup 14}N activation in steel parts exposed to thermal neutron flux in light water reactors. Release of {sup 14}C occurs in the near field of a deep geological repository due to anoxic corrosion of activated steel. Although the {sup 14}C inventory of the L/ILW repository and the sources of {sup 14}C are well known, the formation of {sup 14}C species during steel corrosion is only poorly understood. The aim of the present study was to identify and quantify the {sup 14}C-bearing carbon species formed during the anoxic corrosion of iron and steel and further to determine the {sup 14}C speciation in a corrosion experiment with activated steel. All experiments were conducted in conditions similar to those anticipated in the near field of a cement-based repository.

  8. Microbial Corrosion of API 5L X-70 Carbon Steel by ATCC 7757 and Consortium of Sulfate-Reducing Bacteria

    Directory of Open Access Journals (Sweden)

    Arman Abdullah

    2014-01-01

    Full Text Available Various cases of accidents involving microbiology influenced corrosion (MIC were reported by the oil and gas industry. Sulfate reducing bacteria (SRB have always been linked to MIC mechanisms as one of the major causes of localized corrosion problems. In this study, SRB colonies were isolated from the soil in suspected areas near the natural gas transmission pipeline in Malaysia. The effects of ATCC 7757 and consortium of isolated SRB upon corrosion on API 5L X-70 carbon steel coupon were investigated using a weight loss method, an open circuit potential method (OCP, and a potentiodynamic polarization curves method in anaerobic conditions. Scanning electron microscopy (SEM and energy dispersive X-ray spectroscopy (EDS were then used to determine the corrosion morphology in verifying the SRB activity and corrosion products formation. Results from the study show that the corrosion rate (CR of weight loss method for the isolated SRB is recorded as 0.2017 mm/yr compared to 0.2530 mm/yr for ATCC 7757. The Tafel plot recorded the corrosion rate of 0.3290 mm/yr for Sg. Ular SRB and 0.2500 mm/yr for Desulfovibrio vulgaris. The results showed that the consortia of isolated SRB were of comparable effects and features with the single ATCC 7757 strain.

  9. Evaluation of modified stainless steel surfaces targeted to reduce biofilm formation by common milk sporeformers.

    Science.gov (United States)

    Jindal, Shivali; Anand, Sanjeev; Huang, Kang; Goddard, Julie; Metzger, Lloyd; Amamcharla, Jayendra

    2016-12-01

    The development of bacterial biofilms on stainless steel (SS) surfaces poses a great threat to the quality of milk and other dairy products as the biofilm-embedded bacteria can survive thermal processing. Established biofilms offer cleaning challenges because they are resistant to most of the regular cleaning protocols. Sporeforming thermoduric organisms entrapped within biofilm matrix can also form heat-resistant spores, and may result in a long-term persistent contamination. The main objective of this study was to evaluate the efficacy of different nonfouling coatings [AMC 18 (Advanced Materials Components Express, Lemont, PA), Dursan (SilcoTek Corporation, Bellefonte, PA), Ni-P-polytetrafluoroethylene (PTFE, Avtec Finishing Systems, New Hope, MN), and Lectrofluor 641 (General Magnaplate Corporation, Linden, NJ)] on SS plate heat exchanger surfaces, to resist the formation of bacterial biofilms. It was hypothesized that modified SS surfaces would promote a lesser amount of deposit buildup and bacterial adhesion as compared with the native SS surface. Vegetative cells of aerobic sporeformers, Geobacillus stearothermophilus (ATCC 15952), Bacillus licheniformis (ATCC 6634), and Bacillus sporothermodurans (DSM 10599), were used to study biofilm development on the modified and native SS surfaces. The adherence of these organisms, though influenced by surface energy and hydrophobicity, exhibited no apparent relation with surface roughness. The Ni-P-PTFE coating exhibited the least bacterial attachment and milk solid deposition, and hence, was the most resistant to biofilm formation. Scanning electron microscopy, which was used to visualize the extent of biofilm formation on modified and native SS surfaces, also revealed lower bacterial attachment on the Ni-P-PTFE as compared with the native SS surface. This study thus provides evidence of reduced biofilm formation on the modified SS surfaces. Copyright © 2016 American Dairy Science Association. Published by Elsevier

  10. Influence of sulfate-reducing bacteria on the corrosion of steel in seawater: laboratory and in situ study

    International Nuclear Information System (INIS)

    Benbouzid-Rollet, N.

    1993-01-01

    A fouling reactor was designed to study, the influence of a mixed bio-film on AISI 316 L stainless steel. The bio-film was formed on the steel surface by the fermentative bacterium Vibrio natriegens. The sulfate-reducing bacterium Desulfovibrio vulgaris was then introduced in the reactor and colonized the surface, constituting approximately 5 % of the total population. The settlement of an anaerobic bacterium in the bio-film shows in it the existence of anaerobic micro-niches. Stainless steel electrochemical behavior was analyzed using open circuit potential and potentiodynamic polarization curves. Growth of the bio-film does not induce corrosion, but seems to change the cathodic oxygen reduction kinetics, diminishing the corrosion hazard. This effect increases when D. vulgaris grows in the bio-film. An ennobling of the open circuit potential was observed, similar to field cases already described. A case of drilling corrosion of carbon steel in a harbour area showed the characteristics of anaerobic corrosion related to sulfate-reducing bacteria. The total cultivatable SRB population was quantified and metabolic types were enumerated using specific electron donors. A maximum cell density of 1,1 x 10 8 cells/ cm 2 was estimated, revealing a very important growth of SRB on surfaces. Population structure was different in corroded and non-corroded areas. In corroded area, SRB utilizing benzoate and propionate were more abundant. A strain belonging to the sporulating genus Desulfotomaculum was isolated using these substrates, suggesting a partial aeration in the area of hole appearance. However, in vitro corrosion assays showed that the bacterial population sampled in this area induced a consequent weight loss of steel coupons, in the absence of oxygen. This was observed only with a diversified population, similar to that present in situ. It could not be reproduced with a mixed culture of two purified strains. (author)

  11. Promoter proximal polyadenylation sites reduce transcription activity

    DEFF Research Database (Denmark)

    Andersen, Pia Kjølhede; Lykke-Andersen, Søren; Jensen, Torben Heick

    2012-01-01

    Gene expression relies on the functional communication between mRNA processing and transcription. We previously described the negative impact of a point-mutated splice donor (SD) site on transcription. Here we demonstrate that this mutation activates an upstream cryptic polyadenylation (CpA) site......, which in turn causes reduced transcription. Functional depletion of U1 snRNP in the context of the wild-type SD triggers the same CpA event accompanied by decreased RNA levels. Thus, in accordance with recent findings, U1 snRNP can shield premature pA sites. The negative impact of unshielded pA sites...... on transcription requires promoter proximity, as demonstrated using artificial constructs and supported by a genome-wide data set. Importantly, transcription down-regulation can be recapitulated in a gene context devoid of splice sites by placing a functional bona fide pA site/transcription terminator within ∼500...

  12. Microbial Corrosion of API 5L X-70 Carbon Steel by ATCC 7757 and Consortium of Sulfate-Reducing Bacteria

    OpenAIRE

    Abdullah, Arman; Yahaya, Nordin; Md Noor, Norhazilan; Mohd Rasol, Rosilawati

    2014-01-01

    Various cases of accidents involving microbiology influenced corrosion (MIC) were reported by the oil and gas industry. Sulfate reducing bacteria (SRB) have always been linked to MIC mechanisms as one of the major causes of localized corrosion problems. In this study, SRB colonies were isolated from the soil in suspected areas near the natural gas transmission pipeline in Malaysia. The effects of ATCC 7757 and consortium of isolated SRB upon corrosion on API 5L X-70 carbon steel coupon were i...

  13. Microstructural evolution of HFIR-irradiated low activation F82H and F82H-10B steels

    International Nuclear Information System (INIS)

    Wakai, E.; Shiba, K.; Sawai, T.; Hashimoto, N.; Robertson, J.P.; Klueh, R.L.

    1998-01-01

    Microstructures of reduced-activation F82H (8Cr-2W-0.2V-0.04Ta) and the F82H steels doped with 10 B, irradiated at 250 and 300 C to 3 and 57 dpa in the High Flux Isotope Reactor (HFIR), were examined by TEM. In the F82H irradiated at 250 C to 3 dpa, dislocation loops, small unidentified defect clusters with a high number density, and a few MC precipitates were observed in the matrix. The defect microstructure after 300 C irradiation to 57 dpa is dominated by the loops, and the number density of loops was lower than that of the F82H- 10 B steel. Cavities were observed in the F82H- 10 B steels, but the swelling value is insignificant. Small particles of M 6 C formed on the M 23 C 6 carbides that were present in both steels before the irradiation at 300 C to 57 dpa. A low number density of MC precipitate particles formed in the matrix during irradiation at 300 C to 57 dpa

  14. Preliminary evaluation of microstructure and mechanical properties on low activation ferritic steels

    International Nuclear Information System (INIS)

    Hsu, C.Y.; Lechtenberg, T.A.

    1985-01-01

    Radioactive waste disposal has become a primary concern for the selection of materials for the structural components for fusion reactors. One way to minimize this potential environmental problem is to use structural materials in which the induced radioactivity decays quickly to levels that allow for near-surface disposal under 10CFR61 rules. The primary objective of this work is to develop low activation ferritic steels that exhibit mechanical and physical properties approximately equivalent to the HT-9 and 9Cr-1Mo steels, but which only contain elements that would permit near-surface disposal under 10CFR61 after exposure to fusion neutrons. A preliminary evaluation of the microstructure and mechanical properties of a 9Cr-2.5W-0.3V-0.15C (GA3X) low activation ferritic steel has been performed. An optimum heat treatment condition has been defined for GA3X steel. The properties and microstructure of the quenched and tempered specimens were characterized via hardness measurement and optical metallographic observation. The hot-microhardness and ductility parameter measurements were used to estimate the tensile properties at elevated temperatures. The estimated tensile strengths of GA3X steel at elevated temperatures are comparable to both 9Cr-1Mo and the modified 9Cr-1Mo steels. These preliminary results are encouraging in that they suggest that suitable low activation alloys can be successfully produced in this ferritic alloy class

  15. Electron transfer mediators accelerated the microbiologically influence corrosion against carbon steel by nitrate reducing Pseudomonas aeruginosa biofilm.

    Science.gov (United States)

    Jia, Ru; Yang, Dongqing; Xu, Dake; Gu, Tingyue

    2017-12-01

    Electron transfer is a rate-limiting step in microbiologically influenced corrosion (MIC) caused by microbes that utilize extracellular electrons. Cross-cell wall electron transfer is necessary to transport the electrons released from extracellular iron oxidation into the cytoplasm of cells. Electron transfer mediators were found to accelerate the MIC caused by sulfate reducing bacteria. However, there is no publication in the literature showing the effect of electron transfer mediators on MIC caused by nitrate reducing bacteria (NRB). This work demonstrated that the corrosion of anaerobic Pseudomonas aeruginosa (PAO1) grown as a nitrate reducing bacterium biofilm on C1018 carbon steel was enhanced by two electron transfer mediators, riboflavin and flavin adenine dinucleotide (FAD) separately during a 7-day incubation period. The addition of either 10ppm (w/w) (26.6μM) riboflavin or 10ppm (12.7μM) FAD did not increase planktonic cell counts, but they increased the maximum pit depth on carbon steel coupons considerably from 17.5μm to 24.4μm and 25.0μm, respectively. Riboflavin and FAD also increased the specific weight loss of carbon steel from 2.06mg/cm 2 to 2.34mg/cm 2 and 2.61mg/cm 2 , respectively. Linear polarization resistance, electrochemical impedance spectroscopy and potentiodynamic polarization curves all corroborated the pitting and weight loss data. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. High-pressure stainless steel active membrane microvalves

    International Nuclear Information System (INIS)

    Sharma, G; Svensson, S; Ogden, S; Klintberg, L; Hjort, K

    2011-01-01

    In this work, high-pressure membrane microvalves have been designed, manufactured and evaluated. The valves were able to withstand back-pressures of 200 bar with a response time of less than 0.6 s. These stainless steel valves, manufactured with back-end batch production, utilize the large volume expansion coupled to the solid–liquid phase transition in paraffin wax. When membrane materials were evaluated, parylene coated stainless steel was found to be the best choice as compared to polydimethylsiloxane and polyimide. Also, the influence of the orifice placement and diameter is included in this work. If the orifice is placed too close to the rim of the membrane, the valve can stay sealed even after turning the power off, and the valve will not open until the pressure in the system is released. The developed steel valves, evaluated for both water and air, provide excellent properties in terms of mechanical stability, ease of fabrication, and low cost. Possible applications include sampling at high pressures, chemical microreactors, high performance liquid chromatography, pneumatics, and hydraulics

  17. Development for low-activation concrete design reducing radioactive waste

    International Nuclear Information System (INIS)

    Kimura, Ken-ichi; Kinno, Masaharu; Hasegawa, Akira

    2008-01-01

    Full text: Concrete is very valuable and inexpensive material, however it can be changed to be expensive and hard to deal with in use of a nuclear plant after long operation. One of the counter plans for the above is to use low-activation concrete instead of the ordinary concrete, that will reduce radioactive waste and could be even below clearance level in decommissioning and that is very useful in term of life cycle cost. Radioactive analysis showed that Co and Eu were the major target elements which decide the radioactivity level of reinforced concrete in decommissioning stage, and a several material were selected as a low-activation raw material from wide survey of raw materials for concrete (typically aggregates and cements). With the canditate of raw materials, several low-activation concrete were proposed for various portion of light water reactor plant, which reduction ratio were 1/10 to 1/30 which were mainly consist of limestone and low heat cement or white cement, and 1/100 to 1/300 which were mainly consist of alumina aggregate or quartz and high almina cement, comparing to the ordinary concrete in ΣDi/Ci unit, where 'Di' indicates concentration of each residual radioisotope, Ci defined by IAEA as a clearance level, and suffition of 'i' indicates each radioisotope. National funded project for development of low-activation design method for reduction of radioactive waste below clearance level were started from 2005 with aiming (1) development of a database on the content of target elements, which transform radioactive nuclides, in raw materials of reinforced concrete, (2) development of calculation tools for estimation of residual radioactivity of plant components, and (3) development of low-activation materials for concrete such as cements and reinforcing steel bars for structural components. For the optimized design for applying low-activation concrete to the reactor portion, effective evaluation of neutron spectrum in the certain portion including

  18. Laboratory investigation of microbiologically influenced corrosion of C1018 carbon steel by nitrate reducing bacterium Bacillus licheniformis

    International Nuclear Information System (INIS)

    Xu, Dake; Li, Yingchao; Song, Fengmei; Gu, Tingyue

    2013-01-01

    Nitrate injection is used to suppress reservoir souring in oil and gas fields caused by Sulfate Reducing Bacteria (SRB) through promotion of nitrate respiration by Nitrate Reducing Bacteria (NRB). However, it is not well publicized that nitrate reduction by NRB can cause Microbiologically Influenced Corrosion (MIC) because nitrate reduction coupled with iron oxidation is thermodynamically favorable. NRB benefits bioenergetically from this redox reaction under biocatalysis. This work showed that the Bacillus licheniformis biofilm, when grown as an NRB biofilm, caused a 14.5 μm maximum pit depth and 0.89 mg/cm 2 normalized weight loss against C1018 carbon steel in one-week lab tests

  19. A Method for Monitoring Iron and Steel Factory Economic Activity Based on Satellites

    Directory of Open Access Journals (Sweden)

    Yi Zhou

    2018-06-01

    Full Text Available The Chinese government has promulgated a de-capacity policy for economic growth and environmental sustainability, especially for the iron and steel industry. With these policies, this study aimed to monitor the economic activities and evaluate the production conditions of an iron and steel factory based on satellites via Landsat-8 Thermal Infrared Sensor (TIRS data and high-resolution images from January 2013 to October 2017, and propel next economic adjustment and environmental protection. Our methods included the construction of a heat island intensity index for an iron and steel factory (ISHII, a heat island radio index for an iron and steel factory (ISHRI and a dense classifying approach to monitor the spatiotemporal changes of the internal heat field of an iron and steel factory. Additionally, we used GF-2 and Google Earth images to identify the main production area, detect facility changes to a factory that alters its heat field and verify the accuracy of thermal analysis in a specific time span. Finally, these methods were used together to evaluate economic activity. Based on five iron and steel factories in the Beijing-Tianjin-Hebei region, when the ISHII curve is higher than the seasonal changes in a time series, production is normal; otherwise, there is a shut-down or cut-back. In the spatial pattern analyses, the ISHRI is large in normal production and decreases when cut-back or shut-down occurs. The density classifying images and high-resolution images give powerful evidence to the above-mentioned results. Finally, three types of economic activities of normal production, shut-down or cut-back were monitored for these samples. The study provides a new perspective and method for monitoring the economic activity of an iron and steel factory and provides supports for sustainable development in China.

  20. Heavy concrete shieldings made of recycled radio-active steel

    International Nuclear Information System (INIS)

    Holland, D.; Quade, U.; Sappok, M.; Heim, H.

    1998-01-01

    Maintenance and decommissioning of nuclear installations will generate increasing quantities of radioactively contaminated metallic residues. For many years, Siempelkamp has been melting low-level radioactive scrap in order to re-use it for containers of nuclear industry. Another new recycling path has recently been developed by producing steel granules from the melt. These granules are used as replacement for hematite (iron ore) in the production of heavy concrete shieldings. In the CARLA plant (central plant for the recycling of low-level radioactive waste) of Siempelkamp Nuklear- und Umwelttechnik GmbH and Co., the scrap is melted in a medium frequency induction furnace. The liquid iron is poured into a cooling basin through a water jet, which splits the iron into granules. The shape of these granules is determined by various factors, such as water jet speed, pouring rate of the liquid iron and different additives to the melt. In this process, massive spheres with diameters ranging from 1 to 8 mm can be produced which add to the density of heavy concrete elements for optimum shielding. In close cooperation with Boschert, which indeed is an expert for the production of concrete shieldings, a new technology for manufacturing heavy concrete shieldings, containing low-level radioactive steel granules, has been developed. The portion of steel granules in the concrete is approx. 50 weight-%. A concrete density between 2.4 kg/dm 3 and 4.0 kg/dm 3 is available. The compressive strength for the concrete reaches values up to 65 MPa. Different types of Granulate Shielding Casks (GSC) are offered by Siempelkamp. The most famous one is the GSC 200 for 200 1 drums, which has already been qualified for final storage of radioactive wastes at the German Morsleben final repository (ERAM). This newly developed recycling process further increases the quantities of low-level radioactive metallic wastes available for recycling. Expensive storage area can thus be saved respectively

  1. Studies on A-TIG welding of Low Activation Ferritic/Martensitic (LAFM) steel

    International Nuclear Information System (INIS)

    Vasantharaja, P.; Vasudevan, M.

    2012-01-01

    Low Activation Ferritic–Martensitic steels (LAFM) are chosen as the candidate material for structural components in fusion reactors. The structural components are generally fabricated by welding processes. Activated Tungsten Inert Gas (A-TIG) welding is an emerging process for welding of thicker components. In the present work, attempt was made to develop A-TIG welding technology for LAFM steel plates of 10 mm thick. Activated flux was developed for LAFM steel by carrying out various bead-on-plate TIG welds without flux and with flux. The optimum flux was identified as one which gave maximum depth of penetration at minimum heat input values. With the optimized flux composition, LAFM steel plate of 10 mm thickness was welded in square butt weld joint configuration using double side welding technique. Optical and Scanning Electron Microscopy was used for characterizing the microstructures. Microhardness measurements were made across the weld cross section for as welded and post weld heat treated samples. Tensile and impact toughness properties were determined. The mechanical properties values obtained in A-TIG weld joint were comparable to that obtained in weld joints of LAFM steel made by Electron beam welding process.

  2. Studies on A-TIG welding of Low Activation Ferritic/Martensitic (LAFM) steel

    Science.gov (United States)

    Vasantharaja, P.; Vasudevan, M.

    2012-02-01

    Low Activation Ferritic-Martensitic steels (LAFM) are chosen as the candidate material for structural components in fusion reactors. The structural components are generally fabricated by welding processes. Activated Tungsten Inert Gas (A-TIG) welding is an emerging process for welding of thicker components. In the present work, attempt was made to develop A-TIG welding technology for LAFM steel plates of 10 mm thick. Activated flux was developed for LAFM steel by carrying out various bead-on-plate TIG welds without flux and with flux. The optimum flux was identified as one which gave maximum depth of penetration at minimum heat input values. With the optimized flux composition, LAFM steel plate of 10 mm thickness was welded in square butt weld joint configuration using double side welding technique. Optical and Scanning Electron Microscopy was used for characterizing the microstructures. Microhardness measurements were made across the weld cross section for as welded and post weld heat treated samples. Tensile and impact toughness properties were determined. The mechanical properties values obtained in A-TIG weld joint were comparable to that obtained in weld joints of LAFM steel made by Electron beam welding process.

  3. Texture Design for Reducing Tactile Friction Independent of Sliding Orientation on Stainless Steel Sheet

    OpenAIRE

    Zhang, S.; Zeng, X.; Igartua, A.; Rodriguez Vidal, E.; van der Heide, E.

    2017-01-01

    Surface texture is important for contact mechanical and tribological phenomena such as the contact area and friction. In this research, three different types of geometrical microstructures were designed and fabricated by pulsed laser surface texturing as semi-symmetric (grooved channel), asymmetric fractal (Hilbert curve), and symmetric patterns (grid). A conventionally finished surface as a reference sample from the same stainless steel sheet material was compared. From the experimental appr...

  4. Investigation of the behavior of connection of reduced-beam-section steel beam to reinforced concrete column

    Directory of Open Access Journals (Sweden)

    Ali Babaeenezhad

    2017-11-01

    Full Text Available After recent earthquakes that caused major damages in beam-column connections, scientists and engineers proposed new types of connections to postpone such brittle failures. One of these new connections is the connection of steel beam to concrete column and connection of reduced- beam-section to steel column. However, these new connections have some defects. The aim of this paper is to investigate the combination of RCS and RBS connection and assess the behavior of new combined connection. In this type of connection, a beam with reduced section at the end is connected to a concrete column. In such a detail, the main defect of RCS and RBS connection disappears. The connection was modeled using Abaqus finite element package and the effect of cut of the flange, cover-plate thickness and stiffener thickness in the new system were investigated and compared with those in RCS connection.  The results show that cut of flange has a great influence on compressive damage and tensile damage. Furthermore, cut of flange decreases the stress in the cover-plate, stiffener and reinforcements. Increasing the thickness of cover-plate, reduces stress in cover-plate. The use of reduced-beam-section instead of ordinary connection improves the connection overall performance.

  5. Filter apparatus for actively reducing noise

    NARCIS (Netherlands)

    Berkhoff, Arthur P.; Nijsse, G.

    2010-01-01

    A filter apparatus for reducing noise from a primary noise source, comprising a secondary source signal connector for generating secondary noise to reduce said primary noise and a sensor connector for connecting to a sensor for measuring said primary and secondary noise as an error signal. A first

  6. A filter apparatus for actively reducing noise

    NARCIS (Netherlands)

    Berkhoff, Arthur P.; Nijsse, G.

    2006-01-01

    A filter apparatus for reducing noise from a primary noise source, comprising a secondary source signal connector for generating secondary noise to reduce said primary noise and a sensor connector for connecting to a sensor for measuring said primary and secondary noise as an error signal. A first

  7. Evaluation of properties of low activation Mn-Cr steel. 1. Mechanical properties and weldability

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Shigeru; Fukaya, Kiyoshi; Ishiyama, Shintaro; Eto, Motokuni [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Sato, Ikuo; Kusuhashi, Mikio; Hatakeyama, Takeshi; Takahashi, Heishichiro; Kikuchi, Mitsuru

    1999-10-01

    In JAERI, JT-60SU (Super Upgrade) program is discussed. In the design optimization activity of JT-60SU, it is required for vacuum vessel material to be highly strong, low activated and nonmagnetic. However, there is no suitable material to fulfill all the requirements. Therefore, JAERI started to develop a new material for vacuum vessel together with The Japan Steel Works LTD. (JSW). Chemical composition and production processes were optimized and a new Mn-Cr steel named VC9 with a non-magnetic single {gamma} phase was selected as a candidate material for vacuum vessel of JT-60SU. In this study, characterization of mechanical properties and weldability of VC9 were studied and the results were compared with those of 316L stainless steel. (author)

  8. Evaluation of properties of low activation Mn-Cr steel (2). Physical properties and aging properties

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Shigeru; Fukaya, Kiyoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Ishiyama, Shintaro [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Sato, Ikuo; Kusuhashi, Mikio; Hatakeyama, Takeshi [Japan Steel Works Ltd., Muroran, Hokkaido (Japan). Muroran Plant; Takahashi, Heishichiro [Hokkaido Univ., Sapporo (Japan); Kikuchi, Mitsuru [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

    2000-08-01

    The JT-60SU (Super Upgrade) program is under discussion at JAERI. Its design optimization activity requires the vacuum vessel material to be non-magnetic, very strong and with low induced activation. However, there is no suitable material available to fulfill all the requirements. JAERI started to develop a new material for the vacuum vessel together with the Japan Steel Works LTD. (JSW). Chemical composition and metallurgical processes were optimized and a new steel named VC9, which has the composition of Cr :16wt%, Mn :15.5wt%, C :0.2wt%, N :0.2wt% with nonmagnetic single {gamma} phase, was selected as a candidate material. Here, physical properties and aging properties of VC9 were studied and the results were compared with those of 316L stainless steel. (author)

  9. Mechanical behaviour of steel fibre-reinforced alkali activated slag concrete

    Directory of Open Access Journals (Sweden)

    Puertas, F.

    2009-03-01

    Full Text Available This study addressed the mechanical behaviour of a steel fibre-reinforced alternative concrete made from waterglass (Na2SiO3.nH2O+NaOH- activated Colombian blast furnace slag. The mixes studied were prepared with 400 kg of cement and the fibres were added in proportions of 40 and 120 kg per cubic metre of concrete. 7-, 14- and 28-day concrete was tested for compressive, splitting tensile and flexural strength. The results obtained showed that adding steel fibre to alkaline concrete lowered early age compressive strength, and that this decline was more intense with rising volumes of steel. Flexural and splitting tensile strength grew, however, enhancing the toughness of the material. As a general rule, the mechanical strength of the plain and fibre-reinforced alkaline concretes studied was higher than exhibited by conventional ordinary Portland cement concrete prepared with similar proportions of cement and fibre.En este estudio se investigó el comportamiento mecánico de hormigones alternativos reforzados con fibras de acero, basados en una escoria siderúrgica colombiana activada alcalinamente con waterglass (Na2SiO3.nH2O+NaOH. Las mezclas en estudio fueron preparadas con 400 kg de cemento y las fibras fueron incorporadas en proporciones de 40 kg y 120 kg por metro cúbico de hormigón, respectivamente. Se evaluó el comportamiento mecánico de los hormigones frente a esfuerzos de compresión, tracción indirecta y flexión a edades de curado de 7, 14 y 28 días. Los resultados obtenidos indican que la incorporación de fibras de acero en los hormigones alcalinos reduce la resistencia a la compresión a edades tempranas siendo superior la pérdida de resistencia a mayores volúmenes de fibra incorporados, mientras que la resistencia a la flexión y tracción indirecta se incrementan significativamente, mejorando la tenacidad del material. En términos generales, es posible concluir que el comportamiento mecánico exhibido por los hormigones

  10. Evaluating Active Interventions to Reduce Student Procrastination

    OpenAIRE

    Martin, Joshua Deckert

    2015-01-01

    Procrastination is a pervasive problem in education. In computer science, procrastination and lack of necessary time management skills to complete programming projects are viewed as primary causes of student attrition. The most effective techniques known to reduce procrastination are resource-intensive and do not scale well to large classrooms. In this thesis, we examine three course interventions designed to both reduce procrastination and be scalable for large classrooms. Reflective writ...

  11. Laser, tungsten inert gas, and metal active gas welding of DP780 steel: Comparison of hardness, tensile properties and fatigue resistance

    International Nuclear Information System (INIS)

    Lee, Jeong Hun; Park, Sung Hyuk; Kwon, Hyuk Sun; Kim, Gyo Sung; Lee, Chong Soo

    2014-01-01

    Highlights: • We report the mechanical properties of DP780 steel welded by three methods. • The size of the welded zone increases with heat input (MAG > TIG > laser). • The hardness of the welded zone increases with cooling rate (laser > TIG > MAG). • Tensile and fatigue properties are strongly dependent on welding method. • Crack initiation sites depend on the microstructural features of the welded zone. - Abstract: The microstructural characteristics, tensile properties and low-cycle fatigue properties of a dual-phase steel (DP780) were investigated following its joining by three methods: laser welding, tungsten inert gas (TIG) welding, and metal active gas (MAG) welding. Through this, it was found that the size of the welded zone increases with greater heat input (MAG > TIG > laser), whereas the hardness of the weld metal (WM) and heat-affected zone (HAZ) increases with cooling rate (laser > TIG > MAG). Consequently, laser- and TIG-welded steels exhibit higher yield strength than the base metal due to a substantially harder WM. In contrast, the strength of MAG-welded steel is reduced by a broad and soft WM and HAZ. The fatigue life of laser-and TIG-welded steel was similar, with both being greater than that of MAG-welded steel; however, the fatigue resistance of all welds was inferior to that of the non-welded base metal. Finally, crack initiation sites were found to differ depending on the microstructural characteristics of the welded zone, as well as the tensile and cyclic loading

  12. Trace element assessment of low-alloy and stainless steels with reference to gamma activity

    International Nuclear Information System (INIS)

    Goddard, A.J.H.; Macmahon, T.D.; Gamberini, D.; Taylor, J.M.; Duggan, F.

    1984-01-01

    In order to predict the long-lived gamma activities leading to radiation exposure during dismantling operations it is necessary to know the likely trace element content of the reactor vessel and internals. This work has been concerned with measuring the elements Ni, Nb, Mo, Co, Ag, Eu, Sm and Ho in steels, with particular reference to light-water reactors. Various steel samples have been provided by organizations in Europe. Analyses have been carried out principally by neutron activation analysis, but also by atomic absorption (AA), inductively coupled plasma (ICP) and secondary ion microprobe spectrometry (SIMS). Analyses for Ni, Mo and Co were straightforward and results agreed with analyses carried out elsewhere. A variety of techniques were employed for Nb; ICP was the most successful and results were confirmed using SIMS. In the case of Ag only flameless AA yielded results for all samples. The low concentration of rare earth elements required the development of a preliminary ion exchange technique. Low-alloy steels examined had Nb concentrations less than 10 ppm. Ag levels in the vicinity of 1 ppm were found in all steel samples, indicating that Ag may be the most significant element at long cooling times. Rare earth concentrations from this and other work indicate that these elements are unlikely to give gamma activities exceeding those of 60 Co, 59 Ni, sup(108m)Ag and 94 Nb activities. Illustrative gamma activity decay calculations using the Origen code are presented

  13. The effect of sulphate-reducing bacteria biofilm on passivity and development of pitting on 2205 duplex stainless steel

    International Nuclear Information System (INIS)

    Dec, Weronika; Mosiałek, Michał; Socha, Robert P.; Jaworska-Kik, Marzena; Simka, Wojciech; Michalska, Joanna

    2016-01-01

    Results on biofilm formation and microbiologically influenced corrosion induced by pure D. desulfuricans strain on 2205 duplex stainless steel (DSS) are presented. Biofilm development stimulated by DSM642 standard strain was evaluated with reference to their metabolic activity and to the surface characterization including the structure and configuration of the biofilm. Electrochemical techniques (open circuit potential, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curves) and X-ray photoelectron spectroscopy (XPS) were carried out to determine the effect of bacteria on the passivity and corrosion resistance of 2205 DSS. The electrochemical results showed that the DSS corrosion resistance was affected in the presence of DSM642 biofilm. This statement was based on the significant decrease in the charge transfer resistance (R_1) obtained from EIS and the increase in the measured current densities obtained from potentiodynamic polarization curves. Although the breakdown potentials (E_b) were still high, SEM observations revealed micropits as well as signs of crevice attack on the steel surface. Significant sulphidation of the passive film affected the nature of cathodic behaviour of steel and helped to impede micropit growth. XPS analysis revealed the layered structure of the biofilm. Accumulation of sulphides and hydroxides was proved in the outermost layer, while the increasing contents of disulphides, organometallic and C−N bonds were detected along the biofilm thickness in the XPS analysis.

  14. Optimization in Activation Analysis by Means of Epithermal Neutrons. Determination of Molybdenum in Steel

    Energy Technology Data Exchange (ETDEWEB)

    Brune, D; Jirlow, J

    1963-12-15

    Optimization in activation analysis by means of selective activation with epithermal neutrons is discussed. This method was applied to the determination of molybdenum in a steel alloy without recourse to radiochemical separations. The sensitivity for this determination is estimated to be 10 ppm. With the common form of activation by means of thermal neutrons, the sensitivity would be about one-tenth of this. The sensitivity estimations are based on evaluation of the photo peak ratios of Mo-99/Fe-59.

  15. Electrochemical impedance spectroscopy and Surface Studies of Steel Corrosion by Sulphate-Reducing Bacteria

    International Nuclear Information System (INIS)

    Fathul Karim Sahrani; Zaharah Ibrahim; Madzlan Aziz; Adibah Yahya

    2009-01-01

    Sulphate-reducing bacteria (SRB), implicated in microbiologically influenced corrosion were isolated from the deep subsurface at the vicinity of Pasir Gudang, Johor, Malaysia. Electrochemical impedance spectroscopic (EIS) study was carried out to determine the polarization resistance in various types of culturing solutions, with SRB1, SRB2, combination of SRB1 and SRB2 and without SRBs inoculated (control). EIS results showed that in the presence of SRB1, SRB2 and mixed culture SRB1 and SRB2, polarisation resistance values were 7170, 6370 and 7190 ohms respectively compared to that of control, 92400 ohm. X-ray analysis (EDS) of the specimens indicated high sulphur content in the medium containing SRBs. Localized corrosion was observed on the metal surface which was associated with the SRB activity. (author)

  16. Use of an Electrochemical Split Cell Technique to Evaluate the Influence of Shewanella oneidensis Activities on Corrosion of Carbon Steel.

    Directory of Open Access Journals (Sweden)

    Robert Bertram Miller

    Full Text Available Microbially induced corrosion (MIC is a complex problem that affects various industries. Several techniques have been developed to monitor corrosion and elucidate corrosion mechanisms, including microbiological processes that induce metal deterioration. We used zero resistance ammetry (ZRA in a split chamber configuration to evaluate the effects of the facultatively anaerobic Fe(III reducing bacterium Shewanella oneidensis MR-1 on the corrosion of UNS G10180 carbon steel. We show that activities of S. oneidensis inhibit corrosion of steel with which that organism has direct contact. However, when a carbon steel coupon in contact with S. oneidensis was electrically connected to a second coupon that was free of biofilm (in separate chambers of the split chamber assembly, ZRA-based measurements indicated that current moved from the S. oneidensis-containing chamber to the cell-free chamber. This electron transfer enhanced the O2 reduction reaction on the coupon deployed in the cell free chamber, and consequently, enhanced oxidation and corrosion of that electrode. Our results illustrate a novel mechanism for MIC in cases where metal surfaces are heterogeneously covered by biofilms.

  17. A procedure for the production of steel exhibiting a low specific activity of gamma emitters

    International Nuclear Information System (INIS)

    Dolenek, J.; Raska, P.; Kodrle, L. et al.

    1989-01-01

    Steel exhibiting low specific gamma activity can be obtained from a metallic charge containing liquid and solid pig iron produced from ores, sinters, coke, limestone and other components. This charge is worked up in a metallurgical fining unit using predetermined amounts of slag-forming substances such as lime, limestone and dolomite; fining ore can also be present. The smelt must be kept in constant motion. The pig iron smelt for the production of this steel contains 0.1-1.1% Si and 0.1-1.0% Mn. All equipment with which the charge and steel will come in contact must be free from remains of previous productions and, preferrably, fitted with new lining. This concerns runners, pig iron transportation mixers, ladles and the production unit. (P.A.)

  18. Effects of iron-reducing bacteria and nitrate-reducing bacteria on the transformations of iron corrosion products, magnetite and siderite, formed at the surface of non-alloy steel

    International Nuclear Information System (INIS)

    Etique, Marjorie

    2014-01-01

    Radioactive waste is one of the major problems facing the nuclear industry. To circumvent this issue France plans to store vitrified high-level nuclear waste in a stainless steel container, placed into a non-alloy steel overpack, at a depth of 500 m in an argillaceous formation. The main iron corrosion products formed at the surface of the non-alloy steel are siderite (Fe II CO 3 ) and magnetite (Fe II Fe III 2 O 4 ). These compounds are formed in the anoxic conditions present in the nuclear waste repository and play a protective role against corrosion as a passive layer. This work aims to investigate the activity of nitrate-reducing bacteria (NRB, Klebsiella mobilis) and iron-reducing bacteria (IRB, Shewanella putrefaciens) during the transformation of siderite and magnetite, especially those involved in anoxic iron biogeochemical cycle. Klebsiella mobilis and Shewanella putrefaciens were first incubated with siderite or magnetite suspensions (high surface specific area) in order to exacerbate the microbial iron transformation, subsequently incubated with a magnetite/siderite film synthesized by anodic polarization at applied current density. The transformation of siderite and magnetite by direct or indirect microbial processes led to the formation of carbonated green rust (Fe II 4 Fe III 2 (OH) 12 CO 3 ). As a transient phase shared by several bacterial reactions involving Fe II and Fe III , this compound is the cornerstone of the anoxic iron biogeochemical cycle. The novelty of this thesis is the consideration of bacterial metabolisms of NRB and IRB often overlooked in bio-corrosion processes. (author) [fr

  19. Stimuli reduce the dimensionality of cortical activity

    Directory of Open Access Journals (Sweden)

    Luca eMazzucato

    2016-02-01

    Full Text Available The activity of ensembles of simultaneously recorded neurons can be represented as a set of points in the space of firing rates. Even though the dimension of this space is equal to the ensemble size, neural activity can be effectively localized on smaller subspaces. The dimensionality of the neural space is an important determinant of the computational tasks supported by the neural activity. Here, we investigate the dimensionality of neural ensembles from the sensory cortex of alert rats during periods of ongoing (inter-trial and stimulus-evoked activity. We find that dimensionality grows linearly with ensemble size, and grows significantly faster during ongoing activity compared to evoked activity. We explain these results using a spiking network model based on a clustered architecture. The model captures the difference in growth rate between ongoing and evoked activity and predicts a characteristic scaling with ensemble size that could be tested in high-density multi-electrode recordings. Moreover, we present a simple theory that predicts the existence of an upper bound on dimensionality. This upper bound is inversely proportional to the amount of pair-wise correlations and, compared to a homogeneous network without clusters, it is larger by a factor equal to the number of clusters. The empirical estimation of such bounds depends on the number and duration of trials and is well predicted by the theory. Together, these results provide a framework to analyze neural dimensionality in alert animals, its behavior under stimulus presentation, and its theoretical dependence on ensemble size, number of clusters, and correlations in spiking network models.

  20. Stimuli Reduce the Dimensionality of Cortical Activity.

    Science.gov (United States)

    Mazzucato, Luca; Fontanini, Alfredo; La Camera, Giancarlo

    2016-01-01

    The activity of ensembles of simultaneously recorded neurons can be represented as a set of points in the space of firing rates. Even though the dimension of this space is equal to the ensemble size, neural activity can be effectively localized on smaller subspaces. The dimensionality of the neural space is an important determinant of the computational tasks supported by the neural activity. Here, we investigate the dimensionality of neural ensembles from the sensory cortex of alert rats during periods of ongoing (inter-trial) and stimulus-evoked activity. We find that dimensionality grows linearly with ensemble size, and grows significantly faster during ongoing activity compared to evoked activity. We explain these results using a spiking network model based on a clustered architecture. The model captures the difference in growth rate between ongoing and evoked activity and predicts a characteristic scaling with ensemble size that could be tested in high-density multi-electrode recordings. Moreover, we present a simple theory that predicts the existence of an upper bound on dimensionality. This upper bound is inversely proportional to the amount of pair-wise correlations and, compared to a homogeneous network without clusters, it is larger by a factor equal to the number of clusters. The empirical estimation of such bounds depends on the number and duration of trials and is well predicted by the theory. Together, these results provide a framework to analyze neural dimensionality in alert animals, its behavior under stimulus presentation, and its theoretical dependence on ensemble size, number of clusters, and correlations in spiking network models.

  1. Garcinia kola extract reduced lipopolysaccharide activation of ...

    African Journals Online (AJOL)

    The effect of Garcinia kola heckel seed extract on the promonocytic cell line U937 activated by lipopolysaccharide (LPS) was investigated. 200 l of U937 cells maintained in culture at 5 x 105 cells per ml was delivered into wells of a culture plate according to groups. Cells were pre-treated with 20 l of 100 ng/ml phorbol ...

  2. Development of Zr-containing advanced reduced-activation alloy (ARAA) as structural material for fusion reactors

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Y.B., E-mail: borobang@gmail.com [Nuclear Materials Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kang, S.H. [Nuclear Materials Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, D.W. [Nuclear Fusion Engineering Development Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Cho, S. [National Fusion Research Institute, Daejeon (Korea, Republic of); Jeong, Y.H. [Nuclear Materials Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Żywczak, A. [AGH University of Science and Technology, Academic Centre of Materials and Nanotechnology, Kraków (Poland); Rhee, C.K. [Nuclear Materials Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-11-01

    Highlights: • Creep and impact resistances of reduced activation ferritic–martensitic steel are enhanced by the addition of Zr. • A 5 ton scale heat of Zr containing RAFM steel, ARAA, has been produced for material property evaluation. • The physical, thermal, magnetic and mechanical properties of ARAA are quite similar to those of Eurofer 97. - Abstract: Korea has developed an advanced reduced-activation alloy (ARAA) as a structural material for helium-cooled ceramic reflector test blanket module (HCCR-TBM) applications. The present paper describes the history of alloy development and the properties of ARAA, which has been produced at a 5 t scale using vacuum induction melting and electro-slag re-melting methods. ARAA is a 9Cr–1.2W based ferritic–martensitic steel with 0.01 wt.% Zr. The mechanical properties, thermal properties and physical and magnetic properties of ARAA show similar temperature dependencies to those observed for Eurofer 97. However, ARAA exhibits a much longer creep–rupture time than conventional RAFM steel, which suggests a positive effect on Zr addition. The enhanced creep strength of ARAA by the addition of Zr is attributed to the reduced temperature-dependence of the yield strength.

  3. Outgassing characteristics of F82H ferritic steel as a low activation material for fusion reactor

    International Nuclear Information System (INIS)

    Odaka, Kenji; Satou, Osamu; Ootsuka, Michio; Abe, Tetsuya; Hara, Shigemitsu; Takatsu, Hideyuki; Enoeda, Mikio.

    1997-01-01

    Outgassing characteristics of F82H ferritic steel as a low activation material for the blanket of fusion device were investigated. A test chamber was constructed by welding F82H ferritic steel plates. The inner surface of the chamber was buffed and electropolished. The test chamber was degassed by the prebaking at temperature of 350degC for 20 h in vacuum. Then outgassing rates of the test chamber were measured by the throughput method as a function of pumping time for the cases that the test chamber was baked and not baked. The typical outgassing rate after baking at 250degC for 24 h was 3 x 10 -9 Pa·ms -1 and it seems that this value is sufficiently small to produce pressures at least as low as 10 -9 Pa in the vacuum chamber made of F82H ferritic steel. In the pump-down of the test chamber without baking after exposure to air, the outgassing rate decreases with pumping time and reached 1 x 10 -7 Pa·ms -1 at t = 10 5 s. The activation energy of hydrogen in bulk diffusion in the F82H ferritic steel was measured and found to be 7 kcal/mol. (author)

  4. Some Insights to the Reuse of Dredged Marine Soils by Admixing with Activated Steel Slag

    Directory of Open Access Journals (Sweden)

    Chee-Ming Chan

    2014-01-01

    Full Text Available Regular dredging is necessary for the development of coastal regions and the maintenance of shipping channels. The dredging process dislodges sediments from the seabed, and the removed materials, termed dredged marine soils, are generally considered a geowaste for dumping. However, disposal of the dredged soils offshores can lead to severe and irreversible impact on the marine ecosystem, while disposal on land often incurs exorbitant costs with no guarantee of zero-contamination. It is therefore desirable to reuse the material, and one option is solidification with another industrial waste, that is, steel slag. This paper describes the exploratory work of admixing dredged marine soil with activated steel slag for improvement of the mechanical properties. An optimum activation concentration of NaOH was introduced to the soil-slag mixture for uniform blending. Specimens were prepared at different mix ratios then left to cure for up to 4 weeks. The unconfined compressive strength test was conducted to monitor the changes in strength at predetermined intervals. It was found that the strength does not necessarily increase with higher steel slag content, indicating an optimum slag content required for the maximum solidification effect to take place. Also, regardless of the slag content, longer curing time produces greater strength gain. In conclusion, steel slag addition to dredged sediments can effectively strengthen the originally weak soil structure by both the “cementation” and “filler” effects, though the combined effects were not distinguished in the present study.

  5. The effects of sulphate reducing bacteria on the corrosion of mild steel embedded in a bentonite-granitic groundwater paste

    International Nuclear Information System (INIS)

    Philp, J.C.; Taylor, K.J.

    1987-08-01

    Preliminary experiments were set up to investigate how the corrosion of forged 0.2% carbon steel is affected by the presence of sulphate reducing bacteria (SRB). The tests used cultures of a thermophilic bacterium Desulphotomaculum nigrificans mixed with bentonite and synthetic groundwater, to simulate a bacteria contaminated backfill, and placed in contact with carbon steel disc specimens held in perspex cells at 50 0 C under anaerobic conditions. The rate of corrosion with exposure was monitored by electrochemical techniques, together with changes in near field redox potential, during the course of the tests. After 340 days exposure the test cells were dismantled to measure the nature and extent of any corrosion that had occurred and to assess the residual SRB content of the bentonite. Recovery of relatively large numbers of bacteria after almost a year's incubation at 50 0 C in this moderately alkaline (pH 9.5) medium has confirmed the pH tolerance of the strain. There was evidence of the initiation of enhanced corrosion occurring in at least two of the five cells that contained SRB, at about three times the rate of the control. This was probably associated with the presence of SRB despite the nutritionally poor environment which existed in the bentonite gel. (author)

  6. Influence of sulphate-reducing bacteria on environmental parameters and marine corrosion behavior of Q235 steel in aerobic conditions

    International Nuclear Information System (INIS)

    Wan Yi; Zhang Dun; Liu Huaiqun; Li Yongjuan; Hou Baorong

    2010-01-01

    The growth cycle of sulphate-reducing bacteria (SRB), Desulfovibrio caledoniensis, and the effect of SRB on the environmental parameters and corrosion behavior of Q235 steel during a growth cycle in aerobic (air- and O 2 -saturated culture solutions) and anaerobic (N 2 - saturated culture solutions) conditions were investigated. Oxygen dissolved in the culture solutions induced slow growth and fast decay of SRB. The growth process of SRB under anaerobic and aerobic conditions influenced sulphide anion concentration (C s 2- ), pH, and conductivity (κ). The values of C s 2- and κ under aerobic conditions were lower than those under anaerobic conditions, and the pH values increased from O 2 - to air- to N 2 -saturated culture solutions. Aerobic conditions induced the open circuit potential (E OC ) to shift in the positive direction after the stationary phase of SRB growth. The charge transfer resistance (R ct ) increased quickly during the exponential growth phase, almost maintained stability during the stationary phase, and decreased after the stationary phase in all three conditions, and the impedance magnitude decreased from O 2 - to air- to N 2 -saturated culture solutions. The biofilms induced by SRB were observed by scanning electron microscopy (SEM) under aerobic and anaerobic conditions, and energy dispersive spectroscopy (EDS) was performed in abiotic and SRB-containing systems to distinguish the corrosion products. The reasons for the effects of SRB on the environmental parameters and corrosion behavior of carbon steel are discussed.

  7. Oxide Evolution in ODS Steel Resulting From Friction Stir Welding

    Science.gov (United States)

    2014-06-01

    the SZ on both the AS and RS of 304L stainless steel , from [16]. ...........................................12  Figure 7.  Past research conditions...being done on void swelling and embrittlement effects. Reduced activation ferritic/ martensitic (RAFM) steels and oxide dispersion strengthened (ODS...growth by grain boundary pinning at higher temperatures. Another type of ODS steel is 9-Cr martensitic steel , which is not considered in this research

  8. Corrosion fatigue studies on F82H mod. martensitic steel in reducing water coolant environments

    Energy Technology Data Exchange (ETDEWEB)

    Maday, M F; Masci, A [ENEA, Casaccia (Italy). Centro Ricerche Energia

    1998-03-01

    Load-controlled low cycle fatigue tests have been carried out on F82H martensitic steel in 240degC oxygen-free water with and without dissolved hydrogen, in order to simulate realistic coolant boundary conditions to be approached in DEMO. It was found that water independently of its hydrogen content, determined the same fatigue life reduction compared to the base-line air results. Water cracks exhibited in their first propagation stages similar fracture morphologies which were completely missing on the air cracks, and were attributed to the action of an environment related component. Lowering frequency gave rise to an increase in F82H fatigue lifetimes without any change in cracking mode in air, and to fatigue life reduction by microvoid coalescence alone in water. The data were discussed in terms of (i) frequency dependent concurrent processes for crack initiation and (ii) frequency-dependent competitive mechanisms for crack propagation induced by cathodic hydrogen from F82H corrosion. (author)

  9. Adhesion of food-borne bacteria to stainless steel is reduced by food conditioning films

    DEFF Research Database (Denmark)

    Bernbom, Nete; Ng, Yin; Jorgensen, R.L.

    2009-01-01

    of proteins with similar molecular weight based in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, in several extracts that reduced adhesion but also extracts not containing this protein reduced bacterial adhesion, indicating that several molecular species may be involved in the phenomenon....... It is a common perception that food materials facilitate bacterial adhesion to surfaces; however, this study demonstrates that aqueous coatings of food origin may actually reduce bacterial adhesion. Compounds from food extracts may potentially be used as nontoxic coatings to reduce bacterial attachment to inert...

  10. INVERSE ELECTRON TRANSFER IN PEROXYOXALATE CHEMIEXCITATION USING EASILY REDUCIBLE ACTIVATORS

    NARCIS (Netherlands)

    Bartoloni, Fernando Heering; Monteiro Leite Ciscato, Luiz Francisco; Augusto, Felipe Alberto; Baader, Wilhelm Josef

    2010-01-01

    INVERSE ELECTRON TRANSFER IN PEROXYOXALATE CHEMIEXCITATION USING EASILY REDUCIBLE ACTIVATORS. Chemiluminescence properties of the peroxyoxalate reaction in the presence of activators bearing electron withdrawing substituents were studied, to evaluate the possible occurrence of an inverse electron

  11. Steel framing strategies for highly skewed bridges to reduce/eliminate distortion near skewed supports : [summary].

    Science.gov (United States)

    2014-05-01

    In the past, bridges were aligned normal to crossing roads or obstacles in order to simplify bridge construction. However, the continuing expansion of the interstate system has challenged engineers to provide more horizontal clearance, reduce right-o...

  12. Pitting corrosion of 304 stainless steel in an activated carbon filter

    OpenAIRE

    Martins, J.I.; Martins, C.M.B.

    2016-01-01

    Water leakages of an orange color were found in the cross welding zone and barrel of an activated carbon filter used in a wastewater treatment plant. The analysis of the chloride content in the plant flowsheet showed that the equipment was subjected to unsuited chloride concentration for 304 stainless steel resistance to pitting corrosion. The inside shows holes distributed randomly from about 20 cm above the welding zone to the lower outlet port of the equipment. The rehabilitation of the eq...

  13. Outdoor corrosion of zinc coated carbon steel, determined by thin layer activation

    International Nuclear Information System (INIS)

    Agostini, M.L.; Laguzzi, G.; De Cristofaro, N.; Stroosnijder, M.F.

    2001-01-01

    Thin Layer Activation was applied in the frame of a European programme addressed to the evaluation of the corrosion the behaviour of different steels. This included outdoor exposure of zinc coated carbon steel in a rural-marine climatic environment, for a period of several months. The zinc layer of specimens was 10 micrometers thick. For the TLA studies 65Zn radio nuclides were produced along the full depth of the coating, by a cyclotron accelerated deuteron beam. For quantification of the material release, activity versus depth was determined using different thickness of Zn coatings on top the carbon steel. After exposure corrosion product were removed from the surface using a pickling solution and the residual activity was determined by gamma spectrometry. The high sensitivity of the method allowed the evaluation of relatively small thickness losses (i.e. 1.2 micrometer). Thickness loss results, obtained by the TLA method, were compared with those arising from the Atomic Absorption analysis of zinc detected in the pickling solutions. A good agreement was observed between the different methods

  14. Control of activation levels to simplify waste management of fusion reactor ferritic steel components

    International Nuclear Information System (INIS)

    Wiffen, F.W.; Santoro, R.T.

    1983-01-01

    Activation characteristics of a material for service in the neutron flux of a fusion reactor first wall fall into three areas: waste management, reactor maintenance and repair, and safety. Of these, the waste management area is the most likely to impact the public acceptance of fusion reactors for power generation. The decay of the activity in steels within tens of years could lead to simplified waste disposal or possibly even to materials recycle. Whether or not these can be achieved will be controlled by (1) selection of alloying elements, (2) control of critical impurity elements, and (3) control of cross contamination from other reactor components. Several criteria can be used to judge the acceptability of potential alloying elements in iron, and to define the limits on content of critical impurity elements. One approach is to select and limit alloying additions on the basis of the activity. If material recycle is a goal, N, Al, Ni, Cu, Nb, and Mo must be excluded. If simplified waste storage by shallow land burial is the goal, regulations limit the concentration of only a few isotopes. For first-wall material that will be exposed to 9 MW-y/m 2 service, allowable initial concentration limits include (in at. ppM) Ni < 20,000; Mo < 3650; N < 3650, Cu < 2400; and Nb < 1.0. The other constituent elements of ferritic steels will not be limited. Possible substitutes for the molybdenum normally used to strengthen the steels include W, Ta, Ti, and V

  15. Profiling mild steel welding processes to reduce fume emissions and costs in the workplace.

    Science.gov (United States)

    Keane, Michael J; Siert, Arlen; Chen, Bean T; Stone, Samuel G

    2014-05-01

    To provide quantitative information to choose the best welding processes for minimizing workplace emissions, nine gas metal arc welding (GMAW) processes for mild steel were assessed for fume generation rates, normalized fume generation rates (milligram fume per gram of electrode consumed), and normalized generation rates for elemental manganese, nickel, and iron. Shielded metal arc welding (SMAW) and flux-cored arc-welding (FCAW) processes were also profiled. The fumes were collected quantitatively in an American Welding Society-type fume chamber and weighed, recovered, homogenized, and analyzed by inductively coupled atomic emission spectroscopy for total metals. The processes included GMAW with short circuit, globular transfer, axial spray, pulsed spray, Surface Tension Transfer™, Regulated Metal Deposition™, and Cold Metal Transfer™ (CMT) modes. Flux-cored welding was gas shielded, and SMAW was a single rod type. Results indicate a wide range of fume emission factors for the process variations studied. Fume emission rates per gram of electrode consumed were highest for SMAW (~13 mg fume g(-1) electrode) and lowest for GMAW processes such as pulsed spray (~1.5mg g(-1)) and CMT (~1mg g(-1)). Manganese emission rates per gram of electrode consumed ranged from 0.45 mg g(-1) (SMAW) to 0.08 mg g(-1) (CMT). Nickel emission rates were generally low and ranged from ~0.09 (GMAW short circuit) to 0.004 mg g(-1) (CMT). Iron emission rates ranged from 3.7 (spray-mode GMAW) to 0.49 mg g(-1) (CMT). The processes studied have significantly different costs, and cost factors are presented based on a case study to allow comparisons between processes in specific cost categories. Costs per linear meter of weld were $31.07 (SMAW), $12.37 (GMAW short circuit), and $10.89 (FCAW). Although no single process is the best for minimizing fume emissions and costs while satisfying the weld requirements, there are several processes that can minimize emissions. This study provides

  16. Study of peculiarities of hydrogen isotopes mixture permeation through low activated steel F82H

    International Nuclear Information System (INIS)

    Kenzhin, Ye.A.; Tazhibayeva, I.L; Kulsartov, T.V.; Shestakov, V.P.; Chikhray, Ye.V.; Afanasev, S.E.; Zheldak, Yu.L.

    2003-01-01

    Full text: The problem of diffusion tritium leakage through blanket materials of future fusion device makes some constructive difficulties concerned with protection of personnel and environment and also with losses of tritium, which is planned to be used in the same device. One of the little-studied problems in the tritium leakage process in Fusion Power Plant is that in fact tritium will penetrate through materials while other hydrogen isotopes are present. These are deuterium and hydrogen which always are present in metals. Therefore, for evaluation of tritium leakage in future Fusion Power Plant under such conditions it is necessary to have experimental data about permeation of these hydrogen isotopes through the structure materials.One of proposed structure materials of fusion reactor blanket is low activated steel F82H. The experiment results on evaluation of .hydrogen, deuterium and its mixture interaction parameters with steel F82H are shown in this work. The tests were carried out within temperature range 273-973 K under inlet hydrogen pressure of 100-2000 Pa. Diffusivity, deuterium and hydrogen permeation constants for low activated steel F82H was determined from experiment results. Those experimental results were used for created phenomenology model which describes hydrogen isotope penetration through tube sample from hydrogen isotopes mixture. That model was used so determining the ratios of desorption rates (D-D, D-H, H-H) on outlet side of sample. Using of so obtained results, we can correctly evaluate, the titanium leakage from blanket of fusion machine which will be constructed using low activated steel F82H

  17. Effect of radiation on activity of sulphate reducing bacteria

    International Nuclear Information System (INIS)

    Agaev, N.M.; Smorodin, A.E.; Gusejnov, M.M.

    1985-01-01

    The effect of γ-radiation on activity of sulphate reducing bacteria has been studied. Concentration of biogenic hydrogen, generated in the medium, is the main criterion, characterizing corrosion activity of the bacteria studied. The developed method of suppression of active development of sulfate reducing bacteria considerably reduces, and at lethal doses of γ-radiation eliminates altogether the bacteria activity and formation of the main corrosion agent-hydrogen sulphide-in the medium and that, in its turn, liquidates hydrogen sulphide corrosion

  18. Electrochemistry study of the influence of local hydrogen generation in carbon steel bio-corrosion mechanisms in presence of iron reducing bacteria (Shewanella oneidensis)

    International Nuclear Information System (INIS)

    Moreira, R.; Libert, M.; Tribollet, B.; Vivier, V.

    2012-01-01

    Document available in extended abstract form only. The safe disposal of nuclear waste is a major concern for the nuclear energy industry. The high-level long-lived waste (HLNW) should be maintained for millions of years in clay formations at 500 metres depth in order to prevent the migration of radionuclides. Thence, different kinds of materials such as, carbon steel, stainless steel, concrete, clay, etc., are chosen aiming to last as long as possible and to preserve the radioactivity properties. In contrast, the anoxic corrosion of the different metallic envelopes is an expected phenomenon due to the changes on the environmental conditions (such as re-saturation) within HLNW repositories. In this context, corrosion products like iron oxides (i.e. magnetite, Fe 3 O 4 ), and hydrogen will be also expected. On the one hand, hydrogen poses a significant threat to the nuclear waste repository when it is accumulated for a long time in the surrounding clay - such hydrogen production may damage the barrier properties of the geological formation, affecting the safety of the repository. On the other hand, hydrogen production represents a new energy source for bacterial growth, especially in such environments with low content of biodegradable organic matter. Moreover, some hydrogeno-trophic bacteria can also use Fe 3+ as an electron acceptor for their development. Therefore, the biological activity and biofilm formation could interfere in the metal corrosion behaviour. This phenomenon is widely known by MIC (Microbiologically Influenced Corrosion), which can represent a huge problem when promoting local corrosion. The objective of this study is to better understand the influence of local hydrogen formation in the carbon steel bio-corrosion process in the presence of Shewanella oneidensis MR-1, a model of Iron Reducing Bacteria (IRB), in order to evaluate the impact of the bacterial activity in terms of long term behaviour of geological disposal materials. In this study

  19. Inhibitory activity of Paenibacillus polymyxa on the biofilm formation of Cronobacter spp. on stainless steel surfaces.

    Science.gov (United States)

    Yang, Soonwook; Kim, Seonhwa; Ryu, Jee-Hoon; Kim, Hoikyung

    2013-07-01

    The objective of this study was to control the survival or biofilm formation of Cronobacter spp. on stainless steel surfaces using Paenibacillus polymyxa. The antibacterial activity of a cell-free culture supernatant (CFCS) of P. polymyxa against Cronobacter spp. was found to vary with P. polymyxa incubation time. Maximum activity occurred when P. polymyxa was incubated at 25 or 30 °C for 96 h. When the CFCS was introduced to Cronobacter spp. adhered to stainless steel strips at 25 °C for up to 72 h, the CFCS successfully inhibited Cronobacter biofilm formation. Additionally, stainless steel surfaces with a preformed P. polymyxa biofilm were exposed to Cronobacter spp. suspensions in PBS or 0.1% peptone water at 3, 5, or 7 log CFU/mL to facilitate its attachment. The Cronobacter population significantly decreased on this surface, regardless of inoculum level or carrier, when the P. polymyxa biofilm was present. However, the microbial population decreased within 6 h and remained unchanged thereafter when the surface was immersed in an inoculum suspended in 0.1% peptone water at 5 or 7 log CFU/mL. These results indicate that P. polymyxa is able to use a promising candidate competitive-exclusion microorganism to control Cronobacter spp. © 2013 Institute of Food Technologists®

  20. OPTIFER, a further step in development of Low Activation Martensitic Steels. Results of Characterization Experiments

    International Nuclear Information System (INIS)

    Fernandez, M.P.; Lapena, J.; Hernandez, M.T.; Schirra, M.

    1996-01-01

    Within the framework of the development of low activation structural materials to be used in nuclear fusion reactors four martensitic Fe-9,5 Cr alloys were conceived with different contentsof tungsten-tantalum and/or germanium as substitutions for Mo, Ni, Nb and Al. As a result of recent activation calculations, the maximum concentrations of all accompanying elements, which are not desirable under radiological aspects, were determined for the first time for these OPTIFER steels, and laid down in specifications for the manufacturers of the alloys. After double-vacuum melting, only the real alloys with some of these accompanying elements added are within the specifications. For the majority of alloys the gap between request in radiological terms and the metallurgical/analytical reality is still considerable. The behavior during transformation and heat treatment roughly corresponds to that of conventional martensitic 9-12degree centigree Cr steels. Progress has been conspicuous as regards the notch impact tougness behavior. Both at upper shelf level and in ductile brittle transition (DBTT) the W(Ce) alloyed OPTIFER variant exhibits more favorable values than the conventional MANET-II steel from the fusion program, with better strength characteristics above 500 degree centigree. With only a moderate decrease in strenght values (compared to MANET-II), the Ge (Ce) variant excels by a distinct improvement in notch impact tougness values and, theoretically, a stronger reduction in dose rate than the W(Ce) variant and comes close to the decay curve of pure iron

  1. OPTIFER, a further step in development of Low Activation Martensitic Steels. Results of Characterization Experiments

    International Nuclear Information System (INIS)

    Fernandez, M.P.; Lapena, J.; Hernandez, M.T.; Schirra, M.

    1996-01-01

    Within the framework of the development of low activation structural materials to be used in nuclear fusion reactors four martensitic Fe-9,5 Cr alloys were conceived with different contents of tungsten-tantalum and/or germanium as substitutions for Mo, Ni, Nb and Al. As a result of recent activation calculations, the maximum concentrations of all accompanying elements, which are not desirable under radiological aspects, were determined for the first time for these OPTIFER steels, and laid down in specifications for the manufacturers of the alloys, after double-vacuum melting, only the real alloys with some of these accompanying elements added are within the specifications. For the majority of alloys the gap between request in radiological terms and the metallurgical/analytical reality is still considerable. The behavior during transformation and heat treatment roughly corresponds to that of conventional martensitic 9-12%Cr steels. Progress has been conspicuous as regards the notch impact toughness behavior, both at upper shelf level and in ductile brittle transition (DBTT) the W(Ce) alloyed OPTIFER variant exhibits more favorable values than the conventional MANET-II steel from the fusion program, with better strength characteristics above 500 degree centigree. With only a moderate decrease in strength values (compared to MANET-II), the Ge (Ce) variant excels by a distinct improvement in notch impact toughness values and, theoretically, a stronger reduction in dose rate than the W(Ce) variant and comes close to the decay curve of pure iron. (Author) 21 refs

  2. Characterisation of Wear Resistant Boride Layers on a Tool Steel by Activity Controlled Pack Boronising

    DEFF Research Database (Denmark)

    Fernandes, Frederico Augusto Pires; Christiansen, Thomas Lundin; Somers, Marcel A. J.

    2015-01-01

    The present work addresses the production and characterisation of iron boride layers by pack boronising of a Vanadis 6 tool steel. The boride layers were produced at 900°C for 2h using different pack compositions in order to obtain a single-phase boride layer. The layers were characterized...... by electron microscopy, glow discharge optical emission spectroscopy, X-ray diffraction, Vickers hardness tests and wear testing with a pin-on-disc tribometer. It was found that the type of boride phases (FeB and/or Fe2B) present in the treated layer can be controlled by changing the boron activity...... by pack boronising for all conditions as compared to the heat treated tool steel....

  3. Transmutation and activation of stainless steel 316 SS in a thermal fusion reactor blanket

    International Nuclear Information System (INIS)

    Gruber, J.; Schneider, J.

    1977-10-01

    Using the program MATEXP (matrix exponential method) the influence of neutron flux is calculated for stainless steel 3s16 SS which is used as a structural material in a fusion reactor blanket (CTRD-I). The transmutations, activations and γ-dose rates are determined for an operation time of 20 years. Investigating the decay behaviour after operation time, we found that the long term activity and dose rate was mainly influenced by five nuclides: Fe55, Ni63, Ni59, Co60 and Nb94. (orig.) [de

  4. The effect of stress on magnetic Barkhausen activity in ferromagnetic steels

    International Nuclear Information System (INIS)

    Jiles, D.C.

    1989-01-01

    This paper presents results of measurements of the effect of uniaxial tensile stresses of up to 85 MPa on Barkhausen activity and magnetic properties of AISI 4130 and AISI 4140 steels. The results showed that the location of maximum Barkhausen activity was very close to the coercive point. Barkhausen peak height and the total number of pulses were affected by the stress, although there was considerable scatter in some of the results so that it was not clear how the peak height of the AISI 4130 varied with stress

  5. The relationship between microbial metabolic activity and biocorrosion of carbon steel.

    Science.gov (United States)

    Dzierzewicz, Z; Cwalina, B; Chodurek, E; Wilczok, T

    1997-12-01

    The effect of metabolic activity (expressed by generation time, rate of H2S production and the activity of hydrogenase and adenosine phosphosulphate (APS)-reductase enzymes) of the 8 wild strains of Desulfovibrio desulfuricans and of their resistance to metal ions (Hg2+, Cu2+, Mn2+, Zn2+, Ni2+, Cr3+) on the rate of corrosion of carbon steel was studied. The medium containing lactate as the carbon source and sulphate as the electron acceptor was used for bacterial metabolic activity examination and in corrosive assays. Bacterial growth inhibition by metal ions was investigated in the sulphate-free medium. The rate of H2S production was approximately directly proportional to the specific activities of the investigated enzymes. These activities were inversely proportional to the generation time. The rate of microbiologically induced corrosion (MIC) of carbon steel was directly proportional to bacterial resistance to metal ions (correlation coefficient r = 0.95). The correlation between the MIC rate and the activity of enzymes tested, although weaker, was also observed (r = 0.41 for APS-reductase; r = 0.69 for hydrogenase; critical value rc = 0.30, p = 0.05, n = 40).

  6. Fracture toughness of China low activation martensitic (CLAM) steel at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Li, Kunfeng [University of Science and Technology of China, Hefei, Anhui 230027 (China); Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Liu, Shaojun, E-mail: shaojun.liu@fds.org.cn [Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Huang, Qunying [University of Science and Technology of China, Hefei, Anhui 230027 (China); Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Xu, Gang; Jiang, Siben [Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China)

    2014-04-15

    Highlights: • The fracture toughness of CLAM steel at room temperature is 417.9 kJ/m{sup 2} measured by unloading compliance method according to the ASTM E1820-11. • The fracture toughness of CLAM steel at room temperature can be calculated on the basis of the fractal dimensions measured under plane strain conditions. The calculated result and relative error for this experiment are 454.6 kJ/m{sup 2} and 8.78% respectively. • The calculation method could be used to estimate the fracture toughness of materials with analysis of the fracture surface. - Abstract: The fracture toughness (J{sub IC}) of China low activation martensitic (CLAM) steel was tested at room temperature through the compact tension specimen, the result is 417.9 kJ/m{sup 2}, which is similar to the JLF-1 at same experimental conditions. The microstructural observation of the fracture surface shows that the fracture mode is a typical ductile fracture. Meanwhile, the fracture toughness is also calculated on the basis of the fractal dimension and the calculated result is 454.6 kJ/m{sup 2}, which is consistent well with the experimental result. This method could be used to estimate the fracture toughness of materials by analyzing of the fracture surface.

  7. Correlation of hot-microhardness with elevated-temperature tensile properties of low activation ferritic steel

    International Nuclear Information System (INIS)

    Hsu Chenyih

    1986-01-01

    Hot microhardness and elevated temperature tensile tests have been performed on 9Cr-2.5W-0.3V-0.15C(GA3X) low activation ferritic steel at temperatures from 20 0 C to 650 0 C. The uniform elongation of the tensile test correlated well with the ductility parameter of the microhardness test. The hot-microhardness test showed a sensitive response to the softening and changes in ductility of the GA3X steel. The ultimate tensile strength and 0.2% yield strength of this steel correlated well with hot microhardness data at test temperatures up to 400 0 C using Cahoon's expressions σ uts = (H/2.9)(n/0.217) n and σ ys = (H/3)(0.1) n , respectively, where H is the diamond pyramid hardness and n is the strain hardening exponent. A 20-30% underestimate of tensile strengths were obtained using Cahoon's expressions at temperatures above 400 0 C, which is probably attributed to creep deformation and may be improved by selecting a proper loading condition during the hardness test. (orig.)

  8. Welding of 316L Austenitic Stainless Steel with Activated Tungsten Inert Gas Process

    Science.gov (United States)

    Ahmadi, E.; Ebrahimi, A. R.

    2015-02-01

    The use of activating flux in TIG welding process is one of the most notable techniques which are developed recently. This technique, known as A-TIG welding, increases the penetration depth and improves the productivity of the TIG welding. In the present study, four oxide fluxes (SiO2, TiO2, Cr2O3, and CaO) were used to investigate the effect of activating flux on the depth/width ratio and mechanical property of 316L austenitic stainless steel. The effect of coating density of activating flux on the weld pool shape and oxygen content in the weld after the welding process was studied systematically. Experimental results indicated that the maximum depth/width ratio of stainless steel activated TIG weld was obtained when the coating density was 2.6, 1.3, 2, and 7.8 mg/cm2 for SiO2, TiO2, Cr2O3, and CaO, respectively. The certain range of oxygen content dissolved in the weld, led to a significant increase in the penetration capability of TIG welds. TIG welding with active fluxes can increase the delta-ferrite content and improves the mechanical strength of the welded joint.

  9. Recreational Activities to Reduce Behavioural Symptoms in Dementia

    Science.gov (United States)

    Kolanowski, Ann; Fick, Donna M.; Buettner, Linda

    2009-01-01

    Few clinicians have an educational grounding in the use of nonpharmacological therapies for people with dementia. In this article, we explore the utility of recreational activities as one nonpharmacological intervention that has demonstrated effectiveness for reducing the behavioural symptoms of dementia. The implementation of effective recreational activities involves three components: understanding the evidence for this approach; acknowledging the need to reduce medications that have the potential to interfere with activity effectiveness; and individualizing activities so that the maximum benefit from the intervention is obtained. PMID:20046903

  10. Sensitivity study of reduced models of the activated sludge process ...

    African Journals Online (AJOL)

    2009-08-07

    Aug 7, 2009 ... Sensitivity study of reduced models of the activated sludge process, for the purposes of parameter estimation and process optimisation: Benchmark process with ASM1 and UCT reduced biological models. S du Plessis and R Tzoneva*. Department of Electrical Engineering, Cape Peninsula University of ...

  11. Active power decoupling with reduced converter stress for single ...

    Indian Academy of Sciences (India)

    SUJATA BHOWMICK

    Department of Electronic Systems Engineering, Indian Institute of Science, ... Single phase; double-frequency ripple; active power decoupling; reduced stress; ... sation of renewable energy sources (e.g., PV), potential ... In standard grid connected DC/AC H-bridge configuration, ..... solar inverter with reduced-size dc link.

  12. Systematic review of active workplace interventions to reduce sickness absence.

    Science.gov (United States)

    Odeen, M; Magnussen, L H; Maeland, S; Larun, L; Eriksen, H R; Tveito, T H

    2013-01-01

    The workplace is used as a setting for interventions to prevent and reduce sickness absence, regardless of the specific medical conditions and diagnoses. To give an overview of the general effectiveness of active workplace interventions aimed at preventing and reducing sickness absence. We systematically searched PubMed, Embase, Psych-info, and ISI web of knowledge on 27 December 2011. Inclusion criteria were (i) participants over 18 years old with an active role in the intervention, (ii) intervention done partly or fully at the workplace or at the initiative of the workplace and (iii) sickness absence reported. Two reviewers independently screened articles, extracted data and assessed risk of bias. A narrative synthesis was used. We identified 2036 articles of which, 93 were assessed in full text. Seventeen articles were included (2 with low and 15 with medium risk of bias), with a total of 24 comparisons. Five interventions from four articles significantly reduced sickness absence. We found moderate evidence that graded activity reduced sickness absence and limited evidence that the Sheerbrooke model (a comprehensive multidisciplinary intervention) and cognitive behavioural therapy (CBT) reduced sickness absence. There was moderate evidence that workplace education and physical exercise did not reduce sickness absence. For other interventions, the evidence was insufficient to draw conclusions. The review found limited evidence that active workplace interventions were not generally effective in reducing sickness absence, but there was moderate evidence of effect for graded activity and limited evidence for the effectiveness of the Sheerbrooke model and CBT.

  13. Influence of traps on the deuterium behaviour in the low activation martensitic steels F82H and Batman

    International Nuclear Information System (INIS)

    Serra, E.

    1997-01-01

    A time dependent permeation method is used to measure the permeability, diffusivity and solubility of deuterium in the low activation martensitic steels F82H and Batman. The measurements cover the temperature range from 373 to 743 K which includes the onset of deuterium trapping effects on diffusivity and solubility. The results are interpreted using a trapping model. The number of trap sites and their average energies for deuterium in F82H and Batman steels are determined. (orig.)

  14. Influence of traps on the deuterium behaviour in the low activation martensitic steels F82H and Batman

    Science.gov (United States)

    Serra, E.; Perujo, A.; Benamati, G.

    1997-06-01

    A time dependent permeation method is used to measure the permeability, diffusivity and solubility of deuterium in the low activation martensitic steels F82H and Batman. The measurements cover the temperature range from 373 to 743 K which includes the onset of deuterium trapping effects on diffusivity and solubility. The results are interpreted using a trapping model. The number of trap sites and their average energies for deuterium in F82H and Batman steels are determined.

  15. Simultaneous determination of 56 Mn and 187W in neutron activated steels

    International Nuclear Information System (INIS)

    Melo, M.C. de

    1982-01-01

    The simultaneous determination of the count rates due to 56 Mn and 187 W in the activation analysis of steel samples was carried out through exponential regression using least square fitting. The regression coefficients obtained corresponded to the initial count rates of 56 Mn and 187 W. Later on, the count rates of 56 Mn were correlated to the manganese content in the samples and to the count rates of the same radionuclide, obtained in a region of the gamma spectrum where only 56 Mn was apparent. The correlation coefficients were respectively .968 and .99997, thus demonstrating the applicability of the methodology adopted herein. (Author) [pt

  16. The Optimal Technological Development Path to Reduce Pollution and Restructure Iron and Steel Industry for Sustainable Transition

    OpenAIRE

    Ren, M.; Xu, X.; Ermolieva, T.; Cao, G.-Y.; Yermoliev, Y.

    2018-01-01

    China is the world’s largest iron and steel producer and Jing-Jin-Ji (Beijing-Tianjin-Hebei) region accounts for nearly 1/3 of the national iron and steel production, while it is facing serious air pollution. Among the top 10 worst polluted cities in China, seven were located in Hebei province in 2014. Recent years Jing-Jin-Ji region has been promoted iron & steel industry with green clean technology for accelerating sustainable economic transition. This paper tries to response the basic ques...

  17. Photon and proton activation analysis of iron and steel standards using the internal standard method coupled with the standard addition method

    International Nuclear Information System (INIS)

    Masumoto, K.; Hara, M.; Hasegawa, D.; Iino, E.; Yagi, M.

    1997-01-01

    The internal standard method coupled with the standard addition method has been applied to photon activation analysis and proton activation analysis of minor elements and trace impurities in various types of iron and steel samples issued by the Iron and Steel Institute of Japan (ISIJ). Samples and standard addition samples were once dissolved to mix homogeneously, an internal standard and elements to be determined and solidified as a silica-gel to make a similar matrix composition and geometry. Cerium and yttrium were used as an internal standard in photon and proton activation, respectively. In photon activation, 20 MeV electron beam was used for bremsstrahlung irradiation to reduce matrix activity and nuclear interference reactions, and the results were compared with those of 30 MeV irradiation. In proton activation, iron was removed by the MIBK extraction method after dissolving samples to reduce the radioactivity of 56 Co from iron via 56 Fe(p, n) 56 Co reaction. The results of proton and photon activation analysis were in good agreement with the standard values of ISIJ. (author)

  18. SURFACE FINISHES ON STAINLESS STEEL REDUCE BACTERIAL ATTACHMENT AND EARLY BIOFILM FORMATION: SCANNING ELECTRON AND ATOMIC FORCE MICROSCOPY STUDY

    Science.gov (United States)

    Three common finishing treatments of stainless steel that are used for equipment during poultry processing were tested for resistance to bacterial contamination. Methods were developed to measure attached bacteria and to identify factors that make surface finishes susceptible or ...

  19. Measurement of carbon activity in sodium and steel and the behaviour of carbon-bearing species

    International Nuclear Information System (INIS)

    Rajendran Pillai, S.; Ranganathan, R.; Mathews, C.K.

    1988-01-01

    Carburization or decarburization of structural materials in a sodium system depends on the local differences in carbon activity. The behaviour of carbon-bearing species in sodium influences its carbon activity. In order to understand the behaviour of carbon in these systems, an electrochemical carbon meter was fabricated in our laboratory. The original version of this meter was capable of operating in the temperature range of 850-980 K. Studies are carried out to extend this lower limit of temperature. Employing the carbon meter, experiments were carried out to understand the behaviour of carbon-bearing species. Gas equilibration experiments were also carried out with the same view. A new method for measuring the carbon activity in steels are described which employs the carbon meter. A review on these investigations and the conclusions reached on the behaviour of carbon in fast reactor loops are described

  20. Reducing energy consumption and CO2 emissions by energy efficiency measures and international trading: A bottom-up modeling for the U.S. iron and steel sector

    International Nuclear Information System (INIS)

    Karali, Nihan; Xu, Tengfang; Sathaye, Jayant

    2014-01-01

    Highlights: • Use ISEEM to evaluate energy and emission reduction in U.S. Iron and Steel sector. • ISEEM is a new bottom-up optimization model for industry sector energy planning. • Energy and emission reduction includes efficiency measure and international trading. • International trading includes commodity and carbon among U.S., China and India. • Project annual energy use, CO 2 emissions, production, and costs from 2010 to 2050. - Abstract: Using the ISEEM modeling framework, we analyzed the roles of energy efficiency measures, steel commodity and international carbon trading in achieving specific CO 2 emission reduction targets in the U.S iron and steel sector from 2010 to 2050. We modeled how steel demand is balanced under three alternative emission reduction scenarios designed to include national energy efficiency measures, commodity trading, and international carbon trading as key instruments to meet a particular emission restriction target in the U.S. iron and steel sector; and how production, process structure, energy supply, and system costs change with those scenarios. The results advance our understanding of long-term impacts of different energy policy options designed to reduce energy consumption and CO 2 emissions for U.S. iron and steel sector, and generate insight of policy implications for the sector’s environmentally and economically sustainable development. The alternative scenarios associated with 20% emission-reduction target are projected to result in approximately 11–19% annual energy reduction in the medium term (i.e., 2030) and 9–20% annual energy reduction in the long term (i.e., 2050) compared to the Base scenario

  1. Sox11 Reduces Caspase-6 Cleavage and Activity.

    Directory of Open Access Journals (Sweden)

    Elaine Waldron-Roby

    Full Text Available The apoptotic cascade is an orchestrated event, whose final stages are mediated by effector caspases. Regulatory binding proteins have been identified for caspases such as caspase-3, -7, -8, and -9. Many of these proteins belong to the inhibitor of apoptosis (IAP family. By contrast, caspase-6 is not believed to be influenced by IAPs, and little is known about its regulation. We therefore performed a yeast-two-hybrid screen using a constitutively inactive form of caspase-6 for bait in order to identify novel regulators of caspase-6 activity. Sox11 was identified as a potential caspase-6 interacting protein. Sox11 was capable of dramatically reducing caspase-6 activity, as well as preventing caspase-6 self- cleavage. Several regions, including amino acids 117-214 and 362-395 within sox11 as well as a nuclear localization signal (NLS all contributed to the reduction in caspase-6 activity. Furthermore, sox11 was also capable of decreasing other effector caspase activity but not initiator caspases -8 and -9. The ability of sox11 to reduce effector caspase activity was also reflected in its capacity to reduce cell death following toxic insult. Interestingly, other sox proteins also had the ability to reduce caspase-6 activity but to a lesser extent than sox11.

  2. Bringing MapReduce Closer To Data With Active Drives

    Science.gov (United States)

    Golpayegani, N.; Prathapan, S.; Warmka, R.; Wyatt, B.; Halem, M.; Trantham, J. D.; Markey, C. A.

    2017-12-01

    Moving computation closer to the data location has been a much theorized improvement to computation for decades. The increase in processor performance, the decrease in processor size and power requirement combined with the increase in data intensive computing has created a push to move computation as close to data as possible. We will show the next logical step in this evolution in computing: moving computation directly to storage. Hypothetical systems, known as Active Drives, have been proposed as early as 1998. These Active Drives would have a general-purpose CPU on each disk allowing for computations to be performed on them without the need to transfer the data to the computer over the system bus or via a network. We will utilize Seagate's Active Drives to perform general purpose parallel computing using the MapReduce programming model directly on each drive. We will detail how the MapReduce programming model can be adapted to the Active Drive compute model to perform general purpose computing with comparable results to traditional MapReduce computations performed via Hadoop. We will show how an Active Drive based approach significantly reduces the amount of data leaving the drive when performing several common algorithms: subsetting and gridding. We will show that an Active Drive based design significantly improves data transfer speeds into and out of drives compared to Hadoop's HDFS while at the same time keeping comparable compute speeds as Hadoop.

  3. Neutron activation analysis - NAA: studies of environmental pollution in Steel Valley region, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Veado, Maria Adelaide R.V.; Queiroz, Marluce A.T.; Costa, Alex A., E-mail: mariavasc@unilestemg.b, E-mail: marluce.queiroz@yahoo.com.b, E-mail: alexaderson@ig.com.b [Centro Universitario do Leste de Minas Gerais (UNILESTE-MG), Coronel Fabriciano, MG (Brazil). Curso de Mestrado em Engenharia Industrial; Menezes, Maria Angela de B.C., E-mail: menezes@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Oliveira, Arno H. de, E-mail: heeren@nuclear.ufmg.b [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear

    2009-07-01

    The Steel Valley region in Minas Gerais State, Brazil, receives intense waste from anthropogenic activities: industries (steel, cellulose, ore mining); untreated domestic; sewage and agricultural discharges. This work presents results obtained from analysis of air quality (Ipatinga, Santana do Paraiso, Coronel Fabriciano Timoteo and Marlieria cities) and by the Piracicaba River (surface water, border sediment, and fish muscle - Acara (Geophagus Brasiliensis). Concentrations of Al, Mn, V, As, Br, K, La, Na, Ce, Co, Cr, Cs, Fe, Hg, Rb, Sc, Sm, Th and Zn were determined for Neutron Activation Analysis, NAA. High concentrations were found in sediment and water (Cr, Fe, Co, Zn, As, Al, Mn, V) and in fish muscle (As, Cr, Hg). Results were compared to the maximum limits for metal set by 357/2005 of the National Environmental Council (CONAMA). Terrestrial epiphytic community samples have been used as biomonitor of air pollution. The samples were collected in trees Oiti (Licania tomentosa) and Angico (Piptadenia rigida), very common in studied region. The samples were collected in 17 points and two weather stations: January (rainy) and June (dried) of 2007. The results indicate high concentrations of the elements Al, Au, Co, Cr, Cu, Fe, Hg, Mn, Mg, Zn, V and Th when compared with the values cited in the literature. The biomonitor used in this work, terrestrial epiphytic community, showed an excellent capacity for metals retention by atmospheric contamination. (author)

  4. Reduced ceramide synthase 2 activity causes progressive myoclonic epilepsy

    DEFF Research Database (Denmark)

    Mosbech, Mai-Britt; Olsen, Anne S B; Neess, Ditte

    2014-01-01

    between genes involved in SL metabolism and epilepsy. METHODS: We used quantitative real-time PCR, Western blotting, and enzymatic assays to determine the mRNA, protein, and activity levels of ceramide synthase 2 (CERS2) in fiibroblasts isolated from parental control subjects and from a patient diagnosed...... with progressive myoclonic epilepsy (PME). Mass spectrometry and fluorescence microscopy were used to examine the effects of reduced CERS2 activity on cellular lipid composition and plasma membrane functions. RESULTS: We identify a novel 27 kb heterozygous deletion including the CERS2 gene in a proband diagnosed...... with PME. Compared to parental controls, levels of CERS2 mRNA, protein, and activity were reduced by ˜50% in fibroblasts isolated from this proband, resulting in significantly reduced levels of ceramides and sphingomyelins containing the very long-chain fatty acids C24:0 and C26:0. The change in SL...

  5. Systematic review of active workplace interventions to reduce sickness absence

    OpenAIRE

    Odeen, Magnus; Magnussen, Liv Heide; Mæland, Silje; Larun, Lillebeth; Eriksen, Hege Randi; Tveito, Torill Helene

    2013-01-01

    Background: The workplace is used as a setting for interventions to prevent and reduce sickness absence, regardless of the specific medical conditions and diagnoses. Aims: To give an overview of the general effectiveness of active workplace interventions aimed at preventing and reducing sickness absence. Methods: We systematically searched PubMed, Embase, Psych-info, and ISI web of knowledge on 27 December 2011. Inclusion criteria were (i) participants over 18 years old with ...

  6. Profiling stainless steel welding processes to reduce fume emissions, hexavalent chromium emissions and operating costs in the workplace.

    Science.gov (United States)

    Keane, Michael; Siert, Arlen; Stone, Samuel; Chen, Bean T

    2016-01-01

    Nine gas metal arc welding (GMAW) processes for stainless steel were assessed for fume generation rates, fume generation rates per g of electrode consumed, and emission rates for hexavalent chromium (Cr(6+)). Elemental manganese, nickel, chromium, iron emissions per unit length of weld, and labor plus consumables costs were similarly measured. Flux-cored arc welding and shielded metal arc (SMAW) processes were also studied. The objective was to identify the best welding processes for reducing workplace exposures, and estimate costs for all processes. Using a conical chamber, fumes were collected, weighed, recovered, and analyzed by inductively coupled atomic emission spectroscopy for metals, and by ion chromatography for Cr(6+). GMAW processes used were Surface Tension Transfer, Regulated Metal Deposition, Cold Metal Transfer, short-circuit, axial spray, and pulsed spray modes. Flux-cored welding used gas shielding; SMAW used E308 rods. Costs were estimated as dollars per m length of a ¼ in (6.3 mm) thick horizontal butt weld; equipment costs were estimated as ratios of new equipment costs to a 250 ampere capacity SMAW welding machine. Results indicate a broad range of fume emission factors for the processes studied. Fume emission rates per g of electrode were lowest for GMAW processes such as pulsed-spray mode (0.2 mg/g), and highest for SMAW (8 mg fume/g electrode). Emission rates of Cr(6+) ranged from 50-7800 µg/min, and Cr(6+) generation rates per g electrode ranged from 1-270 µg/g. Elemental Cr generation rates spanned 13-330 µg/g. Manganese emission rates ranged from 50-300 µg/g. Nickel emission rates ranged from 4-140 µg/g. Labor and consumables costs ranged from $3.15 (GMAW pulsed spray) to $7.40 (SMAW) per meter of finished weld, and were measured or estimated for all 11 processes tested. Equipment costs for some processes may be as much as five times the cost of a typical SMAW welding machine. The results show that all of the GMAW processes in this

  7. Effect of carbon activity on the creep behaviour of 21/4Cr, 1Mo steel in sodium

    International Nuclear Information System (INIS)

    Cordwell, J.E.; Charnock, W.; Nicholson, R.D.

    1979-02-01

    The creep endurance and creep cracking behaviour of 2 1/4Cr, 1Mo steel in sodium at 475 0 C have been studied at three different sodium carbon activities. Creep endurance was found to increase with increasing carbon activity of the sodium. Tests carried out in high carbon activity sodium were discontinued before fracture. Creep crack initiation displacement at notches decreased with increasing carbon activity, presumably as a result of notch tip carburisation. The plastic zones at the tips of blunt notches in specimens exposed in high carbon activity sodium were preferentially carburised. These observations were similar to those made previously on 9Cr, 1Mo steel. One difference detected metallographically was that in a high carburising environment uniform carburisation was obtained in the 2 1/4Cr, 1Mo steel specimens whereas carburisation gradients were observed in the 9Cr, 1Mo steel. Creep crack propagation rates for given notch opening displacement rates in low and intermediate carbon activity sodium were indistinguishable. However, the strenthening that resulted from the mild carburisation of the specimen in the intermediate carbon activity sodium caused slower notch opening displacement rates and crack propagation rates than in the low carbon activity sodium, when the rates were compared at the same crack length. (author)

  8. Influence of surface mechanical activation of the X40Cr13 steel on roughness after ion and gas nitriding

    International Nuclear Information System (INIS)

    Jasinski, J.; Wojtal, A.; Jeziorski, L.; Radecki, A.; Ucieklak, S.

    2003-01-01

    The article describes the problem of the thermal and mechanical activation of the surface of the X40Cr13 steel on the state of the ion and gas nitriding. in order to determine the nitriding influence and make the analysis of results, the steel was subjected to: soft annealing, hardening with subsequent tempering at T = 550 o C and also mechanical activation of the surface consisting in peripheral grinding with abrasive papers of the grain size 60, 360, 1000 and mechanical polishing. The main aim of this work was to establish the influence of different surface geometrical structure, depending on X40Cr13 steel structure, on the roughness profile after ion and gas nitriding. With regard to the above, the examinations of basic roughness parameters prior to and after thermochemical processes and the analysis of utilitarian usefulness of activations applied were carried out. (author)

  9. Development and testing of an electrochemical separation process for cutting activated steel components

    International Nuclear Information System (INIS)

    Stang, W.; Fischer, A.; Pott, P.

    1991-01-01

    Electrochemical decontamination has a great importance for the decommissioning works at KRB A. By this method the metal surface is slightly removed due to a galvanic process in an electrolytic solution. Using the same principle it is also possible to remove material locally (ECM-technique). Many advantages of this method indicated that it could be used for cutting activated steel during decommissioning of nuclear power plants. In the frame of this research contract, experiments with non-active material from a reactor pressure vessel were investigated. The essential results demonstrated - which procedures and cathodes are suitable for high cutting velocities - and which amount of sludge (waste) will be produced in the electrolyte. The research programme has been carried out in cooperation with AEG-Elotherm, Remscheid. The test facility, the execution as well as the evaluation of the experiments were made by AEG-Elotherm

  10. Thermally activated growth of lath martensite in Fe–Cr–Ni–Al stainless steel

    DEFF Research Database (Denmark)

    Villa, Matteo; Hansen, Mikkel Fougt; Pantleon, Karen

    2015-01-01

    The austenite to martensite transformation in a semi-austenitic stainless steel containing 17 wt-%Cr, 7 wt-%Ni and 1 wt-%Al was investigated with vibrating sample magnetometry and electron backscatter diffraction. Magnetometry demonstrated that, within experimental accuracy, martensite formation...... can be suppressed on fast cooling to 77 K as well as on subsequent fast heating to 373 K. Surprisingly, martensite formation was observed during moderate heating from 77 K, instead. Electron backscatter diffraction demonstrated that the morphology of martensite is lath type. The kinetics...... of the transformation is interpreted in terms of athermal nucleation of lath martensite followed by thermally activated growth. It is anticipated that substantial autocatalytic martensite formation occurs during thermally activated growth. The observation of a retardation of the transformation followed by a new...

  11. Accelerated low water corrosion of carbon steel in the presence of a biofilm harbouring sulphate-reducing and sulphur-oxidising bacteria recovered from a marine sediment

    Energy Technology Data Exchange (ETDEWEB)

    Beech, Iwona B. [Applied Microbiology and Electrochemistry Group, University of Portsmouth, St. Michael' s Building, White Swan Road, Portsmouth PO1 2DT (United Kingdom)], E-mail: iwona.beech@port.ac.uk; Campbell, Sheelagh A. [Applied Microbiology and Electrochemistry Group, University of Portsmouth, St. Michael' s Building, White Swan Road, Portsmouth PO1 2DT (United Kingdom)

    2008-12-01

    Investigations were undertaken to elucidate causes of accelerated low water corrosion (ALWC) of steel piling in a harbour in Southern England. Visual inspection revealed features characteristic of ALWC such as the presence of poorly adherent, thick corrosion products of varying morphology, often seen as large blisters randomly located on sections of the structure at the low water mark. Upon the removal of blisters, a bright surface covered with shallow pits was exposed. Representative samples of the corrosion products were collected from the structure and water and sediment specimens were retrieved from selected areas in the harbour for microbiological, chemical and microscopy testing. In the laboratory, field samples were enriched to detect and enumerate communities of sulphur-oxidising bacteria (SOB) and sulphate-reducing bacteria (SRB). Biofilms, comprising SRB and SOB populations isolated from a sediment sample were grown under static conditions on surfaces of electrodes manufactured from steel piling material. Linear polarisation resistance (LPR) measurements revealed that the corrosion rate of steel with biofilms (0.518 mm y{sup -1}) was higher than that recorded in sterile seawater alone (0.054 mm y{sup -1}) and in sterile seawater to which nutrient was added (0.218 mm y{sup -1}). Scanning electron microscopy (SEM) imaging demonstrated enhanced pitting under biofilms. The results of our investigation revealed for the first time that the attack on steel piling in the presence of sediment SRB and SOB populations was characteristic of ALWC.

  12. Accelerated low water corrosion of carbon steel in the presence of a biofilm harbouring sulphate-reducing and sulphur-oxidising bacteria recovered from a marine sediment

    International Nuclear Information System (INIS)

    Beech, Iwona B.; Campbell, Sheelagh A.

    2008-01-01

    Investigations were undertaken to elucidate causes of accelerated low water corrosion (ALWC) of steel piling in a harbour in Southern England. Visual inspection revealed features characteristic of ALWC such as the presence of poorly adherent, thick corrosion products of varying morphology, often seen as large blisters randomly located on sections of the structure at the low water mark. Upon the removal of blisters, a bright surface covered with shallow pits was exposed. Representative samples of the corrosion products were collected from the structure and water and sediment specimens were retrieved from selected areas in the harbour for microbiological, chemical and microscopy testing. In the laboratory, field samples were enriched to detect and enumerate communities of sulphur-oxidising bacteria (SOB) and sulphate-reducing bacteria (SRB). Biofilms, comprising SRB and SOB populations isolated from a sediment sample were grown under static conditions on surfaces of electrodes manufactured from steel piling material. Linear polarisation resistance (LPR) measurements revealed that the corrosion rate of steel with biofilms (0.518 mm y -1 ) was higher than that recorded in sterile seawater alone (0.054 mm y -1 ) and in sterile seawater to which nutrient was added (0.218 mm y -1 ). Scanning electron microscopy (SEM) imaging demonstrated enhanced pitting under biofilms. The results of our investigation revealed for the first time that the attack on steel piling in the presence of sediment SRB and SOB populations was characteristic of ALWC

  13. Hydroxychloroquine reduces microglial activity and attenuates experimental autoimmune encephalomyelitis.

    Science.gov (United States)

    Koch, Marcus W; Zabad, Rana; Giuliani, Fabrizio; Hader, Walter; Lewkonia, Ray; Metz, Luanne; Wee Yong, V

    2015-11-15

    Microglial activation is thought to be a key pathophysiological mechanism underlying disease activity in all forms of MS. Hydroxychloroquine (HCQ) is an antimalarial drug with immunomodulatory properties that is widely used in the treatment of rheumatological diseases. In this series of experiments, we explore the effect of HCQ on human microglial activation in vitro and on the development of experimental autoimmune encephalitis (EAE) in vivo. We activated human microglia with lipopolysaccharide (LPS), and measured concentrations of several pro- and anti-inflammatory cytokines in untreated and HCQ pretreated cultures. We investigated the effect of HCQ pretreatment at two doses on the development of EAE and spinal cord histology. HCQ pretreatment reduced the production of pro-inflammatory (TNF-alpha, IL-6, and IL-12) and anti-inflammatory (IL-10 and IL-1 receptor antagonist) cytokines in LPS-stimulated human microglia. HCQ pretreatment delayed the onset of EAE, and reduced the number of Iba-1 positive microglia/macrophages and signs of demyelination in the spinal cords of HCQ treated animals. HCQ treatment reduces the activation of human microglia in vitro, delays the onset of EAE, and decreases the representation of activated macrophages/microglia and demyelination in the spinal cord of treated mice. HCQ is a plausible candidate for further clinical studies in MS. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Role of vanadium carbide traps in reducing the hydrogen embrittlement susceptibility of high strength alloy steels. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, G.L.; Duquette, D.J.

    1998-08-01

    High strength alloy steels typically used for gun steel were investigated to determine their susceptibility to hydrogen embrittlement. Although AISI grade 4340 was quite susceptible to hydrogen embrittlement, ASTM A723 steel, which has identical mechanical properties but slightly different chemistries, was not susceptible to hydrogen embrittlement when exposed to the same conditions. The degree of embrittlement was determined by conducting notched tensile testing on uncharged and cathodically charged specimens. Chemical composition was modified to isolate the effect of alloying elements on hydrogen embrittlement susceptibility. Two steels-Modified A723 (C increased from 0.32% to 0.40%) and Modified 4340 (V increased from 0 to O.12%) were tested. X-ray diffraction identified the presence of vanadium carbide, V{sub 4}C{sub 3}, in A-23 steels, and subsequent hydrogen extraction studies evaluated the trapping effect of vanadium carbide. Based on these tests, it was determined that adding vanadium carbide to 4340 significantly decreased hydrogen embrittlement susceptibility because vanadium carbide traps ties up diffusible hydrogen. The effectiveness of these traps is examined and discussed in this paper.

  15. Influence of direct reduced iron on the energy balance of the electric arc furnace in steel industry

    International Nuclear Information System (INIS)

    Kirschen, Marcus; Badr, Karim; Pfeifer, Herbert

    2011-01-01

    A model of the EAF energy efficiency was developed based on a closed mass and energy balance of the EAF melting process. This model was applied to industrial EAFs in steel industry charged with scrap or with mixes of scrap and DRI. Complex mass and energy conversion in the EAF was simplified with the introduction of mass and energy conversion efficiencies for the conversion of oxygen and the energy conversion of electrical energy in the electric arcs, chemical energy from the oxidation reactions in the melt and energy from the combustion of burner gas. It turned out that close agreement with observed process parameters from 16 EAFs is obtained by slight variations of the efficiency values. Especially the sensitivity of the steel temperature from the energy conversion efficiency of the electric arc energy indicates the importance of efficient foaming slag operation in EAF steel making. Characteristics and process parameters of DRI charged EAFs are discussed. Model results for a series of case studies illustrate the correlations between DRI chemical composition, DRI portion, oxygen consumption, etc. with electrical energy demand in order to indentify cost-effective EAF process conditions. -- Highlights: → Energy demand and carbon dioxide emission figures of EAF steelmaking processes based on steel scrap and DRI. → Complete energy balance of the EAF process using various input materials. → Application of the model to industrial EAF in steel industry in 4 case studies and discussion of model results. → Comparison with other models, critical discussion.

  16. The energetic conditions determining the active dissolution of carbon steel during electrocoagulation in sulfate media

    International Nuclear Information System (INIS)

    Gerónimo-López, Carlos; Vazquez-Arenas, Jorge; Picquart, Michel; González, Ignacio

    2014-01-01

    This study aims to investigate the active dissolution of carbon steel under rotating conditions, necessary for continuous dosing of metal cation in electrocoagulation. A reaction mechanism is proposed for its dissolution in 0.1, 0.3 and 0.5 M Na 2 SO 4 , using electrochemical and chemical techniques (Raman, SEM). A continuous dissolution region was obtained from the potentiodynamic study, as a result of the competition between the rate of electrochemical reactions and the rate at which energetic conditions are imposed on the electrode. On the other hand, the dissolution of carbon steel underwent active, transition and passivation regions in potentiostatic and galvanostatic techniques, which respectively shifted to higher current densities and more positive potentials as the electrolyte concentration (Na 2 SO 4 ) was increased. In general, the increase of Na 2 SO 4 concentration promotes the iron dissolution and tightens the active region. The results revealed that the Na 2 SO 4 concentration, the Fe(II)/Fe(III) interface concentration, and the time of perturbation influence the occurrence and evolution of the Green Rust Sulphate (NaFe 6 II Fe 3 III (OH) 18 (SO 4 ) 2 ) intermediary, a precursor which hinders electrocoagulation through passive film formation. Scanning Electronic Microscopy and Raman spectroscopy showed that in the active dissolution region, the films grown potentiostatically are porous and contain α-FeOOH, δ-FeOOH, and Fe 3 O 4 as the dominant species. In the transition region, these films become less porous and include α-FeOOH, Fe 3 O 4 , α-Fe 2 O 3 , γ-Fe 2 O 3 , while γ-FeOOH was identified in the passive region

  17. Determination of V, W and Mn in high-speed steel by neutron activation source of 241Am/Be

    International Nuclear Information System (INIS)

    Villar, H.P.; Galdino, S.M.L.; Godoy, M.O.; Dantas, C.C.

    1982-01-01

    Alloying elements are responsible for certain characteristics of the steels which enable their utilization for specific purposes. The concentrations of these elements must comply with strict standards, and the determination of these concentrations involve chemical analyses which are as a rule tedious and expensive. It is proposed here a fast and precise analytical process based on the neutron activation analysis. A significant correlation (r = 0.998) between manganese concentration and mean specific count rate of 56 Mn was obtained for activated tool steel samples. Later on, bases for tungsten vanadium determinations were set. (Author) [pt

  18. Determination of V, W and Mn in fast steels by neutron activation analysis of 241Am/Be source

    International Nuclear Information System (INIS)

    Villar, H.P.; Galdino, S.M.L.; Godoy, M.O.; Dantas, C.C.

    1982-01-01

    Alloying elements are responsible for certain characteristics of the steels which enable their utilization for specific purposes. The concentrations of these elements must comply with strict standards, and the determination of these concentrations involve chemical analyses which are as a rule tedious and expensive. It is proposed here a fast and precise analytical process based on the neutron activation analysis. A significant correlation (r = 0.998) between manganese concentration and mean specific count rate of 56 Mn was obtained for activated tool steel sampes. Later on, bases for tungsten vanadium determinations were set. (Author) [pt

  19. Efficacy of humidity retention bags for the reduced adsorption and improved cleaning of tissue proteins including prion-associated amyloid to surgical stainless steel surfaces.

    Science.gov (United States)

    Secker, T J; Pinchin, H E; Hervé, R C; Keevil, C W

    2015-01-01

    Increasing drying time adversely affects attachment of tissue proteins and prion-associated amyloid to surgical stainless steel, and reduces the efficacy of commercial cleaning chemistries. This study tested the efficacy of commercial humidity retention bags to reduce biofouling on surgical stainless steel and to improve subsequent cleaning. Surgical stainless steel surfaces were contaminated with ME7-infected brain homogenates and left to dry for 15 to 1,440 min either in air, in dry polythene bags or within humidity retention bags. Residual contamination pre/post cleaning was analysed using Thioflavin T/SYPRO Ruby dual staining and microscope analysis. An increase in biofouling was observed with increased drying time in air or in sealed dry bags. Humidity retention bags kept both protein and prion-associated amyloid minimal across the drying times both pre- and post-cleaning. Therefore, humidity bags demonstrate a cheap, easy to implement solution to improve surgical instrument reprocessing and to potentially reduce associated hospital acquired infections.

  20. Sensitivity study of reduced models of the activated sludge process ...

    African Journals Online (AJOL)

    The problem of derivation and calculation of sensitivity functions for all parameters of the mass balance reduced model of the COST benchmark activated sludge plant is formulated and solved. The sensitivity functions, equations and augmented sensitivity state space models are derived for the cases of ASM1 and UCT ...

  1. Mechanical Properties and Eco-Efficiency of Steel Fiber Reinforced Alkali-Activated Slag Concrete

    Directory of Open Access Journals (Sweden)

    Sun-Woo Kim

    2015-10-01

    Full Text Available Conventional concrete production that uses ordinary Portland cement (OPC as a binder seems unsustainable due to its high energy consumption, natural resource exhaustion and huge carbon dioxide (CO2 emissions. To transform the conventional process of concrete production to a more sustainable process, the replacement of high energy-consumptive PC with new binders such as fly ash and alkali-activated slag (AAS from available industrial by-products has been recognized as an alternative. This paper investigates the effect of curing conditions and steel fiber inclusion on the compressive and flexural performance of AAS concrete with a specified compressive strength of 40 MPa to evaluate the feasibility of AAS concrete as an alternative to normal concrete for CO2 emission reduction in the concrete industry. Their performances are compared with reference concrete produced using OPC. The eco-efficiency of AAS use for concrete production was also evaluated by binder intensity and CO2 intensity based on the test results and literature data. Test results show that it is possible to produce AAS concrete with compressive and flexural performances comparable to conventional concrete. Wet-curing and steel fiber inclusion improve the mechanical performance of AAS concrete. Also, the utilization of AAS as a sustainable binder can lead to significant CO2 emissions reduction and resources and energy conservation in the concrete industry.

  2. Mechanical Properties and Eco-Efficiency of Steel Fiber Reinforced Alkali-Activated Slag Concrete.

    Science.gov (United States)

    Kim, Sun-Woo; Jang, Seok-Joon; Kang, Dae-Hyun; Ahn, Kyung-Lim; Yun, Hyun-Do

    2015-10-30

    Conventional concrete production that uses ordinary Portland cement (OPC) as a binder seems unsustainable due to its high energy consumption, natural resource exhaustion and huge carbon dioxide (CO₂) emissions. To transform the conventional process of concrete production to a more sustainable process, the replacement of high energy-consumptive PC with new binders such as fly ash and alkali-activated slag (AAS) from available industrial by-products has been recognized as an alternative. This paper investigates the effect of curing conditions and steel fiber inclusion on the compressive and flexural performance of AAS concrete with a specified compressive strength of 40 MPa to evaluate the feasibility of AAS concrete as an alternative to normal concrete for CO₂ emission reduction in the concrete industry. Their performances are compared with reference concrete produced using OPC. The eco-efficiency of AAS use for concrete production was also evaluated by binder intensity and CO₂ intensity based on the test results and literature data. Test results show that it is possible to produce AAS concrete with compressive and flexural performances comparable to conventional concrete. Wet-curing and steel fiber inclusion improve the mechanical performance of AAS concrete. Also, the utilization of AAS as a sustainable binder can lead to significant CO₂ emissions reduction and resources and energy conservation in the concrete industry.

  3. Pitting corrosion resistance of a novel duplex alloy steel in alkali-activated slag extract in the presence of chloride ions

    Science.gov (United States)

    Shi, Jin-jie; Ming, Jing; Liu, Xin

    2017-10-01

    In this study, two types of reinforcing steels (conventional low-carbon steel and a novel duplex alloy steel with Cr and Mo) were exposed to chloride-contaminated extract solutions (ordinary Portland cement (OPC) extract and alkali-activated slag (AAS) extract) to investigate their pitting corrosion resistance. The results confirm that the pitting corrosion resistance of the alloy steel is much higher than that of the low-carbon steel in both extract solutions with various NaCl concentrations. Moreover, for each type of steel, the AAS extract contributes to a higher pitting corrosion resistance compared with the OPC extract in the presence of chloride ions, likely because of the formation of flocculent precipitates on the steel surface.

  4. A reduced energy supply strategy in active vibration control

    Science.gov (United States)

    Ichchou, M. N.; Loukil, T.; Bareille, O.; Chamberland, G.; Qiu, J.

    2011-12-01

    In this paper, a control strategy is presented and numerically tested. This strategy aims to achieve the potential performance of fully active systems with a reduced energy supply. These energy needs are expected to be comparable to the power demands of semi-active systems, while system performance is intended to be comparable to that of a fully active configuration. The underlying strategy is called 'global semi-active control'. This control approach results from an energy investigation based on management of the optimal control process. Energy management encompasses storage and convenient restitution. The proposed strategy monitors a given active law without any external energy supply by considering purely dissipative and energy-demanding phases. Such a control law is offered here along with an analysis of its properties. A suboptimal form, well adapted for practical implementation steps, is also given. Moreover, a number of numerical experiments are proposed in order to validate test findings.

  5. A reduced energy supply strategy in active vibration control

    International Nuclear Information System (INIS)

    Ichchou, M N; Loukil, T; Bareille, O; Chamberland, G; Qiu, J

    2011-01-01

    In this paper, a control strategy is presented and numerically tested. This strategy aims to achieve the potential performance of fully active systems with a reduced energy supply. These energy needs are expected to be comparable to the power demands of semi-active systems, while system performance is intended to be comparable to that of a fully active configuration. The underlying strategy is called 'global semi-active control'. This control approach results from an energy investigation based on management of the optimal control process. Energy management encompasses storage and convenient restitution. The proposed strategy monitors a given active law without any external energy supply by considering purely dissipative and energy-demanding phases. Such a control law is offered here along with an analysis of its properties. A suboptimal form, well adapted for practical implementation steps, is also given. Moreover, a number of numerical experiments are proposed in order to validate test findings

  6. Short communication: Evaluation of a sol-gel-based stainless steel surface modification to reduce fouling and biofilm formation during pasteurization of milk.

    Science.gov (United States)

    Liu, Dylan Zhe; Jindal, Shivali; Amamcharla, Jayendra; Anand, Sanjeev; Metzger, Lloyd

    2017-04-01

    Milk fouling and biofilms are common problems in the dairy industry across many types of processing equipment. One way to reduce milk fouling and biofilms is to modify the characteristics of milk contact surfaces. This study examines the viability of using Thermolon (Porcelain Industries Inc., Dickson, TN), a sol-gel-based surface modification of stainless steel, during thermal processing of milk. We used stainless steel 316L (control) and sol-gel-modified coupons in this study to evaluate fouling behavior and bacterial adhesion. The surface roughness as measured by an optical profiler indicated that the control coupons had a slightly smoother finish. Contact angle measurements showed that the modified surface led to a higher water contact angle, suggesting a more hydrophobic surface. The modified surface also had a lower surface energy (32.4 ± 1.4 mN/m) than the control surface (41.36 ± 2.7 mN/m). We evaluated the susceptibility of control and modified stainless steel coupons to fouling in a benchtop plate heat exchanger. We observed a significant reduction in the amount of fouled layer on modified surfaces. We found an average fouling weight of 19.21 mg/cm 2 and 0.37 mg/cm 2 on the control and modified stainless steel coupons, respectively. We also examined the adhesion of Bacillus and biofilm formation, and observed that the modified stainless steel surface offered greater resistance to biofilm formation. Overall, the Thermolon-modified surface showed potential in the thermal processing of milk, offering significantly lower fouling and bacterial attachment than the control surface. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  7. Active learning reduces annotation time for clinical concept extraction.

    Science.gov (United States)

    Kholghi, Mahnoosh; Sitbon, Laurianne; Zuccon, Guido; Nguyen, Anthony

    2017-10-01

    To investigate: (1) the annotation time savings by various active learning query strategies compared to supervised learning and a random sampling baseline, and (2) the benefits of active learning-assisted pre-annotations in accelerating the manual annotation process compared to de novo annotation. There are 73 and 120 discharge summary reports provided by Beth Israel institute in the train and test sets of the concept extraction task in the i2b2/VA 2010 challenge, respectively. The 73 reports were used in user study experiments for manual annotation. First, all sequences within the 73 reports were manually annotated from scratch. Next, active learning models were built to generate pre-annotations for the sequences selected by a query strategy. The annotation/reviewing time per sequence was recorded. The 120 test reports were used to measure the effectiveness of the active learning models. When annotating from scratch, active learning reduced the annotation time up to 35% and 28% compared to a fully supervised approach and a random sampling baseline, respectively. Reviewing active learning-assisted pre-annotations resulted in 20% further reduction of the annotation time when compared to de novo annotation. The number of concepts that require manual annotation is a good indicator of the annotation time for various active learning approaches as demonstrated by high correlation between time rate and concept annotation rate. Active learning has a key role in reducing the time required to manually annotate domain concepts from clinical free text, either when annotating from scratch or reviewing active learning-assisted pre-annotations. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Reducing matrix effect error in EDXRF: Comparative study of using standard and standard less methods for stainless steel samples

    International Nuclear Information System (INIS)

    Meor Yusoff Meor Sulaiman; Masliana Muhammad; Wilfred, P.

    2013-01-01

    Even though EDXRF analysis has major advantages in the analysis of stainless steel samples such as simultaneous determination of the minor elements, analysis can be done without sample preparation and non-destructive analysis, the matrix issue arise from the inter element interaction can make the the final quantitative result to be in accurate. The paper relates a comparative quantitative analysis using standard and standard less methods in the determination of these elements. Standard method was done by plotting regression calibration graphs of the interested elements using BCS certified stainless steel standards. Different calibration plots were developed based on the available certified standards and these stainless steel grades include low alloy steel, austenitic, ferritic and high speed. The standard less method on the other hand uses a mathematical modelling with matrix effect correction derived from Lucas-Tooth and Price model. Further improvement on the accuracy of the standard less method was done by inclusion of pure elements into the development of the model. Discrepancy tests were then carried out for these quantitative methods on different certified samples and the results show that the high speed method is most reliable for determining of Ni and the standard less method for Mn. (Author)

  9. Active flux tungsten inert gas welding of austenitic stainless steel AISI 304

    Directory of Open Access Journals (Sweden)

    D. Klobčar

    2016-10-01

    Full Text Available The paper presents the effects of flux assisted tungsten inert gas (A-TIG welding of 4 (10 mm thick austenitic stainless steel EN X5CrNi1810 (AISI 304 in the butt joint. The sample dimensions were 300 ´ 50 mm, and commercially available active flux QuickTIG was used for testing. In the planned study the influence of welding position and weld groove shape was analysed based on the penetration depth. A comparison of microstructure formation, grain size and ferrit number between TIG welding and A-TIG welding was done. The A-TIG welds were subjected to bending test. A comparative study of TIG and A-TIG welding shows that A-TIG welding increases the weld penetration depth.

  10. Creep rupture strength of activated-TIG welded 316L(N) stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Sakthivel, T., E-mail: tsakthivel@igcar.gov.in [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Vasudevan, M.; Laha, K.; Parameswaran, P.; Chandravathi, K.S.; Mathew, M.D.; Bhaduri, A.K. [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India)

    2011-06-01

    316L(N) stainless steel plates were joined using activated-tungsten inert gas (A-TIG) welding and conventional TIG welding process. Creep rupture behavior of 316L(N) base metal, and weld joints made by A-TIG and conventional TIG welding process were investigated at 923 K over a stress range of 160-280 MPa. Creep test results showed that the enhancement in creep rupture strength of weld joint fabricated by A-TIG welding process over conventional TIG welding process. Both the weld joints fractured in the weld metal. Microstructural observation showed lower {delta}-ferrite content, alignment of columnar grain with {delta}-ferrite along applied stress direction and less strength disparity between columnar and equiaxed grains of weld metal in A-TIG joint than in MP-TIG joint. These had been attributed to initiate less creep cavitation in weld metal of A-TIG joint leading to improvement in creep rupture strength.

  11. Creep rupture strength of activated-TIG welded 316L(N) stainless steel

    International Nuclear Information System (INIS)

    Sakthivel, T.; Vasudevan, M.; Laha, K.; Parameswaran, P.; Chandravathi, K.S.; Mathew, M.D.; Bhaduri, A.K.

    2011-01-01

    316L(N) stainless steel plates were joined using activated-tungsten inert gas (A-TIG) welding and conventional TIG welding process. Creep rupture behavior of 316L(N) base metal, and weld joints made by A-TIG and conventional TIG welding process were investigated at 923 K over a stress range of 160-280 MPa. Creep test results showed that the enhancement in creep rupture strength of weld joint fabricated by A-TIG welding process over conventional TIG welding process. Both the weld joints fractured in the weld metal. Microstructural observation showed lower δ-ferrite content, alignment of columnar grain with δ-ferrite along applied stress direction and less strength disparity between columnar and equiaxed grains of weld metal in A-TIG joint than in MP-TIG joint. These had been attributed to initiate less creep cavitation in weld metal of A-TIG joint leading to improvement in creep rupture strength.

  12. Creep rupture strength of activated-TIG welded 316L(N) stainless steel

    Science.gov (United States)

    Sakthivel, T.; Vasudevan, M.; Laha, K.; Parameswaran, P.; Chandravathi, K. S.; Mathew, M. D.; Bhaduri, A. K.

    2011-06-01

    316L(N) stainless steel plates were joined using activated-tungsten inert gas (A-TIG) welding and conventional TIG welding process. Creep rupture behavior of 316L(N) base metal, and weld joints made by A-TIG and conventional TIG welding process were investigated at 923 K over a stress range of 160-280 MPa. Creep test results showed that the enhancement in creep rupture strength of weld joint fabricated by A-TIG welding process over conventional TIG welding process. Both the weld joints fractured in the weld metal. Microstructural observation showed lower δ-ferrite content, alignment of columnar grain with δ-ferrite along applied stress direction and less strength disparity between columnar and equiaxed grains of weld metal in A-TIG joint than in MP-TIG joint. These had been attributed to initiate less creep cavitation in weld metal of A-TIG joint leading to improvement in creep rupture strength.

  13. Basic characterization of low-activated F82H-mod steel as compared to OPTIFER

    International Nuclear Information System (INIS)

    Schirra, M.; Adelhelm, C.; Graf, P.; Heger, S.; Kempe, H.; Zimmermann, H.

    1997-12-01

    Low-activated F82H-model steel plate material was made available to the European laboratories by the Japanese side. Basic characterization work is being performed by FZK/IMF. In the present report, the results obtained shall be compared with the European OPTIFER types. The chemical composition and the state as delivered are controlled. In addition, transformation, hardness and tempering behaviors shall be described. Tensile strength and impact bending strength were determined in the ranges of RT to 700 C and -80 C to +80 C, respectively. Particular attention is paid to the creep strength behavior. The current tests cover the range of up to 15000 h at temperatures ranging from 450 to 700 C. It can be noticed that the results measured for some parameters are subject to considerable scattering. As compared to previous tests, the experimental scope therefore had to be increased significantly. (orig.) [de

  14. Effects of two main metabolites of sulphate-reducing bacteria on the corrosion of Q235 steels in 3.5 wt.% NaCl media

    International Nuclear Information System (INIS)

    Bao, Qi; Zhang, Dun; Lv, Dandan; Wang, Peng

    2012-01-01

    Highlights: ► Extracellular polymeric substances have been isolated from a batch culture of sulphate-reducing bacteria successfully. ► Sulphide and extracellular polymeric substances have triggered distinct electrochemical characteristics. ► ATR-IR analysis has confirmed the Fe 2+ -complexing capability of extracellular polymeric substances. ► In situ AFM results show extracellular polymeric substances can form a densely packed film on Q235 steels. ► The adsorbed extracellular polymeric substances film has protected the Q235 steels to a certain degree. - Abstract: The electrochemical corrosion behaviour of Q235 steels in 3.5 wt.% NaCl solutions with sulphide and extracellular polymeric substances (EPS), the two main metabolites of sulphate-reducing bacteria, was separately investigated through potentiodynamic polarisation and electrochemical impedance spectroscopy. Either sulphide or EPS increased the anodic current density by nearly one order of magnitude and negatively shifted the corrosion potential. The effects of EPS at the initial stage of corrosion may be ascribed to the Fe 2+ -complexing capability and the quickly adsorbed film. Moreover, the feeble protective effect of EPS after 16 d of immersion was observed through scanning electron microscopy.

  15. Reduced activation structural materials for fusion power plants - The European Union program

    International Nuclear Information System (INIS)

    Schaaf, B. van der; Le Marois, G.; Moeslang, A.; Victoria, M.

    2003-01-01

    The competition of fusion power plants with the renewable energy sources in the second half of the 21st century requires structural materials operating at high temperatures, and sufficient radiation resistance to ensure high plant efficiency and availability. The reduced activation materials development in the EU counts several steps regarding the radiation damage resistance: 75 dpa for DEMO and 150 dpa and beyond for power plants. The maximum operating temperature development line ranges from the present day from the present day feasible 600 K up to 1300- K in advanced power plants. The reduced activation steel, RAS, forms the reference for the development efforts. EUROFER has been manufactured in the EU on industrial scale with specified purity and mechanical properties up to 825 K. The oxide dispersion strengthened , ODS, variety of RAS should reach the 925 K operation limit. The EU has selected silicon carbide ceramic composite as the primary high temperature, 1300 K, goal. On a small scale the potential of tungsten alloys for higher temperatures is investigated. The present test environments for radiation resistance are insufficient to provide data for DEMO. Hence the support of the EU for the International Fusion Materials Irradiation facility. The computational modelling is expected to guide the materials development and the design of near plasma components. The EU co-operates closely with Japan, the RF and US in IEA and IAEA co-ordinated agreements, which are highly beneficial for the fusion structural materials development. (author)

  16. Studies on the effects of sulphate-reducing bacteria on mild carbon-steel relevant to radioactive waste disposal in the UK

    International Nuclear Information System (INIS)

    Philp, J.C.; Christofi, N.; Taylor, K.J.; West, J.M.

    1987-01-01

    Sulphate-reducing bacteria (SRB) have been used to determine their maximum effect on mild carbon-steel (BS4360 grade 43A) of relevance to waste disposal. Batch (static) and continuous culture studies were carried out and corrosion effects monitored by measuring weight loss and pitting. Results show that corrosion increases linearly with increased ferrous iron concentrations. Maximum corrosion was obtained in continuous culture where the organisms were maintained in the exponential phase of growth. Corrosion by SRB has been monitored in model systems mimicking low groundwater flow, deep rock formations in which steel coupons were subjected to a synthetic granitic water/bentonite environment with or without microorganisms. At termination of the experiment corrosion in the presence of SRB was almost three times higher than in their absence. (author)

  17. The roles of the micro-organisms and chromium content in the corrosion of iron-chromium steels in the presence of sulfate-reducing bacteria

    International Nuclear Information System (INIS)

    Ferrante, V.

    1991-09-01

    If it is widely accepted that the presence of sulfate-reducing bacteria can increase the aqueous corrosion of steels, the induced mechanisms are still not definitively established. The aim of this work is to specify the roles, for corrosion, of the presence of bacteria (D. Vulgaris) in one part and of chemical parameters as the composition of the material and the accumulation of sulfides in another part. The use of experimental techniques coming from microbiology, electrochemistry or chemical analysis has revealed the interdependence which exists between the bacteria and the material, and the importance of the steel composition towards the adhesion of microorganisms and the generalized corrosion. The bacteria and the dissolved sulfides do not seem to influence remarkably the generalized corrosion. Nevertheless, the alterations of the surface state they induce could be the cause of localized corrosion phenomena. (O.M.)

  18. The roles of the micro-organisms and chromium content in the corrosion of iron-chromium steels in the presence of sulfate-reducing bacteria

    International Nuclear Information System (INIS)

    Ferrante, V.

    1991-12-01

    Although the ability of sulfate-reducing bacteria to enhance the corrosion of steel is now widely accepted, the actual processes involved in such phenomena are still discussed. This work is dedicated to the study of the exact roles played in corrosion processes firstly, by the presence of D. vulgaris cells and, secondly, by chemical factors such as the material composition and the accumulation of sulfide ions in the solution. The use of microbiological, electrochemical and analytical experimental techniques lead to results that show the interdependence of the bacteria and the material as well as the importance of the steel composition in the adhesion of the micro-organisms and the general corrosion rates. The bacteria cells and dissolved sulfide ions do not markedly influence the general corrosion rates. They however induce surface state modifications that can result in localized corrosion phenomena

  19. Research for Actively Reducing Infrared Radiation by Thermoelectric Refrigerator

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hoon; Kim, Kyomin; Kim, Woochul [Yonsei Univ., Seoul (Korea, Republic of)

    2017-03-15

    We introduced a technology for reducing infrared radiation through the active cooling of hot surfaces by using a thermoelectric refrigerator. Certain surfaces were heated by aerodynamic heating, and the heat generation processes are proposed here. We calculated the temperatures and radiations from surfaces, while using thermoelectric refrigerators to cool the surfaces. The results showed that the contrast between the radiations of certain surfaces and the ambient environments can be removed using thermoelectric refrigerators.

  20. Metabolism of sulfate-reducing bacteria and corrosion behavior of carbon steel in the continuous culturing medium; Renzoku baiyo baichichu ni okeru ryusan`en kangen no taisha to tansoko no fushoku kyodo

    Energy Technology Data Exchange (ETDEWEB)

    Baba, F.; Suzuki, T. [Ajinomoto Co. Inc., Tokyo (Japan); Seo, M. [Hokkaido University, Sapporo (Japan)

    1997-08-25

    Investigations were made on metabolism of sulfate-reducing bacteria and corrosion behavior of carbon steel in the continuous culturing medium. Sulfate-reducing bacteria were cultured for 50 days by supplying the culturing medium prepared to a prescribed chemical composition (containing Fe {sup 2+} at 0.01 mol/kg) at a rate of 10 cm {sup 3}/h, and drawing them out at the same rate. Test carbon steel pieces were immersed into this culturing medium. As a result, the following matters were clarified: the number of bacteria is maintained at more than 10 {sup 10}/cm{sup 3} after several days since inauguration of the immersion, with the bacteria stably producing H2S and FeS until the culturing is finished; comma-shaped bacteria which move actively and rod-shaped bacteria which do not move very actively exist in the culturing medium; a black film has been produced on surface of the test pieces throughout the culturing period, and satin-like corrosion was found underneath the surface; and weight increase of this film and weight decrease of the lower layer progress as the time lapses (the weight decrease of the lower layer has reached 40 mg/cm{sup 2} in 50 days). 28 refs., 8 figs., 1 tab.

  1. Implementation Intentions Reduce Implicit Stereotype Activation and Application.

    Science.gov (United States)

    Rees, Heather Rose; Rivers, Andrew Michael; Sherman, Jeffrey W

    2018-05-01

    Research has found that implementation intentions, if-then action plans (e.g., "if I see a Black face, I will think safe"), reduce stereotyping on implicit measures. However, it is unknown by what process(es) implementation intentions reduce implicit stereotyping. The present research examines the effects of implementation intentions on stereotype activation (e.g., extent to which stereotypic information is accessible) and stereotype application (e.g., extent to which accessible stereotypes are applied in judgment). In addition, we assessed the efficiency of implementation intentions by manipulating cognitive resources (e.g., digit-span, restricted response window) while participants made judgments on an implicit stereotyping measure. Across four studies, implementation intentions reduced implicit stereotyping. This decrease in stereotyping was associated with reductions in both stereotype activation and application. In addition, these effects of implementation intentions were highly efficient and associated with reduced stereotyping even for groups for which people may have little practice inhibiting stereotypes (e.g., gender).

  2. Activation calculation of steel of the control rods of TRIGA Mark III reactor

    International Nuclear Information System (INIS)

    Garcia M, T.; Cruz G, H. S.; Ruiz C, M. A.; Angeles C, A.

    2014-10-01

    In the pool of TRIGA Mark III reactor of the Instituto Nacional de Investigaciones Nucleares (ININ), there are control rods that were removed from the core, and which are currently on shelves of decay. These rods were part of the reactor core when only had fuel standard (from 1968-1989). To conduct a proper activation analysis of the rods, is very important to have well-characterized the materials which are built, elemental composition of the same ones, the atomic densities and weight fractions of the elements that constitute them. To determine the neutron activation of the control rods MCNP5 code was used, this code allows us to have well characterized the radionuclides inventory that were formed during irradiation of the control rods. This work is limited to determining the activation of the steel that is part of the shielding of the control rods, the nuclear fuel that is in the fuel follower does not include. The calculation model of the code will be validated with experimental measurements and calculating the activity of fission products of the fuel follower which will take place at the end of 2014. (Author)

  3. Some observations on the carburization of type 316 stainless steel foil in a low carbon activity sodium environment

    International Nuclear Information System (INIS)

    Thorley, A.W.; Jeffcoat, P.J.

    1982-01-01

    Work currently being undertaken to establish the equilibrium composition of carbides which form in stainless steel foils during their exposure to low carbon activity sodium environment is described. The time it takes the carbon to reach equilibrium during exposure to sodium of different carbon activity is discussed. The lowest carbon activity measureable in test loops where the sodium is just above carburizing to stainless steel is reported. Analytical techniques are used to determine the composition of the carbide and the austenite matrix and hence estimate the carbon activity of the equilibrium structure. This provides a comparison with carbon activity values determined by alternative methods such as the Harwell Carbon Meter and nickel tab techniques

  4. Reduced auditory efferent activity in childhood selective mutism.

    Science.gov (United States)

    Bar-Haim, Yair; Henkin, Yael; Ari-Even-Roth, Daphne; Tetin-Schneider, Simona; Hildesheimer, Minka; Muchnik, Chava

    2004-06-01

    Selective mutism is a psychiatric disorder of childhood characterized by consistent inability to speak in specific situations despite the ability to speak normally in others. The objective of this study was to test whether reduced auditory efferent activity, which may have direct bearings on speaking behavior, is compromised in selectively mute children. Participants were 16 children with selective mutism and 16 normally developing control children matched for age and gender. All children were tested for pure-tone audiometry, speech reception thresholds, speech discrimination, middle-ear acoustic reflex thresholds and decay function, transient evoked otoacoustic emission, suppression of transient evoked otoacoustic emission, and auditory brainstem response. Compared with control children, selectively mute children displayed specific deficiencies in auditory efferent activity. These aberrations in efferent activity appear along with normal pure-tone and speech audiometry and normal brainstem transmission as indicated by auditory brainstem response latencies. The diminished auditory efferent activity detected in some children with SM may result in desensitization of their auditory pathways by self-vocalization and in reduced control of masking and distortion of incoming speech sounds. These children may gradually learn to restrict vocalization to the minimal amount possible in contexts that require complex auditory processing.

  5. Blockade of mast cell activation reduces cutaneous scar formation.

    Directory of Open Access Journals (Sweden)

    Lin Chen

    Full Text Available Damage to the skin initiates a cascade of well-orchestrated events that ultimately leads to repair of the wound. The inflammatory response is key to wound healing both through preventing infection and stimulating proliferation and remodeling of the skin. Mast cells within the tissue are one of the first immune cells to respond to trauma, and upon activation they release pro-inflammatory molecules to initiate recruitment of leukocytes and promote a vascular response in the tissue. Additionally, mast cells stimulate collagen synthesis by dermal fibroblasts, suggesting they may also influence scar formation. To examine the contribution of mast cells in tissue repair, we determined the effects the mast cell inhibitor, disodium cromoglycate (DSCG, on several parameters of dermal repair including, inflammation, re-epithelialization, collagen fiber organization, collagen ultrastructure, scar width and wound breaking strength. Mice treated with DSCG had significantly reduced levels of the inflammatory cytokines IL-1α, IL-1β, and CXCL1. Although DSCG treatment reduced the production of inflammatory mediators, the rate of re-epithelialization was not affected. Compared to control, inhibition of mast cell activity caused a significant decrease in scar width along with accelerated collagen re-organization. Despite the reduced scar width, DSCG treatment did not affect the breaking strength of the healed tissue. Tryptase β1 exclusively produced by mast cells was found to increase significantly in the course of wound healing. However, DSCG treatment did not change its level in the wounds. These results indicate that blockade of mast cell activation reduces scar formation and inflammation without further weakening the healed wound.

  6. Large roads reduce bat activity across multiple species.

    Science.gov (United States)

    Kitzes, Justin; Merenlender, Adina

    2014-01-01

    Although the negative impacts of roads on many terrestrial vertebrate and bird populations are well documented, there have been few studies of the road ecology of bats. To examine the effects of large roads on bat populations, we used acoustic recorders to survey bat activity along ten 300 m transects bordering three large highways in northern California, applying a newly developed statistical classifier to identify recorded calls to the species level. Nightly counts of bat passes were analyzed with generalized linear mixed models to determine the relationship between bat activity and distance from a road. Total bat activity recorded at points adjacent to roads was found to be approximately one-half the level observed at 300 m. Statistically significant road effects were also found for the Brazilian free-tailed bat (Tadarida brasiliensis), big brown bat (Eptesicus fuscus), hoary bat (Lasiurus cinereus), and silver-haired bat (Lasionycteris noctivagans). The road effect was found to be temperature dependent, with hot days both increasing total activity at night and reducing the difference between activity levels near and far from roads. These results suggest that the environmental impacts of road construction may include degradation of bat habitat and that mitigation activities for this habitat loss may be necessary to protect bat populations.

  7. Inhibiting mild steel corrosion from sulfate-reducing bacteria using antimicrobial-producing biofilms in Three-Mile-Island process water.

    Science.gov (United States)

    Zuo, R; Ornek, D; Syrett, B C; Green, R M; Hsu, C-H; Mansfeld, F B; Wood, T K

    2004-04-01

    Biofilms were used to produce gramicidin S (a cyclic decapeptide) to inhibit corrosion-causing, sulfate-reducing bacteria (SRB). In laboratory studies these biofilms protected mild steel 1010 continuously from corrosion in the aggressive, cooling service water of the AmerGen Three-Mile-Island (TMI) nuclear plant, which was augmented with reference SRB. The growth of both reference SRB (Gram-positive Desulfosporosinus orientis and Gram-negative Desulfovibrio vulgaris) was shown to be inhibited by supernatants of the gramicidin-S-producing bacteria as well as by purified gramicidin S. Electrochemical impedance spectroscopy and mass loss measurements showed that the protective biofilms decreased the corrosion rate of mild steel by 2- to 10-fold when challenged with the natural SRB of the TMI process water supplemented with D. orientis or D. vulgaris. The relative corrosion inhibition efficiency was 50-90% in continuous reactors, compared to a biofilm control which did not produce the antimicrobial gramicidin S. Scanning electron microscope and reactor images also revealed that SRB attack was thwarted by protective biofilms that secrete gramicidin S. A consortium of beneficial bacteria (GGPST consortium, producing gramicidin S and other antimicrobials) also protected the mild steel.

  8. Experimental study on the formation and growth of electroless nickel-boron coatings from borohydride-reduced bath on mild steel

    Energy Technology Data Exchange (ETDEWEB)

    Vitry, Veronique, E-mail: veronique.vitry@umons.ac.be [Service de Metallurgie, Universite de Mons, Rue de l' Epargne 56, 7000 Mons (Belgium); Sens, Adeline [Service de Metallurgie, Universite de Mons, Rue de l' Epargne 56, 7000 Mons (Belgium); Kanta, Abdoul-Fatah [Service de Sciences des Materiaux, Universite de Mons, Rue de l' Epargne 56, 7000 Mons (Belgium); Delaunois, Fabienne [Service de Metallurgie, Universite de Mons, Rue de l' Epargne 56, 7000 Mons (Belgium)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer Initiation mechanism of electroless Ni-B on St-37 steel has been identified. Black-Right-Pointing-Pointer Different phases of the plating process were observed and identified. Black-Right-Pointing-Pointer Influence of chemical heterogeneity on coating morphology was revealed. Black-Right-Pointing-Pointer Batch replenishment of the plating bath induces new germination phase. - Abstract: Quality and homogeneity of electroless nickel-boron coatings are very important for applications in corrosion and electronics and are completely dependent on the formation of the deposit. The growth and formation process of electroless nickel-boron was investigated by immersing mild steel (St-37) samples in an un-replenished bath for various periods of time (from 5 s to 1 h). The coatings obtained at the different stages of the process were then characterized: thickness was measured by SEM, morphology was observed, weight gain was recorded and top composition of the coatings was obtained from XPS. Three main phases were identified during the coating formation and links between plating time, instantaneous deposition rate, chemistry of last formed deposit and morphology were established. The mechanism for initial deposition on steel substrate for borohydride-reduced electroless nickel bath was also observed. Those results were confronted with chemistry evolution in the unreplenished plating bath during the process. This allowed getting insight about phenomena occurring in the plating bath and their influence on coating formation.

  9. Electrochemical study of bio-corrosion mechanisms at the carbon steel interface in presence of iron-reducing and hydrogenotrophic bacteria in the nuclear waste disposal context

    International Nuclear Information System (INIS)

    Leite-de-Souza-Moreira, Rebeca

    2013-01-01

    The safety of deep geological repository for nuclear waste is a very important and topical matter especially for the nuclear industry. Such as nuclear fuel the high level waste have to be stored for time frames of millions of years in metallic containers. Typically these containers should be placed in deep geological clay formations 500 metres underground. Corrosion processes, will take place after the re-saturation of the geological medium and under the prevalent anoxic conditions may lead to the generation of hydrogen. This gas accumulates in clay environment through the years and eventually becomes hazardous for steel containers. In the particular environment of geological repositories does not provide much biodegradable substances. This is the reason that hydrogen represents a new suitable energy source for hydrogenotrophic bacteria. Thereby formed bacterial bio-films on the containers may contribute to a process of fast decay of the steel, the so called bio-corrosion. The aim of this study is to characterize the electrochemical interfaces in order to obtain the mechanisms of bio-corrosion of carbon steels in presence of iron reducing and hydrogenotrophic bacterium Shewanella oneideinsis. The products of corrosion processes, namely hydrogen and iron (III) oxides are used as electron donor and acceptor, respectively. The amount of hydrogen consumed by Shewanella could be estimated with 10"-"4 mol s"-"1 using Scanning Electrochemical Microscopy (SECM) techniques. The influence of the local hydrogen generation was evaluated via chrono-amperometry. When hydrogen was locally generated above a carbon steel substrate an accelerated corrosion process can be observed. Eventually, using Local Electrochemical Impedance Spectroscopy (LEIS) techniques, the mechanism of the generalised corrosion process was demonstrated. (author)

  10. EIS Response of MIC on Carbon Steel

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Maahn, Ernst

    1998-01-01

    Abstract Microbially influenced corrosion of carbon steel under sulphate reducing (sulphide-producing) bacterial activity (SRB) results in the formation of both ferrous sulphides as well as biofilm on the metal surface. The electrochemical characteristics of the ferrous sulphide/steel interface...... as compared to the biofilm/ferrous sulphide/steel interface has been studied with EIS, DC polarisations (Tafel, LPR) and a potentiostatic step technique. The electrochemical response is related to a threshold sulphide concentration above which very characteristic changes such as indications of finite...

  11. Reduced superoxide dismutase activity in xeroderma pigmentosum fibroblasts

    International Nuclear Information System (INIS)

    Nishigori, C.; Miyachi, Y.; Imamura, S.; Takebe, H.

    1989-01-01

    This study was performed in order to assess the possible protective effect of superoxide dismutase (SOD) on ultraviolet (UV) damage in xeroderma pigmentosum (XP) fibroblasts. SOD activity in fibroblasts originating from seven xeroderma pigmentosum (XP) patients was significantly lower than that in normal cells (p less than 0.005). Average SOD activity in XP cells belonging to complementation group A was 3.68 +/- 0.54 (n = 7) and that in normal human cells was 5.79 +/- 1.59 (n = 6). Addition of SOD before and during UV irradiation (UVB and UVC) to the cells caused no change in the amount of unscheduled DNA synthesis and UV survival. A possible involvement of reduced SOD in XP and a possible protective effect by SOD on UV damage is discussed

  12. Interdiffusion behaviors of iron aluminide coatings on China low activation martensitic steel

    Science.gov (United States)

    Zhu, X. X.; Yang, H. G.; Yuan, X. M.; Zhao, W. W.; Zhan, Q.

    2014-12-01

    The iron aluminide coating on China Low Activation Martensitic (CLAM) steel was prepared by pack cementation and subsequent heat treatment. A surface Fe2Al5 layer was formed on CLAM substrate by pack cementation process with Fe2Al5 donor powder and NH4Cl activator. Diffusion heat treatment was performed in order to allow the phase transformation from Fe2Al5 to a phase with lower aluminum content. Morphology and composition of the coatings were characterized by optical microscopy (OM), scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS), glow discharge optical emission spectroscopy (GDOES) and X-ray diffraction (XRD). There is a need to study the interdiffusion behaviors in these Al containing systems, as a basis for controlling the formation and subsequent degradation of the coating. In this paper, a predictive model was developed to describe the phase transformation of Fe2Al5 as a function of processing parameters. The Wagner's equation was used to calculate the interdiffusion coefficients based on the analysis of the Al concentration profiles. The results showed that the interdiffusion coefficients in the FeAl and α-Fe(Al) phase strongly depends on Al content and showed a maximum at about 28 at.% Al.

  13. Interdiffusion behaviors of iron aluminide coatings on China low activation martensitic steel

    International Nuclear Information System (INIS)

    Zhu, X.X.; Yang, H.G.; Yuan, X.M.; Zhao, W.W.; Zhan, Q.

    2014-01-01

    The iron aluminide coating on China Low Activation Martensitic (CLAM) steel was prepared by pack cementation and subsequent heat treatment. A surface Fe 2 Al 5 layer was formed on CLAM substrate by pack cementation process with Fe 2 Al 5 donor powder and NH 4 Cl activator. Diffusion heat treatment was performed in order to allow the phase transformation from Fe 2 Al 5 to a phase with lower aluminum content. Morphology and composition of the coatings were characterized by optical microscopy (OM), scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS), glow discharge optical emission spectroscopy (GDOES) and X-ray diffraction (XRD). There is a need to study the interdiffusion behaviors in these Al containing systems, as a basis for controlling the formation and subsequent degradation of the coating. In this paper, a predictive model was developed to describe the phase transformation of Fe 2 Al 5 as a function of processing parameters. The Wagner’s equation was used to calculate the interdiffusion coefficients based on the analysis of the Al concentration profiles. The results showed that the interdiffusion coefficients in the FeAl and α-Fe(Al) phase strongly depends on Al content and showed a maximum at about 28 at.% Al

  14. Adoption of an activity based costing model in an Indian steel plant

    Directory of Open Access Journals (Sweden)

    Rishi Dwivedi

    2016-10-01

    Full Text Available In the age of relentless global competition, constantly improving technology and better information systems, managers are often compelled to devise new strategies to maintain sustained competitive advantage while adopting new business management approaches. So, in this paper, an activity based costing (ABC model is proposed for a raw material handling section of an Indian steel plant. The results obtained from ABC model application in the said department facilitates quantification of the unit cost of each process, analysis of various activities in order to identify inefficiency, setting-up of better budget allocation, initiation of cost minimization procedure and establishment of an efficient resource requirement plan. Moreover, the cost information derived from ABC model is compared with that extracted from the traditional costing system to demonstrate that ABC model can significantly minimize the product cost distortion resulting from unsystematic allocation of overhead costs. This paper also discusses the practical implication of the implemented ABC model with respect to its critical role in effective resource control, improved strategic and operational decision making, and aid in continuous improvement through internal cost minimization in the department.

  15. Plating on stainless steel alloys

    International Nuclear Information System (INIS)

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

    1981-01-01

    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

  16. A Study to Increase Weld Penetration in P91 Steel During TIG Welding by using Activating Fluxes

    Science.gov (United States)

    Singh, Akhilesh Kumar; Kumar, Mayank; Dey, Vidyut; Naresh Rai, Ram

    2017-08-01

    Activated Flux TIG (ATIG) welding is a unique joining process, invented at Paton Institute of electric welding in 1960. ATIG welding process is also known as flux zoned TIG (FZTIG). In this process, a thin layer of activating flux is applied along the line on the surface of the material where the welding is to be carries out. The ATIG process aids to increase the weld penetration in thick materials. Activating fluxes used in the literature show the use of oxides like TiO2, SiO2, Cr2O3, ZnO, CaO, Fe2O3, and MnO2 during welding of steels. In the present study, ATIG was carried out on P-91 steel. Though, Tungsten Inert Gas welding gives excellent quality welds, but the penetration obtained in such welding is still demanding. P91 steel which is ferritic steel is used in high temperature applications. As this steel is, generally, used in thick sections, fabrication of such structures with TIG welding is limited, due to its low depth of penetration. To increase the depth of penetration in P91while welding with ATIG, the role of various oxides were investigated. Apart from the oxides mentioned above, in the present study the role of B2O3, V2O5 and MgO, during ATIG welding of P91 was investigated. It was seen that, compared to TIG welding, there was phenomenal increase in weld penetration during ATIG welding. Amongst all the oxides used in this study, maximum penetration was achieved in case of B2O3. The measurements of weld penetration, bead width and heat affected zone of the weldings were carried out using an image analysis technique.

  17. Meditation leads to reduced default mode network activity beyond an active task.

    Science.gov (United States)

    Garrison, Kathleen A; Zeffiro, Thomas A; Scheinost, Dustin; Constable, R Todd; Brewer, Judson A

    2015-09-01

    Meditation has been associated with relatively reduced activity in the default mode network, a brain network implicated in self-related thinking and mind wandering. However, previous imaging studies have typically compared meditation to rest, despite other studies having reported differences in brain activation patterns between meditators and controls at rest. Moreover, rest is associated with a range of brain activation patterns across individuals that has only recently begun to be better characterized. Therefore, in this study we compared meditation to another active cognitive task, both to replicate the findings that meditation is associated with relatively reduced default mode network activity and to extend these findings by testing whether default mode activity was reduced during meditation, beyond the typical reductions observed during effortful tasks. In addition, prior studies had used small groups, whereas in the present study we tested these hypotheses in a larger group. The results indicated that meditation is associated with reduced activations in the default mode network, relative to an active task, for meditators as compared to controls. Regions of the default mode network showing a Group × Task interaction included the posterior cingulate/precuneus and anterior cingulate cortex. These findings replicate and extend prior work indicating that the suppression of default mode processing may represent a central neural process in long-term meditation, and they suggest that meditation leads to relatively reduced default mode processing beyond that observed during another active cognitive task.

  18. Reducing braking distance by control of semi-active suspension

    Energy Technology Data Exchange (ETDEWEB)

    Niemz, T.

    2007-07-01

    This thesis presents a control algorithm for semi-active suspensions to reduce the braking distance of passenger cars. Active shock absorbers are controlled and used to influence the vertical dynamics during ABS-controlled full braking. The core of the approach presented in this paper is based on a switching control logic. The control algorithm is implemented in a compact class passenger car. Test drives on a real road, using a braking machine for reproducibility reasons, have been executed. It could be shown that it is possible to reduce the braking distance by affecting on the vertical dynamics of a passenger car in general. This is the first experimental result of this kind published ever. The amount of reduction depends on the height profile of the testing track chosen and on the initial velocity. On a road with an unevenness comparable to the one on a typical German Autobahn an average reduction of 1-2%, compared to the best passive damping, was achieved. (orig.)

  19. Active fans and grizzly bears: Reducing risks for wilderness campers

    Science.gov (United States)

    Sakals, M. E.; Wilford, D. J.; Wellwood, D. W.; MacDougall, S. A.

    2010-03-01

    Active geomorphic fans experience debris flows, debris floods and/or floods (hydrogeomorphic processes) that can be hazards to humans. Grizzly bears ( Ursus arctos) can also be a hazard to humans. This paper presents the results of a cross-disciplinary study that analyzed both hydrogeomorphic and grizzly bear hazards to wilderness campers on geomorphic fans along a popular hiking trail in Kluane National Park and Reserve in southwestern Yukon Territory, Canada. Based on the results, a method is proposed to reduce the risks to campers associated with camping on fans. The method includes both landscape and site scales and is based on easily understood and readily available information regarding weather, vegetation, stream bank conditions, and bear ecology and behaviour. Educating wilderness campers and providing a method of decision-making to reduce risk supports Parks Canada's public safety program; a program based on the principle of user self-sufficiency. Reducing grizzly bear-human conflicts complements the efforts of Parks Canada to ensure a healthy grizzly bear population.

  20. Reducing vibration transfer from power plants by active methods

    Science.gov (United States)

    Kiryukhin, A. V.; Milman, O. O.; Ptakhin, A. V.

    2017-12-01

    The possibility of applying the methods of active damping of vibration and pressure pulsations for reducing their transfer from power plants into the environment, the seating, and the industrial premises are considered. The results of experimental works implemented by the authors on the active broadband damping of vibration and dynamic forces after shock-absorption up to 15 dB in the frequency band up to 150 Hz, of water pressure pulsations in the pipeline up to 20 dB in the frequency band up to 600 Hz, and of spatial low-frequency air noise indoors of a diesel generator at discrete frequency up to 20 dB are presented. It is shown that a reduction of vibration transfer through a vibration-isolating junction (expansion joints) of pipelines with liquid is the most complicated and has hardly been developed so far. This problem is essential for vibration isolation of power equipment from the seating and the environment through pipelines with water and steam in the power and transport engineering, shipbuilding, and in oil and gas pipelines in pumping stations. For improving efficiency, reducing the energy consumption, and decreasing the overall dimensions of equipment, it is advisable to combine the work of an active system with passive damping means, the use of which is not always sufficient. The executive component of the systems of active damping should be placed behind the vibration isolators (expansion joints). It is shown that the existence of working medium and connection of vibration with pressure pulsations in existing designs of pipeline expansion joints lead to growth of vibration stiffness of the expansion joint with the environment by two and more orders as compared with the static stiffness and makes difficulties for using the active methods. For active damping of vibration transfer through expansion joints of pipelines with a liquid, it is necessary to develop expansion joint structures with minimal connection of vibrations and pulsations and minimal

  1. Measurements of {sup 55}Fe activity in activated steel samples with GEMPix

    Energy Technology Data Exchange (ETDEWEB)

    Curioni, A. [CERN, 1211 Geneva 23 (Switzerland); Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy); Dinar, N. [CERN, 1211 Geneva 23 (Switzerland); Université de Paris VII, 5 rue Thomas-Mann, 75013 Paris (France); La Torre, F.P. [CERN, 1211 Geneva 23 (Switzerland); Leidner, J., E-mail: johannes.leidner@cern.ch [CERN, 1211 Geneva 23 (Switzerland); RWTH Aachen, Templergraben 55, 52056 Aachen (Germany); Murtas, F. [CERN, 1211 Geneva 23 (Switzerland); INFN-LNF, Via E. Fermi 40, 00044 Frascati (Italy); Puddu, S.; Silari, M. [CERN, 1211 Geneva 23 (Switzerland)

    2017-03-21

    In this paper we present a novel method, based on the recently developed GEMPix detector, to measure the {sup 55}Fe content in samples of metallic material activated during operation of CERN accelerators and experimental facilities. The GEMPix, a gas detector with highly pixelated read-out, has been obtained by coupling a triple Gas Electron Multiplier (GEM) to a quad Timepix ASIC. Sample preparation, measurements performed on 45 samples and data analysis are described. The calibration factor (counts per second per unit specific activity) has been obtained via measurements of the {sup 55}Fe activity determined by radiochemical analysis of the same samples. Detection limit and sensitivity to the current Swiss exemption limit are calculated. Comparison with radiochemical analysis shows inconsistency for the sensitivity for only two samples, most likely due to underestimated uncertainties of the GEMPix analysis. An operative test phase of this technique is already planned at CERN.

  2. PARP1 Val762Ala polymorphism reduces enzymatic activity

    International Nuclear Information System (INIS)

    Wang Xiaogan; Wang Zhaoqi; Tong Weimin; Shen Yan

    2007-01-01

    Poly(ADP-ribose) polymerase 1 (PARP1) modifies a variety of nuclear proteins by poly(ADP-ribosyl)ation, and plays diverse roles in molecular and cellular processes. A common PARP1 single nucleotide polymorphism (SNP) at codon 762, resulting in the substitution of alanine (Ala) for valine (Val) in the catalytic domain has been implicated in susceptibility to cancer. To characterize the functional effect of this polymorphism on PARP1, we performed in vitro enzymatic analysis on PARP1-Ala762 and PARP1-Val762. We found that PARP1-Ala762 displayed 57.2% of the activity of PARP1-Val762 for auto-poly(ADP-ribosyl)ation and 61.9% of the activity of PARP1-Val762 for trans-poly(ADP-ribosyl)ation of histone H1. The kinetic characterization revealed that the K m of PARP1-Ala762 was increased to a 1.2-fold of the K m of PARP1-Val762 for trans-poly(ADP-ribosyl)ation. Thus, the PARP1 Val762Ala polymorphism reduces the enzymatic activity of PARP1 by increasing K m . This finding suggests that different levels of poly(ADP-ribosyl)ation by PARP1 might aid in understanding Cancer risk of carriers of the PARP1 Val762Ala polymorphism

  3. Accelerated aging embrittlement of cast duplex stainless steel: Activation energy for extrapolation

    International Nuclear Information System (INIS)

    Chung, H.M.; Chopra, O.K.

    1989-05-01

    Cast duplex stainless steels, used extensively in LWR systems for primary pressure boundary components such as primary coolant pipes, valves, and pumps, are susceptible to thermal aging embrittlement at reactor operating or higher temperatures. Since a realistic aging embrittlement for end-of-life or life-extension conditions (i.e., 32--50 yr of aging at 280--320 degree C) cannot be produced, it is customary to simulate the metallurgical structure by accelerated aging at ∼400 degree C. Over the past several years, extensive data on accelerated aging have been reported from a number of laboratories. The most important information from these studies is the activation energy, namely, the temperature dependence of the aging kinetics between 280 and 400 degree C, which is used to extrapolate the aging characteristics to reactor operating conditions. The activation energies (in the range of 18--50 kcal/mole) are, in general, sensitive to material grade, chemical composition, and fabrication process, and a few empirical correlations, obtained as a function of bulk chemical composition, have been reported. In this paper, a mechanistic understanding of the activation energy is described on the basis of the results of microstructural characterization of various heats of CF-3, -8, and -8M grades that were used in aging studies at different laboratories. The primary mechanism of aging embrittlement at temperatures between 280 and 400 degree C is the spinodal decomposition of the ferrite phase, and M 23 C 6 carbide precipitation on the ferrite/austenite boundaries is the secondary mechanism for high-carbon CF-8 grade. 20 refs., 10 figs., 3 tabs

  4. Hydroforming simulation and preparation of low activation martensitic steel Y-shapes

    International Nuclear Information System (INIS)

    Guo, X.Z.; Tao, J.; Yuan, Z.; Tang, Q.S.

    2011-01-01

    Highlights: → We hydroformed CLAM Y-shapes successfully after optimizing important parameters. → The feed of left punch decreased with the increasing protrusion angle. → The axial feed of the right punch increased with increasing the angle. → To obtain the highest protrusion, loading path 3 was the optimum. → The friction coefficient value of 0.07 is relatively superior. - Abstract: The hydroforming process to prepare China low activation Martensitic steel (CLAM) Y-shapes with desired protrusion height and uniform thinning rate was studied in this work. The axial feed distances for Y-shapes of the different protrusion angles were determined. Then, the effects of the loading path and the friction coefficient on the protrusion height and the distribution of thinning rate of the 45 o Y-shapes were investigated by numerical simulation, respectively. The optimized parameters were obtained: left axial feed 79 mm, right axial feed 60 mm and friction coefficient 0.07. In addition, the optimal loading path with the maximum rise rate of the internal pressure was determined. Subsequently, CLAM Y-shapes were hydroformed successfully based on the simulation results. The experimental results were approximately accordant with the simulative ones. It was indicated that the qualified CLAM Y-shapes could be obtained by the optimized hydroforming process.

  5. Activation analysis of stainless steel flux monitors using 252Cf neutron sources

    International Nuclear Information System (INIS)

    Williams, J.G.; Newton, T.H. Jr.; Cogburn, C.O.

    1984-01-01

    Activation analysis was performed on stainless steel beads from a chain which is used in reactor pressure vessel surveillance experiments at the Arkansas Power and Light Company reactors. The beads allow monitoring of two fast and three thermal neutron induced reactions: 58 Ni(n,p) 58 Co, 54 Fe(n,p) 54 Mn, 58 Fe(n,γ) 59 Fe, 59 Co(n,γ) 60 Co and 50 Cr(n,γ) 51 Cr. The analysis was performed using 12 beads from various positions along 5 different batches of chain and standard materials in an H 2 O moderator tank using two intense californium sources which had a total neutron emission rate of 3.97 x 10 10 /s. Semiconductor gamma spectrometers were used to count the products of the above reactions in the specimens. The percentage by weight of the iron, chromium and cobalt in the beads were found to be 62.1%, 20.2% and 0.120%, respectively. The excellent uniformity found in the bead compositions demonstrates the reproducibility of the experimental techniques and enhances considerably the value of the beads as neutron flux montitors

  6. Neural-network analysis of irradiation hardening in low-activation steels

    Energy Technology Data Exchange (ETDEWEB)

    Kemp, R. [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ, UK (United Kingdom)]. E-mail: rk237@cam.ac.uk; Cottrell, G.A. [EURATOM/UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB, UK (United Kingdom); Bhadeshia, H.K.D.H. [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ, UK (United Kingdom); Odette, G.R. [Department of Mechanical and Environmental Engineering and Department of Materials, University of California Santa Barbara, Santa Barbara, CA 93106 (United States); Yamamoto, T. [Department of Mechanical and Environmental Engineering and Department of Materials, University of California Santa Barbara, Santa Barbara, CA 93106 (United States); Kishimoto, H. [Department of Mechanical and Environmental Engineering and Department of Materials, University of California Santa Barbara, Santa Barbara, CA 93106 (United States)

    2006-02-01

    An artificial neural network has been used to model the irradiation hardening of low-activation ferritic/martensitic steels. The data used to create the model span a range of displacement damage of 0-90 dpa, within a temperature range of 273-973 K and contain 1800 points. The trained model has been able to capture the non-linear dependence of yield strength on the chemical composition and irradiation parameters. The ability of the model to generalise on unseen data has been tested and regions within the input domain that are sparsely populated have been identified. These are the regions where future experiments could be focused. It is shown that this method of analysis, because of its ability to capture complex relationships between the many variables, could help in the design of maximally informative experiments on materials in future irradiation test facilities. This will accelerate the acquisition of the key missing knowledge to assist the materials choices in a future fusion power plant.

  7. Electrodeposition of metallic tungsten coating from binary oxide molten salt on low activation steel substrate

    International Nuclear Information System (INIS)

    Liu, Y.H.; Zhang, Y.C.; Jiang, F.; Fu, B.J.; Sun, N.B.

    2013-01-01

    Tungsten is considered a promising plasma facing armor material for future fusion devices. An electrodeposited metallic tungsten coating from Na 2 WO 4 –WO 3 binary oxide molten salt on low activation steel (LAS) substrate was investigated in this paper. Tungsten coatings were deposited under various pulsed currents conditions at 1173 K in atmosphere. Cathodic current density and pulsed duty cycle were investigated for pulsed current electrolysis. The crystal structure and microstructure of tungsten coatings were characterized by X-ray diffractometry, scanning electron microscopy, and energy X-ray dispersive analysis techniques. The results indicated that pulsed current density and duty cycle significantly influence tungsten nucleation and electro-crystallization phenomena. The average grain size of the coating becomes much larger with increasing cathodic current density, which demonstrates that appropriate high cathodic current density can accelerate the growth of grains on the surface of the substrate. The micro-hardness of tungsten coatings increases with the increasing thickness of coatings; the maximum micro-hardness is 482 HV. The prepared tungsten coatings have a smooth surface, a porosity of less than 1%, and an oxygen content of 0.024 wt%

  8. Application of thin layer activation technique for monitoring corrosion of carbon steel in hydrocarbon processing environment.

    Science.gov (United States)

    Saxena, R C; Biswal, Jayashree; Pant, H J; Samantray, J S; Sharma, S C; Gupta, A K; Ray, S S

    2018-05-01

    Acidic crude oil transportation and processing in petroleum refining and petrochemical operations cause corrosion in the pipelines and associated components. Corrosion monitoring is invariably required to test and prove operational reliability. Thin Layer Activation (TLA) technique is a nuclear technique used for measurement of corrosion and erosion of materials. The technique involves irradiation of material with high energy ion beam from an accelerator and measurement of loss of radioactivity after the material is subjected to corrosive environment. In the present study, TLA technique has been used to monitor corrosion of carbon steel (CS) in crude oil environment at high temperature. Different CS coupons were irradiated with a 13 MeV proton beam to produce Cobalt-56 radioisotope on the surface of the coupons. The corrosion studies were carried out by subjecting the irradiated coupons to a corrosive environment, i.e, uninhibited straight run gas oil (SRGO) containing known amount of naphthenic acid (NA) at high temperature. The effects of different parameters, such as, concentration of NA, temperature and fluid velocity (rpm) on corrosion behaviour of CS were studied. Copyright © 2018 Elsevier Ltd. All rights reserved.

  9. Electrodeposition of metallic tungsten coating from binary oxide molten salt on low activation steel substrate

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Y. H. [School of Materials Science and Engineering, University of Science and Technology BeiJing, Beijing (China); State Nuclear Power Research Institute, Xicheng District, Beijing (China); Zhang, Y.C., E-mail: zycustb@163.com [School of Materials Science and Engineering, University of Science and Technology BeiJing, Beijing (China); Jiang, F.; Fu, B. J.; Sun, N. B. [School of Materials Science and Engineering, University of Science and Technology BeiJing, Beijing (China)

    2013-11-15

    Tungsten is considered a promising plasma facing armor material for future fusion devices. An electrodeposited metallic tungsten coating from Na{sub 2}WO{sub 4}–WO{sub 3} binary oxide molten salt on low activation steel (LAS) substrate was investigated in this paper. Tungsten coatings were deposited under various pulsed currents conditions at 1173 K in atmosphere. Cathodic current density and pulsed duty cycle were investigated for pulsed current electrolysis. The crystal structure and microstructure of tungsten coatings were characterized by X-ray diffractometry, scanning electron microscopy, and energy X-ray dispersive analysis techniques. The results indicated that pulsed current density and duty cycle significantly influence tungsten nucleation and electro-crystallization phenomena. The average grain size of the coating becomes much larger with increasing cathodic current density, which demonstrates that appropriate high cathodic current density can accelerate the growth of grains on the surface of the substrate. The micro-hardness of tungsten coatings increases with the increasing thickness of coatings; the maximum micro-hardness is 482 HV. The prepared tungsten coatings have a smooth surface, a porosity of less than 1%, and an oxygen content of 0.024 wt%.

  10. High-frequency TRNS reduces BOLD activity during visuomotor learning.

    Directory of Open Access Journals (Sweden)

    Catarina Saiote

    Full Text Available Transcranial direct current stimulation (tDCS and transcranial random noise stimulation (tRNS consist in the application of electrical current of small intensity through the scalp, able to modulate perceptual and motor learning, probably by changing brain excitability. We investigated the effects of these transcranial electrical stimulation techniques in the early and later stages of visuomotor learning, as well as associated brain activity changes using functional magnetic resonance imaging (fMRI. We applied anodal and cathodal tDCS, low-frequency and high-frequency tRNS (lf-tRNS, 0.1-100 Hz; hf-tRNS 101-640 Hz, respectively and sham stimulation over the primary motor cortex (M1 during the first 10 minutes of a visuomotor learning paradigm and measured performance changes for 20 minutes after stimulation ceased. Functional imaging scans were acquired throughout the whole experiment. Cathodal tDCS and hf-tRNS showed a tendency to improve and lf-tRNS to hinder early learning during stimulation, an effect that remained for 20 minutes after cessation of stimulation in the late learning phase. Motor learning-related activity decreased in several regions as reported previously, however, there was no significant modulation of brain activity by tDCS. In opposition to this, hf-tRNS was associated with reduced motor task-related-activity bilaterally in the frontal cortex and precuneous, probably due to interaction with ongoing neuronal oscillations. This result highlights the potential of lf-tRNS and hf-tRNS to differentially modulate visuomotor learning and advances our knowledge on neuroplasticity induction approaches combined with functional imaging methods.

  11. Lightweight Steel Solutions for Automotive Industry

    International Nuclear Information System (INIS)

    Lee, Hong Woo; Kim, Gyosung; Park, Sung Ho

    2010-01-01

    Recently, improvement in fuel efficiency and safety has become the biggest issue in worldwide automotive industry. Although the regulation of environment and safety has been tightened up more and more, the majority of vehicle bodies are still manufactured from stamped steel components. This means that the optimized steel solutions enable to demonstrate its ability to reduce body weight with high crashworthiness performance instead of expensive light weight materials such as Al, Mg and composites. To provide the innovative steel solutions for automotive industry, POSCO has developed AHSS and its application technologies, which is directly connected to EVI activities. EVI is a technical cooperation program with customer covering all stages of new car project from design to mass production. Integrated light weight solutions through new forming technologies such as TWB, hydroforming and HPF are continuously developed and provided for EVI activities. This paper will discuss the detailed status of these technologies especially light weight steel solutions based on innovative technologies.

  12. Mechanical properties and microstructure changes of low-activation 3Cr-2W-V-Ti ferritic steels developed for nuclear applications

    International Nuclear Information System (INIS)

    Asakura, Kentaro; Kohyama, Akira; Yamada, Takemi.

    1990-01-01

    The effects of alloying elements such as Cr, W, V and Mn on tensile strength at elevated temperatures, creep-rupture properties and toughness of low activation (2.25-3)Cr-(2-2.5)W-V-Ti steels were investigated together with their microstructure change during high temperature exposure. These steels were normalized to produce bainitic structures in the same manner as that for a conventional 2.25Cr-1Mo steel. They presented superior tensile strength at elevated temperatures and creep-rupture strength in comparison with a conventional 2.25Cr-1Mo steel. The creep-rupture strength of the steels at 500degC for 100 000 h demonstrated about twice that of the conventional 2.25Cr-1Mo steel. The 3Cr-2.5W-0.2V-0.01Ti steel is recommended as a potential low activation ferritic steel for nuclear applications with well optimized mechanical properties, such as tensile strength at elevated temperatures, creep-rupture strength and toughness. The effects of alloying elements were discussed with correlating microstructural and mechanical aspects. (author)

  13. Towards a reduced activation structural materials database for fusion DEMO reactors

    International Nuclear Information System (INIS)

    Moeslang, A.; Diegele, E.; Laesser, R.; Klimiankou, M.; Lindau, R.; Materna-Morris, E.; Rieth, M.; Lucon, E.; Petersen, C.; Schneider, H.-C.; Pippan, R.; Rensman, J.W.; Schaaf, B. van der; Tavassoli, F.

    2005-01-01

    The development of First Wall, Blanket and Divertor materials which are capable of withstanding many years the high neutron and heat fluxes, is a critical path to fusion power. Therefore, the timely availability of a sound materials database has become an indispensable element in international fusion road maps. In order to provide materials design data for short term needs of ITER Test Blanket Modules and for a DEMOnstration fusion reactor, a wealth of R and D results on the European reduced activation ferritic-martensitic steel EUROFER, and on oxide dispersion strengthened variants are being characterized, mainly in the temperature window 250-650 deg. C. The characterisation includes irradiations up to 15 dpa in the mixed spectrum reactor HFR and up to 75 dpa in the fast breeder reactor BOR60. Industrial EUROFER-batches of 3.5 and 7.5 tons have been produced with a variety of semi-finished, quality-assured product forms. To increase thermal efficiency of blankets, high temperature resistant SiC f /SiC channel inserts for liquid metal coolant tubes are also developed. Regarding radiation damage resistance, a broad based reactor irradiation programs counts several steps from ≤5dpa (ITER TBMs) up to 75 dpa (DEMO). For the European divertor designers, a materials data base is presently being set up for pure W and W alloys, and related reactor irradiations are foreseen with temperatures from 650-1000 deg. C. (author)

  14. Active slag filters-simple and sustainable phosphorus removal from wastewater using steel industry byproduct.

    Science.gov (United States)

    Pratt, C; Shilton, A

    2010-01-01

    Active filtration, where effluent is passed through a reactive substrate such as steel slag, offers a simple and cost-effective option for removing phosphorus (P) from effluent. This work summarises a series of studies that focused on the world's only full-scale active slag filter operated through to exhaustion. The filter achieved 75% P-removal during its first 5 years, reaching a retention capacity of 1.23 g P/kg slag but then its performance sharply declined. Scanning electron microscopy, X-ray diffraction, X-ray fluorescence, and chemical extractions revealed that P sequestration was primarily achieved via adsorption onto iron (Fe) oxyhydroxides on the slag's surface. It was concluded that batch equilibrium tests, whose use has been repeatedly proposed in the literature, cannot be used as an accurate predictor of filter adsorption capacity because Fe oxyhydroxides form via chemical weathering in the field, and laboratory tests don't account for this. Research into how chemical conditions affect slag's P retention capacity demonstrated that near-neutral pH and high redox are optimal for Fe oxyhydroxide stability and overall filter performance. However, as Fe oxyhydroxide sites fill up, removal capacity becomes exhausted. Attempts to regenerate P removal efficiency using physical techniques proved ineffective contrary to dogma in the literature. Based on the newly-developed understanding of the mechanisms of P removal, chemical regeneration techniques were investigated and were shown to strip large quantities of P from filter adsorption sites leading to a regenerated P removal efficiency. This raises the prospect of developing a breakthrough technology that can repeatedly remove and recover P from effluent.

  15. Determination of chemical activities of Fe, Cr, Ni and Mn in stainless steel 316 by Knudsen effusion cell mass spectrometry

    International Nuclear Information System (INIS)

    Venugopal, V.; Kulkarni, S.G.; Subbanna, C.S.; Sood, D.D.

    1995-01-01

    Cold-worked austenitic stainless steel of the type AISI 316 is being used as the cladding and wrapper materials in fast reactor fuel pins. Knowledge of the thermodynamic activities of the steel constituents is necessary to predict the possibility of fuel-cladding, coolant-cladding or fission product-cladding chemical reactions. The thermodynamic activities of Fe, Cr, Ni and Mn for stainless steel 316 were determined by measuring their partial pressures in the temperature range 1293-2120 K, using Knudsen effusion cell mass spectrometry. High purity Ag was used as an internal calibrant. The chemical activities of Fe (a Fe ), Cr (a Cr ), Ni (a Ni ) and Mn (a Mn ) were evaluated using literature data for the vapour pressures of pure metals. log a Fe ±0.18=-1.586+2074/T (T=1293-1872 K)log a Cr ±0.30=-2.350+2612/T (T=1293-2120 K)log a Ni ±0.20=-2.140+1794/T (T=1468-1974 K)log a Mn ±0.23=-2.041-5478/T (T=1302-1894 K) ((orig.))

  16. The steel scrap age.

    Science.gov (United States)

    Pauliuk, Stefan; Milford, Rachel L; Müller, Daniel B; Allwood, Julian M

    2013-04-02

    Steel production accounts for 25% of industrial carbon emissions. Long-term forecasts of steel demand and scrap supply are needed to develop strategies for how the steel industry could respond to industrialization and urbanization in the developing world while simultaneously reducing its environmental impact, and in particular, its carbon footprint. We developed a dynamic stock model to estimate future final demand for steel and the available scrap for 10 world regions. Based on evidence from developed countries, we assumed that per capita in-use stocks will saturate eventually. We determined the response of the entire steel cycle to stock saturation, in particular the future split between primary and secondary steel production. During the 21st century, steel demand may peak in the developed world, China, the Middle East, Latin America, and India. As China completes its industrialization, global primary steel production may peak between 2020 and 2030 and decline thereafter. We developed a capacity model to show how extensive trade of finished steel could prolong the lifetime of the Chinese steelmaking assets. Secondary steel production will more than double by 2050, and it may surpass primary production between 2050 and 2060: the late 21st century can become the steel scrap age.

  17. Biological fate of cobalt-60 released during the corrosion of neutron-activated stanless steel in seawater

    International Nuclear Information System (INIS)

    Young, J.S.

    1982-03-01

    Passing seawater over radioactive Type 347 stainless steel in a sediment/seawater laboratory system and exposing marine animals to this environment provided information on the bioaccumulation of 60 Co from radioactive structural material. Exposure of marine organisms to radioactive corrosion products and directly to radioactive stainless steel in seawater simulated some of the possible conditions which could arise from the deposition of radioactive stainless steel on the ocean floor. Detectable levels of 60 Co in marine animals were not observed on a short term basis (5 weeks). Longterm (13 months) exposure of marine animals in a sediment/seawater system resulted in 60 Co bioaccumulation. The specific activity of 60 Co in the organisms was as much as one million times less than that initially present in the radioactive stainless steel. This was due to the dilution of 60 Co by stable cobalt in the seawater, sediments and organisms. As expected the 60 Co specific activity of the organisms never increased above that of the radioactive source. This is because 60 Co is chemicaly indistinguishable from stable Co. Increasing 60 Co concentration factors with decreasing 60 Co concentrations in the seawater and sediment media coupled with relatively constant 60 Co specific activities suggest a possible homeostatic control of cobalt concentrations in certain marine organisms. The evidence indicates that the marine animals derived more of the accumulated 60 Co from the sediments and interstitial water than from seawater. Cobalt-60 concentration factors were generally found to be lower than published cobalt concentration factors due to the predominantly insoluble nature of the corrosion products. Baseline information is provided on trace element concentrations in deep-sea organisms. Stable Co and twenty other elements were measured in abyssal invertebrates and a fish

  18. The potential for reducing the radiological consequences of reactor decommissioning through selection of construction materials for activated components

    International Nuclear Information System (INIS)

    Woollam, P.B.

    1984-08-01

    This report considers whether it may be possible to reduce the radiological consequences of reactor decommissioning by careful attention to the specification of the elemental concentration of materials used in the reactor's construction. In particular, consideration is given to the potential for reduction of the concentration of elements known to activate to long lived daughter isotopes. Two particular areas are addressed, both applied to Sizewell 'B' PWR. The first is the choice of raw materials for the construction of the concrete bioshield to minimise future waste arisings. The second is the specification of some trace element concentrations in the steel pressure vessel and reactor internal structures to minimise personnel exposure at decommissioning time. The report presents extensive analyses of many of the candidate raw materials for Sizewell 'B' concrete, including PFA, and derives the radiological consequences for the eventual disposal of these materials to a hypothetical municipal land fill waste site. Data are also presented on the concentrations of important elements activating to gamma emitting daughters in type 304 stainless steels, leading to an assessment of likely dose equivalent rates at decommissioning time from the pressure vessel and from the internal components. (author)

  19. Thermal stability of manganese-stabilized stainless steels

    International Nuclear Information System (INIS)

    Klueh, R.L.; Kenik, E.A.

    1993-01-01

    Previous work on a series of experimental high-manganese reduced-activation austenitic stainless steels demonstrated that they have improved tensile properties relative to type 316 stainless steel in both the annealed and 20% cold-worked conditions. Steels were tested with an Fe-20Mn-12Cr-0.25C (in weight percent) base composition, to which various combinations of Ti, W, V, P, and B were added. Tensile tests have now been completed on these steels after thermal aging at 600 degrees C. Thermal stability varied with composition, but the alloys were as stable or more stable than type 316 stainless steel. the strength of the annealed steels increased slightly after aging to 5000 h, while a strength decrease occurred for the cold worked steel. In both conditions, a steel containing a combination of all the alloying elements was most stable and had the best strength after thermal aging 5000 h at 600 degrees C. Despite having much higher strength than 316 stainless steel after aging, the ductility of the strongest experimental alloy was still as good as that of 316 stainless steel

  20. Nitrate and sulfate reducers-retrievable number of bacteria and their activities in Indian waters

    Digital Repository Service at National Institute of Oceanography (India)

    LokaBharathi, P.A.; Nair, S.; Chandramohan, D.

    Culturable heterotrophic, nitrate reducing and sulfate reducing bacteria (HB, NRB and SRB) were enumerated from 25, 50, 100 and 200 m depths at 15 stations and their potential activities viz. Nitrate reducing (NRA) and Sulfate reducing (SRA) were...

  1. Photocatalytic activity of ferric oxide/titanium dioxide nanocomposite films on stainless steel fabricated by anodization and ion implantation

    Science.gov (United States)

    Zhan, Wei-ting; Ni, Hong-wei; Chen, Rong-sheng; Yue, Gao; Tai, Jun-kai; Wang, Zi-yang

    2013-08-01

    A simple surface treatment was used to develop photocatalytic activity for stainless steel. AISI 304 stainless steel specimens after anodization were implanted by Ti ions at an extracting voltage of 50 kV with an implantation dose of 3 × 1015 atoms·cm-2 and then annealed in air at 450°C for 2 h. The morphology was observed by scanning electron microscopy. The microstructure was characterized by X-ray diffraction and X-ray photoelectron spectroscopy. The photocatalytic degradation of methylene blue solution was carried out under ultraviolet light. The corrosion resistance of the stainless steel was evaluated in NaCl solution (3.5 wt%) by electrochemical polarization curves. It is found that the Ti ions depth profile resembles a Gaussian distribution in the implanted layer. The nanostructured Fe2O3/TiO2 composite film exhibits a remarkable enhancement in photocatalytic activity referenced to the mechanically polished specimen and anodized specimen. Meanwhile, the annealed Ti-implanted specimen remains good corrosion resistance.

  2. Low activation steels welding with PWHT and coating for ITER Test Blanket Modules and DEMO

    International Nuclear Information System (INIS)

    Aubert, P.; Tavassoli, F.; Rieth, M.; Diegele, E.; Poitevin, Y.

    2009-01-01

    Eurofer weldability is established for data base assessment and TBM manufacturing support. Electron Beam, Hybrid (Laser combined with MIG/MAG), Laser and Narrow Gap TIG processes have been carried out on Eurofer Low activation steel. Electron Beam produces very narrow fusion zone width, in the range of 3 to 4 mm, and too strong enhanced weld shape with brittle joints with δ-ferrite and pores. This process is considered only for low penetration depth (cooling plates). The other processes produce 2 families of similar results: one for Hybrid (MIG + Laser) and Laser processes, and a second one for TIG and Narrow Gap TIG processes. The first one procures less distortion and coarsened fusion zone, due to higher cooling rate. For all the welding processes, high hardness values, increasing brittleness and softening effects in the Heat Affected Zone are observed for each welding configuration that could signal creep problems. The Fusion Zones are typically composed of martensite laths, with small grain sizes. In the Heat Affected Zones, martensite grains are observed with carbide precipitation. Eurofer filler wire with optimized chemical composition is developed for producing welds with good properties and high joint coefficient value. To restore mechanical properties after welding, PWHT have been developed: single step for the first family and 2 steps for the second one. Distortions of different mock-ups with and without PWHT have been managed to assess manufacturing rules and clamping devices. Welding data base has thus been established. W coating on the TBM structure has shown no strong effect on the TBM structure. (author)

  3. Geodetic monitoring (TLS of a steel transport trestle bridge located in an active mining exploitation site

    Directory of Open Access Journals (Sweden)

    Skoczylas Arkadiusz

    2016-09-01

    Full Text Available Underground mining exploitation causes, in general, irregular vertical and horizontal shifts in the superficial layer of the rock mass. In the case of construction objects seated on this layer, a deformation of the object’s foundation can be observed. This leads to additional loads and deformations. Identification of surface geometry changes in construction objects located within the premises of underground mining exploitation areas is an important task as far as safety of mining sites is concerned. Surveys targeting shifts and deformations in engineering objects preformed with the use of classic methods are of a selective nature and do not provide the full image of the phenomenon being the subject of the observation. This paper presents possibilities of terrestrial laser scanning technology application in the monitoring of engineering objects that allows for a complete spatial documentation of an object subjected to the influence of an active mining exploitation. This paper describes an observation of a 100 m section of a steel transport trestle bridge located on the premises of hard coal mine Lubelski Węgiel “Bogdanka” S.A. carried out in 2015. Measurements were carried out using a Z+F Imager 5010C scanner at an interval of 3.5 months. Changes in the structure’s geometry were determined by comparing the point clouds recorded during the two measurement periods. The results of the analyses showed shifts in the trestle bridge towards the exploited coal wall accompanied by object deformation. The obtained results indicate the possibility of of terrestrial laser scanning application in studying the aftereffects of underground mining exploitation on surface engineering objects.

  4. A computer language for reducing activation analysis data

    International Nuclear Information System (INIS)

    Friedman, M.H.; Tanner, J.T.

    1978-01-01

    A program, written in FORTRAN, which defines a language for reducing activation analysis data is described. An attempt was made to optimize the choice of commands and their definitions so as to concisely express what should be done, make the language natural to use and easy to learn, arranqe a system of checks to guard against communication errors and have the language be inclusive. Communications are effected through commands, and these can be given in almost any order. Consistency checks are done and diagnostic messages are printed automatically to guard against the incorrect use of commands. Default options on the commands allow instructions to be expressed concisely while providing a capability to specify details for the data reduction process. The program has been implemented on a UNIVAC 1108 computer. A complete description of the commands, the algorithms used, and the internal consistency checks used are given elsewhere. The applications of the program and the methods for obtaining data automatically have already been described. (T.G.)

  5. Fabrication and characterization of a Spanish RAFM steel

    International Nuclear Information System (INIS)

    Rodriguez, D.; Serrano, M.; Moran, A.; Artimez, J. M.

    2009-01-01

    One of the main challenges for the realization of the future fusion reactor is the development and qualification of structural materials for first wall and breeding blanket. The fusion reactor application requires materials resistant to radiation damage, with excellent mechanical properties at high temperatures, good corrosion behaviour and reduced activation potential. Reduced Activation (RAFM) 9Cr Ferritic/Martenistic steels are the main candidates for first wall and blanket of fusion reactors, due to their resistance to swelling and excellent structural and thermal properties. These steels are based on the classical Cr-Mo steel grades but with a chemical composition modified in order to fulfil the low activation requirements, substituting the alloying elements with long decay times due to high activation by neutron irradiation. For this purpose the Mo is replaced by W, the Nb by Ta and Ni is removed. A summary of the activities related to the evaluation of the microstructural and mechanical properties of a reduced activation ferritic/martensitic steel fabricated at a semi-industrial scale in Spain will be presented in this paper. The steel chemical composition fulfils or is very close to the compositional specifications and metallurgical properties of the EUROFER steel. This activity corresponds to the ITMA and CIEMAT participation on Task 4 of the CONSOLIDER TECNO F US INGENIO 2010, financed by the Spanish Ministry of Science and Innovation. (author)

  6. Reducing the energy consumption and CO2 emissions of energy intensive industries through decision support systems – An example of application to the steel industry

    International Nuclear Information System (INIS)

    Porzio, Giacomo Filippo; Fornai, Barbara; Amato, Alessandro; Matarese, Nicola; Vannucci, Marco; Chiappelli, Lisa; Colla, Valentina

    2013-01-01

    Highlights: • We describe an application of decision-support system to iron and steel industries. • The realised tool is useful in monitoring energy and CO 2 performances of the plant. • Key processes are modelled through flowsheeting approach and included in the tool. • A mathematical optimisation model for the process gas management has been realised. • Implementation of the tool can help reducing plant costs and environmental impact. - Abstract: The management of process industries is becoming in the recent years more and more challenging, given the stringent environmental policies as well as raising energy costs and the always-present drive for profit. A way to help plant decision makers in their daily choices is to refer to decision-support tools, which can give advice on the best practices on how to operate a plant in order to reduce the energy consumption and the CO 2 emissions keeping at the same time the costs under control. Such an approach can be useful in a variety of industries, particularly the most energy-intensive ones such as iron and steel industries. In this paper, an approach to the realisation of a software system, which allows to generate internal reports on the plant performances, as well as to simulate the plant behaviour in different scenarios, is described. The main production processes (coke plant, blast furnace, steel shop, hot rolling mill) are described and simulated focusing on the prediction of products flow rates and composition, energy consumption and GHGs (Greenhouse Gases) emissions in different operating conditions. The importance of a correct management of the CO 2 within the plant is underlined, particularly with regard to the new EU Emission Trading System, which will be based on European benchmarks. The software tool is illustrated and a case study is included, which focuses on the simultaneous minimisation of the CO 2 emissions and maximisation of the profit through an optimised management of the by-product gases

  7. Influence of bacteria and bacterial activity on the evolution of the free corrosion potentials of stainless steels in natural seawater

    International Nuclear Information System (INIS)

    Dupont, I.

    1996-10-01

    The free corrosion potential of a stainless steel under seawater increases. This increase depends of a lot of parameters, among them is found in particular: the temperature, the presence of molecular oxygen and the microorganisms. The aim of this work is to describe the role of the sea bacteria and of their activities on the increase of this potential. Stainless steel test-pieces have been put in natural seawater at different temperatures and their corrosion potential determined. It has been shown that the potential increases at 20 C but not at 40 C. The marine bacteria, present in seawater and fixed on the test-pieces at 20 and 40 C have been quantified by epi-fluorescence microscopy. The number of bacteria fixed at these two temperatures are similar. A sample of bacteria has been cut off on test-pieces and in seawater at 20 and 40 C. Their phenotypic analysis has allowed to classify them by numerical taxonomy in different phenons and by their metabolic spectra, it has been possible to distinguish the bacteria fixed at 20 C and those fixed at 40 C. The presence of an important bio-film at 40 C in the absence of a change of potential shows that the fixation of bacteria on stainless steel, if it is necessary, is not a sufficient condition for the starting of this phenomenon. The addition of a microbial enzyme in sterile seawater, the glucose oxidase, catalyzing the oxygen reduction in presence of glucose leads to an increase of the potential. The formation of hydrogen peroxide and the decrease of the pH of the medium seem responsible of this phenomenon. All these results have led us to propose a mechanism clarifying the increase of the potential of stainless steel in natural seawater. (O.M.)

  8. A study of the prospects for development of low-activation martensitic stainless steels for first-wall and blanket structures in fusion reactors

    International Nuclear Information System (INIS)

    Tupholme, K.W.; Orr, J.; Dulieu, D.; Butterworth, G.J.

    1986-04-01

    This study examines the potential of the elemental substitution approach to the design of low-activity martensitic stainless steels, subject to the requirement that the contact γ dose rate falls to a value that would allow essentially unrestricted handling of discarded material after a cooling period of 100 years. The factors governing the structure and properties of the 9-12%Cr martensitic steels are reviewed. Practicable substitutes for the proscribed elements molybdenum, nickel and niobium include tungsten, tantalum and an increased vanadium content in conjunction with optimised carbon, nitrogen and boron levels. Given the generally attractive combination of properties offered by the martensitic steels, the prospects for developing a satisfactory low-activity composition appear favourable. A series of experimental compositions and a programme of investigations are proposed to explore possible alloys with the objective of reproducing, as far as possible, the characteristics of existing fully martensitic high strength stainless steels. (author)

  9. (60)Co in cast steel matrix: A European interlaboratory comparison for the characterisation of new activity standards for calibration of gamma-ray spectrometers in metallurgy.

    Science.gov (United States)

    Tzika, Faidra; Burda, Oleksiy; Hult, Mikael; Arnold, Dirk; Marroyo, Belén Caro; Dryák, Pavel; Fazio, Aldo; Ferreux, Laurent; García-Toraño, Eduardo; Javornik, Andrej; Klemola, Seppo; Luca, Aurelian; Moser, Hannah; Nečemer, Marijan; Peyrés, Virginia; Reis, Mario; Silva, Lidia; Šolc, Jaroslav; Svec, Anton; Tyminski, Zbigniew; Vodenik, Branko; Wätjen, Uwe

    2016-08-01

    Two series of activity standards of (60)Co in cast steel matrix, developed for the calibration of gamma-ray spectrometry systems in the metallurgical sector, were characterised using a European interlaboratory comparison among twelve National Metrology Institutes and one international organisation. The first standard, consisting of 14 disc shaped samples, was cast from steel contaminated during production ("originally"), and the second, consisting of 15 similar discs, from artificially-contaminated ("spiked") steel. The reference activity concentrations of (60)Co in the cast steel standards were (1.077±0.019) Bqg(-1) on 1 January 2013 12h00 UT and (1.483±0.022) Bqg(-1) on 1 June 2013 12h00 UT, respectively. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  10. Effect of temperature on the mechanical characteristics of cold-worked steel OKh16N15M3B with active tension and creep

    International Nuclear Information System (INIS)

    Erasov, V.S.; Konoplenko, V.P.; Pirogov, E.N.

    1986-01-01

    Steel OKh16N15M3B is used extensively for the manufacture of atomic reactor fuel-element shells. The aim of this work is a study of the mechanical characteristics of this steel cold-worked by 20% with active tension and creep in the temperature range 973-1323 0 K, which is necessary for predicting the behavior of fuel-element shells in critical situations. It is found that above 973 0 K there is active loss of strength for cold-worked steel OKh16N15M3B. Strength characteristics in the region 973-1323 0 K decrease by more than a factor of six. Thermal activation analysis of the plastic deformation process, showing a sharp increase in activation energy above 1073 0 K, suggests a change in the mechanisms of plastic deformation taking place. For active tension and creep the same temperature range is obtained for a marked change in activation energy

  11. Method of solution mining subsurface orebodies to reduce restoration activities

    Energy Technology Data Exchange (ETDEWEB)

    Hartman, G.J.

    1984-01-24

    A method of solution mining is claimed wherein a lixiviant containing both leaching and oxidizing agents is injected into the subsurface orebody. The composition of the lixiviant is changed by reducing the level of oxidizing agent to zero so that soluble species continue to be removed from the subsurface environment. This reduces the uranium level of the ground water aquifer after termination of the lixiviant injection.

  12. Effect of Aluminum Alloying on the Hot Deformation Behavior of Nano-bainite Bearing Steel

    Science.gov (United States)

    Yang, Z. N.; Dai, L. Q.; Chu, C. H.; Zhang, F. C.; Wang, L. W.; Xiao, A. P.

    2017-12-01

    Interest in using aluminum in nano-bainite steel, especially for high-carbon bearing steel, is gradually growing. In this study, GCr15SiMo and GCr15SiMoAl steels are introduced to investigate the effect of Al alloying on the hot deformation behavior of bearing steel. Results show that the addition of Al not only notably increases the flow stress of steel due to the strong strengthening effect of Al on austenite phase, but also accelerates the strain-softening rates for its increasing effect on stacking fault energy. Al alloying also increases the activation energy of deformation. Two constitutive equations with an accuracy of higher than 0.99 are proposed. The constructed processing maps show the expanded instability regions for GCr15SiMoAl steel as compared with GCr15SiMo steel. This finding is consistent with the occurrence of cracking on the GCr15SiMoAl specimens, revealing that Al alloying reduces the high-temperature plasticity of the bearing steel. On the contrary, GCr15SiMoAl steel possesses smaller grain size than GCr15SiMo steel, manifesting the positive effect of Al on bearing steel. Attention should be focused on the hot working process of bearing steel with Al.

  13. Environmental assessment for the natural fluctuation of water level in Par Pond and reduced water flow in Steel Creek below L-Lake at the Savannah River Site

    International Nuclear Information System (INIS)

    1995-08-01

    The Savannah River Operations Office Strategic Plan directs Savannah River Site (SRS) to find ways to reduce operating costs, and to determine what site infrastructure must be maintained and what infrastructure is surplus. Because of the mission change, L-Lake, Par Pond, and the river water system are no longer needed to support current missions and therefore provide an opportunity for operating cost reduction. If SRS determines that L-Lake, Par Pond, and the river water system are no longer needed to support future missions and are considered surplus, appropriate NEPA documentation will be prepared. The purpose of the proposed action in this Environmental Assessment is to begin an examination of the need for the Site's river water system by (1) developing data needed to evaluate the potential environmental impacts of further reducing or eliminating the flow demands from the Site's river water system and; (2) evaluating the potential of reducing operating costs by allowing the water level in Par Pond to fluctuate naturally through reduced pumping. This action also includes reducing the current flow rates from L-Lake to Steel Creek to natural stream flows while maintaining full pool. The recently approved Par Pond CERCLA Interim Action Proposed Plan (IAPP) committed to evaluate in a NEPA document the environmental consequences of this proposed action. This document evaluated the remediation of human health and ecological risks associated with the three year drawdown of Par Pond. Should any of the parameters sampled in the reservoir and streams (e.g., water quality, biota, etc.) exceed established threshold levels during the implementation of the proposed action, water would again be pumped into the reservoir to minimize any impacts by bringing the water level back to an appropriate level about 58.2 m (195 ft)

  14. Environmental assessment for the natural fluctuation of water level in Par Pond and reduced water flow in Steel Creek below L-Lake at the Savannah River Site

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-08-01

    The Savannah River Operations Office Strategic Plan directs Savannah River Site (SRS) to find ways to reduce operating costs, and to determine what site infrastructure must be maintained and what infrastructure is surplus. Because of the mission change, L-Lake, Par Pond, and the river water system are no longer needed to support current missions and therefore provide an opportunity for operating cost reduction. If SRS determines that L-Lake, Par Pond, and the river water system are no longer needed to support future missions and are considered surplus, appropriate NEPA documentation will be prepared. The purpose of the proposed action in this Environmental Assessment is to begin an examination of the need for the Site`s river water system by (1) developing data needed to evaluate the potential environmental impacts of further reducing or eliminating the flow demands from the Site`s river water system and; (2) evaluating the potential of reducing operating costs by allowing the water level in Par Pond to fluctuate naturally through reduced pumping. This action also includes reducing the current flow rates from L-Lake to Steel Creek to natural stream flows while maintaining full pool. The recently approved Par Pond CERCLA Interim Action Proposed Plan (IAPP) committed to evaluate in a NEPA document the environmental consequences of this proposed action. This document evaluated the remediation of human health and ecological risks associated with the three year drawdown of Par Pond. Should any of the parameters sampled in the reservoir and streams (e.g., water quality, biota, etc.) exceed established threshold levels during the implementation of the proposed action, water would again be pumped into the reservoir to minimize any impacts by bringing the water level back to an appropriate level about 58.2 m (195 ft).

  15. Stainless steel grafting of hyperbranched polymer brushes with an antibacterial activity: synthesis, characterization, and properties.

    Science.gov (United States)

    Ignatova, Milena; Voccia, Samule; Gabriel, Sabine; Gilbert, Bernard; Cossement, Damien; Jerome, Robert; Jerome, Christine

    2009-01-20

    Two strategies were used for the preparation of hyperbranched polymer brushes with a high density of functional groups: (a) the cathodic electrografting of stainless steel by poly[2-(2-chloropropionate)ethyl acrylate] [poly(cPEA)], which was used as a macroinitiator for the atom transfer radical polymerization of an inimer, 2-(2-bromopropionate)ethyl acrylate in the presence or absence of heptadecafluorodecyl acrylate, (b) the grafting of preformed hyperbranched poly(ethyleneimine) onto poly(N-succinimidyl acrylate) previously electrografted onto stainless steel. The hyperbranched polymer, which contained either bromides or amines, was quaternized because the accordingly formed quaternary ammonium or pyridinium groups are known for antibacterial properties. The structure, chemical composition, and morphology of the quaternized and nonquaternized hyperbranched polymer brushes were characterized by ATR-FTIR reflectance, Raman spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscopy. The peeling test confirmed that the grafted hyperbranched polymer films adhered much more strongly to stainless steel than the nongrafted solvent-cast films. The quaternized hyperbranched polymer brushes were more effective in preventing both protein adsorption and bacterial adhesion than quaternary ammonium containing poly(cPEA) primary films, more likely because of the higher hydrophilicity and density of cationic groups.

  16. Aircraft Steels

    Science.gov (United States)

    2009-02-19

    component usage. PH 13-8Mo is a precipitation-hardenable martensitic stainless steel combining excellent corrosion resistance with strength. Custom 465 is...a martensitic , age-hardenable stainless steel capable of about 1,724 MPa (250 ksi) UTS when peak-aged (H900 condition). Especially, this steel can...NOTES 14. ABSTRACT Five high strength steels (4340, 300M, AerMet 100, Ferrium S53, and Hy-Tuf) and four stainless steels (High Nitrogen, 13

  17. Carbon fiber/SiC composite for reduced activation

    International Nuclear Information System (INIS)

    Noda, T.; Araki, H.; Abe, F.; Okada, M.

    1991-01-01

    A carbon fiber/SiC composite fabricated by a chemical vapor infiltration process at 1173-1623 K was studied to develop a low-activation material. A high-purity composite was obtained with the total amount of impurities less than 0.02 wt%. The microstructure and the mechanical properties using a bend test were examined. A composite with woven carbon yarn showed both high strength and toughness. Further, the induced activity of the material was evaluated by calculations simulating fusion neutron irradiation. The carbon fiber/SiC composite shows an excellent low-activation behavior. (orig.)

  18. On the electrocatalytic activity of nitrogen-doped reduced graphene ...

    Indian Academy of Sciences (India)

    ... battery applications. The heteroatom-doped graphene/reduced graphene oxide (rGO) ... over, in the membrane electrode assembly of fuel cell, the carbon supported ..... Wang Y, Shao Y, Matson D W, Li J and Lin Y 2010. ACS Nano 4 1790.

  19. On the electrocatalytic activity of nitrogen-doped reduced graphene ...

    Indian Academy of Sciences (India)

    The heteroatom-doped graphene/reduced graphene oxide (rGO)is very promising and the nitrogen-doped rGO (N-rGO) is emerging as a new inexpensive electrocatalyst foroxygen reduction reaction (ORR). Herein, we describe the effect of the chemical nature and amount of nitrogenin N-rGO towards ORR in acidic solution ...

  20. Impaired cognitive control and reduced cingulate activity during mental fatigue

    NARCIS (Netherlands)

    Lorist, M.M.; Boksem, M.A.S.; Ridderinkhof, K.R.

    2005-01-01

    Neurocognitive mechanisms underlying the effects of mental fatigue are poorly understood. Here, we examined whether error-related brain activity, indexing performance monitoring by the anterior cingulate cortex (ACC), and strategic behavioural adjustments were modulated by mental fatigue, as induced

  1. Impaired cognitive control and reduced cingulate activity during mental fatigue

    NARCIS (Netherlands)

    Lorist, MM; Boksem, MAS; Ridderinkhof, KR

    Neurocognitive mechanisms underlying the effects of mental fatigue are poorly understood. Here, we examined whether error-related brain activity, indexing performance monitoring by the anterior cingulate cortex (ACC), and strategic behavioural adjustments were modulated by mental fatigue, as induced

  2. Spectroscopic investigations of plasma nitriding processes: A comparative study using steel and carbon as active screen materials

    Science.gov (United States)

    Hamann, S.; Burlacov, I.; Spies, H.-J.; Biermann, H.; Röpcke, J.

    2017-04-01

    Low-pressure pulsed DC H2-N2 plasmas were investigated in the laboratory active screen plasma nitriding monitoring reactor, PLANIMOR, to compare the usage of two different active screen electrodes: (i) a steel screen with the additional usage of CH4 as carbon containing precursor in the feeding gas and (ii) a carbon screen without the usage of any additional gaseous carbon precursor. Applying the quantum cascade laser absorption spectroscopy, the evolution of the concentration of four stable molecular species, NH3, HCN, CH4, and C2H2, has been monitored. The concentrations were found to be in a range of 1012-1016 molecules cm-3. By analyzing the development of the molecular concentrations at variations of the screen plasma power, a similar behavior of the monitored reaction products has been found for both screen materials, with NH3 and HCN as the main reaction products. When using the carbon screen, the concentration of HCN and C2H2 was 30 and 70 times higher, respectively, compared to the usage of the steel screen with an admixture of 1% CH4. Considering the concentration of the three detected hydrocarbon reaction products, a combustion rate of the carbon screen of up to 69 mg h-1 has been found. The applied optical emission spectroscopy enabled the determination of the rotational temperature of the N2+ ion which has been in a range of 650-900 K increasing with the power in a similar way in the plasma of both screens. Also with power the ionic component of nitrogen molecules, represented by the N2+ (0-0) band of the first negative system, as well as the CN (0-0) band of the violet system increase strongly in relation to the intensity of the neutral nitrogen component, i.e., the N2 (0-0) band of the second positive system. In addition, steel samples have been treated with both the steel and the carbon screen resulting in a formation of a compound layer of up to 10 wt. % nitrogen and 10 wt. % carbon, respectively, depending on the screen material.

  3. Localized corrosion of carbon steels due to sulfate-reducing bacteria. Development of a specific sensor; Corrosion localisee des aciers au carbone induite par des bacteries sulfato-reductrices. Developpement d'un capteur specifique

    Energy Technology Data Exchange (ETDEWEB)

    Monfort Moros, N.

    2001-11-01

    This work concerns the microbiologically influenced corrosion of carbon steels in saline anaerobic media (3% of NaCl) containing sulfato-reducing bacteria (Desulfovibrio gabonensis, DSM 10636). In these media, extreme localised corrosion occurs by pitting under the bio-film covering the metallic substrate. A sensor with concentric electrodes was designed to initiate the phenomenon of bio-corrosion, recreating the favourable conditions for growth of a corrosion pit, and then measuring the corrosion current maintained by bacterial activity. The pit initiation was achieved through either of two methods. The electrochemical conditioning involved driving the potential difference between inner and outer electrodes to values corresponding to a galvanic corrosion that can be maintained by the bacterial metabolism. The mechanical process involved removal of a portion of the bio-film by scratching, yielding galvanic potential differences equivalent to that found by the conditioning technique. This protocol was found to be applicable to a bio-corrosion study on industrial site for the monitoring of the metallic structures deterioration (patent EN 00/06114, May 2000). Thereafter, a fundamental application uses the bio-corrosion sensor for Electrochemical Impedance Spectroscopy (EIS), Electrochemical Noise Analysis (ENA) and current density cartography by the means of micro-electrodes. Thus, the EIS technique reveals the importance of the FeS corrosion products for initiation of bio-corrosion start on carbon steel. In addition, depending on the method used to create a pit, the ENA gives rise to supplementary processes (gaseous release) disturbing the bio-corrosion detection. The beginning of a bio-corrosion process on a clean surface surrounded with bio-film was confirmed by the current density cartography. These different results establish the sensor with concentric electrodes as an indispensable tool for bio-corrosion studies, both in the laboratory and on industrial sites

  4. Carvacrol, (-)-borneol and citral reduce convulsant activity in rodents ...

    African Journals Online (AJOL)

    ... compounds were efficient in preventing the tonic convulsions (p < 0.05) induced by MES. However, the GABAergic neurotransmitter system might be involved, at least in BOR effects. Henceforth, our results suggest that CARV, BOR and CIT possess anticonvulsant activity effect against PTZ-induced convulsions and MES.

  5. Reduced graphene oxide wrapped Ag nanostructures for enhanced SERS activity

    Science.gov (United States)

    Nair, Anju K.; Kala, M. S.; Thomas, Sabu; Kalarikkal, Nandakumar

    2018-04-01

    Graphene - metal nanoparticle hybrids have received great attention due to their unique electronic properties, large specific surface area, very high conductivity and more charge transfer. Thus, it is extremely advantages to develop a simple and efficient process to disperse metal nanostructures over the surface of graphene sheets. Herein, we report a hydrothermal assisted strategy for developing reduced graphene oxide /Ag nanomorphotypes (cube, wire) for surface enhanced Raman scattering (SERS) applications, considering the advantages of synergistic effect of graphene and plasmonic properties of Ag nanomorphotypes.

  6. Burnout Is Associated with Reduced Parasympathetic Activity and Reduced HPA Axis Responsiveness, Predominantly in Males

    Directory of Open Access Journals (Sweden)

    Wieke de Vente

    2015-01-01

    Full Text Available There is mounting evidence that burnout is a risk factor for cardiovascular disease (CVD. Stress-related dysregulation of the sympathetic and parasympathetic system and the hypothalamic pituitary adrenal (HPA axis may explain the enhanced risk for CVD. To test this hypothesis, 55 patients (34 males and 21 females with burnout on sickness absence and 40 healthy participants (16 males and 24 females were exposed to a psychosocial stressor consisting of mental arithmetic and public speech. Physiological variables (i.e., blood pressure, heart rate, cardiac output, vascular resistance, cortisol, and alpha-amylase were measured. Basal levels, reactivity, and recovery were compared between groups. In male patients, baseline systolic blood pressure was higher, whereas basal alpha-amylase and cortisol reactivity were lower than in healthy males. In female patients, a tendency for lower basal cortisol was found as compared to healthy females. Furthermore, reduced basal heart rate variability and a trend for elevated basal cardiac output were observed in both male and female patients. Burnout is characterised by dysregulation of the sympathetic and parasympathetic system and the HPA axis, which was more pronounced in males than in females. This study further supports burnout as being a risk factor for CVD through dysregulation of the sympathetic and parasympathetic system and the HPA axis.

  7. Reduced activation calculations for the STARFIRE first wall

    International Nuclear Information System (INIS)

    Mann, F.M.

    1983-10-01

    The activation of 27 elements (Li, Be, B, C, N, O, Mg, Al, Si, P, S, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Sn, Hf, Ta, W, and Pb) was calculated for a two-year exposure at the STARFIRE first-wall position. Based on a reasonable extension of current NRC regulations for near-surface land disposal, restrictions on N, Al, Ni, Cu, Nb, Mo, and Pb concentrations in first-wall materials may be required

  8. Barriers associated with reduced physical activity in COPD patients.

    Science.gov (United States)

    Amorim, Priscila Batista; Stelmach, Rafael; Carvalho, Celso Ricardo Fernandes; Fernandes, Frederico Leon Arrabal; Carvalho-Pinto, Regina Maria; Cukier, Alberto

    2014-10-01

    To evaluate the ability of COPD patients to perform activities of daily living (ADL); to identify barriers that prevent these individuals from performing ADL; and to correlate those barriers with dyspnea severity, six-minute walk test (6MWT), and an ADL limitation score. In COPD patients and healthy, age-matched controls, the number of steps, the distance walked, and walking time were recorded with a triaxial accelerometer, for seven consecutive days. A questionnaire regarding perceived barriers and the London Chest Activity of Daily Living (LCADL) scale were used in order to identify the factors that prevent the performance of ADL. The severity of dyspnea was assessed with two scales, whereas submaximal exercise capacity was determined on the basis of the 6MWT. We evaluated 40 COPD patients and 40 controls. In comparison with the control values, the mean walk time was significantly shorter for COPD patients (68.5 ± 25.8 min/day vs. 105.2 ± 49.4 min/day; p barriers to performing ADL were lack of infrastructure, social influences, and lack of willpower. The 6MWT distance correlated with the results obtained with the accelerometer but not with the LCADL scale results. Patients with COPD are less active than are healthy adults of a comparable age. Physical inactivity and the barriers to performing ADL have immediate implications for clinical practice, calling for early intervention measures.

  9. Evaluation of multistage filtration to reduce sand filter exhaust activity

    International Nuclear Information System (INIS)

    Zippler, D.B.

    1975-01-01

    Air from the Savannah River Plant Fuel Reprocessing facilities is filtered through deep bed sand filters consisting of 8 1 / 2 feet of gravel and sand. These filters have performed satisfactorily for the past 18 years in maintaining radioactive release levels to a minimum. The apparent filter efficiency has been determined for many years by measurements of the quantity of radioactivity in the air stream before and after the filter. Such tests have indicated efficiencies of 99.9 percent or better. Even with sand filter efficiency approaching a single stage HEPA filter, new emphasis on further reduction in release of plutonium activity to the environment prompted a study to determine what value backup HEPA filtration could provide. To evaluate the specific effect additional HEPA filtration would have on the removal of Pu from the existing sand filter exhaust stream, a test was conducted by passing a sidestream of sand-filtered air through a standard 24 x 24 x 11 1 / 2 in. HEPA filter. Isokinetic air samples were withdrawn upstream and downstream of the HEPA filter and counted for alpha activity. Efficiency calculations indicated that backup HEPA filtration could be expected to provide an additional 99 percent removal of the Pu activity from the present sand-filter exhaust. (U.S.)

  10. Myostatin Attenuation In Vivo Reduces Adiposity, but Activates Adipogenesis.

    Science.gov (United States)

    Li, Naisi; Yang, Qiyuan; Walker, Ryan G; Thompson, Thomas B; Du, Min; Rodgers, Buel D

    2016-01-01

    A potentially novel approach for treating obesity includes attenuating myostatin as this increases muscle mass and decreases fat mass. Notwithstanding, conflicting studies report that myostatin stimulates or inhibits adipogenesis and it is unknown whether reduced adiposity with myostatin attenuation results from changes in fat deposition or adipogenesis. We therefore quantified changes in the stem, transit amplifying and progenitor cell pool in white adipose tissue (WAT) and brown adipose tissue (BAT) using label-retaining wild-type and mstn(-/-) (Jekyll) mice. Muscle mass was larger in Jekyll mice, WAT and BAT mass was smaller and label induction was equal in all tissues from both wild-type and Jekyll mice. The number of label-retaining cells, however, dissipated quicker in WAT and BAT of Jekyll mice and was only 25% and 17%, respectively, of wild-type cell counts 1 month after induction. Adipose cell density was significantly higher in Jekyll mice and increased over time concomitant with label-retaining cell disappearance, which is consistent with enhanced expansion and differentiation of the stem, transit amplifying and progenitor pool. Stromal vascular cells from Jekyll WAT and BAT differentiated into mature adipocytes at a faster rate than wild-type cells and although Jekyll WAT cells also proliferated quicker in vitro, those from BAT did not. Differentiation marker expression in vitro, however, suggests that mstn(-/-) BAT preadipocytes are far more sensitive to the suppressive effects of myostatin. These results suggest that myostatin attenuation stimulates adipogenesis in vivo and that the reduced adiposity in mstn(-/-) animals results from nutrient partitioning away from fat and in support of muscle.

  11. Barriers associated with reduced physical activity in COPD patients

    Directory of Open Access Journals (Sweden)

    Priscila Batista Amorim

    2014-10-01

    Full Text Available OBJECTIVE: To evaluate the ability of COPD patients to perform activities of daily living (ADL; to identify barriers that prevent these individuals from performing ADL; and to correlate those barriers with dyspnea severity, six-minute walk test (6MWT, and an ADL limitation score. METHODS: In COPD patients and healthy, age-matched controls, the number of steps, the distance walked, and walking time were recorded with a triaxial accelerometer, for seven consecutive days. A questionnaire regarding perceived barriers and the London Chest Activity of Daily Living (LCADL scale were used in order to identify the factors that prevent the performance of ADL. The severity of dyspnea was assessed with two scales, whereas submaximal exercise capacity was determined on the basis of the 6MWT. RESULTS: We evaluated 40 COPD patients and 40 controls. In comparison with the control values, the mean walk time was significantly shorter for COPD patients (68.5 ± 25.8 min/day vs. 105.2 ± 49.4 min/day; p < 0.001, as was the distance walked (3.9 ± 1.9 km/day vs. 6.4 ± 3.2 km/day; p < 0.001. The COPD patients also walked fewer steps/day. The most common self-reported barriers to performing ADL were lack of infrastructure, social influences, and lack of willpower. The 6MWT distance correlated with the results obtained with the accelerometer but not with the LCADL scale results. CONCLUSIONS: Patients with COPD are less active than are healthy adults of a comparable age. Physical inactivity and the barriers to performing ADL have immediate implications for clinical practice, calling for early intervention measures.

  12. Technology development and production of elongated shell for reactor vessel active zone of WWER-TOI project from steel 15Cr2NiMoVN class 1

    International Nuclear Information System (INIS)

    Shklyaev, S.Eh.; Titova, T.I.; Ratushev, D.V.; Shul'gan, N.A.; Eroshkin, S.B.; Durynin, V.A.; Efimov, S.V.; Dub, V.S.; Kulikov, A.P.; Romashkin, A.N.

    2015-01-01

    Production process for the elongated shell blank of the active zone of the reactor pressure vessel made from steel 15Cr2NiMoVN Class 1 with finished sizes Dext=4.655 mm, Dint=4.240 mm, H=4.910 mm (height for heat treatment – 5.750 mm) is presented. For the first time in Russia in production site of OMZ-Special steel LLC a unique elongated shell blank of the reactor vessel active zone was made from ingot 420.0 t for WWER-TOI project fully meeting the specified requirements in terms of metallurgical quality and set of service properties [ru

  13. Functionally Selective AT(1) Receptor Activation Reduces Ischemia Reperfusion Injury

    DEFF Research Database (Denmark)

    Hostrup, Anders; Christensen, Gitte Lund; Bentzen, Bo Hjort

    2012-01-01

    of the physiological functions of AngII. The AT(1)R mediates its effects through both G protein-dependent and independent signaling, which can be separated by functionally selective agonists. In the present study we investigate the effect of AngII and the ß-arrestin biased agonist [SII]AngII on ischemia......]AngII had a protective effect. Together these results demonstrate a cardioprotective effect of simultaneous blockade of G protein signaling and activation of G protein independent signaling through AT(1 )receptors....

  14. Corrosion Behavior of Metal Active Gas Welded Joints of a High-Strength Steel for Automotive Application

    Science.gov (United States)

    Garcia, Mainã Portella; Mantovani, Gerson Luiz; Vasant Kumar, R.; Antunes, Renato Altobelli

    2017-10-01

    In this work, the corrosion behavior of metal active gas-welded joints of a high-strength steel with tensile yield strength of 900 MPa was investigated. The welded joints were obtained using two different heat inputs. The corrosion behavior has been studied in a 3.5 wt.% NaCl aqueous solution using electrochemical impedance spectroscopy and potentiodynamic polarization tests. Optical microscopy images, scanning electron microscopy and transmission electron microscopy with energy-dispersive x-ray revealed different microstructural features in the heat-affected zone (HAZ) and the weld metal (WM). Before and after the corrosion process, the sample was evaluated by confocal laser scanning microscopy to measure the depth difference between HAZ and WM. The results showed that the heat input did not play an important role on corrosion behavior of HSLA steel. The anodic and cathodic areas of the welded joints could be associated with depth differences. The HAZ was found to be the anodic area, while the WM was cathodic with respect to the HAZ. The corrosion behavior was related to the amount and orientation nature of carbides in the HAZ. The microstructure of the HAZ consisted of martensite and bainite, whereas acicular ferrite was observed in the weld metal.

  15. Joining of CBN abrasive grains to medium carbon steel with Ag-Cu/Ti powder mixture as active brazing alloy

    International Nuclear Information System (INIS)

    Ding, W.F.; Xu, J.H.; Shen, M.; Su, H.H.; Fu, Y.C.; Xiao, B.

    2006-01-01

    In order to develop new generation brazed CBN grinding wheels, the joining experiments of CBN abrasive grains and medium carbon steel using the powder mixture of Ag-Cu alloy and pure Ti as active brazing alloy are carried out at elevated temperature under high vacuum condition. The relevant characteristics of the special powder mixture, the microstructure of the interfacial region, which are both the key factors for determining the joining behavior among the CBN grains, the filler layer and the steel substrate, are investigated extensively by means of differential thermal analysis (DTA), scanning electron microscope (SEM) and energy dispersion spectrometer (EDS), as well X-ray diffraction (XRD) analysis. The results show that, similar to Ag-Cu-Ti filler alloy, Ag-Cu/Ti powder mixture exhibits good soakage capability to CBN grains during brazing. Moreover, Ti in the powder mixture concentrates preferentially on the surface of the grains to form a layer of needlelike Ti-N and Ti-B compounds by chemical metallurgic interaction between Ti, N and B at high temperature. Additionally, based on the experimental results, the brazing and joining mechanism is deeply discussed in a view of thermodynamic criterion and phase diagram of Ti-B-N ternary system

  16. Laser cladding of stainless steel with a copper-silver alloy to generate surfaces of high antimicrobial activity

    Science.gov (United States)

    Hans, Michael; Támara, Juan Carlos; Mathews, Salima; Bax, Benjamin; Hegetschweiler, Andreas; Kautenburger, Ralf; Solioz, Marc; Mücklich, Frank

    2014-11-01

    Copper and silver are used as antimicrobial agents in the healthcare sector in an effort to curb infections caused by bacteria resistant to multiple antibiotics. While the bactericidal potential of copper and silver alone are well documented, not much is known about the antimicrobial properties of copper-silver alloys. This study focuses on the antibacterial activity and material aspects of a copper-silver model alloy with 10 wt% Ag. The alloy was generated as a coating with controlled intermixing of copper and silver on stainless steel by a laser cladding process. The microstructure of the clad was found to be two-phased and in thermal equilibrium with minor Cu2O inclusions. Ion release and killing of Escherichia coli under wet conditions were assessed with the alloy, pure silver, pure copper and stainless steel. It was found that the copper-silver alloy, compared to the pure elements, exhibited enhanced killing of E. coli, which correlated with an up to 28-fold increased release of copper ions. The results show that laser cladding with copper and silver allows the generation of surfaces with enhanced antimicrobial properties. The process is particularly attractive since it can be applied to existing surfaces.

  17. PPARγ agonist pioglitazone reduces matrix metalloproteinase-9 activity and neuronal damage after focal cerebral ischemia

    International Nuclear Information System (INIS)

    Lee, Seong-Ryong; Kim, Hahn-Young; Hong, Jung-Suk; Baek, Won-Ki; Park, Jong-Wook

    2009-01-01

    Pioglitazone, a peroxisome proliferator-activated receptor gamma (PPARγ) agonist, has shown protective effects against ischemic insult in various tissues. Pioglitazone is also reported to reduce matrix metalloproteinase (MMP) activity. MMPs can remodel extracellular matrix components in many pathological conditions. The current study was designed to investigate whether the neuroprotection of pioglitazone is related to its MMP inhibition in focal cerebral ischemia. Mice were subjected to 90 min focal ischemia and reperfusion. In gel zymography, pioglitazone reduced the upregulation of active form of MMP-9 after ischemia. In in situ zymograms, pioglitazone also reduced the gelatinase activity induced by ischemia. After co-incubation with pioglitazone, in situ gelatinase activity was directly reduced. Pioglitazone reduced the infarct volume significantly compared with controls. These results demonstrate that pioglitazone may reduce MMP-9 activity and neuronal damage following focal ischemia. The reduction of MMP-9 activity may have a possible therapeutic effect for the management of brain injury after focal ischemia.

  18. Acute sex hormone suppression reduces skeletal muscle sympathetic nerve activity.

    Science.gov (United States)

    Day, Danielle S; Gozansky, Wendolyn S; Bell, Christopher; Kohrt, Wendy M

    2011-10-01

    Comparisons of sympathetic nervous system activity (SNA) between young and older women have produced equivocal results, in part due to inadequate control for potential differences in sex hormone concentrations, age, and body composition. The aim of the present study was to determine the effect of a short-term reduction in sex hormones on tonic skeletal muscle sympathetic nerve activity (MSNA), an indirect measure of whole body SNA, using an experimental model of sex hormone deficiency in young women. We also assessed the independent effects of estradiol and progesterone add-back therapy on MSNA. MSNA was measured in 9 women (30±2 years; mean±SE) on three separate occasions: during the mid-luteal menstrual cycle phase, on the fifth day of gonadotropin-releasing hormone antagonist (GnRHant) administration, and after 5 days add-back of either estradiol (n=4) or progesterone (n=3) during continued GnRHant administration. In response to GnRHant, there were significant reductions in serum estradiol and progesterone (both psuppression attenuates MSNA and that this may be related to the suppression of progesterone rather than estradiol.

  19. Steel making

    CERN Document Server

    Chakrabarti, A K

    2014-01-01

    "Steel Making" is designed to give students a strong grounding in the theory and state-of-the-art practice of production of steels. This book is primarily focused to meet the needs of undergraduate metallurgical students and candidates for associate membership examinations of professional bodies (AMIIM, AMIE). Besides, for all engineering professionals working in steel plants who need to understand the basic principles of steel making, the text provides a sound introduction to the subject.Beginning with a brief introduction to the historical perspective and current status of steel making together with the reasons for obsolescence of Bessemer converter and open hearth processes, the book moves on to: elaborate the physiochemical principles involved in steel making; explain the operational principles and practices of the modern processes of primary steel making (LD converter, Q-BOP process, and electric furnace process); provide a summary of the developments in secondary refining of steels; discuss principles a...

  20. Proceedings of the IEA Working Group meeting on ferritic/martensitic steels

    International Nuclear Information System (INIS)

    Klueh, R.L.

    1996-01-01

    An IEA working group on ferritic/martensitic steels for fusion applications, consisting of researchers from Japan, European Union, USA, and Switzerland, met at the headquarters of the Joint European Torus, Culham, UK. At the meeting, preliminary data generated on the large heats of steels purchased for the IEA program and on other heats of steels were presented and discussed. Second purpose of the meeting was to continue planning and coordinating the collaborative test program in progress on reduced-activation ferritic/martensitic steels. The majority of this report consists of viewographs for the presentations

  1. Activity of disinfectants against foodborne pathogens in suspension and adhered to stainless steel surfaces

    Directory of Open Access Journals (Sweden)

    Tatiane Karen Cabeça

    2012-09-01

    Full Text Available The purpose of this study was to investigate and compare the efficacy of various disinfectants on planktonic cells and biofilm cells of Listeria monocytogenes, Staphylococcus aureus and Escherichia coli. Numbers of viable biofilm cells decreased after treatment with all tested disinfectants (iodine, biguanide, quaternary ammonium compounds, peracetic acid and sodium hypochlorite. Sodium hypochlorite was the most effective disinfectant against biofilm cells, while biguanide was the least effective. Scanning electron microscopy observations revealed that cells adhered on stainless steel surface after treatment with the disinfectants. No viable planktonic cells were observed after treatment with the same disinfectants. Based on our findings, we concluded that biofilm cells might be more resistant to disinfectants than plancktonic cells.

  2. R and D of low activated Fe-Mn-Cr high strength non-magnetic steel, (I). Screening test for constituent optimization and fundamental characterization test

    Energy Technology Data Exchange (ETDEWEB)

    Ishiyama, Shintaro; Fukaya, Kiyoshi; Eto, Motokuni; Kikuchi, Mituru [Japan Atomic Energy Research Inst., Tokyo (Japan); Sato, Ikuo; Kusuhashi, Mikio; Hatakeyama, Tuyoshi [Japan Steel Works Ltd., Tokyo (Japan); Takahashi, Heishitiro [Center for Advanced Research of Energy Technology, Hokkaido Univ., Sapporo (Japan)

    2000-02-01

    It is very important to develop low activated/non-magnetic materials as large scale structural materials for fusion reactors. In the structural design of JT-60SU, low activated/non-magnetic materials with high specific strength and low decay heat characterizations are required. In the present paper, a new low activated/non-magnetic material (15.5 Mn-16Cr-0.2N-0.3Si-0.2C (wt%)) based on the conventional high manganese steel with lower Ni, CO, C, N and Mn contents for the purpose of lower activation and decay heat was developed and the mass production conditions of the material were optimized. Fundamental material characterization tests of the new material developed in present study were carried out, and the following conclusions are derived ; (1) Lower activation characterizations with the new materials in the order of 1/10 of that of SUS316L steel, (2) Higher strength of the material in the order of 2{approx}3 of SUS316L steel and (3) Lower decay heat with higher thermal conductivity with comparison of SUS316L steel. (author)

  3. Chemical segregation behavior under thermal aging of the low-activation F82H-modified steel

    International Nuclear Information System (INIS)

    Lapena, J.; Garcia-Mazario, M.; Fernandez, P.; Lancha, A.M.

    2000-01-01

    In this work, thermal aging of the low-activation F82H-modified steel has been performed at temperatures in the range 300-600 deg. C during periods up to 5000 h. A detailed mechanical and microstructural characterization has been carried out in the aged materials, as well as in the as-received state material for reference. Auger electron spectroscopy (AES) analysis has been performed for these materials to study the microchemistry at the grain boundaries. The results show a decrease of the impact properties after aging at 600 deg. C that has been related to the precipitation of the Laves phase. Auger analyses show chromium enrichment and iron depletion at grain boundaries in all material conditions. In addition, sulphur and tungsten have been observed by this technique at grain boundaries, their presence and distribution being dependent on the material state

  4. Microbial Corrosion and Cracking in Steel

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    1998-01-01

    The aim of the report is to give a fundamental understanding of the response of different electrochemical techniques on carbon steel in a sulphide environment as well as in a biologically active sulphate-reducing environment (SRB). This will form the basis for further studies and for recommendati......The aim of the report is to give a fundamental understanding of the response of different electrochemical techniques on carbon steel in a sulphide environment as well as in a biologically active sulphate-reducing environment (SRB). This will form the basis for further studies...... will be based on results from the entire 3 year period, but only selected experimental data primarily from the latest experiments will be presented in detail here.Microbial corrosion of carbon steel under influence of sulphate-reducing bacteria (SRB) is characterised by the formation of both biofilm...... and corrosion products (ferrous sulphides) on the metal surface. Experiments have been conducted on carbon steel exposed in near neutral (pH 6 to 8.5) saline hydrogen sulphide environment (0 to 100 mg/l total dissolved sulphide) for a period of 14 days. Furthermore coupons have been exposed in a bioreactor...

  5. Development of low-chromium, chromium-tungsten steels for fusion

    International Nuclear Information System (INIS)

    Klueh, R.L.; Alexander, D.J.; Kenik, E.A.

    1995-01-01

    High-chromium (9-12% Cr) Cr-Mo and Cr-W ferritic steels are favored as candidates for fusion applications. In early work to develop reduced-activation steels, an Fe-2.25Cr-2W-0.25V-0.1C steel (designated 2.25Cr-2WV) had better strength than an Fe-9Cr-2W-0.25V-0.07Ta-0.1C (9Cr-2WVTa) steel (compositions are in weight percent). However, the 2.25Cr-2WV had poor impact properties, as determined by the ductile-brittle transition temperature and upper-shelf energy of subsize Charpy impact specimens. Because low-chromium steels have some advantages over high-chromium steels, a program to develop low-chromium steels is in progress. Microstructural analysis indicated that the reason for the inferior impact toughness of the 2.25Cr-2WV was the granular bainite obtained when the steel was normalized. Properties can be improved by developing an acicular bainite microstructure by increasing the cooling rate after austenitization. Alternatively, acicular bainite can be promoted by increasing the hardenability. Hardenability was changed by adding small amounts of boron and additional chromium to the 2.25Cr-2WV composition. A combination of B, Cr, and Ta additions resulted in low-chromium reduced-activation steels with mechanical properties comparable to those of 9Cr-2WVTa. (orig.)

  6. Study of occupational health impact of atmospheric pollution on exposed workers at an iron and steel complex by using neutron activation analysis of scalp hair

    International Nuclear Information System (INIS)

    Chai, Z.F.; Qian, Q.F.; Feng, X.Q.; Zhang, P.Q.; Liu, N.Q.; Feng, W.Y.

    2004-01-01

    The occupational health impact of atmospheric pollution on exposed workers at one iron and steel complex was studied by instrumental neutron activation analysis of workers' hair samples and medical examination. The experimental results indicate that there is a positive correlation between the high inhalation amounts of iron and other trace elements by the exposed workers and the symptom of their high blood pressure and hypoglycemia, which implies that the atmospheric environment polluted by iron and steel industry has an adverse health impact on the exposed workers. The measures to relieve and abate the occupational diseases caused by air-borne particulate matter should be taken. (author)

  7. Corrosion detection of steel reinforced concrete using combined carbon fiber and fiber Bragg grating active thermal probe

    International Nuclear Information System (INIS)

    Li, Weijie; Ho, Siu Chun Michael; Song, Gangbing

    2016-01-01

    Steel reinforcement corrosion is one of the dominant causes for structural deterioration for reinforced concrete structures. This paper presents a novel corrosion detection technique using an active thermal probe. The technique takes advantage of the fact that corrosion products have poor thermal conductivity, which will impede heat propagation generated from the active thermal probe. At the same time, the active thermal probe records the temperature response. The presence of corrosion products can thus be detected by analyzing the temperature response after the injection of heat at the reinforcement-concrete interface. The feasibility of the proposed technique was firstly analyzed through analytical modeling and finite element simulation. The active thermal probe consisted of carbon fiber strands to generate heat and a fiber optic Bragg grating (FBG) temperature sensor. Carbon fiber strands are used due to their corrosion resistance. Wet-dry cycle accelerated corrosion experiments were performed to study the effect of corrosion products on the temperature response of the reinforced concrete sample. Results suggest a high correlation between corrosion severity and magnitude of the temperature response. The technique has the merits of high accuracy, high efficiency in measurement and excellent embeddability. (paper)

  8. Tritium activity balance in hairless rats following skin-contact exposure to tritium-gas-contaminated stainless-steel surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Trivedi, A

    1994-06-01

    Studies using animals and human volunteers have demonstrated that the dosimetry for skin-contact exposure to contaminated metal surfaces differs from that for the intake of tritiated water or tritium gas. However, despite the availability of some information on the dosimetry for skin-contact with tritium-gas-contaminated metal surfaces, uncertainties in estimating skin doses remain, because of poor accounting for the applied tritium activity in the body (Eakins et al., 1975; Trivedi, 1993). Experiments on hairless rats were performed to account for the tritium activity applied onto the skin. Hairless rats were contaminated through skin-contact exposure to tritium-gas-contaminated stainless-steel planchets. The activity in the first smear was about 35% of the total removable activity (measured by summing ten consecutive swipes). The amount of tritium applied onto the skin can be approximated by estimating the tritium activity in the first smear removed form the contaminated surfaces. 87 {+-} 9% of the transferred tritium was retained in the exposed skin 30 min post-exposure. 30 min post exposure, the unexposed skin and the carcass retained 8 {+-} 6% and 3 {+-} 2% of the total applied tritium activity, respectively. The percentage of tritium evolved from the body or breathed out was estimated to be 2 {+-} 1% of the total applied activity 30 min post-exposure. It is recommended that to evaluate accurately the amount of tritium transferred to the skin, alternative measurement approaches are required that can directly account for the transferred activity onto the skin. 15 refs., 13 tabs., 7 figs.

  9. Neutron activation analysis and activity in the vessel steel of a BWR reactor for their study without radiological risks in microscopy and spectrometry

    International Nuclear Information System (INIS)

    Moranchel, M.; Garcia B, A.; Longoria G, L. C.

    2012-01-01

    The vessel material of nuclear reactors is subject to irradiation damage induced by the bombardment of neutrons coming from the reactor core. Neutrons are classified as fast and thermal, which produce different effects. Fast neutrons cause damage to the material by dislocation or displacement of atoms in the crystal structure, while the effect of thermal neutrons is a nuclear transmutation that can significantly change the properties of the material. The type and intensity of damage is based on the characteristics of the material, the flow of neutrons and the modes of neutrons interaction with the atomic structures of the material, among others. This work, alluding to nuclear transmutation, makes an analysis of neutron activation of all isotopes in a steel boiling water nuclear reactor (BWR) vessel. An analytical expression is obtained in order to model activity of steel, on the basis of the weight percentage of its atomic components. Its activity is theoretically estimated in a witness sample of the same material as that of the vessel, placed within the nuclear reactor since the beginning of its commercial operation in April 1995, up to August 2010. It was theoretically determined that the witness sample, with a 0.56 g mass (1 x 1 x 0.07 cm 3 dimensions or equivalent) does not present a radiological risks during the stage of preparation, observation and analysis of it in electron microscopy and X-ray diffraction equipment s. The theoretical results were checked experimentally by measuring the activity of the sample by means of gamma spectrometry, measurement of the exposure levels around the sample, as well as the induced level to whole body and limbs, using thermo-luminescent dosimetry (TLD). As a result of the theoretical analysis, new chemical elements are predicted, as a result of the activation phenomena and radioactive decay, whose presence can be a fundamental factor of change in the properties of the vessel. This work is a preamble to the investigation of

  10. Study of carbonitriding thermochemical treatment by plasma screen in active with pressures main austenitic stainless steels AISI 409 and AISI 316L

    International Nuclear Information System (INIS)

    Melo, M.S.; Oliveira, A.M.; Leal, V.S.; Sousa, R.R.M. de; Alves Junior, C.; Centro Federal de Educacao Tecnologica do Piaui; Universidade Federal do Rio Grande do Norte

    2010-01-01

    The technique called Active Screen Plasma Nitriding (ASPN) is being used as an alternative once it offers several advantages with respect to conventional DC plasma. In this method, the plasma does not form directly in the sample's surface but on a screen, in such a way that undesired effects such as the edge effect is minimized. Stainless steels present not very satisfactory wearing characteristics. However, plasma carbonitriding has been used as to improve its resistance to wearing due to the formation of a fine surface layer with good properties. In this work, samples of stainless steel AISI 316L and AISI 409 were treated at pressures of 2.5 and 5 mbar. After the treatments they were characterized by microhardness, microscopy and Xray diffraction. Microscopy and hardness analysis showed satisfactory layers and toughness in those steels. (author)

  11. Corrosive Metabolic Activity of Desulfovibrio sp. on 316L Stainless Steel

    Science.gov (United States)

    Arkan, Simge; Ilhan-Sungur, Esra; Cansever, Nurhan

    2016-12-01

    The present study investigated the effects of chemical parameters (SO4 2-, PO4 3-, Cl-, pH) and the contents of extracellular polymeric substances (EPS) regarding the growth of Desulfovibrio sp. on the microbiologically induced corrosion of 316L stainless steel (SS). The experiments were carried out in laboratory-scaled test and control systems. 316L SS coupons were exposed to Desulfovibrio sp. culture over 720 h. The test coupons were removed at specific sampling times for enumeration of Desulfovibrio sp., determination of the corrosion rate by the weight loss measurement method and also for analysis of carbohydrate and protein in the EPS. The chemical parameters of the culture were also established. Biofilm/film formation and corrosion products on the 316L SS surfaces were investigated by scanning electron microscopy and energy-dispersive x-ray spectrometry analyses in the laboratory-scaled systems. It was found that Desulfovibrio sp. led to the corrosion of 316L SS. Both the amount of extracellular protein and chemical parameters (SO4 2- and PO4 3-) of the culture caused an increase in the corrosion of metal. There was a significantly positive relationship between the sessile and planktonic Desulfovibrio sp. counts ( p < 0.01). It was detected that the growth phases of the sessile and planktonic Desulfovibrio sp. were different from each other and the growth phases of the sessile Desulfovibrio sp. vary depending on the subspecies of Desulfovibrio sp. and the type of metal when compared with the other published studies.

  12. Effect of activation cross section uncertainties in the assessment of primary damage for MFE/IFE low-activation steels irradiated in IFMIF

    International Nuclear Information System (INIS)

    Cabellos, O.; Sanz, J.; Garcia-Herranz, N.; Otero, B.

    2009-01-01

    The present study is mainly aimed to provide the primary damage (displacements per atom, generation of solid transmutants and gas production rates) of structural materials irradiated in the high and medium flux test modules of the International Fusion Materials Irradiation Facility (IFMIF). We have investigated if the change of the composition during the irradiation time has effect on the prediction of the atomic displacements. The effect of the activation cross section uncertainties in the assessment of both solid transmutants and hydrogen and helium production is also analyzed. The results are provided element-by-element, so that the primary damage of any material irradiated in such neutron environments can be easily assessed; in this paper, we have predicted the primary damage of the low activation steel Eurofer.

  13. Effect of activation cross section uncertainties in the assessment of primary damage for MFE/IFE low-activation steels irradiated in IFMIF

    Energy Technology Data Exchange (ETDEWEB)

    Cabellos, O. [Instituto de Fusion Nuclear, Universidad Politecnica de Madrid (UPM), C/Jose Gutierrez Abascal, n2, 28006 Madrid (Spain); Dept. de Ingenieria Nuclear, Universidad Politecnica de Madrid, 28006 Madrid (Spain)], E-mail: cabellos@din.upm.es; Sanz, J. [Instituto de Fusion Nuclear, Universidad Politecnica de Madrid (UPM), C/Jose Gutierrez Abascal, n2, 28006 Madrid (Spain); Dept. de Ingenieria Energetica, Universidad Nacional de Educacion a Distancia, 28045 Madrid (Spain); Garcia-Herranz, N. [Instituto de Fusion Nuclear, Universidad Politecnica de Madrid (UPM), C/Jose Gutierrez Abascal, n2, 28006 Madrid (Spain); Dept. de Ingenieria Nuclear, Universidad Politecnica de Madrid, 28006 Madrid (Spain); Otero, B. [Dept. de Ingenieria Nuclear, Universidad Politecnica de Madrid, 28006 Madrid (Spain)

    2009-04-30

    The present study is mainly aimed to provide the primary damage (displacements per atom, generation of solid transmutants and gas production rates) of structural materials irradiated in the high and medium flux test modules of the International Fusion Materials Irradiation Facility (IFMIF). We have investigated if the change of the composition during the irradiation time has effect on the prediction of the atomic displacements. The effect of the activation cross section uncertainties in the assessment of both solid transmutants and hydrogen and helium production is also analyzed. The results are provided element-by-element, so that the primary damage of any material irradiated in such neutron environments can be easily assessed; in this paper, we have predicted the primary damage of the low activation steel Eurofer.

  14. Corrosion behavior of carbon steel exposed for long time to an inoculation medium of sulfate-reducing bacteria; Ryusan`en kangenkin ga seisokusuru baichi ni chokikan shinshinshita tansoko no fushoku kyodo

    Energy Technology Data Exchange (ETDEWEB)

    Baba, F.; Suzuki, T. [Ajinomoto Co. Inc., Kawasaki (Japan). Technology and Engineering Lab.; Seo, M. [Hokkaido Univ., Sapporo (Japan). Graduate School of Engineering

    1996-10-15

    In this paper, carbon steel was exposed more than six weeks to an inoculation medium of the sulfate-reducing bacteria in which the Fe{sup 2+} concentration was adjusted to a fixed value, the corrosion behavior of carbon steel was investigated by measuring the weight change and surface analysis using EPMA. As a result, the conclusions were obtained as follows: in the case of the medium with high Fe{sup 2+} concentration, the corrosion rate reached a maximum. In this case, the corrosion rate was suppressed to be low during the exposure for up to three weeks, and was increased above four weeks. The corrosion rate became 0.06 mm year{sup -1} by extrapolating the weight loss during the exposure up to six weeks. This value was higher than the average corrosion rate of carbon steel in a neutral solution with deaeration. It was shown from the analysis results using the EPMA that the FeS scale area covered on the surface of carbon steel would act as a cathode, and the other area would act as an anode. The formation of a scale effectively acting as a cathode depended on the exposure time and the formation of FeS in the medium. 15 refs., 10 figs., 1 tab.

  15. Accelerated corrosion of stainless steel in thiocyanate-containing solutions

    Energy Technology Data Exchange (ETDEWEB)

    Pistorius, P Chris; Li, Wen

    2012-09-19

    It is known that reduced sulfur compounds (such as thiocyanate and thiosulfate) can accelerate active corrosion of austenitic stainless steel in acid solutions, but before we started this project the mechanism of acceleration was largely unclear. This work combined electrochemical measurements and analysis using scanning electron microscopy (SEM) and X-ray photo-electron spectroscopy (XPS), which provided a comprehensive understanding of the catalytic effect of reduced sulfur species on the active corrosion of stainless steel. Both the behavior of the pure elements and the steel were studied and the work focused on the interaction between the pure elements of the steel, which is the least understood area. Upon completion of this work, several aspects are now much clearer. The main results from this work can be summarized as follows: The presence of low concentrations (around 0.1 mM) of thiocyanate or tetrathionate in dilute sulfuric acid greatly accelerates the anodic dissolution of chromium and nickel, but has an even stronger effect on stainless steels (iron-chromium-nickel alloys). Electrochemical measurements and surface analyses are in agreement with the suggestion that accelerated dissolution really results from suppressed passivation. Even well below the passivation potential, the electrochemical signature of passivation is evident in the electrode impedance; the electrode impedance shows clearly that this pre-passivation is suppressed in the presence of thiocyanate. For the stainless steels, remarkable changes in the morphology of the corroded metal surface and in the surface concentration of chromium support the suggestion that pre-passivation of stainless steels is suppressed because dissolution of chromium is accelerated. Surface analysis confirmed that adsorbed sulfur / sulfide forms on the metal surfaces upon exposure to solutions containing thiocyanate or thiosulfate. For pure nickel, and steels containing nickel (and residual copper), bulk sulfide

  16. Oxytocin reduces amygdala activity, increases social interactions, and reduces anxiety-like behavior irrespective of NMDAR antagonism.

    Science.gov (United States)

    Sobota, Rosanna; Mihara, Takuma; Forrest, Alexandra; Featherstone, Robert E; Siegel, Steven J

    2015-08-01

    Standard dopamine therapies for schizophrenia are not efficacious for negative symptoms of the disease, including asociality. This reduced social behavior may be due to glutamatergic dysfunction within the amygdala, leading to increased fear and social anxiety. Several studies have demonstrated the prosocial effects of oxytocin in schizophrenia patients. Therefore, this study evaluates the effect of subchronic oxytocin on EEG activity in amygdala of mice during performance of the three-chamber social choice and open field tests following acute ketamine as a model of glutamatergic dysfunction. Oxytocin did not restore social deficits introduced by ketamine but did significantly increase sociality in comparison to the control group. Ketamine had no effect on time spent in the center during the open field trials, whereas oxytocin increased overall center time across all groups, suggesting a reduction in anxiety. Amygdala activity was consistent across all drug groups during social and nonsocial behavioral trials. However, oxytocin reduced overall amygdala EEG power during the two behavioral tasks. Alternatively, ketamine did not significantly affect EEG power throughout the tasks. Decreased EEG power in the amygdala, as caused by oxytocin, may be related to both reduced anxiety and increased social behaviors. Data suggest that separate prosocial and social anxiety pathways may mediate social preference. (c) 2015 APA, all rights reserved).

  17. Martensitic transformation in Eurofer-97 and ODS-Eurofer steels: A comparative study

    International Nuclear Information System (INIS)

    Zilnyk, K.D.; Oliveira, V.B.; Sandim, H.R.Z.; Möslang, A.; Raabe, D.

    2015-01-01

    Highlights: • Martensitic transformation of RAFM steels promotes significant grain fragmentation. • Austenite grain growth occurs in Eurofer-97 steel but not in ODS-Eurofer steel. • Boundary misorientation distribution of the as-quenched steels show two maxima peaks. • The amount of retained austenite varies from one steel to another. - Abstract: Reduced-activation ferritic–martensitic Eurofer-97 and ODS-Eurofer steels are potential candidates for structural applications in advanced nuclear reactors. Samples of both steel grades in the as-tempered condition were austenitized in vacuum for 1 h from 900 °C to 1300 °C followed by air cooling to room temperature. The microstructure was characterized by dilatometry, electron backscatter diffraction (EBSD), and X-ray diffraction (XRD). Thermodynamic calculations provided by Thermo-Calc software were used to determine their transformation temperatures. Even having similar chemical composition, important changes were observed after martensitic transformation in these steels. Significant austenitic grain growth was observed in Eurofer-97 steel leading to the development of coarser martensitic packets. Contrastingly, austenitic grain growth was prevented in ODS-Eurofer steel due to fine and stable dispersion of Y-based particles

  18. Report on evaluation of research and development of direct steel-making using high-temperature reducing gas. Phase 1. Draft; Koon kangen gas riyo ni yoru chokusetsu seitetsu no kenkyu kaihatsu (daiikki) ni kansuru hyoka hokokusho (an)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1981-01-01

    Described herein is development of direct steel-making using high-temperature reducing gas. A light hydrocarbon fraction (boiling point: 230 degrees C or lower), produced by steam cracking of vacuum residua, is reformed into a reducing gas in the presence of steam, using heat to be supplied by a nuclear plant which produces high-temperature gases for various purposes. This reducing gas is then supplied to a plant for producing reduced iron. This project has established basic techniques for designing, constructing and operating a direct steel-making pilot plant, to be connected to a 50 MWt high-temperature gas test furnace. The closed iron-making system and greatly reduced SOx emissions to several fractions of the current level are some of the expected effects. The environmental impacts of the high-temperature gas furnace will be on a level with those associated with a light-water reactor. Cracking and gasification of vacuum residua, which has found limited purposes so far, should expand its applicable areas and reduce dependence on fossil resources, leading to diversification of energy sources. The overall thermal efficiency of the high-temperature gas furnace is expected to increase to at least 60%, because its high-temperature gases of around 1,000 degrees C can be used for heating processes, and the waste heat can be further used for generation of steam for power production. (NEDO)

  19. The Influence of Calcium Carbonate Composition and Activated Carbon in Pack Carburizing Low Carbon Steel Process in The Review of Hardness and Micro Structure

    Science.gov (United States)

    Hafni; Hadi, Syafrul; Edison

    2017-12-01

    Carburizing is a way of hardening the surface by heating the metal (steel) above the critical temperature in an environment containing carbon. Steel at a temperature of the critical temperature of affinity to carbon. Carbon is absorbed into the metal form a solid solution of carbon-iron and the outer layer has high carbon content. When the composition of the activator and the activated charcoal is right, it will perfect the carbon atoms to diffuse into the test material to low carbon steels. Thick layer of carbon Depending on the time and temperature are used. Pack carburizing process in this study, using 1 kg of solid carbon derived from coconut shell charcoal with a variation of 20%, 10% and 5% calcium carbonate activator, burner temperature of 950 0C, holding time 4 hours. The test material is low carbon steel has 9 pieces. Each composition has three specimens. Furnace used in this study is a pack carburizing furnace which has a designed burner box with a volume of 1000 x 600 x 400 (mm3) of coal-fired. Equipped with a circulation of oxygen from the blower 2 inches and has a wall of refractory bricks. From the variation of composition CaCO3, microstructure formed on the specimen with 20% CaCO3, better diffusion of carbon into the carbon steel, it is seen by the form marten site structure after quenching, and this indicates that there has been an increase of or adding carbon to in the specimen. This led to the formation of marten site specimen into hard surfaces, where the average value of hardness at one point side (side edge) 31.7 HRC

  20. Critically evaluate techniques for the in situ testing of steel tendon grouting effectiveness as a basis for reducing fall of ground injuries and fatalities

    CSIR Research Space (South Africa)

    Kelly, AM

    1996-10-01

    Full Text Available The quality of installation and grouting of rock reinforcing tendons is seen as a serious problem by the mining industry. Up to half of all full-column grouted steel tendons or rock bolts installed in South African gold and platinum mines...

  1. Activity measurement and its use in predicting phase relationships in stainless steels

    International Nuclear Information System (INIS)

    Lee, M.C.Y.

    1989-01-01

    A combination Knudsen cell-mass spectrometer apparatus has been developed by the Bureau of Mines. This apparatus is accurate enough to permit the activity of many alloy components to be measured directly as the ratio of the ion currents of an appropriate isotope evaporated from the alloy and from the pure component. This apparatus has been used to determine the activity of each component as a function of temperature in 75Fe-10Cr-15Ni, 73Fe-6Cr-15Ni-6Al, and 75Fe-4Cr-15Ni-2Al-4Si (at%). The data indicate that additions of Ni, Cr, Al, and/or Si have practically no effect on the activity coefficient of Fe and that the partial substitution of Cr by Al and/or Si decreases the activity coefficient of Ni. In the case of Cr, temperature influences the activity coefficient more than does the content of Al and/or Si. The activity coefficient of Cr in each alloy increases with decreasing temperature, while the activity coefficients of Fe and Ni are temperature insensitive. The resistance of Fe-Ni-Cr base alloys to oxidation and sulfidation and the stability of the austentic phase in such alloys are discussed in light of these activity changes. (orig.)

  2. Monitoring Techniques for Microbially Influenced Corrosion of Carbon Steel

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    2000-01-01

    corrosion rates, when biofilm and corrosion products cover the steel surface. However, EIS might be used for detection of MIC. EN is a suitable technique to characterise the type of corrosion attack, but is unsuitable for corrosion rate estimation. The concentric electrodes galvanic probe arrangement......Abstract Monitoring Techniques for Microbially Influenced Corrosion of Carbon Steel Microbially influenced corrosion (MIC) of carbon steel may occur in media with microbiological activity of especially sulphate-reducing bacteria, e.g. on pipelines buried in soil and on marine structures. MIC...... of carbon steel must be monitored on-line in order to provide an efficient protection and control the corrosion. A number of monitoring techniques is industrially used today, and the applicability and reliability of these for monitoring MIC is evaluated. Coupons and ER are recommended as necessary basic...

  3. Regular physical activity has differential association with reduced obesity among diverse youth in the United States.

    Science.gov (United States)

    Fradkin, Chris; Wallander, Jan L; Elliott, Marc N; Cuccaro, Paula; Schuster, Mark A

    2016-08-01

    This study examined whether daily or almost daily lower-intensity physical activity was associated with reduced obesity, among 4824 African American, Hispanic, and White youth assessed in fifth and seventh grades. Regular lower-intensity physical activity was associated with reduced obesity only among Hispanic and White males and only in seventh grade, and not among youth in fifth grade, females, or African American males or females. Findings from this study suggest that the reduced obesity risk generally attributed to physical activity may not be consistent across racial/ethnic and gender groups of early adolescents. © The Author(s) 2014.

  4. Measurement of the activity coefficient of carbon in steels in liquid sodium

    International Nuclear Information System (INIS)

    Surville, G.

    1983-06-01

    In sodium cooled fast reactors carbon is both a carbon impurity and element of structural materials. Carbon transfert through liquid sodium can produce carburization or decarburization of structural materials. Carbon content in sodium is determined with thin foils of austenitic alloys, when equilibrium is reached thermodynamic activity of carbon in sodium is deduced from carbon activity in alloys. Studied alloys are FeMn 20%, FeNi 30%, Z2CN 18-10 and Z3CND17-13. Carbon activity of alloys in sodium was between 5.10 -3 and 10 -1 at 600 and 650 0 C. Calibration was obtained with the alloys FeNi 30% in gaseous mixtures He-CO-CO 2 of known activity [fr

  5. Microstructural Development during Welding of TRIP steels

    NARCIS (Netherlands)

    Amirthalingam, M.

    2010-01-01

    The Advanced High Strength Steels (AHSS) are promising solutions for the production of lighter automobiles which reduce fuel consumption and increase passenger safety by improving crash-worthiness. Transformation Induced Plasticity Steel (TRIP) are part of the advanced high strength steels which

  6. Positron annihilation lifetime measurements of austenitic stainless and ferritic/martensitic steels irradiated in the SINQ target irradiation program

    Science.gov (United States)

    Sato, K.; Xu, Q.; Yoshiie, T.; Dai, Y.; Kikuchi, K.

    2012-12-01

    Titanium-doped austenitic stainless steel (JPCA) and reduced activated ferritic/martensitic steel (F82H) irradiated with high-energy protons and spallation neutrons were investigated by positron annihilation lifetime measurements. Subnanometer-sized (steel, the positron annihilation lifetime of the bubbles decreased with increasing irradiation dose and annealing temperature because the bubbles absorb additional He atoms. In the case of JPCA steel, the positron annihilation lifetime increased with increasing annealing temperature above 773 K, in which case the dissociation of complexes of vacancy clusters with He atoms and the growth of He bubbles was detected. He bubble size and density were also discussed.

  7. Trying To Reduce Your Technostress?: Helpful Activities for Teachers and Library Media Specialists.

    Science.gov (United States)

    McKenzie, Barbara K.; And Others

    1997-01-01

    As pressure increases to integrate technology into instruction, many teachers and library media specialists are having difficulty coping with "technostress." Presents suggestions and activities for teachers and library media specialists designed to reduce "technostress." (PEN)

  8. Fetoscopic laser coagulation of intertwin anastomoses reduces discordant placental autophagic activities in discordant twin growth

    Directory of Open Access Journals (Sweden)

    Yao-Lung Chang

    2015-10-01

    Conclusion: The discordance of placenta autophagic activity in the monochorionic twin with sIUGR was reduced after laser coagulation of the intertwin anastomoses, which may result from the effect of correction of the discordant intertwin placenta perfusion.

  9. Application of Thin Layer Activation Technique for Wear and Corrosion Studies in Stainless Steel Using Neutron Sources

    International Nuclear Information System (INIS)

    Mohamed, R.F.I.

    2013-01-01

    In this work elemental analysis for three types of stainless steel samples was performed to compare between their compositions. First the stainless samples were analyzed using Energy Dispersive X-ray (EDX) Spectrometer and Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) as conventional tools for elemental analysis. Second, the samples were subjected to detailed neutron activation analysis (NAA) using Pu-Be neutron source with applying γ-rays spectroscopic measurements for the irradiated samples. The first sample was in the form of thin foils. Eight radioactive isotopes were detected in the measured spectra namely 56 Mn, 59 Fe, 58 Co, 60 Co, 24 Na, 187 W, 99 Mo and 51 Cr which resulted from different neutron reactions with this sample. The other two samples were commercial and the NAA results for one of them show that all of the elements reported in the foil sample are the same except the absence of Mo and the presence of Cr.On the other hand the third sample shows a different composition where only Mn, Fe, and Ni were identified from the measured γ- ray spectra. Stacks of irradiated stainless steal foil and pellets were measured to obtain the activity as a function of thickness using the most intense gamma ray lines of the produced radionuclides. The obtained linear activity-thickness relations for the measured radionuclides were fitted to determine the slope and the maximum thickness which can be measured by this technique. The comparison between these curves showed that the most sensitive radioisotope for detecting slight changes in the thickness is 51 Cr which is formed through the 50 Cr (n,γ) 51 Cr reaction.

  10. Neighborhood level health risk assessment of lead paint removal activities from elevated steel bridges

    Energy Technology Data Exchange (ETDEWEB)

    Conway, R.F.; Cohen, J.T.; Bowers, T.

    1999-07-01

    The New York City Department of Transportation (NYCDOT) has adopted strict containment and monitoring procedures during paint removal activities on its bridges because of the increasing awareness about lead poisoning in children in urban environments and the potential risk of lead-based paint releases during those activities. NYCDOT owns nearly 800 bridges scattered throughout New York City. Before undertaking paint removal activities as part of its ongoing preventive maintenance and rehabilitation program, NYCDOT recently conducted an analysis to determine the public health risk posed to children living near them. The analysis the first of its kind to assess the actual public health risk potential during both routine operations and upset conditions, or accidental releases evaluated the total and incremental blood lead levels from paint removal activities on more than 5,000 children from 6 months to 6 years old. Increases in baseline blood lead levels were estimated using several models, including EPA's Integrated Exposure Uptake Biokinetic (IEUBK) Model. This model estimates steady-state blood lead levels in children, reflecting exposure to lead in multiple media over an extended period of time. Increases in lead exposure from paint removal activities in the area surrounding the bridges was estimated using EPA's Industrial Source Complex (ISC3) model to calculate ambient air and deposition levels. Potential releases from the containment and ancillary equipment used in the paint removal process were modeled based on different release scenarios ranging from routine operations to complete failure of containment. To estimate the paint removal activities' contribution to long-term exterior dust lead levels (and its related interior component), a stochastic simulation model was developed for each block in the study area.

  11. Comparative study in the induced corrosion by sulfate reducing microorganisms, in a stainless steel 304L sensitized and a carbon steel API X65; Estudio comparativo de la corrosion inducida por microorganismos sulfatorreductores, en un acero inoxidable 304L sensibilizado y un acero al carbono API X65

    Energy Technology Data Exchange (ETDEWEB)

    Diaz S, A.; Gonzalez F, E.; Arganis J, C.; Luna C, P.; Carapia M, L. [ININ, Carretera Mexico-Toluca Km. 36.5, 52045 Estado de Mexico (Mexico)]. e-mail: ads@nuclear.inin.mx

    2004-07-01

    In spite of the operational experience related with the presence of the phenomenon of microbiological corrosion (MIC) in industrial components, it was not but until the decade of the 80 s when the nuclear industry recognized its influence in some systems of Nuclear Generating Power plants. At the moment, diverse studies that have tried to explain the generation mechanism of this phenomenon exist; however, they are even important queries that to solve, especially those related with the particularities of the affected metallic substrates. Presently work, the electrochemical behavior of samples of stainless steel AISI 304L sensitized is evaluated and the carbon steel APIX65, before the action of sulfate reducing microorganisms low the same experimental conditions; found that for the APIX65 the presence of this type of bacteria promoted the formation of a stable biofilm that allowed the maintenance of the microorganisms that damaged the material in isolated places where stings were generated; while in the AISI 304L, it was not detected damage associated to the inoculated media. The techniques of Resistance to the Polarization and Tafel Extrapolation, allowed the calculation of the speed of uniform corrosion, parameter that doesn't seem to be influenced by the presence of the microorganisms; while that noise electrochemical it distinguished in real time, the effect of the sulfate reducing in the steel APIX65. (Author)

  12. Corrosion of bare carbon steel as a passive sensor to assess moisture availability for biological activity in Atacama Desert soils.

    Science.gov (United States)

    Cáceres, Luis; Davila, Alfonso F; Soliz, Alvaro; Saldivia, Jessica

    2018-02-28

    Here we consider that the corrosion of polished bared metal coupons can be used as a passive sensor to detect or identify the lower limit of water availability suitable for biological activity in Atacama Desert soils or solid substrates. For this purpose, carbon steel coupons were deposited at selected sites along a west-east transect and removed at predetermined times for morphological inspection. The advantage of this procedure is that the attributes of the oxide layer (corrosion extent, morphology and oxide phases) can be considered as a fingerprint of the atmospheric moisture history at a given time interval. Two types of coupons were used, long rectangular shaped ones that were half-buried in a vertical position, and square shaped ones that were deposited on the soil surface. The morphological attributes observed by SEM inspection were found to correlate to the so-called humectation time which is determined from local meteorological parameters. The main finding was that the decreasing trend of atmospheric moisture along the transect was closely related to corrosion behaviour and water soil penetration. For instance, at the coastal site oxide phases formed on the coupon surface rapidly evolve into well-crystallized species, while at the driest inland site Lomas Bayas only amorphous oxide was observed on the coupons.

  13. Evaluation of the reinforcing steel corrosion in concrete mixes that will be used for constructing mid activity disposal repositories

    International Nuclear Information System (INIS)

    Moreno, Manuel; Alvarez, Marta G.; Duffo, Gustavo S.

    2000-01-01

    This study presents an evaluation of the reinforcing steel bars (rebars) corrosion behavior embedded in high performance concrete's prepared with three different cement types (normal Portland, Sulfate resistant and with furnace slag). The results of the study will provide the basis to select the materials used for constructing the mid activity radioactive disposals containers. The effect of aggressive ions such as chlorides and sulfates, as well as concrete carbonation, on the rebar corrosion process is evaluated using concrete specimens containing rebar segments. The electrochemical parameters that characterize the rebar corrosion process (corrosion potential (E corr ), polarization resistance (Rp) and electrical resistivity of concrete (ρ)) where periodically monitored after a conditioning period of 100 days. The results show that under all exposure conditions evaluated the rebar segments in contact with the three concrete mixes achieve a passive state of corrosion. Due to the continuos curing process of concrete the values of ρ present an increasing trend within time, even in the specimens exposed to the immersed conditions. (author)

  14. Assessment of Stress Corrosion Cracking Resistance of Activated Tungsten Inert Gas-Welded Duplex Stainless Steel Joints

    Science.gov (United States)

    Alwin, B.; Lakshminarayanan, A. K.; Vasudevan, M.; Vasantharaja, P.

    2017-12-01

    The stress corrosion cracking behavior of duplex stainless steel (DSS) weld joint largely depends on the ferrite-austenite phase microstructure balance. This phase balance is decided by the welding process used, heat input, welding conditions and the weld metal chemistry. In this investigation, the influence of activated tungsten inert gas (ATIG) and tungsten inert gas (TIG) welding processes on the stress corrosion cracking (SCC) resistance of DSS joints was evaluated and compared. Boiling magnesium chloride (45 wt.%) environment maintained at 155 °C was used. The microstructure and ferrite content of different weld zones are correlated with the outcome of sustained load, SCC test. Irrespective of the welding processes used, SCC resistance of weld joints was inferior to that of the base metal. However, ATIG weld joint exhibited superior resistance to SCC than the TIG weld joint. The crack initiation and final failure were in the weld metal for the ATIG weld joint; they were in the heat-affected zone for the TIG weld joint.

  15. Corrosion of Bare Carbon Steel as a Passive Sensor to Assess Moisture Availability for Biological Activity in Atacama Desert Soils

    Science.gov (United States)

    Caceres, Luis; Davila, Alfonso F.; Soliz, Alvaro; Saldivia, Jessica

    2018-01-01

    In this work we suggest the corrosion of polished bared metal coupons as a passive sensor to detect or identify the lower limit of water availability that could be suitable for biological activity in the Atacama Desert on soil or solid substrates. For this purpose, carbon steel coupons were deposited in selected sites along a west-east transect and removed at predetermined times for morphological inspection. The advantage of this procedure is that the attributes of the oxide layer (corrosion extent, morphology and oxide phases) can be considered as a fingerprint of the atmospheric moisture history at a given time interval. Two types of coupons were used, a long rectangular shape that are half-buried in a vertical position, and square shape that are deposited on the soil surface. The morphological attributes observed by SEM inspection is correlated to the so-called humectation time which is determined from local meteorological parameters. The main result is that the decreasing trend of atmospheric moisture along the transect is closely related to corrosion behavior and water soil penetration. For instance, while in the coastal site oxide phases formed on the coupon surface rapidly evolve to well- crystallized species, in the driest inland site Lomas Bayas only amorphous oxide is observed.

  16. Clean steels for fusion

    International Nuclear Information System (INIS)

    Gelles, D.S.

    1995-03-01

    Fusion energy production has an inherent advantage over fission: a fuel supply with reduced long term radioactivity. One of the leading candidate materials for structural applications in a fusion reactor is a tungsten stabilized 9% chromium Martensitic steel. This alloy class is being considered because it offers the opportunity to maintain that advantage in the reactor structure as well as provide good high temperature strength and radiation induced swelling and embrittlement resistance. However, calculations indicate that to obtain acceptable radioactivity levels within 500 years after service, clean steel will be required because the niobium impurity levels must be kept below about 2 appm and nickel, molybdenum, nitrogen, copper, and aluminum must be intentionally restricted. International efforts are addressing the problems of clean steel production. Recently, a 5,000 kg heat was vacuum induction melted in Japan using high purity commercial raw materials giving niobium levels less than 0.7 appm. This paper reviews the need for reduced long term radioactivity, defines the advantageous properties of the tungsten stabilized Martensitic steel class, and describes the international efforts to produce acceptable clean steels

  17. Effects of irradiation conditions and environment on the reflectivity of different steel mirrors for ITER diagnostics systems

    International Nuclear Information System (INIS)

    Hernandez, Teresa; Martin, Piedad; Fernandez, Pilar; Hodgson, Eric R.

    2009-01-01

    In this work possible degradation of the reflectivity for mirrors made from various steels subjected to ionizing radiation, at moderate temperature and in different environments (vacuum, air, or nitrogen) up to a total dose of 9 MGy, has been examined. Mirrors were prepared from conventional austenitic stainless steel (316L) and also reduced activation ferritic/martensitic (RAFM) steels (Eurofer, ODS-Eurofer, F82H), and the reflectivity studied from ultraviolet to near infrared, before and after different treatments. Under all conditions the austenitic steel mirrors only degrade slightly (<10%), however for the reduced activation steels important reflectivity degradation for wavelengths below 1000 nm are observed for the different conditions. Surface morphology and microstructure has been also investigated using scanning electron microscopy (SEM). The production of near surface nitrides is considered to be the possible cause of the optical degradation.

  18. Mechanical and microstructural characterization of low activation steels as first wall of nuclear fusion reactors

    International Nuclear Information System (INIS)

    Hernandez, M.T.; Lapena, J.; Diego, G. de; Schirra, M.

    1996-01-01

    Currently, the design development of fusion reactors and the possible materials to use in them are being studied in parallel. One of the most critical problems in this research is the structural materials selection for the first wall and blanket. The aim of the present work is to study three low activation alloys designed in Germany in which niobium has been substituted by tantalum or cerium. The mechanical results show that the alloys containing cerium are in the same order of the low activation materials known to date, but the tantalum doped alloy produces TaC 3 precipitation that destabilizes the matrix and provokes large microstructural changes. This causes a decrease of the mechanical properties at about 600 degree centigree. This fact makes this alloy insuitable for the first wall on fusion reactors, because the working temperature is near 550 degree centigree. (Author) 11 refs

  19. Activation of TZM and stainless steel divertor materials in the NET fusion machine

    International Nuclear Information System (INIS)

    Cepraga, D.G.; Menapace, E.; Cambi, G.; Ciattaglia, S.; Petrizzi, L.; Cavallone, G.; Costa, M.; Broccoli, U.

    1994-01-01

    This paper presents the results of the activation and decay heat calculations for the divertor plate materials of the Next European Torus (NET). The basic option assessed enables molybdenum alloy TZM and AISI 316L as material for divertor cooling channels. Burn time, effective irradiation time history, and fluence dependence on activation, decay heat, and contact dose is assessed. Impact of the material impurity level on the radioactive inventory is also investigated. The ANITA code is used, with updated cross sections and decay data libraries based on EFF-2 and EAF-3 evaluation files. The flux-weighted spectrum provided by XSDRNPM or ANISN 1-D codes has been used. The real NET geometry was modelled with the 3-D MCNP Monte Carlo neutron transport code. ((orig.))

  20. Activation of TZM and stainless steel divertor materials in the NET fusion machine

    Energy Technology Data Exchange (ETDEWEB)

    Cepraga, D G [ENEA, INN-FIS, 8 Viale Ercolani, 40138, Bologna (Italy); Menapace, E [ENEA, INN-FIS, 8 Viale Ercolani, 40138, Bologna (Italy); Cambi, G [Bologna University, Physics Department, 33 Via Irnerio, 40126, Bologna (Italy); Ciattaglia, S [ENEA, NUC-FUS, 27 Via E. Fermi, 00044, Frascati (Italy); Petrizzi, L [ENEA, NUC-FUS, 27 Via E. Fermi, 00044, Frascati (Italy); Cavallone, G [NIER S.r.l., 16 Via S. Stefano, 40125, Bologna (Italy); Costa, M [NIER S.r.l., 16 Via S. Stefano, 40125, Bologna (Italy); Broccoli, U [ENEA, NUC-RIN, 4 Via Martiri del Sole, 40100, Bologna (Italy)

    1994-09-01

    This paper presents the results of the activation and decay heat calculations for the divertor plate materials of the Next European Torus (NET). The basic option assessed enables molybdenum alloy TZM and AISI 316L as material for divertor cooling channels. Burn time, effective irradiation time history, and fluence dependence on activation, decay heat, and contact dose is assessed. Impact of the material impurity level on the radioactive inventory is also investigated. The ANITA code is used, with updated cross sections and decay data libraries based on EFF-2 and EAF-3 evaluation files. The flux-weighted spectrum provided by XSDRNPM or ANISN 1-D codes has been used. The real NET geometry was modelled with the 3-D MCNP Monte Carlo neutron transport code. ((orig.))

  1. Recycle Alaska: Reduce, Reuse, Recycle. Activities Handbook, Teacher's Guide, and Student Worksheets.

    Science.gov (United States)

    Alaska State Dept. of Education, Juneau.

    Recycling is a very important aspect of conserving the environment for future generations. This guide addresses the topic of litter prevention for the Alaskan environment and contains 42 activities. Activity topics covered include Natural Cycles, Human Interruption of Natural Cycles, Reduce, Reuse, Recycle and Recycled Classroom. Grade level,…

  2. Solid Waste Educational Resources and Activities: Let's Reduce, Reuse, and Recycle. [CD-ROM].

    Science.gov (United States)

    Environmental Protection Agency, Washington, DC. Solid Waste and Emergency Response.

    This contains games, activities, publications, and resources for students and teachers on how to reduce, reuse, recycle, and properly manage waste. It also contains a screen saver featuring runners-up from the Earth Day 2000 art contest. Activities and games include titles such as "Planet Protectors,""Recycle City,""Trash…

  3. Exceptionally strong sorption of infochemicals to activated carbon reduces their bioavailability to fish

    NARCIS (Netherlands)

    Jonker, Michiel T O; van Mourik, Louise

    2014-01-01

    The addition of activated carbon (AC) to sediments is a relatively new approach to remediate contaminated sites. Activated carbon strongly sorbs hydrophobic organic contaminants, thereby reducing their bioavailability and uptake in organisms. Because of its high sorption capacity, AC might, however,

  4. Determination of selected metals in the body tissues of occupationally exposed stainless steel workers by neutron activation analysis

    International Nuclear Information System (INIS)

    Kucera, J.; Soukal, L.; Randa, Z.; Borska, L.; Bencko, V.; Tejral, J.

    2002-01-01

    Occupational exposure was examined in a group of 20 workers dealing mainly with welding, polishing, and assembling of stainless steel constructions. Biological monitoring of exposure involved the determination of Cr, Mn, Mo, Ni and V in hair and nails by instrumental neutron activation analysis (INAA), urinary Cr and Mn, serum Cr and blood Mn by neutron activation analysis with radiochemical separation (RNAA). The RNAA procedures employed are briefly described. Significantly elevated levels were found for Cr in hair, nails, serum and urine, Mo in hair, and Mn in blood in the exposed subjects compared to controls. The ratios of the mean elemental concentrations for the exposed/control subjects were as follows: 12.5 for hair Cr, 4.4 for nail Cr, 9.6 for serum Cr, 9.0 for urinary Cr, 1.4 for hair Mo and 1.3 for blood Mn. For quality control purposes a number of biological intercomparison and reference materials were analysed. A good agreement obtained with consensus and/or certified values proved the accuracy of our results. The results for the control group compared also well with reference values, thus indicating that no contamination occurred on sampling and sample treatment prior to irradiation. To be able to evaluate the health effects of exposure, haematological, genotoxicity and immunological parameters were also assayed. A number of immunological parameters were altered in the exposed group compared to controls. However, no significant correlations were found between exposure of the individual workers measured with the aid of personal air particulate samplers and the biological indicators of exposure. A comparison of direct and biological monitoring indicates the complexity of the assessment of health effects of occupational exposure. (author)

  5. Martensitic/ferritic steels as container materials for liquid mercury target of ESS

    International Nuclear Information System (INIS)

    Dai, Y.

    1996-01-01

    In the previous report, the suitability of steels as the ESS liquid mercury target container material was discussed on the basis of the existing database on conventional austenitic and martensitic/ferritic steels, especially on their representatives, solution annealed 316 stainless steel (SA 316) and Sandvik HT-9 martensitic steel (HT-9). Compared to solution annealed austenitic stainless steels, martensitic/ferritic steels have superior properties in terms of strength, thermal conductivity, thermal expansion, mercury corrosion resistance, void swelling and irradiation creep resistance. The main limitation for conventional martensitic/ferritic steels (CMFS) is embrittlement after low temperature (≤380 degrees C) irradiation. The ductile-brittle transition temperature (DBTT) can increase as much as 250 to 300 degrees C and the upper-shelf energy (USE), at the same time, reduce more than 50%. This makes the application temperature range of CMFS is likely between 300 degrees C to 500 degrees C. For the present target design concept, the temperature at the container will be likely controlled in a temperature range between 180 degrees C to 330 degrees C. Hence, CMFS seem to be difficult to apply. However, solution annealed austenitic stainless steels are also difficult to apply as the maximum stress level at the container will be higher than the design stress. The solution to the problem is very likely to use advanced low-activation martensitic/ferritic steels (LAMS) developed by the fusion materials community though the present database on the materials is still very limited

  6. Promoting physical activity and reducing climate change : Opportunities to replace short car trips with active transportation

    NARCIS (Netherlands)

    Maibach, E.; Steg, L.; Anable, J.

    2009-01-01

    Automobile use is a significant contributor to climate change, local air pollution, pedestrian injuries and deaths, declines in physical activity and obesity. A significant proportion of car use is for short trips that can relatively easily be taken with active transportation options - walking or

  7. Effect of activation cross section uncertainties in transmutation analysis of realistic low-activation steels for IFMIF

    Energy Technology Data Exchange (ETDEWEB)

    Cabellos, O.; Garcya-Herranz, N.; Sanz, J. [Institute of Nuclear Fusion, UPM, Madrid (Spain); Cabellos, O.; Garcya-Herranz, N.; Fernandez, P.; Fernandez, B. [Dept. of Nuclear Engineering, UPM, Madrid (Spain); Sanz, J. [Dept. of Power Engineering, UNED, Madrid (Spain); Reyes, S. [Safety, Environment and Health Group, ITER Joint Work Site, Cadarache Center (France)

    2008-07-01

    We address uncertainty analysis to draw conclusions on the reliability of the activation calculation in the International Fusion Materials Irradiation Facility (IFMIF) under the potential impact of activation cross section uncertainties. The Monte Carlo methodology implemented in ACAB code gives the uncertainty estimates due to the synergetic/global effect of the complete set of cross section uncertainties. An element-by-element analysis has been demonstrated as a helpful tool to easily analyse the transmutation performance of irradiated materials.The uncertainty analysis results showed that for times over about 24 h the relative error in the contact dose rate can be as large as 23 per cent. We have calculated the effect of cross section uncertainties in the IFMIF activation of all different elements. For EUROFER, uncertainties in H and He elements are 7.3% and 5.6%, respectively. We have found significant uncertainties in the transmutation response for C, P and Nb.

  8. Summary report for ITER Task -- D4: Activation calculations for the stainless steel ITER design

    International Nuclear Information System (INIS)

    Attaya, H.

    1995-02-01

    Detailed activation analysis for ITER has been performed as a part of ITER Task D4. The calculations have been performed for the shielding blanket (SS/water) and for the breeding blanket (LiN) options. The activation code RACC-P, which has been modified under IFER Task-D-10 for pulsed operation, has been used in this analysis. The spatial distributions of the radioactive inventory, decay heat, biological hazard potential, and the contact dose were calculated for the two designs for different operation modes and targeted fluences. A one-dimensional toroidal geometrical model has been utilized to determine the neutron fluxes in the two designs. The results are normalized for an inboard and outboard neutron wall loadings of 0.91 and 1.2 MW/M 2 , respectively. The point-wise distributions of the decay gamma sources have been calculated everywhere in the reactor at several times after the shutdown of the two designs and are then used in the transport code ONEDANT to calculate the biological dose everywhere in the reactor. The point-wise distributions of all the responses have also been calculated. These calculations have been performed for neutron fluences of 3.0 MWa/M 2 , which corresponds to the target fluence of ITER, and 0.1 MWa/M 2 , which is anticipated to correspond to the beginning of an extended maintenance period

  9. Activated charcoal and baking soda to reduce odor associated with extensive blistering disorders.

    Science.gov (United States)

    Chakravarthi, Arun; Srinivas, C R; Mathew, Anil C

    2008-01-01

    Skin disease leading to extensive blistering and loss of skin is associated with a characteristic smell. Odor can cause physiologic disturbances such as increase in heart rate and respiratory rate. It can also cause nausea and vomiting and is disturbing to bystanders. To test odor reducing capability of activated charcoal. In this blinded experimental study we used putrefied amniotic membrane to produce odor and studied the effectiveness of activated charcoal and soda-bi-carbonate to reduce odor. Statistical analysis with Kruskal Wall's Chi Square Test and Man Whitney U test showed significant reduction of odor using activated charcoal by itself or along with soda-bi-carbonate. We recommend the usage of activated charcoal with/without soda bicarbonate as an inexpensive practical measure to reduce foul odor associated with extensive skin loss.

  10. Activated charcoal and baking soda to reduce odor associated with extensive blistering disorders

    Directory of Open Access Journals (Sweden)

    Chakravarthi Arun

    2008-01-01

    Full Text Available Background: Skin disease leading to extensive blistering and loss of skin is associated with a characteristic smell. Odor can cause physiologic disturbances such as increase in heart rate and respiratory rate. It can also cause nausea and vomiting and is disturbing to bystanders. Aims: To test odor reducing capability of activated charcoal. Methods: In this blinded experimental study we used putrefied amniotic membrane to produce odor and studied the effectiveness of activated charcoal and soda-bi-carbonate to reduce odor. Results: Statistical analysis with Kruskal Wall′s Chi Square Test and Man Whitney U test showed significant reduction of odor using activated charcoal by itself or along with soda-bi-carbonate. Conclusion: We recommend the usage of activated charcoal with/without soda bicarbonate as an inexpensive practical measure to reduce foul odor associated with extensive skin loss.

  11. Overview of French activities on neutron radiation embrittlement of pressure vessel steel

    Energy Technology Data Exchange (ETDEWEB)

    Brillaud, C [Electricite de France (EDF), 37 - Tours (France); Keroulas, F de [Electricite de France (EDF), 93 - Saint-Denis (France); Pichon, C [Electricite de France (EDF), 69 - Villeurbanne (France); Teissier, A [Electricite de France (EDF), 92 - Courbevoie (France). Service Etudes et Projets Thermiques et Nucleaires

    1994-12-31

    This paper describes recent developments in France`s pressure vessel surveillance program, particularly aimed at assessing the irradiation-caused embrittlement of EDF`s PWRs. The first part presents surveillance program results for base metal, weld metal and heat-affected zones for 74 capsules removed from 34 units. Fluence ranges from 0.3.10{sup 19} n.cm{sup -2} to 5.5.10{sup 19} n.cm{sup -2}. The second part considers research and development activities in this area: these include the metallurgical structure effects of segregated bands on mechanical properties and the embrittlement rate under irradiation, as well as the effect of irradiation parameters such as flux and neutron spectrum on irradiation embrittlement, and more especially to obtain the best damage assessment. (authors). 14 refs., 5 figs., 1 tab.

  12. Metallurgical comparison between the experimental ED-ODS and commercial ODS steels

    International Nuclear Information System (INIS)

    Fernandez, P.; Serrano, M.; Lapena, J.

    2007-01-01

    Full text of publication follows: Recently, reduced activation oxide dispersion strengthened ferritic/martensitic steels have been identified as potential structural material candidates for first wall and blanket structures of fusion devices. These steels allow to increase the operation temperature of the fusion reactor, around of 100 deg. C or even more, because of their excellent thermal creep resistance. ODS steels are being developed and investigated for nuclear fission and fusion applications in Japan, Europe and the United States. Commercial ODS products, such as MA956 and PM2000 are available and are being used for high temperature applications. Since no reduced activation ferritic/martensitic steels are commercially available at present, the European Materials Fusion Programme has considered in the last years initiate adequate research activities to produce and characterize these materials to evaluate the feasibility of their use in the different blanket designs. Nowadays, the ODS steel that are being extensively investigated in Europe is the denominated EU-ODS. This alloy has the basic composition of the Eurofer'97 with 0.3% of Y 2 O 3 particles. In this paper, the metallurgical properties (microstructural, Charpy, etc) of the newly developed EU-ODS steel are presented and discussed together with the properties of the commercial MA956 and PM2000 ODS steels, also studied in this work, in order to show the differences and similarities between these ODS alloys. (authors)

  13. Pituitary adenylate cyclase activating polypeptide reduces A-type K+ currents and caspase activity in cultured adult mouse olfactory neurons.

    Science.gov (United States)

    Han, P; Lucero, M T

    2005-01-01

    Pituitary adenylate cyclase activating polypeptide has been shown to reduce apoptosis in neonatal cerebellar and olfactory receptor neurons, however the underlying mechanisms have not been elucidated. In addition, the neuroprotective effects of pituitary adenylate cyclase activating polypeptide have not been examined in adult tissues. To study the effects of pituitary adenylate cyclase activating polypeptide on neurons in apoptosis, we measured caspase activation in adult olfactory receptor neurons in vitro. Interestingly, we found that the protective effects of pituitary adenylate cyclase activating polypeptide were related to the absence of a 4-aminopyridine (IC50=144 microM) sensitive rapidly inactivating potassium current often referred to as A-type current. In the presence of 40 nM pituitary adenylate cyclase activating polypeptide 38, both A-type current and activated caspases were significantly reduced. A-type current reduction by pituitary adenylate cyclase activating polypeptide was blocked by inhibiting the phospholipase C pathway, but not the adenylyl cyclase pathway. Our observation that 5 mM 4-aminopyridine mimicked the caspase inhibiting effects of pituitary adenylate cyclase activating polypeptide indicates that A-type current is involved in apoptosis. This work contributes to our growing understanding that potassium currents are involved with the activation of caspases to affect the balance between cell life and death.

  14. Tool steels

    DEFF Research Database (Denmark)

    Højerslev, C.

    2001-01-01

    On designing a tool steel, its composition and heat treatment parameters are chosen to provide a hardened and tempered martensitic matrix in which carbides are evenly distributed. In this condition the matrix has an optimum combination of hardness andtoughness, the primary carbides provide...... resistance against abrasive wear and secondary carbides (if any) increase the resistance against plastic deformation. Tool steels are alloyed with carbide forming elements (Typically: vanadium, tungsten, molybdenumand chromium) furthermore some steel types contains cobalt. Addition of alloying elements...... serves primarily two purpose (i) to improve the hardenabillity and (ii) to provide harder and thermally more stable carbides than cementite. Assuming proper heattreatment, the properties of a tool steel depends on the which alloying elements are added and their respective concentrations....

  15. The effects of temperature and strain rate on the dynamic flow behaviour of different steels

    International Nuclear Information System (INIS)

    Lee, W.-S.; Liu, C.-Y.

    2006-01-01

    A compressive type split-Hopkinson pressure bar is utilized to compare the impact plastic behaviour of three steels with different levels of carbon content. S15C low carbon steel, S50C medium alloy heat treatable steel (abbreviated hereafter to medium carbon steel) and SKS93 tool steel with a high carbon and low alloy content (abbreviated hereafter to high carbon steel) are tested under strain rates ranging from 1.1 x 10 3 s -1 to 5.5 x 10 3 s -1 and temperatures ranging from 25 to 800 deg. C. The effects of the carbon content, strain rate and temperature on the mechanical responses of the three steels are evaluated. The microstructures of the impacted specimens are studied using a transmission electron microscope (TEM). It is found that an increased carbon content enhances the dynamic flow resistance of the three steels. Additionally, the flow stress increases with strain and strain rate in every case. A thermal softening effect is identified in the plastic behaviour of the three steels. The activation energy, ΔG * , varies as a function of the strain rate and temperature, but is apparently insensitive to the carbon content level. The present study identifies maximum ΔG * values of 58 kJ/mol for the S15C low carbon steel, 54.9 kJ/mol for the S50C medium carbon steel, and 56.4 kJ/mol for the SKS93 high carbon steel. A Zerilli-Armstrong BCC constitutive model with appropriate coefficients is applied to describe the high strain rate plastic behaviours of the S15C, S50C and SKS93 steels. The errors between the calculated stress and the measured stress are found to be less than 5%. The microstructural observations reveal that the dislocation density and the degree of dislocation tangling increase with increasing strain rate in all three steels. Additionally, the TEM observations indicate that a higher strain rate reduces the size of the dislocation cells. The annihilation of dislocations occurs more readily at elevated temperatures. The square root of the dislocation

  16. Historical summary of the heavy-section steel technology program and some related activities in light-water reactor pressure vessel safety research

    International Nuclear Information System (INIS)

    Whitman, G.D.

    1986-03-01

    The accomplishments of the Heavy-Section Steel Technology Program and other programs having a close relationship to the development of information used in the assessment of light-water reactor pressure vessel integrity are reviewed. The early Pressure Vessel Research Committee planning, the principals contributing to program formulation, the role of the US Atomic Energy Commission, and the developments under the US Nuclear Regulatory Commission sponsorship are identified. The need for major research and development accomplishments in fracture mechanics, heavy-section steel procurement, materials properties, irradiation effects, fatigue crack growth, and structural testing are summarized. The impact of program results on regulatory issues and the development of data used in the preparation of codes, standards, and guides are discussed. Continuing activities and recommendations for future research and development in support of pressure vessel integrity assessments are presented

  17. Creep Deformation and Rupture Behavior of Single- and Dual-Pass 316LN Stainless-Steel-Activated TIG Weld Joints

    Science.gov (United States)

    Vijayanand, V. D.; Vasudevan, M.; Ganesan, V.; Parameswaran, P.; Laha, K.; Bhaduri, A. K.

    2016-06-01

    Creep deformation and rupture behavior of single-pass and dual-pass 316LN stainless steel (SS) weld joints fabricated by an autogenous activated tungsten inert gas welding process have been assessed by performing metallography, hardness, and conventional and impression creep tests. The fusion zone of the single-pass joint consisted of columnar zones adjacent to base metals with a central equiaxed zone, which have been modified extensively by the thermal cycle of the second pass in the dual-pass joint. The equiaxed zone in the single-pass joint, as well as in the second pass of the dual-pass joint, displayed the lowest hardness in the joints. In the dual-pass joint, the equiaxed zone of the first pass had hardness comparable to the columnar zone. The hardness variations in the joints influenced the creep deformation. The equiaxed and columnar zone in the first pass of the dual-pass joint was more creep resistant than that of the second pass. Both joints possessed lower creep rupture life than the base metal. However, the creep rupture life of the dual-pass joint was about twofolds more than that of the single-pass joint. Creep failure in the single-pass joint occurred in the central equiaxed fusion zone, whereas creep cavitation that originated in the second pass was blocked at the weld pass interface. The additional interface and strength variation between two passes in the dual-pass joint provides more restraint to creep deformation and crack propagation in the fusion zone, resulting in an increase in the creep rupture life of the dual-pass joint over the single-pass joint. Furthermore, the differences in content, morphology, and distribution of delta ferrite in the fusion zone of the joints favors more creep cavitation resistance in the dual-pass joint over the single-pass joint with the enhancement of creep rupture life.

  18. Energy activity guide : simple steps to reduce your household energy use

    Energy Technology Data Exchange (ETDEWEB)

    Byckalo-Khan, F.; Wallace, C.L. (ed.)

    2003-07-01

    This guide presents 13 practical activities that can help households reduce energy consumption in order to create a more sustainable lifestyle and to help meet Canada's Kyoto commitment to reduce greenhouse gas emissions. Most energy sources create pollution that harms both human health and the Earth. The burning of fossil fuels creates greenhouse gas emissions that contribute to climate change, smog, pollution and adverse health effects. This guide offers suggestions on how households can reduce the impact on the environment while saving money. Some of the initiatives include lowering the thermostat, replacing incandescent light bulbs with compact fluorescent light bulbs, turning off appliances when not in use, weatherising building envelopes, using a clothes line to dry clothes instead of a dryer, laundering clothes with cold water, and proper maintenance of heating equipment. An energy use chart is included with this guide to help track activities and to estimate how much time and money is required by each activity. refs., figs.

  19. Energy activity guide : simple steps to reduce your household energy use

    Energy Technology Data Exchange (ETDEWEB)

    Byckalo-Khan, F; Wallace, C L [ed.

    2003-07-01

    This guide presents 13 practical activities that can help households reduce energy consumption in order to create a more sustainable lifestyle and to help meet Canada's Kyoto commitment to reduce greenhouse gas emissions. Most energy sources create pollution that harms both human health and the Earth. The burning of fossil fuels creates greenhouse gas emissions that contribute to climate change, smog, pollution and adverse health effects. This guide offers suggestions on how households can reduce the impact on the environment while saving money. Some of the initiatives include lowering the thermostat, replacing incandescent light bulbs with compact fluorescent light bulbs, turning off appliances when not in use, weatherising building envelopes, using a clothes line to dry clothes instead of a dryer, laundering clothes with cold water, and proper maintenance of heating equipment. An energy use chart is included with this guide to help track activities and to estimate how much time and money is required by each activity. refs., figs.

  20. Experimental investigation of activities and tolerance of denitrifying bacteria under alkaline and reducing condition

    International Nuclear Information System (INIS)

    Mine, Tatsuya; Mihara, Morihiro; Ooi, Takao

    2000-07-01

    In the geological disposal system of TRU wastes, nitrogen generation by denitrifying bacteria could provide significant impact on the assessment of this system, because nitrate contained in process concentrated liquid waste might be electron acceptor for denitrifying bacteria. In this study, the activities and tolerance of denitrifying under disposal condition were investigated. Pseudomonas denitrificans as denitrifying bacteria was used. The results showed that Pseudomonas denitrificans had activity under reducing condition, but under high pH condition (pH>9.5), the activity of Pseudomonas denitrificans was not detected. It is possible that the activity of Pseudomonas denitrificans would be low under disposal condition. (author)

  1. Crack growth in first wall made of reduced activation ferritic steel by transient creep due to long pulse operation

    International Nuclear Information System (INIS)

    Honda, T.; Kudo, Y.; Hatano, T.; Kikuchi, K.; Nishimura, T.; Saito, M.

    2003-01-01

    The long pulse operation is assumed in ITER and future reactor. If the first wall has a defect, the crack may be propagated by cyclic thermal loads. In addition, flattop of more than 300 s during plasma burning is expected in ITER, so the crack propagation behavior will depend on the operation duration period. This study deals with the crack propagation behavior on F82H under high thermal load cycles. The high heat flux tests were performed under three types of duration periods to investigate creep fatigue behavior. To clarify the crack growth mechanism and the effects of transient creep, three-dimensional analyses were performed. It was concluded that the creep effect during the operation duration period enlarges stress intensity factor K in the cooling period and that consequently, the crack propagation length was increased

  2. Modification of vacuum plasma sprayed tungsten coating on reduced activation ferritic/martensitic steels by friction stir processing

    International Nuclear Information System (INIS)

    Tanigawa, Hiroyasu; Ozawa, Kazumi; Morisada, Yoshiaki; Noh, Sanghoon; Fujii, Hidetoshi

    2015-01-01

    Highlights: • Friction stir processing (FSP) was applied on vacuum plasma spray (VPS) W to improve its low thermal conductivity and weakness due to high porosity. • FSP can achieve significant improvement both in mechanical and thermal properties of VPS-W coating. • It was indicated that the double pass FSP at 600 rpm/50 mm/min/2 ton on VPS-W show the most dense microstructure and hardest mechanical property. • Hardness test over FSPed VPS-W layer revealed that the hardness of W becomes higher than that of bulk W. • The thermal conductivity of double pass FSPed VPS-W was about 80% of bulk W at 200 °C, and it becomes equivalent to that of bulk W over 800 °C. - Abstract: Tungsten (W) is the primary candidate material as a plasma facing material in fusion devices, as for its high melting temperature, good thermal conductivity and low sputtering rate, and vacuum plasma spray (VPS) technique is preferred as it is applicable for large area without brittle interlayer, but the thermal conductivity of W layer is very poor, and easy to detach, mainly caused by its porous structure. W Friction stir processing (FSP) was applied on VPS-W to improve these poor properties, and it was suggested that FSP can contribute to significant improvement in both mechanical and thermal properties of the VPS-W coating.

  3. The significance of reduced respiratory chain enzyme activities: clinical, biochemical and radiological associations.

    Science.gov (United States)

    Mordekar, S R; Guthrie, P; Bonham, J R; Olpin, S E; Hargreaves, I; Baxter, P S

    2006-03-01

    Mitochondrial diseases are an important group of neurometabolic disorders in children with varied clinical presentations and diagnosis that can be difficult to confirm. To report the significance of reduced respiratory chain enzyme (RCE) activity in muscle biopsy samples from children. Retrospective odds ratio was used to compare clinical and biochemical features, DNA studies, neuroimaging, and muscle biopsies in 18 children with and 48 without reduced RCE activity. Children with reduced RCE activity were significantly more likely to have consanguineous parents, to present with acute encephalopathy and lactic acidaemia and/or within the first year of life; to have an axonal neuropathy, CSF lactate >4 mmol/l; and/or to have signal change in the basal ganglia. There were positive associations with a maternal family history of possible mitochondrial cytopathy; a presentation with failure to thrive and lactic acidaemia, ragged red fibres, reduced fibroblast fatty acid oxidation and with an abnormal allopurinol loading test. There was no association with ophthalmic abnormalities, deafness, epilepsy or myopathy. The association of these clinical, biochemical and radiological features with reduced RCE activity suggests a possible causative link.

  4. Differential responses of nitrate reducer community size, structure, and activity to tillage systems.

    Science.gov (United States)

    Chèneby, D; Brauman, A; Rabary, B; Philippot, L

    2009-05-01

    The main objective of this study was to determine how the size, structure, and activity of the nitrate reducer community were affected by adoption of a conservative tillage system as an alternative to conventional tillage. The experimental field, established in Madagascar in 1991, consists of plots subjected to conventional tillage or direct-seeding mulch-based cropping systems (DM), both amended with three different fertilization regimes. Comparisons of size, structure, and activity of the nitrate reducer community in samples collected from the top layer in 2005 and 2006 revealed that all characteristics of this functional community were affected by the tillage system, with increased nitrate reduction activity and numbers of nitrate reducers under DM. Nitrate reduction activity was also stimulated by combined organic and mineral fertilization but not by organic fertilization alone. In contrast, both negative and positive effects of combined organic and mineral fertilization on the size of the nitrate reducer community were observed. The size of the nitrate reducer community was a significant predictor of the nitrate reduction rates except in one treatment, which highlighted the inherent complexities in understanding the relationships the between size, diversity, and structure of functional microbial communities along environmental gradients.

  5. Lipid reducing activity and toxicity profiles of a library of polyphenol derivatives.

    Science.gov (United States)

    Urbatzka, Ralph; Freitas, Sara; Palmeira, Andreia; Almeida, Tiago; Moreira, João; Azevedo, Carlos; Afonso, Carlos; Correia-da-Silva, Marta; Sousa, Emilia; Pinto, Madalena; Vasconcelos, Vitor

    2018-05-10

    Obesity is an increasing epidemic worldwide and novel treatments are urgently needed. Polyphenols are natural compounds derived from plants, which are known in particular for their antioxidant properties. However, some polyphenols were described to possess anti-obesity activities in vitro and in vivo. In this study, we aimed to screen a library of 85 polyphenol derivatives for their lipid reducing activity and toxicity. Compounds were analyzed at 5 μM with the zebrafish Nile red fluorescence fat metabolism assay and for general toxicity in vivo. To improve the safety profile, compounds were screened at 50 μM in murine preadipocytes in vitro for cytotoxicity. Obtained activity data were used to create a 2D-QSAR (quantitative structure activity relationship) model. 38 polyphenols showed strong lipid reducing activity. Toxicity analysis revealed that 18 of them did not show any toxicity in vitro or in vivo. QSAR analysis revealed the importance of the number of rings, fractional partial positively charged surface area, relative positive charge, relative number of oxygen atoms, and partial negative surface area for lipid-reducing activity. The five most potent compounds with EC 50 values in the nanomolar range for lipid reducing activity and without any toxic effects are strong candidates for future research and development into anti-obesity drugs. Molecular profiling for fasn, sirt1, mtp and ppary revealed one compound that reduced significantly fasn mRNA expression. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  6. Measurement of carbon activity in sodium by Fe-Mn 20% alloy, and by strainless austenitic steel 304L and 316L

    International Nuclear Information System (INIS)

    Oberlin, C.; Saint Paul, P.; Baque, P.; Champeix, L.

    1980-01-01

    Precise knowledge of carbon activity in sodium used as coolant in fast breeder reactors, is essential for continuous survey of carburization-decarburization processes. Carbon activity can be periodically surveyed by measuring the carbon concentration or by hot trap like metal alloy strip placed in sodium loop. In fact, in equilibrium, activity of carbon in sodium is equal to the activity in metal alloy. Thus if the relation between concentration of carbon and it activity in the alloy is known, it is possible to estimate the activity of carbon in sodium. Materials to be used should have high solubility in carbon at the needed temperature. They should quickly attain equilibrium with sodium and they should not contain impurities that can affect the results. Materials chosen according to these criteria were Fe-Mn 20%, stainless austenitic steel AISI 304L and 316L

  7. Stop and revive? The effectiveness of nap and active rest breaks for reducing driver sleepiness.

    Science.gov (United States)

    Watling, Christopher N; Smith, Simon S; Horswill, Mark S

    2014-11-01

    The purpose of this study was to compare the effects of two commonly utilized sleepiness countermeasures: a nap break and an active rest break. The effects of the countermeasures were evaluated by physiological (EEG), subjective, and driving performance measures. Participants completed 2 h of simulated driving, followed by a 15-min nap break or a 15-min active rest break, then completed the final hour of simulated driving. The nap break reduced EEG and subjective sleepiness. The active rest break did not reduce EEG sleepiness, with sleepiness levels eventually increasing, and resulted in an immediate reduction of subjective sleepiness. No difference was found between the two breaks for the driving performance measure. The immediate reduction of subjective sleepiness after the active rest break could leave drivers with erroneous perceptions of their sleepiness, particularly with increases of physiological sleepiness after the break. Copyright © 2014 Society for Psychophysiological Research.

  8. AMP-activated protein kinase reduces inflammatory responses and cellular senescence in pulmonary emphysema.

    Science.gov (United States)

    Cheng, Xiao-Yu; Li, Yang-Yang; Huang, Cheng; Li, Jun; Yao, Hong-Wei

    2017-04-04

    Current drug therapy fails to reduce lung destruction of chronic obstructive pulmonary disease (COPD). AMP-activated protein kinase (AMPK) has emerged as an important integrator of signals that control energy balance and lipid metabolism. However, there are no studies regarding the role of AMPK in reducing inflammatory responses and cellular senescence during the development of emphysema. Therefore, we hypothesize that AMPK reduces inflammatroy responses, senescence, and lung injury. To test this hypothesis, human bronchial epithelial cells (BEAS-2B) and small airway epithelial cells (SAECs) were treated with cigarette smoke extract (CSE) in the presence of a specific AMPK activator (AICAR, 1 mM) and inhibitor (Compound C, 5 μM). Elastase injection was performed to induce mouse emphysema, and these mice were treated with a specific AMPK activator metformin as well as Compound C. AICAR reduced, whereas Compound C increased CSE-induced increase in IL-8 and IL-6 release and expression of genes involved in cellular senescence. Knockdown of AMPKα1/α2 increased expression of pro-senescent genes (e.g., p16, p21, and p66shc) in BEAS-2B cells. Prophylactic administration of an AMPK activator metformin (50 and 250 mg/kg) reduced while Compound C (4 and 20 mg/kg) aggravated elastase-induced airspace enlargement, inflammatory responses and cellular senescence in mice. This is in agreement with therapeutic effect of metformin (50 mg/kg) on airspace enlargement. Furthermore, metformin prophylactically protected against but Compound C further reduced mitochondrial proteins SOD2 and SIRT3 in emphysematous lungs. In conclusion, AMPK reduces abnormal inflammatory responses and cellular senescence, which implicates as a potential therapeutic target for COPD/emphysema.

  9. Efficacy of reduced dose of intravitreal triamcinolone acetonide in a case of active serpiginous choroiditis

    Directory of Open Access Journals (Sweden)

    Avirupa Ghose

    2016-01-01

    Full Text Available Active serpiginous choroiditis (SC is a vision-threatening condition which requires intensive treatment using corticosteroids and/or immunosuppressives, especially if the lesions are involving or encroaching on the macula. Use of oral and intravenous high-dose steroids are contraindicated in uncontrolled diabetics. Intravitreal steroid delivers a localized dose in such situations. This case report highlights the efficacy of reduced dose of intravitreal triamcinolone acetonide (2 mg in the treatment of active SC.

  10. Lead reduces tension development and the myosin ATPase activity of the rat right ventricular myocardium

    Directory of Open Access Journals (Sweden)

    D.V. Vassallo

    2008-09-01

    Full Text Available Lead (Pb2+ poisoning causes hypertension, but little is known regarding its acute effects on cardiac contractility. To evaluate these effects, force was measured in right ventricular strips that were contracting isometrically in 45 male Wistar rats (250-300 g before and after the addition of increasing concentrations of lead acetate (3, 7, 10, 30, 70, 100, and 300 µM to the bath. Changes in rate of stimulation (0.1-1.5 Hz, relative potentiation after pauses of 15, 30, and 60 s, effect of Ca2+ concentration (0.62, 1.25, and 2.5 mM, and the effect of isoproterenol (20 ng/mL were determined before and after the addition of 100 µM Pb2+. Effects on contractile proteins were evaluated after caffeine treatment using tetanic stimulation (10 Hz and measuring the activity of the myosin ATPase. Pb2+ produced concentration-dependent force reduction, significant at concentrations greater than 30 µM. The force developed in response to increasing rates of stimulation became smaller at 0.5 and 0.8 Hz. Relative potentiation increased after 100 µM Pb2+ treatment. Extracellular Ca2+ increment and isoproterenol administration increased force development but after 100 µM Pb2+ treatment the force was significantly reduced suggesting an effect of the metal on the sarcolemmal Ca2+ influx. Concentration of 100 µM Pb2+ also reduced the peak and plateau force of tetanic contractions and reduced the activity of the myosin ATPase. Results showed that acute Pb2+ administration, although not affecting the sarcoplasmic reticulum activity, produces a concentration-dependent negative inotropic effect and reduces myosin ATPase activity. Results suggest that acute lead administration reduced myocardial contractility by reducing sarcolemmal calcium influx and the myosin ATPase activity. These results also suggest that lead exposure is hazardous and has toxicological consequences affecting cardiac muscle.

  11. The influence of local glucose oxidase activity on the potential/current distribution on stainless steel: A study by the wire beam electrode method

    Energy Technology Data Exchange (ETDEWEB)

    Wang Wei [Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, College of Chemistry and Chemical Engineering, Qingdao, 266100 (China)], E-mail: wwei@ouc.edu.cn; Zhang Xia [Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, College of Chemistry and Chemical Engineering, Qingdao, 266100 (China); Wang Jia [Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, College of Chemistry and Chemical Engineering, Qingdao, 266100 (China); State Key Laboratory for Corrosion and Protection, Shenyang, 110016 (China)

    2009-09-30

    The wire beam electrode (WBE) method was first used to study the activity of local glucose oxidase (GOD) on stainless steel surface in seawater. Glucose oxidase was immobilized in calcium alginate gel capsules, which were embedded in a layer of artificial biofilm (calcium alginate gel) on the WBE surface. The potential/current distributions on the WBE surface were mapped using a newly developed device for the WBE method in our lab. The results demonstrated that the catalysis of H{sub 2}O{sub 2} formation by GOD can produce local noble potential peaks and cathodic current zones on the stainless steel surface. An interesting fluctuant current distribution around cathodic zones was observed the first time. The potential and current maps showed that the enzyme heterogeneity of the artificial biofilm caused a corresponding electrochemical heterogeneity at the biofilm/metal interface. The application of the WBE method to ennoblement study enables us to observe the heterogeneous electrochemistry at biofilm/stainless steel interface directly, providing us with a powerful tool to investigate other biofilm-related processes such as microbially influenced corrosion (MIC)

  12. The influence of local glucose oxidase activity on the potential/current distribution on stainless steel: A study by the wire beam electrode method

    International Nuclear Information System (INIS)

    Wang Wei; Zhang Xia; Wang Jia

    2009-01-01

    The wire beam electrode (WBE) method was first used to study the activity of local glucose oxidase (GOD) on stainless steel surface in seawater. Glucose oxidase was immobilized in calcium alginate gel capsules, which were embedded in a layer of artificial biofilm (calcium alginate gel) on the WBE surface. The potential/current distributions on the WBE surface were mapped using a newly developed device for the WBE method in our lab. The results demonstrated that the catalysis of H 2 O 2 formation by GOD can produce local noble potential peaks and cathodic current zones on the stainless steel surface. An interesting fluctuant current distribution around cathodic zones was observed the first time. The potential and current maps showed that the enzyme heterogeneity of the artificial biofilm caused a corresponding electrochemical heterogeneity at the biofilm/metal interface. The application of the WBE method to ennoblement study enables us to observe the heterogeneous electrochemistry at biofilm/stainless steel interface directly, providing us with a powerful tool to investigate other biofilm-related processes such as microbially influenced corrosion (MIC).

  13. Investigations on structure–property relationships of activated flux TIG weldments of super-duplex/austenitic stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Devendranath Ramkumar, K., E-mail: ramdevendranath@gmail.com; Bajpai, Ankur; Raghuvanshi, Shubham; Singh, Anshuman; Chandrasekhar, Aditya; Arivarasu, M.; Arivazhagan, N.

    2015-06-25

    This research work articulated the effect of SiO{sub 2} flux assisted tungsten inert gas (TIG) welding on the microstructure and mechanical properties of marine grade stainless steel weldments, such as super-duplex stainless steel (UNS S32750) and austenitic stainless steel (AISI 316L). The studies showed that the use of flux decreased the heat input required to obtain complete penetration. Microstructure studies revealed the presence of ferrite at the heat affected zone of AISI 316L and the fusion zone which obviated the hot cracking tendency. Tensile studies corroborated that the joint strength was sufficiently greater than that of the parent metals. Impact toughness slightly impoverished owing to the presence of large platelets of Widmanstätten austenite in the fusion zone. The study also explored the structure–property relationships of the flux assisted weldments using the combined techniques of optical and scanning electron microscopy analysis. Owing to the better metallurgical and mechanical properties, this study recommends the use of SiO{sub 2} flux for joining the dissimilar metals involving austenitic and super-duplex stainless steels.

  14. Investigations on structure–property relationships of activated flux TIG weldments of super-duplex/austenitic stainless steels

    International Nuclear Information System (INIS)

    Devendranath Ramkumar, K.; Bajpai, Ankur; Raghuvanshi, Shubham; Singh, Anshuman; Chandrasekhar, Aditya; Arivarasu, M.; Arivazhagan, N.

    2015-01-01

    This research work articulated the effect of SiO 2 flux assisted tungsten inert gas (TIG) welding on the microstructure and mechanical properties of marine grade stainless steel weldments, such as super-duplex stainless steel (UNS S32750) and austenitic stainless steel (AISI 316L). The studies showed that the use of flux decreased the heat input required to obtain complete penetration. Microstructure studies revealed the presence of ferrite at the heat affected zone of AISI 316L and the fusion zone which obviated the hot cracking tendency. Tensile studies corroborated that the joint strength was sufficiently greater than that of the parent metals. Impact toughness slightly impoverished owing to the presence of large platelets of Widmanstätten austenite in the fusion zone. The study also explored the structure–property relationships of the flux assisted weldments using the combined techniques of optical and scanning electron microscopy analysis. Owing to the better metallurgical and mechanical properties, this study recommends the use of SiO 2 flux for joining the dissimilar metals involving austenitic and super-duplex stainless steels

  15. Atomic emission spectroelectrochemistry applied to dealloying phenomena II. Selective dissolution of iron and chromium during active-passive cycles of an austenitic stainless steel

    International Nuclear Information System (INIS)

    Ogle, K.; Mokaddem, M.; Volovitch, P.

    2010-01-01

    Atomic emission spectroelectrochemistry was used to investigate selective dissolution of a 304 austenitic stainless steel sample in 2 M H 2 SO 4 . The partial dissolution rates of Fe, Cr, Ni, Mn, Mo, and Cu were measured as function of time during a series of potentiostatic triggered activation/passivation cycles. When first exposed to sulfuric acid solution, the steel sample was in a passive state with a total steady state ionic dissolution rate expressed as an equivalent current density of 10 μA cm -2 . A transition into the active and passive state could be triggered by cathodic (-700 mV vs. Ag/AgCl) and anodic (+400 to +700 mV vs. Ag/AgCl) potentiostatic pulses respectively of variable time. Excess Cr dissolution was observed during the activation cycle as compared to Fe and a depletion of Cr dissolution was observed during the passivation cycle. These results are interpreted in terms of the dissolution of a Cr rich passive layer during activation and selective dissolution of Fe, Mn, Ni and other elements to form a Cr rich passive layer during passivation. Quantitative analysis of the excess Cr showed that the residual film contained approximately 0.38 μg Cr/cm 2 . Fe does not appear to be incorporated into the film at this early stage of passive film growth. Residual films of metallic nickel and copper were formed on the surface during the active period that subsequently dissolved during passivation.

  16. Development of new high-performance stainless steels

    International Nuclear Information System (INIS)

    Park, Yong Soo

    2002-01-01

    This paper focused on high-performance stainless steels and their development status. Effect of nitrogen addition on super-stainless steel was discussed. Research activities at Yonsei University, on austenitic and martensitic high-performance stainless, steels, and the next-generation duplex stainless steels were introduced

  17. Altered biomarkers of mucosal immunity and reduced vaginal Lactobacillus concentrations in sexually active female adolescents.

    Directory of Open Access Journals (Sweden)

    Rebecca Pellett Madan

    Full Text Available Genital secretions collected from adult women exhibit in vitro activity against herpes simplex virus (HSV and Escherichia coli (E. coli, but prior studies have not investigated this endogenous antimicrobial activity or its mediators in adolescent females.Anti-HSV and anti-E.coli activity were quantified from cervicovaginal lavage (CVL specimens collected from 20 sexually active adolescent females (15-18 years. Soluble immune mediators that may influence this activity were measured in CVL, and concentrations of Lactobacillus jensenii and crispatus were quantified by PCR from vaginal swabs. Results for adolescents were compared to those obtained from 54 healthy, premenopausal adult women. Relative to specimens collected from adults, CVL collected from adolescent subjects had significantly reduced activity against E. coli and diminished concentrations of protein, IgG, and IgA but significantly increased anti-HSV activity and concentrations of interleukin (IL-1α, IL-6 and IL-1 receptor antagonist. Vaginal swabs collected from adolescent subjects had comparable concentrations of L. crispatus but significantly reduced concentrations of L. jensenii, relative to adult swabs.Biomarkers of genital mucosal innate immunity may differ substantially between sexually active adolescents and adult women. These findings warrant further study and may have significant implications for prevention of sexually transmitted infections in adolescent females.

  18. Placental Vesicles Carry Active Endothelial Nitric Oxide Synthase and Their Activity is Reduced in Preeclampsia.

    Science.gov (United States)

    Motta-Mejia, Carolina; Kandzija, Neva; Zhang, Wei; Mhlomi, Vuyane; Cerdeira, Ana Sofia; Burdujan, Alexandra; Tannetta, Dionne; Dragovic, Rebecca; Sargent, Ian L; Redman, Christopher W; Kishore, Uday; Vatish, Manu

    2017-08-01

    Preeclampsia, a multisystem hypertensive disorder of pregnancy, is associated with increased systemic vascular resistance. Placentae from patients with preeclampsia have reduced levels of endothelial nitric oxide synthase (eNOS) and, thus, less nitric oxide (NO). Syncytiotrophoblast extracellular vesicles (STBEV), comprising microvesicles (STBMV) and exosomes, carry signals from the syncytiotrophoblast to the mother. We hypothesized that STBEV-bound eNOS (STBEV-eNOS), capable of producing NO, are released into the maternal circulation. Dual-lobe ex vivo placental perfusion and differential centrifugation was used to isolate STBEV from preeclampsia (n=8) and normal pregnancies (NP; n=11). Plasma samples of gestational age-matched preeclampsia and NP (n=6) were used to isolate circulating STBMV. STBEV expressed placental alkaline phosphatase, confirming placental origin. STBEV coexpressed eNOS, but not inducible nitric oxide synthase, confirmed using Western blot, flow cytometry, and immunodepletion. STBEV-eNOS produced NO, which was significantly inhibited by N   G -nitro-l-arginine methyl ester (eNOS inhibitor; P preeclampsia-perfused placentae had lower levels of STBEV-eNOS (STBMV; P preeclampsia women had lower STBEV-eNOS expression compared with that from NP women ( P preeclampsia placentae, as well as in plasma. The lower STBEV-eNOS NO production seen in preeclampsia may contribute to the decreased NO bioavailability in this disease. © 2017 The Authors.

  19. Reduced In-Plane, Low Frequency Helicopter Noise of an Active Flap Rotor

    Science.gov (United States)

    Sim, Ben W.; Janakiram, Ram D.; Barbely, Natasha L.; Solis, Eduardo

    2009-01-01

    Results from a recent joint DARPA/Boeing/NASA/Army wind tunnel test demonstrated the ability to reduce in-plane, low frequency noise of the full-scale Boeing-SMART rotor using active flaps. Test data reported in this paper illustrated that acoustic energy in the first six blade-passing harmonics could be reduced by up to 6 decibels at a moderate airspeed, level flight condition corresponding to advance ratio of 0.30. Reduced noise levels were attributed to selective active flap schedules that modified in-plane blade airloads on the advancing side of the rotor, in a manner, which generated counteracting acoustic pulses that partially offset the negative pressure peaks associated with in-plane, steady thickness noise. These favorable reduced-noise operating states are a strong function of the active flap actuation amplitude, frequency and phase. The associated noise reductions resulted in reduced aural detection distance by up to 18%, but incurred significant vibratory load penalties due to increased hub shear forces. Small reductions in rotor lift-to-drag ratios, of no more than 3%, were also measured

  20. Reduced ADAMTS13 activity is associated with thrombotic risk in systemic lupus erythematosus.

    Science.gov (United States)

    Martin-Rodriguez, S; Reverter, J C; Tàssies, D; Espinosa, G; Heras, M; Pino, M; Escolar, G; Diaz-Ricart, M

    2015-10-01

    Severe deficiency of ADAMTS13 activity leads to von Willebrand factor (VWF) ultralarge multimers with high affinity for platelets, causing thrombotic thrombocytopenic purpura. Other pathological conditions with moderate ADAMTS13 activity exhibit a thrombotic risk. We examined the ADAMTS13 activity in systemic lupus erythematosus (SLE) and its value as a thrombotic biomarker. ADAMTS13 activity, VWF antigen and multimeric structure, and vascular cell adhesion molecule 1 (VCAM-1) were measured in plasma samples from 50 SLE patients and 50 healthy donors. Disease activity (systemic lupus erythematosus disease activity index; SLEDAI) and organ damage (systemic lupus international collaborating clinics) scores, thrombotic events, antiphospholipid syndrome (APS) and antiphospholipid antibodies (aPLs) were registered. SLE patients showed decreased ADAMTS13 activity and high VWF levels compared with controls (66 ± 27% vs. 101 ±