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Sample records for steel-ht-9

  1. Helium-induced weld degradation of HT-9 steel

    International Nuclear Information System (INIS)

    Wang, Chin-An; Chin, B.A.; Lin, Hua T.; Grossbeck, M.L.

    1992-01-01

    Helium-bearing Sandvik HT-9 ferritic steel was tested for weldability to simulate the welding of structural components of a fusion reactor after irradiation. Helium was introduced into HT-9 steel to 0.3 and 1 atomic parts per million (appm) by tritium doping and decay. Autogenous single pass full penetration welds were produced using the gas tungsten arc (GTA) welding process under laterally constrained conditions. Macroscopic examination showed no sign of any weld defect in HT-9 steel containing 0.3 appm helium. However, intergranular micro cracks were observed in the HAZ of HT-9 steel containing 1 appm helium. The microcracking was attributed to helium bubble growth at grain boundaries under the influence of high stresses and temperatures that were present during welding. Mechanical test results showed that both yield strength (YS) and ultimate tensile strength (UTS) decreased with increasing temperature, while the total elongation increased with increasing temperature for all control and helium-bearing HT-9 steels

  2. Thermal conductivity and thermal expansion of stainless steels D9 and HT9

    International Nuclear Information System (INIS)

    Leibowitz, L.; Blomquist, R.A.

    1988-01-01

    Renewed interest in the use of metallic fuels in liquid-metal fast breeder reactors has prompted study of the thermodynamic and transport properties of its materials. Two stainless steels are of particular interest because of their good performance under irradiation. These are D9, an austenitic steel, and HT9, a ferritic steel. Thermal conductivity and thermal expansion data for these alloys are of particular interest in assessing in-reactor behavior. Because literature data were inadequate, measurements of these two properties for the two steels were performed and are reported to 1200 K. Of particular interest is the influence on these properties of a phase transition in HT9

  3. Creep characterization of type 316LN and HT-9 stainless steels by the K-R creep damage model

    International Nuclear Information System (INIS)

    Kim, Woo Gon; Kim, Sung Ho; Ryu, Woo Seog

    2001-01-01

    The Kachanov and Rabotnov (K-R) creep damage model was interpreted and applied to type 316LN and HT-9 stainless steels. Seven creep constants of the model, A, B, k, m, λ, γ, and q were determined for type 316LN stainless steel. In order to quantify a damage parameter, the cavity was interruptedly traced during creep for measuring cavity area to be reflected into the damage equation. For type 316LN stainless steel, λ=ε R /ε * and λ f =ε/ε R were 3.1 and increased with creep strain. The creep curve with λ=3.1 depicted well the experimental data to the full lifetime and its damage curve showed a good agreement when γ=24. However for the HT-9 stainless steel, the values of λ and λ f were different as λ=6.2 and λ f =8.5, and their K-R creep curves did not agree with the experimental data. This mismatch in the HT-9 steel was due to the ductile fracture by softening of materials rather than the brittle fracture by cavity growth. The differences of the values in the above steels were attributed to creep ductilities at the secondary and the tertiary creep stages

  4. Liquid metal reactor core material HT9

    International Nuclear Information System (INIS)

    Kim, S. H.; Kuk, I. H.; Ryu, W. S. and others

    1998-03-01

    A state-of-the art is surveyed on the liquid metal reactor core materials HT9. The purpose of this report is to give an insight for choosing and developing the materials to be applied to the KAERI prototype liquid metal reactor which is planned for the year of 2010. In-core stability of cladding materials is important to the extension of fuel burnup. Austenitic stainless steel (AISI 316) has been used as core material in the early LMR due to the good mechanical properties at high temperatures, but it has been found to show a poor swelling resistance. So many efforts have been made to solve this problem that HT9 have been developed. HT9 is 12Cr-1MoVW steel. The microstructure of HT9 consisted of tempered martensite with dispersed carbide. HT9 has superior irradiation swelling resistance as other BCC metals, and good sodium compatibility. HT9 has also a good irradiation creep properties below 500 dg C, but irradiation creep properties are degraded above 500 dg C. Researches are currently in progress to modify the HT9 in order to improve the irradiation creep properties above 500 dg C. New design studies for decreasing the core temperature below 500 dg C are needed to use HT9 as a core material. On the contrary, decrease of the thermal efficiency may occur due to lower-down of the operation temperature. (author). 51 refs., 6 tabs., 19 figs

  5. Gap Analysis of Material Properties Data for Ferritic/Martensitic HT-9 Steel

    International Nuclear Information System (INIS)

    Brown, Neil R.; Serrano De Caro, Magdalena; Rodriguez, Edward A.

    2012-01-01

    The US Department of Energy (DOE), Office of Nuclear Energy (NE), is supporting the development of an ASME Code Case for adoption of 12Cr-1Mo-VW ferritic/martensitic (F/M) steel, commonly known as HT-9, primarily for use in elevated temperature design of liquid-metal fast reactors (LMFR) and components. In 2011, Los Alamos National Laboratory (LANL) nuclear engineering staff began assisting in the development of a small modular reactor (SMR) design concept, previously known as the Hyperion Module, now called the Gen4 Module. LANL staff immediately proposed HT-9 for the reactor vessel and components, as well as fuel clad and ducting, due to its superior thermal qualities. Although the ASME material Code Case, for adoption of HT-9 as an approved elevated temperature material for LMFR service, is the ultimate goal of this project, there are several key deliverables that must first be successfully accomplished. The most important key deliverable is the research, accumulation, and documentation of specific material parameters; physical, mechanical, and environmental, which becomes the basis for an ASME Code Case. Time-independent tensile and ductility data and time-dependent creep and creep-rupture behavior are some of the material properties required for a successful ASME Code case. Although this report provides a cursory review of the available data, a much more comprehensive study of open-source data would be necessary. This report serves three purposes: (a) provides a list of already existing material data information that could ultimately be made available to the ASME Code, (b) determines the HT-9 material properties data missing from available sources that would be required and (c) estimates the necessary material testing required to close the gap. Ultimately, the gap analysis demonstrates that certain material properties testing will be required to fulfill the necessary information package for an ASME Code Case.

  6. Effect of multiple austenitizing treatments on HT-9 steels

    International Nuclear Information System (INIS)

    Emigh, R.A.

    1985-12-01

    The effect of multiple austenitizing treatments on the toughness of an Fe-12Cr-1.0Mo-0.5W-0.3V (HT-9) steel was studied. The resulting microstructures were characterized by their mechanical properties, precipitated carbide distribution, and fracture surface appearance. It was proposed that multiple transformations would refine the martensite structure and improve toughness. Optical and scanning electron microscopic observations revealed that the martensite packet structure was somewhat refined by a second austenite transformation. Transmission electron microscopy studies of carbon extraction replicas showed that this multiple step treatment had eliminated grain boundary carbide films seen in single treated specimens on prior austenite grain boundaries. The 0.2% yield strength, tensile strength, and elongation were relatively unchanged, but the toughness measured by fatigue pre-cracked Charpy impact tests increased for the multiple step specimens

  7. Elemental volatility of HT-9 fusion reactor alloy

    International Nuclear Information System (INIS)

    Henslee, S.P.; Neilson, R.M. Jr.

    1985-01-01

    The volatility of elemental constituents from HT-9, a ferritic steel, proposed for fusion reactor structures, was investigated. Tests were conducted in flowing air at temperatures from 800 to 1200 0 C for durations of 1 to 20 h. Elemental volatility was calculated in terms of the weight fraction of the element volatilized from the initial alloy; molybdenum, manganese, and nickel were the primary constituents volatilized. Comparisons with elemental volatilities observed for another candidate fusion reactor materials. Primary Candidate Alloy (PCA), an austenitic stainless steel, indicate significant differences between the volatilities of these steels that may impact fusion reactor safety analysis and alloy selection. Scanning electron microscopy and energy dispersive spectrometry were used to investigate the oxide layers formed on HT-9 and to measure elemental contents within these layers

  8. Effect of microstructure on the mechanical properties of a commercial 12Cr-1Mo steel (HT-9)

    International Nuclear Information System (INIS)

    Lechtenberg, T.A.

    1981-08-01

    The microstructure of a commercial 12Cr-1Mo steel (HT-9) and its associated effect on strength and toughness properties is being studied in a continuing program aimed at qualifying the alloy for use in fusion energy machines. Interim results show this alloy is subject to a degree of tempered martensite embrittlement and temper embrittlement. For applications projected for fusion machines at lower temperatures, a new heat treatment (1000 0 C, 1 h, air-cooled followed by 650 0 C tempering) at lower temperatures and shorter times than the vendor-recommended heat treatment has been identified. Microstructural differences between the treatments are discussed, and mechanical properties are correlated. 6 figures

  9. Role of grain boundary engineering in the SCC behavior of ferritic-martensitic alloy HT-9

    International Nuclear Information System (INIS)

    Gupta, G.; Ampornrat, P.; Ren, X.; Sridharan, K.; Allen, T.R.; Was, G.S.

    2007-01-01

    This paper focuses on the role of grain boundary engineering (GBE) in stress corrosion cracking (SCC) of ferritic-martensitic (F-M) alloy HT-9 in supercritical water (SCW) at 400 deg. C and 500 deg. C. Constant extension rate tensile (CERT) tests were conducted on HT-9 in as-received (AR) and coincident site lattice enhanced (CSLE) condition. Both unirradiated and irradiated specimens (irradiated with 2 MeV protons at 400 deg. C and 500 deg. C to a dose of 7 dpa) were tested. Ferritic-martensitic steel HT-9 exhibited intergranular stress corrosion cracking when subjected to CERT tests in an environment of supercritical water at 400 deg. C and 500 deg. C and also in an inert environment of argon at 500 deg. C. CSL-enhancement reduces grain boundary carbide coarsening and cracking susceptibility in both the unirradiated and irradiated condition. Irradiation enhanced coarsening of grain boundary carbides and cracking susceptibility of HT-9 for both the AR and CSLE conditions. Intergranular (IG) cracking of HT-9 results likely from fracture of IG carbides and seems consistent with the mechanism that coarser carbides worsen cracking susceptibility. Oxidation in combination with wedging stresses is the likely cause of the observed environmental enhancement of high temperature IG cracking in HT-9

  10. Study of the effects of austenitizing and tempering heat treatments on the alloy HT-9

    International Nuclear Information System (INIS)

    Redmon, J.W.

    1982-01-01

    This paper investigates the potential use of the ferritic alloy Sandvik HT-9 (12 Cr - 1 Mo) as an alternative to stainless steels used in high-neutron-fluence environments. The neutron radiation influences embrittlement where the impact-energy versus test-temperature curve is seen displaced to the right. As a result, commercially effective solutioning and tempering processes are needed to suppress this effect in the pre-irradiated condition. The effects of austenitizing treatments on the impact energy of HT-9 were identified. 18 figures, 6 tables

  11. Vanadium diffusion coating on HT-9 cladding for mitigating the fuel cladding chemical interactions

    Science.gov (United States)

    Lo, Wei-Yang; Yang, Yong

    2014-08-01

    Fuel cladding chemical interaction (FCCI) has been identified as one of the crucial issues for developing Ferritic/Martensitic (F/M) stainless steel claddings for metallic fuels in a fast reactor. The anticipated elevated temperature and high neutron flux can significantly aggravate the FCCI, in terms of formation of inter-diffusion and lower melting point eutectic phases. To mitigate the FCCI, vanadium carbide coating as a diffusion barrier was deposited on the HT-9 substrate using a pack cementation diffusion coating (PCDC) method, and the processing temperature was optimized down to 730 °C. A solid metallurgical bonding between the coating layer and substrate was achieved, and the coating is free from through depth cracks. The microstructural characterizations using SEM and TEM show a nanostructured grain structure. EDS/WDS and XRD analysis confirm the phase of coating layer as V2C. Diffusion couple tests at 660 °C for 100 h demonstrate that V2C layer with a thickness of less than 5 μm can effectively eliminate the inter-diffusion between the lanthanide cerium and HT-9 steel.

  12. Vanadium diffusion coating on HT-9 cladding for mitigating the fuel cladding chemical interactions

    Energy Technology Data Exchange (ETDEWEB)

    Lo, Wei-Yang; Yang, Yong, E-mail: yongyang@ufl.edu

    2014-08-01

    Fuel cladding chemical interaction (FCCI) has been identified as one of the crucial issues for developing Ferritic/Martensitic (F/M) stainless steel claddings for metallic fuels in a fast reactor. The anticipated elevated temperature and high neutron flux can significantly aggravate the FCCI, in terms of formation of inter-diffusion and lower melting point eutectic phases. To mitigate the FCCI, vanadium carbide coating as a diffusion barrier was deposited on the HT-9 substrate using a pack cementation diffusion coating (PCDC) method, and the processing temperature was optimized down to 730 °C. A solid metallurgical bonding between the coating layer and substrate was achieved, and the coating is free from through depth cracks. The microstructural characterizations using SEM and TEM show a nanostructured grain structure. EDS/WDS and XRD analysis confirm the phase of coating layer as V{sub 2}C. Diffusion couple tests at 660 °C for 100 h demonstrate that V{sub 2}C layer with a thickness of less than 5 μm can effectively eliminate the inter-diffusion between the lanthanide cerium and HT-9 steel.

  13. Low-cycle fatigue behavior of HT-9 alloy in a flowing-lithium environment

    International Nuclear Information System (INIS)

    Chopra, O.K.; Smith, D.L.

    1983-06-01

    Low-cycle fatigue data have been obtained on normalized/tempered or lithium-preexposed HT-9 alloy at 755 K in flowing lithium of controlled purity. The results show that the fatigue life of this material decreases with an increase in nitrogen content in lithium. A reduction in strain rate also decreases the fatigue life in high-nitrogen lithium. However, in the range from approx. 4 x 10 - 4 to 4 x 10 - 2 s - 1 , the strain rate has no effect on fatigue life in lithium containing <200 wppM nitrogen. The fatigue life of the HT-9 alloy in low-nitrogen lithium is significantly greater than the fatigue life of Fe-9Cr-1Mo steel or Type 403 martensitic steel in air. Furthermore, a 4.0-Ms preexposure to low-nitrogen lithium has no influence on fatigue life. The reduction in fatigue life in high-nitrogen lithium is attributed to internal corrosive attack of the material. The specimens tested in high-nitrogen lithium show internal corrosion along grain and martensitic lathe boundaries and intergranular fracture. This behavior is not observed in specimens tested in low-nitrogen lithium. Results for a constant-load corrosion test in flowing lithium are also presented

  14. Transient failure behavior of HT9

    International Nuclear Information System (INIS)

    Huang, F.H.

    1994-07-01

    Alloy HT9 has-been chosen as candidate materials for fast and fusion reactor applications because the.material exhibits excellent resistance to void swelling. However, ferritic alloys are known to undergo a ductile-brittle transition as the test temperature is decreased. This inherent problem has limited their applications to reactor component materials subjected to low neutron exposures. Despite the ductile-brittle transition problem, results show that the materials exhibit superior resistance to fracture under very high neutron fluences at irradiation temperatures above 380C. Results also show that the transient behavior for HT9 cladding specimens taken from the fuel column region and cladding taken from outside the fuel column or unirradiated cladding are the same. HT9 cladding maintained its transient strength with irradiation to a fluence of 9 x 10 22 n/cm 2 (E > 0.1 MeV)

  15. Capability demonstration of simultaneous proton beam irradiation during exposure to molten lead–bismuth eutectic for HT9 steel

    International Nuclear Information System (INIS)

    Qvist, Staffan; Bolind, Alan Michael; Hosemann, Peter; Wang, Yongqiang; Tesmer, Joseph; De Caro, Magdalena Serrano; Bourke, Mark

    2013-01-01

    We report the design and assembly of a corrosion station to enable simultaneous proton irradiation of a metallic surface that was also in contact with molten lead–bismuth eutectic (LBE). The capability has been established at the ion beam materials laboratory at Los Alamos National Laboratory (LANL). The engineering design focused on temperature and oxygen content control in the LBE, as well as the ability to achieve doses significantly in excess of 1 dpa in the contact region over the irradiation campaigns. In the preliminary demonstration of capability reported here, a sample made of HT9 steel was placed in contact with LBE at 450 °C and irradiated for 58 h at an average proton beam current of 0.3 μA/mm 2 . SRIM [1] calculations indicate that the nominal surface dose ranged from approximately 3–22 dpa. This paper outlines the experimental setup and design constraints. Characterization of the sample will be reported in a subsequent paper.

  16. Capability demonstration of simultaneous proton beam irradiation during exposure to molten lead–bismuth eutectic for HT9 steel

    Energy Technology Data Exchange (ETDEWEB)

    Qvist, Staffan, E-mail: staffan@berkeley.edu [University of California, Berkeley (United States); Bolind, Alan Michael [University of California, Berkeley (United States); Japan Atomic Energy Agency (Japan); Hosemann, Peter [University of California, Berkeley (United States); Wang, Yongqiang; Tesmer, Joseph; De Caro, Magdalena Serrano; Bourke, Mark [Los Alamos National Laboratory (United States)

    2013-01-11

    We report the design and assembly of a corrosion station to enable simultaneous proton irradiation of a metallic surface that was also in contact with molten lead–bismuth eutectic (LBE). The capability has been established at the ion beam materials laboratory at Los Alamos National Laboratory (LANL). The engineering design focused on temperature and oxygen content control in the LBE, as well as the ability to achieve doses significantly in excess of 1 dpa in the contact region over the irradiation campaigns. In the preliminary demonstration of capability reported here, a sample made of HT9 steel was placed in contact with LBE at 450 °C and irradiated for 58 h at an average proton beam current of 0.3 μA/mm{sup 2}. SRIM [1] calculations indicate that the nominal surface dose ranged from approximately 3–22 dpa. This paper outlines the experimental setup and design constraints. Characterization of the sample will be reported in a subsequent paper.

  17. Analysis of Current HT9 Creep Correlations and Modification

    International Nuclear Information System (INIS)

    Lee, Cheol Min; Sohn, Dongseong; Cheon, Jin Sik

    2014-01-01

    It has high thermal conductivity, high mechanical strength and low irradiation induced swelling. However high temperature creep of HT9 has always been a life limiting factor. Above 600 .deg. C, the dislocation density in HT9 is decreased and the M 23 C 6 precipitates coarsen, these processes are accelerated if there is irradiation. Finally microstructural changes at high temperature lead to lower creep strength and large creep strain. For HT9 to be used as a future cladding, creep behavior of the HT9 should be predicted accurately based on the physical understanding of the creep phenomenon. Most of the creep correlations are composed of irradiation creep and thermal creep terms. However, it is certain that in-pile thermal creep and out-of-pile thermal creep are different because of the microstructure changes induced from neutron irradiation. To explain creep behavior more accurately, thermal creep contributions other than neutron irradiation should be discriminated in a creep correlation. To perform this work, existing HT9 creep correlations are analyzed, and the results are used to develop more accurate thermal creep correlation. Then, the differences between in-pile thermal creep and out-of-pile thermal creep are examined

  18. Charpy impact behavior of manganese-stabilized martensitic steels

    International Nuclear Information System (INIS)

    Hu, W.L.; Gelles, D.S.

    1986-05-01

    Tests were conducted to evaluate the irradiation-induced shift in ductile-to-brittle transition behavior of two manganese stabilized martensitic steels. Miniature Charpy specimens were fabricated from two heats of steel similar in composition to HT-9 but with 0.1% C and Mn contents ranging from 3.3 to 6.6.%. The 3.3% Mn steel showed a transition temperature similar to that of HT-9 in both the unirradiated condition and in specimens irradiated to 11.3 dpa. The steel containing 6.6% Mn exhibited a higher transition temperature after irradiation than the steel containing 3.3% Mn. The upper shelf energy (USE) after irradiation for the manganese stabilized alloys was much higher than for HT-9. 6 refs., 3 figs., 2 tabs

  19. Development of Advanced 9Cr Ferritic-Martensitic Steels and Austenitic Stainless Steels for Sodium-Cooled Fast Reactors

    International Nuclear Information System (INIS)

    Sham, T.-L.; Tan, L.; Yamamoto, Y.

    2013-01-01

    Summary of creep, thermal aging and weldability aspects: • The creep resistance of advanced 9Cr FM steels was greatly enhanced by optimizing their compositions as well as by using TMT. – Up to about 700 times increase in creep life, compared to Gr91, was achieved under the accelerated test conditions at 600°C. • The increased density of ultrafine precipitates facilitated the increase in strength and thermal aging resistance, leading to the improved creep resistance. • Properties of four candidate austenitic alloys, HT-UPS, NF709, and two modified HT-UPS alloy (designated Alloys A and B), have been evaluated and compared with 316H. – Alloys A and B showed successful improvement in weldability. – Only a little difference in thermal stability of the alloys in solution annealed conditions. 10% cold work increased the yield strength of the alloys for more than 200% compared to the HT-UPS without cold work. – HT-UPS exhibited the best creep properties among the alloys with and without cold work, and NF709 followed

  20. Performance of HT9 clad metallic fuel at high temperature

    International Nuclear Information System (INIS)

    Pahl, R.G.; Lahm, C.E.; Hayes, S.L.

    1992-01-01

    Steady-state testing of HT9 clad metallic fuel at high temperatures was initiated in EBR-II in November of 1987. At that time U-10 wt. % Zr fuel clad with the low-swelling ferritic/martensitic alloy HT9 was being considered as driver fuel options for both EBR-II and FFTF. The objective of the X447 test described here was to determine the lifetime of HT9 cladding when operated with metallic fuel at beginning of life inside wall temperatures approaching ∼660 degree C. Though stress-temperature design limits for HT9 preclude its use for high burnup applications under these conditions due to excessive thermal creep, the X447 test was carried out to obtain data on high temperature breach phenomena involving metallic fuel since little data existed in that area

  1. Corrosion Properties of Dissimilar Friction Stir Welded 6061 Aluminum and HT590 Steel

    Science.gov (United States)

    Seo, Bosung; Song, Kuk Hyun; Park, Kwangsuk

    2018-05-01

    Corrosion properties of dissimilar friction stir welded 6061 aluminum and HT590 steel were investigated to understand effects of galvanic corrosion. As cathode when coupled, HT590 was cathodically protected. However, the passivation of AA6061 made the aluminum alloy cathode temporarily, which leaded to corrosion of HT590. From the EIS analysis showing Warburg diffusion plot in Nyquist plots, it can be inferred that the stable passivation layer was formed on AA6061. However, the weld as well as HT590 did not show Warburg diffusion plot in Nyquist plots, suggesting that there was no barrier for corrosion or even if it exists, the barrier had no function for preventing and/or retarding charge transport through the passivation layer. The open circuit potential measurements showed that the potential of the weld was similar to that of HT590, which lied in the pitting region for AA6061, making the aluminum alloy part of the weld keep corrosion state. That resulted in the cracked oxide film on AA6061 of the weld, which could not play a role of corrosion barrier.

  2. Activation product transport in a FLiBe-vanadium alloy-HT9 system

    International Nuclear Information System (INIS)

    Klein, A.C.; Sze, D.K.

    1985-01-01

    An assessment is made of the gamma radiation hazards likely to be found around a fusion reactor heat transfer and tritium breeding loop which employs a vanadium alloy for the blanket and first wall structure and the ferritic-steel HT9 for the remainder of the loop. The coolant/tritium breeding fluid is the molten metallic salt FliBe. Since the radiation levels near the primary loop components are found to be less than 100 mR/hr 3-5 days after shutdown after three years of continuous full power operation, limited hands-on maintenance could be allowed. The very short half-lives of the predominant corrosion products make this result possible and make such a system very attractive

  3. Impact fracture behavior of HT9 duct

    International Nuclear Information System (INIS)

    Huang, F.H.; Gelles, D.S.

    1994-07-01

    Ferritic alloys are known to undergo a ductile-brittle transition as the test temperature is decreased. This inherent problem has limited their applications to reactor component materials subjected to low neutron exposures. However, the excellent resistance to void swelling exhibited by these alloys has led to choosing the materials as candidate materials for fast and fusion reactor applications. Despite the ductile-brittle transition problem, results show that the materials exhibit superior resistance to fracture under very high neutron fluences at irradiation temperatures above 380 degrees C. Impact testing on FFTF duct sections of HT9 indicates that HT9 ducts have adequate fracture toughness at much higher temperatures for handling operations at room temperature and refueling operations

  4. Degradation of HT9 under simultaneous ion beam irradiation and liquid metal corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Frazer, D., E-mail: davefrazer@berkeley.edu [Department of Nuclear Engineering, University of California, Berkeley, Berkeley, CA United States (United States); Qvist, S. [Department of Nuclear Engineering, University of California, Berkeley, Berkeley, CA United States (United States); Department of Physics and Astronomy, Uppsala University (Sweden); Parker, S.; Krumwiede, D.L. [Department of Nuclear Engineering, University of California, Berkeley, Berkeley, CA United States (United States); Caro, M.; Tesmer, J.; Maloy, S.A.; Wang, Y.Q. [Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM United States (United States); Hosemann, P. [Department of Nuclear Engineering, University of California, Berkeley, Berkeley, CA United States (United States)

    2016-10-15

    A potentially promising coolant/structural material pair for a liquid-metal-cooled fast reactors is lead bismuth eutectic (LBE) coolant with the ferritic/martensitic steel HT9. The challenge of deploying LBE, however, is the corrosive environment it creates for structural materials. This corrosion can be mitigated with precise oxygen content control in the LBE to allow for the growth of passive protective oxide layers on the surface of the steel. In this paper, results are reported from the Irradiation Corrosion Experiment II (ICE-II), which allowed the simultaneous irradiation of a sample while in contact with LBE. It was found that a characteristic multilayer structure with an outer Fe{sub 3}O{sub 4} oxide and inner FeCr{sub 2}O{sub 4} spinel was grown and the oxidation was significantly larger in the irradiated region when compared to the region that was only exposed to LBE corrosion. Possible mechanisms are discussed to help understand this irradiation enhanced corrosion behavior.

  5. Fracture behavior of unirradiated HT-9 and modified 9Cr-1Mo welds

    International Nuclear Information System (INIS)

    Huang, F.H.; Gelles, D.S.

    1983-05-01

    Fracture toughness tests on HT-9 weld and HAZ samples and modified 9Cr-1Mo weld samples were performed at 93, 205, 427 and 538 0 C. Specimens were of circular compact tension type fabricated from welded material with the notch orientation parallel to the fusion line. The test results were analyzed using the J-integral approach. The results demonstrated that the toughness of HT-9 and 9Cr-1Mo was not significantly reduced due to welding. However, the tearing modulus of the welded material was lower than that of base metal, indicating that the alloys become less resistant to crack propagation as a result of welding

  6. Chemical durability and degradation mechanisms of HT9 based alloy waste forms with variable Zr content

    Energy Technology Data Exchange (ETDEWEB)

    Olson, L. N. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-10-30

    In Corrosion studies were undertaken on alloy waste forms that can result from advanced electrometallurgical processing techniques to better classify their durability and degradation mechanisms. The waste forms were based on the RAW3-(URe) composition, consisting primarily of HT9 steel and other elemental additions to simulate nuclear fuel reprocessing byproducts. The solution conditions of the corrosion studies were taken from an electrochemical testing protocol, and meant to simulate conditions in a repository. The alloys durability was examined in alkaline and acidic brines.

  7. J/sub 1c/ fracture toughness transition behavior of HT-9

    International Nuclear Information System (INIS)

    Huang, F.H.

    1984-01-01

    Small compact tension specimens of two heats of HT-9 were tested at temperatures ranging from room temperature to -192 0 C. The ductile-brittle transition toughness of HT-9 was evaluated using the J-integral approach. There were two loading rates of 2.1 x 10 -5 m/s and 3.2 x 10 -2 m/s. The ductile-brittle transition temperatures of HT-9 (number 1 heat) tested at 2.1 x 10 -5 m/s and HT-9 (number 2 heat) tested at 3.2 x 10 -2 m/s were found to be -60 and -10 0 C, respectively. Results showed the fracture toughness of the former was not sensitive to loading rate and the lower shelf toughness decreased with temperature to a J/sub 1c/ value of 5 kJ/m 2 at -190 0 C. Furthermore, the values of J/sub 1c/ were valid since the thickness of the test specimens was well above the thickness criterion

  8. In situ neutron diffraction and Elastic–Plastic Self-Consistent polycrystal modeling of HT-9

    International Nuclear Information System (INIS)

    Clausen, B.; Brown, D.W.; Bourke, M.A.M.; Saleh, T.A.; Maloy, S.A.

    2012-01-01

    Qualifying materials for use in reactors with fluences greater than 200 dpa (displacements per atom) requires development of advanced alloys and irradiations in fast reactors to test these alloys. Research into the mechanical behavior of these materials under reactor conditions is ongoing. In order to probe changes in deformation mechanisms due to radiation in these materials, samples of HT-9 were tested in tension in situ on the SMARTS instrument at Los Alamos Neutron Science Center. Experimental results, confirmed with modeling, show significant load sharing between the carbides and parent phase of the steel beyond yield, displaying the critical role of carbides during deformation, along with basic texture development.

  9. In situ neutron diffraction and Elastic-Plastic Self-Consistent polycrystal modeling of HT-9

    Energy Technology Data Exchange (ETDEWEB)

    Clausen, B., E-mail: clausen@lanl.gov [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Brown, D.W.; Bourke, M.A.M.; Saleh, T.A.; Maloy, S.A. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2012-06-15

    Qualifying materials for use in reactors with fluences greater than 200 dpa (displacements per atom) requires development of advanced alloys and irradiations in fast reactors to test these alloys. Research into the mechanical behavior of these materials under reactor conditions is ongoing. In order to probe changes in deformation mechanisms due to radiation in these materials, samples of HT-9 were tested in tension in situ on the SMARTS instrument at Los Alamos Neutron Science Center. Experimental results, confirmed with modeling, show significant load sharing between the carbides and parent phase of the steel beyond yield, displaying the critical role of carbides during deformation, along with basic texture development.

  10. Irradiation creep and void swelling of two LMR heats of HT9 at ∝400 C and 165 dpa

    International Nuclear Information System (INIS)

    Toloczko, M.B.; Garner, F.A.

    1996-01-01

    Two nominally identical heats of HT9 ferritic-martensitic steel were produced, fabricated into pressurized tubes, and then irradiated in FFTF, using identical procedures. After reaching 165 dpa at ∝400 C, small differences in strains associated with both phase-related changes in lattice parameter and void swelling were observed in comparing the two heats. The creep strains, while different, exhibited the same functional dependence on swelling behavior. The derived creep coefficients, the one associated with creep in the absence of swelling and the one directly responsive to swelling, were essentially identical for the two heats. Even more significantly, the creep coefficients for this bcc ferritic-martensitic steel appear to be very similar and possibly identical to those routinely derived from creep experiments on fcc austenitic steels. (orig.)

  11. Irradiation creep and void swelling of two LMR heat of HT9 at ∼400 degrees C and 165 dpa

    International Nuclear Information System (INIS)

    Toloczko, M.B.; Garner, F.A.

    1996-01-01

    Two nominally identical heats of HT9 ferritic-martensitic steel were produced, fabricated into pressurized tubes, and then irradiated in FFTF, using identical procedures. After reaching 165 dpa at ∼400C, small differences in strains associated with both phase-related change in lattice parameter and void swelling were observed in comparing the two heats. The creep strains, while different, exhibited the same functional relationship to the swelling behavior. The derived creep coefficients, the one associated with creep in the absence of swelling and the one directly responsive to swelling, were essentially identical for the two heats. Even more significantly, the creep coefficients for this bcc ferritic-martensitic steel appear to be very similar and possibly identical to those routinely derived from creep experiments on fcc austenitic steels

  12. Design limits for HT9 cladding using stress-induced aging data

    International Nuclear Information System (INIS)

    Fox, G.L.

    1986-04-01

    Stress-temperature design guidelines are developed for the ferritic/martensitic cladding material HT9. High temperature operation for HT9 may cause microstructural changes/aging which softens the structure and causes increased creep rates. Higher creep strains means cladding breech becomes more probable before the end of the expected pin lifetime. Tertiary creep is considered an indication of microstructural changes and is to be avoided in fuel pin operation. The creep rate correlation, which includes tertiary creep, is examined for information on stress-temperature relationships which promote aging. This approach leads to design limits for HT9 which are compared with expected hot channel conditions for fuel pins in the Core Demonstration Experiment (CDE) planned for FFTF. The results show aging should not be significant for CDE

  13. Interdiffusion between U-Zr-Mo and stainless steel cladding

    International Nuclear Information System (INIS)

    Hwang, J. Y.; Lee, B. S.; Lee, J. T.; Kang, Y. H.

    1998-01-01

    Interdiffusion investigations were carried out at 700 deg C for 200 hours for the diffusion couples assembled with the U-Zr-Mo ternary fuel versus austenitic stainless steel D9 and the U-Zr-Mo ternary fuel versus martensitic stainless steel HT9 respectively to investigate the fuel-cladding compatibility. SEM-EDS analysis was utilized to determine the composition and the penetration depths of the reaction layers. In the case of Fuel/D9 couple, (Fe, Cr, Ni) of the cladding elements formed the precipitates with the Zr, Mo and diminished the U concentration upto 800μ length from the fuel side. Composition of the precipitates was varied with the penetrated elements. In Fuel/HT9 couple, reaction layer was smaller than that of D9 couples and was less affected by cladding elements. The eutectic reaction appeared partially in the Fuel/HT9 diffusion couple

  14. Development of Preliminary HT9 Cladding Tube for Sodium-cooled Fast Reactor (SFR)

    International Nuclear Information System (INIS)

    Kim, Jun Hwan; Baek, Jong Hyuk; Heo, Hyeong Min; Park, Sang Gyu; Kim, Sung Ho; Lee, Chan Bock

    2013-01-01

    To achieve manufacturing technology of the fuel cladding tube in order to keep pace with the predetermined schedule in developing SFR fuel, KAERI has launched in developing fuel cladding tube in cooperation with a domestic steelmaking company. After fabricating medium-sized 1.1 ton HT9 ingot, followed by the multiple processes of hot and cold working, preliminary samples of HT9 seamless cladding tube having 7.4mm in outer diameter, 0.56mm in thickness, and 3m in length were fabricated. The objective of this study is to summarize the brief development status of the HT9 cladding tubes. Mechanical properties like axial tension, biaxial burst, pressurized creep and sodium compatibility of the cladding tubes were carried out to set up the performance evaluation technology to test the prototype FMS cladding tube which is going to be manufactured in next stage. As a part of developing fuel cladding for the Sodium-cooled Fast Reactor (SFR), preliminary HT9 cladding tube was fabricated in cooperation with a domestic steelmaking company. Microstructure as well as mechanical tests like axial tensile test, biaxial burst test, and pressurized creep test of the fuel cladding were carried out. Performance of the domestic HT9 tube was revealed to be similar in the previously fabricated foreign HT9 tube. Further prototype FMS cladding tube is going to be manufactured in next year based on this experience. Various test items like mechanical test, sodium compatibility test, microstructural analysis, basic property, cladding performance under transient situation, and performance under ion and neutron irradiation are going be performed in the future to set up the relevant technology for the licensing of the SFR cladding tube

  15. Effects of HFIR irradiation at 550C on the microstructure and toughness of HT-9 and 9Cr-1Mo

    International Nuclear Information System (INIS)

    Gelles, D.S.; Hu, W.L.; Huang, F.H.; Johnson, G.D.

    1984-01-01

    Results are reported for base metal and weld metal specimens of HT-9 and Modified 9Cr-1Mo following irradiation in HFIR at 55 0 C to 5 dpa. The DBTT shifts in irradiated base metal specimens were 30 0 C for HT-9 and 90 0 C for 9Cr-1Mo with further shifts of 20 0 C for weld metal. Concurrently, strength as measured by hardness increased 15 percent for HT-9 and 25 percent for 9Cr-1Mo. The hardness increases can be attributed in part to defect clusters 1.5 to 3.0 nm in diameter at densities approaching 10 17 cm -3 and also to lower rates of cavity nucleation ahead of the propagating crack

  16. Experimental specifications for eutectic reaction between metallic fuel and HT-9

    International Nuclear Information System (INIS)

    Hwang, Woan; Nam, Cheol; Lee, Byoung Oon; Ryu, Woo Seog

    1998-10-01

    The chemical interaction between metallic fuel and cladding is important in designing the fuel pin of the KALIMER. When metal fuel and cladding are contacted, the elements in fuel and cladding are inter-diffuse each other, forming the reaction layers at interface. The reaction layers may cause two important factors in aspects of fuel pin integrity. Firstly, it degrades cladding strength by reducing effective cladding thickness. Secondly, these layers accelerate eutectic reaction at transient conditions. To evaluate these phenomena, the diffusion couple experiment is planned by using metal fuels with various zirconium contents and HT-9 steel. The U-Zr fuel alloys will be used for the experiment with the different zirconium contents, these are 8, 10 and 12 weight %. This experiment aims to evaluate the effects of zirconium content on the chemical reaction. Furthermore, the reaction rate and threshold temperature of the eutectic melting will be determined as a function of the zirconium content. This document describes the detail experimental specifications for the eutectic reaction such as test setup, test requirements and test procedure. (author). 10 refs

  17. Corrosion of martensitic steels in flowing 17Li83Pb alloy

    International Nuclear Information System (INIS)

    Flament, T.; Fauvet, P.; Hocde, B.; Sannier, J.

    1988-01-01

    Corrosion of three martensitic steels - 1.4914, HT9 and T91 - in the presence of flowing 17Li83Pb is investigated in thermal convection loops Tulip entirely made of 1.4914 steel. Two 3000-hour tests were performed at maximal temperatures of respectively 450 and 475 0 C with a δT of 60 0 C and an alloy velocity of about 0.08 m.s -1 . In both tests, corrosion is characterized by an homogeneous dissolution of the steel without formation of a corrosion layer. Corrosion rate is constant and very temperature dependent: the sound-metal loss of 1.4914 steel is 22 μm. year -1 at 450 0 C and 40 μm.year -1 at 475 0 C. Behaviours of 1.4914 and HT9 steels are very similar whereas T91 steel is about 20% less corroded

  18. Mechanical properties of irradiated 9Cr-2WVTa steel

    International Nuclear Information System (INIS)

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

    1998-01-01

    An Fe-9Cr-2W-0.25V-0.07Ta-0.1C (9Cr-2WVTa) steel has excellent strength and impact toughness before and after irradiation in the Fast Flux Test Facility and the High Flux Reactor (HFR). The ductile-brittle transition temperature (DBTT) increased only 32 C after 28 dpa at 365 C in FFTF, compared to a shift of ∼60 C for a 9Cr-2WV steel--the same as the 9Cr-2WVTa steel but without tantalum. This difference occurred despite the two steels having similar tensile but without tantalum. This difference occurred despite the two steels having similar tensile properties before and after irradiation. The 9Cr-2WVTa steel has a smaller prior-austenite grain size, but otherwise microstructures are similar before irradiation and show similar changes during irradiation. The irradiation behavior of the 9Cr-2WVTa steel differs from the 9Cr-2WV steel and other similar steels in two ways: (1) the shift in DBTT of the 9Cr-2WVTa steel irradiated in FFTF does not saturate with fluence by ∼28 dpa, whereas for the 9Cr-2WV steel and most similar steels, saturation occurs at <10 dpa, and (2) the shift in DBTT for 9Cr-2WVTa steel irradiated in FFTF and HFR increased with irradiation temperature, whereas it decreased for the 9Cr-2WV steel, as it does for most similar steels. The improved properties of the 9Cr-2WVTa steel and the differences with other steels were attributed to tantalum in solution

  19. Fractographic examination of HT-9 and 9Cr-1Mo Charpy specimens irradiated in the AD-2 test

    International Nuclear Information System (INIS)

    Gelles, D.S.; Hu, W.L.

    1983-01-01

    Fracture surface topologies have been examined using scanning electron microscopy for 20 selected half sized Charpy impact specimens of HT-9 and Modified 9Cr-1Mo in order to provide improved understanding of fracture toughness degradation as a result of irradiation for Path E alloys. The specimen matrix included unirradiated specimens and specimens irradiated in EBR-II in the AD-2 experiment. Also, hardness measurements have been made on selected irradiated Charpy specimens. The results of examinations indicate that irradiation hardening due to G-phase formation at 390 0 C is responsible for the large shift in ductile-to-brittle transition temperature (DBTT) found in HT-9. Toughness degradation in HT-9 observed following higher temperature irradiations is attributed to precipitation at delta ferrite stringers. Reductions in toughness as a consequence of irradiation in Modified 9Cr-1Mo are attributed to in-reactor precipitation of (V,Nb)C and M 23 C 6 . It is shown that crack propagation rates for ductile and brittle failure modes can be measured, that they differ by over an order of magnitude and that unexpected multiple shifts in fracture mode from ductile to brittle failure can be attributed to the effect of delta ferrite stringers on crack propagation rates

  20. Oxidation/volatilization rates in air for candidate fusion reactor blanket materials, PCA and HT-9

    International Nuclear Information System (INIS)

    Piet, S.J.; Kraus, H.G.; Neilson, R.M. Jr.; Jones, J.L.

    1986-01-01

    Large uncertainties exist in the quantity of neutron-induced activation products that can be mobilized in potential fusion accidents. The accidental combination of high temperatures and oxidizing conditions might lead to mobilization of a significant amount of activation products from structural materials. Here, the volatilization of constituents of PCA and HT-9 resulting from oxidation in air was investigated. Tests were conducted in flowing air at temperatures from 600 to 1300 0 C for 1, 5, or 20 h. Elemental volatility was calculated in terms of the weight fraction of the element volatilized from the initial alloy. Molybdenum and manganese were the radiologically significant primary constituents most volatilizized, suggesting that molybdenum and manganese should be minimized in fusion steel compositions. Higher chromium content appears beneficial in reducing hazards from mobile activation products. Scanning electron microscopy and energy dispersive spectroscopy were used to study the oxide layer on samples. (orig.)

  1. Oxidation/volatilization rates in air for candidate fusion reactor blanket materials, PCA and HT-9

    International Nuclear Information System (INIS)

    Piet, S.J.; Kraus, H.G.; Neilson, R.M. Jr.; Jones, J.L.

    1986-01-01

    Large uncertainties exist in the quantity of neutron-induced activation products that can be mobilized in potential fusion accidents. The accidental combination of high temperatures and oxidizing conditions might lead to mobilization of a significant amount of activation products from structural materials. Here, the volatilization of constituents of PCA and HT-9 resulting from oxidation in air was investigated. Tests were conducted in flowing air at temperatures from 600 to 1300 0 C for 1, 5, or 20 hours. Elemental volatility was calculated in terms of the weight fraction of the element volatilized from the initial alloy. Molybdenum and manganese were the radiologically significant primary constituents most volatilized, suggesting that molybdenum and manganese should be minimized in fusion steel compositions. Higher chromium content appears beneficial in reducing hazards from mobile activation products. Scanning electron microscopy and energy dispersive spectroscopy were used to study the oxide layer on samples

  2. Substitution of modified 9 Cr-1 Mo steel for austentic stainless steels

    International Nuclear Information System (INIS)

    Sikka, V.K.

    1982-04-01

    This report describes the current program to develop a high-strength ferritic-martensitic steel. The alloy is essentially Fe-9% Cr-1% Mo with small additions of V and Nb and is known as modifed 9 Cr-1 Mo steel. Its elevated-temperature properties and design allowable stresses match those of type 304 stainless steel for temperatures up to 600 0 C and exceed those of other ferritic steels by factors of 2 to 3. The improved strength of this alloy permits its use in place of stainless steels for many applications

  3. Friction Stir Welding of HT9 Ferritic-Martensitic Steel: An Assessment of Microstructure and Properties

    Science.gov (United States)

    2013-06-01

    report of FSW on a ferritic- martensitic stainless steel is the work of Chung, which applied this approach to a dissimilar weld between F82H (ferritic... martensitic ) and SUS304 (austenitic stainless ) [43]. 7 D. CORROSION OF FERRITIC/ MARTENSITIC STEELS IN HIGH TEMPERATURE MOLTEN SALT COOLANTS In...Philadelphia, PA, 1992, pp. 1267–1286, March 1990. [15] S. Rosenwasser, ―The application of martensitic stainless steels in a lifelong fusion first wall

  4. Irradiation experience with HT9-clad metallic fuel

    International Nuclear Information System (INIS)

    Pahl, R.G.; Lahm, C.E.; Tsai, H.; Billone, M.C.

    1991-01-01

    The safe and reliable performance of metallic fuel is currently under study and demonstration in the Integral Fast Reactor program. In-reactor tests of HT9-clad metallic fuel have now reached maturity and have all shown good performance characteristics to burnups exceeding 17.5 at. % in the lead assembly. Because this low-swelling tempered martensitic alloy is the cladding of choice for high fluence applications, the experimental observations and performance modelling efforts reported in this paper play an important role in demonstrating reliability

  5. Synergies Between ' and Cavity Formation in HT-9 Following High Dose Neutron Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Parish, Chad M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Saleh, Tarik A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Eftink, Benjamin P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-06-01

    Candidate cladding materials for advanced nuclear power reactors including fast reactor designs require materials capable of withstanding high dose neutron irradiation at elevated temperatures. One candidate material, HT-9, through various research programs have demonstrated the ability to withstand significant swelling and other radiation-induced degradation mechanisms in the high dose regime (>50 displacements per atom, dpa) at elevated temperatures (>300 C). Here, high efficiency multi-dimensional scanning transmission electron microscopy (STEM) acquisition with the aid of a three-dimensional (3D) reconstruction and modeling technique is used to probe the microstructural features that contribute to the exceptional swelling resistance of HT-9. In particular, the synergies between ' and fine-scale and moderate-scale cavity formation is investigated.

  6. Long-term Stability of 9- to 12 % Cr Steels

    DEFF Research Database (Denmark)

    Hald, John

    2004-01-01

    In the recent 25 years creep rupture strength of 9- to 12 %Cr steels for steam pipes and turbines has been doubled by development of new alloys. This development has formed a basis for improved efficiency of fossil fired steam power plants by introduction of advanced steam temperatures...... and pressures. Newly developed steam pipe steels are based on modifications of well-established steels like the X 20CrMoV12 1. Balanced addition of V, Nb and N to a 9Cr 1 Mo steel led to the Modified 9 Cr steel P 91. Addition of 1% W to a 9Cr 1 MoVNbN base composition led to steel E 911 and partial replacement...... of Mo with 1.8 % W combined with a slight amount of Boron led to steel P 92. The creep rupture strength of these new alloys are now secured with long-term tests up to 100,000 hours, which demonstrate improvements of 50% (P 91), 75 % (E 911) and 100 % (P 92) in strength compared to X 20CrMoV12 1....

  7. Evaluation of Microstructural and Mechanical Property of Medium-sized HT9 Cladding Forged Material for Sodium-cooled Fast Reactor

    International Nuclear Information System (INIS)

    Kim, Jun Hwan; Lee, Kang Soo; Kim, Sung Ho; Lee, Chan Bock

    2012-01-01

    Microstructural and mechanical property were evaluated at the medium-sized HT9 (12Cr-1MoWV) forged steel which was considered as primary candidate for the fuel cladding in sodium-cooled fast reactor (SFR). Material was forged at 1170 degrees C after the induction melting to make round bar as 160 mm diameter, 7000 mm length then the radial distribution of microstructure as well as microhardness was evaluated. The results showed that overall microstructure exhibited as ferrite-martensite structure, where small amount (2-3%) of delta ferrite was formed throughout the specimen and maximum 15% of transformed ferrite was formed at the center, where it gradually decreased toward the radial direction. Sensitivity analysis of the cooling curve and Time-Temperature-Transformation (TTT) diagram revealed that formation of transformed ferrite could be avoided when the diameter was decreased down to 120 mm.

  8. Z-phase in 9-12% Cr Steels

    DEFF Research Database (Denmark)

    Danielsen, Hilmar; Hald, John

    2004-01-01

    The complex nitride Z-phase, Cr(V,Nb)N, has recently been identified as a major cause for premature breakdown in creep strength of a number of new 9-12%Cr martensitic steels. A thermodynamic model of the Z-phase has been created based on the Thermo-Calc software. The model predicts the Z-phase to......The complex nitride Z-phase, Cr(V,Nb)N, has recently been identified as a major cause for premature breakdown in creep strength of a number of new 9-12%Cr martensitic steels. A thermodynamic model of the Z-phase has been created based on the Thermo-Calc software. The model predicts the Z......-phase to be stable in all of the new 9-12%Cr martensitic steels. This has generally been confirmed by the performed experiments. Z-phase precipitation seems to be a kinetic problem, and drivning force calculations using Thermo-Calc with the developed model have been used to predict steel compositions, which...

  9. Postirradiation fracture toughness tests of ESR alloy HT-9 and modified 9Cr-1Mo alloy from UBR reactor experiments

    International Nuclear Information System (INIS)

    Hawthorne, J.R.; Reed, J.R.; Sprague, J.A.

    1984-01-01

    Alloy HT-9 and Modified 9Cr-1Mo are being evaluated for potential applications as first wall materials in magnetic fusion reactors. Objectives of the current research task were to test fatigue-precracked Charpy-V (PCC/sub v/) specimens from representative plates irradiated in the UBR reactor at 149 0 C or 300 0 C, and, to compare the results against postirradiation notch ductility data developed previously for the materials. Both plates represent electroslag refined (ESR) melt processing. PCC/sub v/ specimens of Alloy HT-9 and Modified 9Cr-1Mo alloy were irradiated at 300 0 C and 149 0 C, respectively, to approx.0.8 X 10 20 n/cm 2 , E > 0.1 MeV. During this period, postirradiation tests for fracture toughness were completed and results compared to notch ductility determinations from standard Charpy-V (C/sub v/) specimens irradiated in the same reactor experiments. Fracture surface examinations by SEM are also reported

  10. 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

  11. Irradiation proposition of ferritic steels in a russian reactor

    International Nuclear Information System (INIS)

    Seran, J.L.; Decours, J.; Levy, L.

    1987-04-01

    Using the low temperatures of russian reactors, a sample irradiation is proposed to study mechanical properties and swelling of martensitic steels (EM10, T91, 1.4914, HT9), ferrito-martensitic (EM12) and ferritic (F17), at temperatures lower than 400 0 C [fr

  12. 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

  13. Behaviour of Z phase in 9–12%Cr steels

    DEFF Research Database (Denmark)

    Danielsen, Hilmar Kjartansson; Hald, John

    2006-01-01

    The literature on the behaviour of modified Z phase Cr(V,Nb)N in creep resistant martensitic 9–12%Cr steels is briefly reviewed. Ten different 9–12%Cr steels were investigated after prolonged exposure at 600–660uC; the modified Z phase was found in all of them. In steels with high Cr content (11......–12%), Z phase precipitates much faster than in 9%Cr steels. Precipitation of Z phase is associated with dissolution of MX carbonitrides, and causes a breakdown in long term creep strength in 9–12%Cr steels. High Cr steels show creep instabilities accompanied with Z phase precipitation, whereas low Cr...... steels show good long term creep stability. A niobium free CrVN variant of the modified Z phase was observed for the first time during the course of this work. The solution temperature of the Cr(V,Nb)N and CrVN modified Z phases was found to be close to 800uC for 11–12%Cr steels, much lower than the 1200...

  14. 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

  15. Time-temperature characteristics of the various heat-affected zones in HT-9 weldments

    International Nuclear Information System (INIS)

    Foulds, J.R.

    1984-01-01

    Temperatures at different distances from the fusion boundary were measured during GTA weld depositing MTS-4 filler wire on 9.52-mm (3/8 in.) thick HT-9 plate. Peak temperature measurements indicate each of the heat-affected regions to be austenitized. An exponential expression has been used to describe the cooling curves as a function of peak temperature (or distance) from the fusion boundary

  16. TEM observations of HT-9 as-welded weldment microstructures

    International Nuclear Information System (INIS)

    Foulds, J.R.; Lechtenberg, T.A.

    1984-01-01

    TEM studies of different locations in an HT-9 weldment indicated delta-ferrite (delta) occurrence, M 23 C 6 precipitation at delta-martensite interfaces, fine carbide precipitation at prior austenite grain boundaries, and martensite lath and lath packet size to be the distinguishable microstructure features observed. Furthermore, retained austenite films were observed in the weld metal and the HAZ adjacent to the weld metal that reached the highest temperature during joining. The microstructures correlate well with the observed room temperature microhardness except for the fusion boundary in weld metal which exhibited a hardness drop and an unexpected minimum amount of delta-ferrite

  17. Microstructural stability of 21-6-9 stainless steel

    International Nuclear Information System (INIS)

    Krenzer, R.W.; Sanderson, E.C.

    1978-01-01

    Two experiments were designed to better define parameters for thermomechanical processing of 21-6-9 stainless steel. This steel is one of the nitrogen-strengthened chromium, manganese, and nickel austenitic stainless steels having mechanical properties that can be improved by a combination of plastic deformation and heat treatments. By heat-treating coupons, the time-temperature relationship of the precipitate phase, and the solutionizing, recrystallizing, and stress-relieving temperature ranges in 21-6-9 were established. Secondly, mechanical properties and microstructure as a function of percent deformation and stress-relieving temperature are reported

  18. 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.

  19. Eutectic reaction analysis between TRU-50%Zr alloy fuel and HT-9 cladding, and temperature prediction of eutectic reaction under steady-state

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Woan; Lee, Byoung Oon; Lee, Bong Sang; Park, Won Seok

    2001-02-01

    Blanket fuel assembly for HYPER contains a bundle of pins arrayed in triangular pitch, which has hexagonal bundle structure. The reference blanket fuel pin consists of the fuel slug of TRU-50wt%Zr alloy and the cladding material of ferritic martensite steel, HT-9. Chemical interaction between fuel slug and cladding is one of the major concerns in metallic fuel rod design. The contact of metallic fuel slug and stainless steel cladding in a fuel rod forms a complex multi-component diffusion couple at elevated temperatures. The potential problem of inter-diffusion of fuel and cladding components is essentially two-fold weakening of cladding mechanical strength due to the formation of diffusion zones in the cladding, and the formation of comparatively low melting point phases in the fuel/cladding interface to develop eutectic reaction. The main components of fuel slug are composed of zirconium alloying element in plutonium matrix, including neptunium, americium and uranium additionally. Therefore basic eutectic reaction change of Pu-Fe binary system can be assessed, while it is estimated how much other elements zirconium, uranium, americium and neptunium influence on plutonium phase stability. Afterwards it is needed that eutectic reaction is verified through experimental necessarily.

  20. Eutectic reaction analysis between TRU-50%Zr alloy fuel and HT-9 cladding, and temperature prediction of eutectic reaction under steady-state

    International Nuclear Information System (INIS)

    Hwang, Woan; Lee, Byoung Oon; Lee, Bong Sang; Park, Won Seok

    2001-02-01

    Blanket fuel assembly for HYPER contains a bundle of pins arrayed in triangular pitch, which has hexagonal bundle structure. The reference blanket fuel pin consists of the fuel slug of TRU-50wt%Zr alloy and the cladding material of ferritic martensite steel, HT-9. Chemical interaction between fuel slug and cladding is one of the major concerns in metallic fuel rod design. The contact of metallic fuel slug and stainless steel cladding in a fuel rod forms a complex multi-component diffusion couple at elevated temperatures. The potential problem of inter-diffusion of fuel and cladding components is essentially two-fold weakening of cladding mechanical strength due to the formation of diffusion zones in the cladding, and the formation of comparatively low melting point phases in the fuel/cladding interface to develop eutectic reaction. The main components of fuel slug are composed of zirconium alloying element in plutonium matrix, including neptunium, americium and uranium additionally. Therefore basic eutectic reaction change of Pu-Fe binary system can be assessed, while it is estimated how much other elements zirconium, uranium, americium and neptunium influence on plutonium phase stability. Afterwards it is needed that eutectic reaction is verified through experimental necessarily

  1. 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.)

  2. Creep constitutive equation of dual phase 9Cr-ODS steel

    International Nuclear Information System (INIS)

    Sakasegawa, Hideo; Ukai, Shigeharu; Tamura, Manabu; Ohtsuka, Satoshi; Tanigawa, Hiroyasu; Ogiwara, Hiroyuki; Kohyama, Akira; Fujiwara, Masayuki

    2008-01-01

    9Cr-ODS (oxide dispersion strengthened) steels developed by JAEA (Japan Atomic Energy Agency) have superior creep properties compared with conventional heat resistant steels. The ODS steels can enormously contribute to practical applications of fast breeder reactors and more attractive fusion reactors. Key issues are developments of material processing procedures for mass production and creep life prediction methods in present R and D. In this study, formulation of creep constitutive equation was performed against the backdrop. The 9Cr-ODS steel displaying an excellent creep property is a dual phase steel. The ODS steel is strengthened by the δ ferrite which has a finer dispersion of oxide particles and shows a higher hardness than the α' martensite. The δ ferrite functions as a reinforcement in the dual phase 9Cr-ODS steel. Its creep behavior is very unique and cannot be interpreted by conventional theories of heat resistant steels. Alternative qualitative model of creep mechanism was formulated at the start of this study using the results of microstructural observations. Based on the alternative creep mechanism model, a novel creep constitutive equation was formulated using the exponential type creep equation extended by a law of mixture

  3. Plasma discharge in ferritic first wall vacuum vessel of the Hitachi Tokamak HT-2

    International Nuclear Information System (INIS)

    Abe, Mitsushi; Nakayama, Takeshi; Asano, Katsuhiko; Otsuka, Michio

    1997-01-01

    A tokamak discharge with ferritic material first wall was tried successfully. The Hitachi Tokamak HT-2 had a stainless steel SUS304 vacuum vessel and modified to have a ferritic plate first wall for experiments to investigate the possibility of ferritic material usage in magnetic fusion devices. The achieved vacuum pressure and times used for discharge cleaning was roughly identical with the stainless steel first wall or the original HT-2. We concluded that ferritic material vacuum vessel is possible for tokamaks. (author)

  4. Comparison of the mechanical strength properties of several high-chromium ferritic steels

    International Nuclear Information System (INIS)

    Booker, M.K.; Sikka, V.K.; Booker, B.L.P.

    1981-01-01

    A modified 9 Cr-1 Mo ferritic steel has been selected as an alternative material for breeder reactors. Different 9 Cr-1 Mo steels are already being used commercially in UK and USA and a 9 Cr-2 Mo steel (EM12) is being used commercially in France. The 12% Cr steel alloy HT9 is also often recommended for high-temperature service. Creep-rupture data for all six seels were analyzed to yield rupture life as a function of stress, temperature, and lot-to-lot variations. Yield and tensile strength data for the three 9 Cr-1 Mo materials were also examined. All results were compared with Type 304 stainless steel, and the tensile and creep properties of the modified and British 9 Cr-1 Mo materials were used to calculate allowable stress values S 0 per Section VIII, Division 1 and S/sub m/ per code Case N-47 to section III of the ASME Boiler and Pressure Vessel Code. these values were compared with code listings for American commercial 9 Cr-1 Mo steel, 2 1/4 Cr-1 Mo steel, and Type 304 stainless steel. The conclusion is made that the modified 9 Cr-1 Mo steel displays tensile and creep strengths superior to those of the other ferritic materials examined and is at least comparable to Type 304 stainless steel from room temperature to about 625 0 C. 31 figures

  5. Strength and rupture-life transitions caused by secondary carbide precipitation in HT-9 during high-temperature low-rate mechanical testing

    International Nuclear Information System (INIS)

    DiMelfi, R.J.; Gruber, E.E.; Kramer, J.M.; Hughes, T.H.

    1992-01-01

    The martensitic-ferritic alloy HT-9 is slated for long-term use as a fuel-cladding material in the Integral Fast Reactor. Analysis of published high-temperature mechanical property data suggests that secondary carbide precipitation would occur during service life causing substantial strengthening of the as-heat-treated material. Aspects of the kinetics of this precipitation process are extracted from calculations of the back stress necessary to produce the observed strengthening effect under various creep loading conditions. The resulting Arrhenius factor is shown to agree quantitatively with shifts to higher strength of crept material in reference to the intrinsic strength of HT-9. The results of very low constant strain-rate high-temperature tensile tests on as-heat-treated HT-9 that focus on the transition in strength with precipitation will be presented and related to rupture-life

  6. Structure and Properties of Burnished and Nitrided AISI D2 Tool Steel

    Directory of Open Access Journals (Sweden)

    Daniel TOBOŁA

    2015-11-01

    Full Text Available D2 belongs to traditional steels, frequently used in metalworking industry. Shot peening and nitriding are known to improve the wear resistance of D2. In this work we focus on processes of slide burnishing and industrial low temperature gas nitriding. The D2 steel specimens were first subjected to heat treatments (HT prescribed by the manufacturer, turning (T, then burnishing (B and nitriding (N. The reason for turning was achieving appropriate surface roughness. Deformation induced in slide burnishing can be better controlled then in shot peening because of deterministic nature of this process. Four different paths to prepare surfaces were employed: HT + T, HT + T + B, HT + T + N, HT + T + B + N. D2 steel is very sensitive to the final finishing, wear rates vary up to 300 %. Two of our procedures (HT + T + N and HT + T + B + N are much superior to the others. Moreover, in the HT + T + N case, apparently the surface fatigue scaling off takes place.DOI: http://dx.doi.org/10.5755/j01.ms.21.4.7224

  7. 5-HT causes splanchnic venodilation.

    Science.gov (United States)

    Seitz, Bridget M; Orer, Hakan S; Krieger-Burke, Teresa; Darios, Emma S; Thompson, Janice M; Fink, Gregory D; Watts, Stephanie W

    2017-09-01

    Serotonin [5-hydroxytryptamine (5-HT)] causes relaxation of the isolated superior mesenteric vein, a splanchnic blood vessel, through activation of the 5-HT 7 receptor. As part of studies designed to identify the mechanism(s) through which chronic (≥24 h) infusion of 5-HT lowers blood pressure, we tested the hypothesis that 5-HT causes in vitro and in vivo splanchnic venodilation that is 5-HT 7 receptor dependent. In tissue baths for measurement of isometric contraction, the portal vein and abdominal inferior vena cava relaxed to 5-HT and the 5-HT 1/7 receptor agonist 5-carboxamidotryptamine; relaxation was abolished by the 5-HT 7 receptor antagonist SB-269970. Western blot analyses showed that the abdominal inferior vena cava and portal vein express 5-HT 7 receptor protein. In contrast, the thoracic vena cava, outside the splanchnic circulation, did not relax to serotonergic agonists and exhibited minimal expression of the 5-HT 7 receptor. Male Sprague-Dawley rats with chronically implanted radiotelemetry transmitters underwent repeated ultrasound imaging of abdominal vessels. After baseline imaging, minipumps containing vehicle (saline) or 5-HT (25 μg·kg -1 ·min -1 ) were implanted. Twenty-four hours later, venous diameters were increased in rats with 5-HT-infusion (percent increase from baseline: superior mesenteric vein, 17.5 ± 1.9; portal vein, 17.7 ± 1.8; and abdominal inferior vena cava, 46.9 ± 8.0) while arterial pressure was decreased (~13 mmHg). Measures returned to baseline after infusion termination. In a separate group of animals, treatment with SB-269970 (3 mg/kg iv) prevented the splanchnic venodilation and fall in blood pressure during 24 h of 5-HT infusion. Thus, 5-HT causes 5-HT 7 receptor-dependent splanchnic venous dilation associated with a fall in blood pressure. NEW & NOTEWORTHY This research is noteworthy because it combines and links, through the 5-HT 7 receptor, an in vitro observation (venorelaxation) with in vivo events

  8. Characterization of neutron-irradiated HT-UPS steel by high-energy X-ray diffraction microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xuan, E-mail: xuanzhang@anl.gov [Nuclear Engineering Division, Argonne National Laboratory, Lemont, IL 60439 (United States); Park, Jun-Sang; Almer, Jonathan [Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439 (United States); Li, Meimei [Nuclear Engineering Division, Argonne National Laboratory, Lemont, IL 60439 (United States)

    2016-04-01

    This paper presents the first measurement of neutron-irradiated microstructure using far-field high-energy X-ray diffraction microscopy (FF-HEDM) in a high-temperature ultrafine-precipitate-strengthened (HT-UPS) austenitic stainless steel. Grain center of mass, grain size distribution, crystallographic orientation (texture), diffraction spot broadening and lattice constant distributions of individual grains were obtained for samples in three different conditions: non-irradiated, neutron-irradiated (3dpa/500 °C), and irradiated + annealed (3dpa/500 °C + 600 °C/1 h). It was found that irradiation caused significant increase in grain-level diffraction spot broadening, modified the texture, reduced the grain-averaged lattice constant, but had nearly no effect on the average grain size and grain size distribution, as well as the grain size-dependent lattice constant variations. Post-irradiation annealing largely reversed the irradiation effects on texture and average lattice constant, but inadequately restored the microstrain.

  9. Evaluation of temper embrittlement of martensitic and ferritic-martensitic steels by acoustic emission

    International Nuclear Information System (INIS)

    Lu, Yusho; Takahashi, Hideaki; Shoji, Tetsuo

    1987-01-01

    Martensitic (HT-9) and ferritic-martensitic steels (9Cr-2Mo) are considered as fusion first wall materials. In this investigation in order to understand the sensitivity of temper embrittlement in these steels under actual service condition, fracture toughness testing was made by use of acoustic emission technique. The temper embrittlement was characterized in terms of fracture toughness. The fracture toughness of these steels under 500 deg C, 100 hrs, and 1000 hrs heat treatment was decreased and their changes in micro-fracture process have been observed. The fracture toughness changes by temper embrittlement was discussed by the characteristic of AE, AE spectrum analysis and fractographic investigation. The relation between micro-fracture processes and AE has been clarified. (author)

  10. Steamside Oxidation Behavior of Experimental 9%Cr Steels

    Energy Technology Data Exchange (ETDEWEB)

    Dogan, O.N.; Holcomb, G.R.; Alman, D.E.; Jablonski, P.D.

    2007-10-01

    Reducing emissions and increasing economic competitiveness require more efficient steam power plants that utilize fossil fuels. One of the major challenges in designing these plants is the availability of materials that can stand the supercritical and ultra-supercritical steam conditions at a competitive cost. There are several programs around the world developing new ferritic and austenitic steels for superheater and reheater tubes exposed to the advanced steam conditions. The new steels must possess properties better than current steels in terms of creep strength, steamside oxidation resistance, fireside corrosion resistance, and thermal fatigue resistance. This paper introduces a series of experimental 9%Cr steels containing Cu, Co, and Ti. Stability of the phases in the new steels is discussed and compared to the phases in the commercially available materials. The steels were tested under both the dry and moist conditions at 650ºC for their cyclical oxidation resistance. Results of oxidation tests are presented. Under the moist conditions, the experimental steels exhibited significantly less mass gain compared to the commercial P91 steel. Microstructural characterization of the scale revealed different oxide compositions.

  11. Electrochemical studies of novel corrosion inhibitor for mild steel in 1 M hydrochloric acid

    Directory of Open Access Journals (Sweden)

    Ahmed A. Al-Amiery

    2018-06-01

    Full Text Available The electrochemical performance of a novel organic corrosion inhibitor 6-(4-hydroxyphenyl-3-mercapto-7,8-dihydro-[1,2,4]triazolo[4,3-b][1,2,4,5]tetrazine [HT3], for mild steel in 1 M hydrochloric acid is evaluated by potentiodynamic curves. The experimental results show that the investigated inhibitor [HT3], which can effectively retard the corrosion process that occurs to mild steel with a hydrochloric acid solution by providing a protective coating for the mild steel that, can be weakened by increasing the temperature. Furthermore, the inhibition efficiency of [HT3] increased with increasing the concentrations of the inhibitors and decreased with increasing temperature. Keywords: Corrosion, Inhibitor, Mild steel, Potentiodynamic polarization, HT3, NMR, FT-IR

  12. Postirradiation notch ductility tests of ESR alloy HT-9 and modified 9Cr-1Mo alloy from UBR reactor experiments

    International Nuclear Information System (INIS)

    Hawthorne, J.R.

    1984-01-01

    During this period, irradiation exposures at 300 0 C and 150 0 C to approx. 8 x 10 19 n/cm 2 , E > 0.1 MeV, were completed for the Alloy HT-9 plate and the modified Alloy 9Cr-1Mo plates, respectively. Postirradiation tests of Charpy-V (C/sub v/) specimens were completed for both alloys; other specimen types included in the reactor assemblies were fatigue precracked Charpy-V (PCC/sub v/), half-size Charpy-V, and in the case of the modified 9Cr-1Mo, 2.54 mm thick compact tension specimens

  13. Heat-to-heat variability of irradiation creep and swelling of HT9 irradiated to high neutron fluence at 400-600{degrees}C

    Energy Technology Data Exchange (ETDEWEB)

    Toloczko, M.B.; Garner, F.A. [Pacific Northwest National Lab., Richland, WA (United States)

    1996-10-01

    Irradiation creep data on ferritic/martensitic steels are difficult and expensive to obtain, and are not available for fusion-relevant neutron spectra and displacement rates. Therefore, an extensive creep data rescue and analysis effort is in progress to characterize irradiation creep of ferritic/martensitic alloys in other reactors and to develop a methodology for applying it to fusion applications. In the current study, four tube sets constructed from three nominally similar heats of HT9 subjected to one of two heat treatments were constructed as helium-pressurized creep tubes and irradiated in FFTF-MOTA at four temperatures between 400 and 600{degrees}C. Each of the four heats exhibited a different stress-free swelling behavior at 400{degrees}C, with the creep rate following the swelling according to the familiar B{sub o} + DS creep law. No stress-free swelling was observed at the other three irradiation temperatures. Using a stress exponent of n = 1.0 as the defining criterion, {open_quotes}classic{close_quotes} irradiation creep was found at all temperatures, but, only over limited stress ranges that decreased with increasing temperature. The creep coefficient B{sub o} is a little lower ({approx}50%) than that observed for austenitic steel, but the swelling-creep coupling coefficient D is comparable to that of austenitic steels. Primary transient creep behavior was also observed at all temperatures except 400{degrees}C, and thermal creep behavior was found to dominate the deformation at high stress levels at 550 and 600{degrees}C.

  14. Enhancement of cortical extracellular 5-HT by 5-HT1A and 5-HT2C receptor blockade restores the antidepressant-like effect of citalopram in non-responder mice.

    Science.gov (United States)

    Calcagno, Eleonora; Guzzetti, Sara; Canetta, Alessandro; Fracasso, Claudia; Caccia, Silvio; Cervo, Luigi; Invernizzi, Roberto W

    2009-07-01

    We recently found that the response of DBA/2 mice to SSRIs in the forced swim test (FST) was impaired and they also had a smaller basal and citalopram-stimulated increase in brain extracellular serotonin (5-HT) than 'responder' strains. We employed intracerebral microdialysis, FST and selective antagonists of 5-HT1A and 5-HT2C receptors to investigate whether enhancing the increase in extracellular 5-HT reinstated the anti-immobility effect of citalopram in the FST. WAY 100635 (0.3 mg/kg s.c.) or SB 242084 (1 mg/kg s.c.), respectively a selective 5-HT1A and 5-HT2C receptor antagonist, raised the effect of citalopram (5 mg/kg) on extracellular 5-HT in the medial prefrontal cortex of DBA/2N mice (citalopram alone 5.2+/-0.3 fmol/20 microl, WAY 100635+citalopram 9.9+/-2.1 fmol/20 microl, SB 242084+ citalopram 7.6+/-1.0 fmol/20 microl) to the level reached in 'responder' mice given citalopram alone. The 5-HT receptor antagonists had no effect on the citalopram-induced increase in extracellular 5-HT in the dorsal hippocampus. The combination of citalopram with WAY 100635 or SB 242084 significantly reduced immobility time in DBA/2N mice that otherwise did not respond to either drug singly. Brain levels of citalopram in mice given citalopram alone or with 5-HT antagonists did not significantly differ. The results confirm that impaired 5-HT transmission accounts for the lack of effect of citalopram in the FST and suggest that enhancing the effect of SSRIs on extracellular 5-HT, through selective blockade of 5-HT1A and 5-HT2C receptors, could be a useful strategy to restore the response in treatment-resistant depression.

  15. 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.

  16. 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.))

  17. Evaluation of toughness degradation by small punch (SP) tests for neutron irradiated structural steels

    International Nuclear Information System (INIS)

    Misawa, Toshihei; Hamaguchi, Yoshikazu; Kimura, Akihiko; Eto, Motokuni; Suzuki, Masahide; Nakajima, Nobuya.

    1992-01-01

    The small punch (SP) test as one of the useful small specimen testing technique (SSTT) has been developed to evaluate the fracture toughness, ductile-brittle transition temperature (DBTT) and tensile properties for neutron irradiated structural materials. The SP tests using the miniaturized specimens of φ3 mm TEM disk and 10 mm 2 coupon were performed for six kinds of ferritic steels of F-82, F-82H, HT-9, JFMS, 2.25-1Mo and SQV2A. It was shown that the temperature dependence of SP fracture energies with scatter in miniaturized testing can give reliable information on the DBTT by use of the statistical analysis based on the Weibull distribution. A good correlation between the DBTT of the SP tests and that of the standard CVN test has been obtained for the various nuclear ferritic steels. The SP test was performed for cryogenic austenitic steels as a way of evaluating elastic-plastic fracture toughness, J IC , on the basis of a universal empirical relationship between J IC and SP equivalent fracture strain, ε-bar qf . The SP testing using the neutron irradiated specimens of 2.25Cr-1Mo, F-82, F-82H and HT-9 steels was successfully applied and presented the neutron radiation induced changes on the DBTT, fracture toughness and tensile properties. (author)

  18. Microstructure of a high boron 9-12% chromium steel

    Energy Technology Data Exchange (ETDEWEB)

    Andren, H.O. [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Applied Physics

    2008-07-01

    Additions of small amounts of boron (10-100 ppm) to 9-12% chromium steels are often made since they have been found to be beneficial for the creep strength up to and above 600 C. The effect of boron is to restrict the coarsening of M{sub 23}C{sub 6} precipitates during service. It was found that increasing the boron content from 9 to 40 ppm gave a decrease in coarsening constant at 600 C by a factor of 2. The present understanding of boron solution, non-equilibrium grain boundary segregation, incorporation into M{sub 23}C{sub 6}, and diffusion is reviewed in the paper. A very high boron addition (300 ppm) was made in the trial TAF steel already in the 1950'ies. The microstructure of a similar trial steel, FT3B, has been studied detail. In this steel large Mo, Cr, Fe and V containing metal borides are formed rather than the expected BN, with the crystal structure M{sub 2}B{sub 2}. Nitrogen is therefore still available for the formation of VN. Due to tempering at a low temperature (690 C) to a high strength (830 MPa), this steel contained a dense distribution of very small VN precipitates, 5-15 nm in size. A similar VN distribution is probably the cause of the still unsurpassed creep strength of the TAF steel. (orig.)

  19. Microstructural comparison of HT-9 irradiated in HFIR and EBR-II

    International Nuclear Information System (INIS)

    Gelles, D.S.

    1985-05-01

    A series of specimens of HT-9 heat 91354 have been examined following irradiation in HFIR to 39 dpa at 300, 400, 500 and 600 0 C and following irradiation in EBR-II to 29 dpa at 390 and 500 0 C. HFIR irradiation was found to have promoted helium bubble formation at all temperatures and voids at 400 0 C. Cavitation had not been observed at lower fluence, nor was it found in EBR-II irradiated specimens. The onset of void swelling in HFIR is attributed to helium generation. The observations provide an explanation for saturation of ductile-brittle transition temperature shifts with increasing fluence

  20. Fundamental modelling of particle strengthened 9-12% Cr steels

    Energy Technology Data Exchange (ETDEWEB)

    Magnusson, Hans; Sandstroem, Rolf [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Materials Science and Engineering; Royal Inst. of Tech., Stockholm (Sweden). Brinell Centre

    2010-07-01

    Creep strength of particle strengthened 9-12% Cr steels can be predicted by fundamental modelling. The creep strength is evaluated from the state of the microstructure during creep. Particle hardening at high temperatures can be predicted by taking dislocation climb across particles into account. Work hardening is calculated from immobile dislocations in subgrain interiors and at boundaries using the composite theory. Subgrain coarsening will lower the influence of the mechanically hard boundaries. Recovery in dislocation density is predicted through static recovery by climb and dynamic recovery by locking and dipole formation. Solid solution hardening is needed in order to explain the difference in creep strength between different 9-12% Cr steels. The accumulation of large atoms such as Mo and W will slow down the dislocation climb velocity, and thereby the microstructure recovery rate. 100000h rupture strength is predicted for X20, P91, P92 steels without any use of fitting parameters. The creep strength of P91 steel with different microstructure due to Al additions. Z-phase transformation and heat affected material is presented. (orig.)

  1. Damage development in 9%Cr steels

    International Nuclear Information System (INIS)

    Rauch, M.; Maile, K.

    2003-01-01

    Modern 9-11% martensitic steels are candidate materials to be used in modern fossil fired power plants with high efficiency rates. The focus of the R and D work is put on the further development and optimisation, the determination of material characteristics but also on the identification and quantification of damage mechanisms and the damage evolution. For this purpose extensive experiments such as long creep tests on specimens under internal pressure, metallurgical examinations and theoretical investigations for determination of stress-strain state which have been conducted. The laboratory tests are completed by examination of real components. As a result an empirical description of the creep cavity density as a function of deformation and multiaxiality of stress state has been carried out which can be used in further FE-calculations determining the damage state. The results of all metallographical examinations on specimens with different heat treatments and service loads are summarised in a structure atlas and are published for further usage. Damage development, martensitic 9 % Cr steels, creep cavity density, creep tests under multiaxial load, metallographical investigations, and measurements on pipe bends. (author)

  2. Elevated-Temperature Ferritic and Martensitic Steels and Their Application to Future Nuclear Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Klueh, RL

    2005-01-31

    In the 1970s, high-chromium (9-12% Cr) ferritic/martensitic steels became candidates for elevated-temperature applications in the core of fast reactors. Steels developed for conventional power plants, such as Sandvik HT9, a nominally Fe-12Cr-1Mo-0.5W-0.5Ni-0.25V-0.2C steel (composition in wt %), were considered in the United States, Europe, and Japan. Now, a new generation of fission reactors is in the planning stage, and ferritic, bainitic, and martensitic steels are again candidates for in-core and out-of-core applications. Since the 1970s, advances have been made in developing steels with 2-12% Cr for conventional power plants that are significant improvements over steels originally considered. This paper will review the development of the new steels to illustrate the advantages they offer for the new reactor concepts. Elevated-temperature mechanical properties will be emphasized. Effects of alloying additions on long-time thermal exposure with and without stress (creep) will be examined. Information on neutron radiation effects will be discussed as it applies to ferritic and martensitic steels.

  3. Elevated temperature tensile properties of P9 steel towards ferritic steel wrapper development for sodium cooled fast reactors

    Energy Technology Data Exchange (ETDEWEB)

    Choudhary, B.K., E-mail: bkc@igcar.gov.in; Mathew, M.D.; Isaac Samuel, E.; Christopher, J.; Jayakumar, T.

    2013-11-15

    Tensile deformation and fracture behaviour of the three developmental heats of P9 steel for wrapper applications containing varying silicon in the range 0.24–0.60% have been examined in the temperature range 300–873 K. Yield and ultimate tensile strengths in all the three heats exhibited gradual decrease with increase in temperature from room to intermediate temperatures followed by rapid decrease at high temperatures. A gradual decrease in ductility to a minimum at intermediate temperatures followed by an increase at high temperatures has been observed. The fracture mode remained transgranular ductile. The steel displayed signatures of dynamic strain ageing at intermediate temperatures and dominance of recovery at high temperatures. No significant difference in the strength and ductility values was observed for varying silicon in the range 0.24–0.60% in P9 steel. P9 steel for wrapper application displayed strength and ductility values comparable to those reported in the literature.

  4. Elevated temperature tensile properties of P9 steel towards ferritic steel wrapper development for sodium cooled fast reactors

    Science.gov (United States)

    Choudhary, B. K.; Mathew, M. D.; Isaac Samuel, E.; Christopher, J.; Jayakumar, T.

    2013-11-01

    Tensile deformation and fracture behaviour of the three developmental heats of P9 steel for wrapper applications containing varying silicon in the range 0.24-0.60% have been examined in the temperature range 300-873 K. Yield and ultimate tensile strengths in all the three heats exhibited gradual decrease with increase in temperature from room to intermediate temperatures followed by rapid decrease at high temperatures. A gradual decrease in ductility to a minimum at intermediate temperatures followed by an increase at high temperatures has been observed. The fracture mode remained transgranular ductile. The steel displayed signatures of dynamic strain ageing at intermediate temperatures and dominance of recovery at high temperatures. No significant difference in the strength and ductility values was observed for varying silicon in the range 0.24-0.60% in P9 steel. P9 steel for wrapper application displayed strength and ductility values comparable to those reported in the literature.

  5. Elevated temperature tensile properties of P9 steel towards ferritic steel wrapper development for sodium cooled fast reactors

    International Nuclear Information System (INIS)

    Choudhary, B.K.; Mathew, M.D.; Isaac Samuel, E.; Christopher, J.; Jayakumar, T.

    2013-01-01

    Tensile deformation and fracture behaviour of the three developmental heats of P9 steel for wrapper applications containing varying silicon in the range 0.24–0.60% have been examined in the temperature range 300–873 K. Yield and ultimate tensile strengths in all the three heats exhibited gradual decrease with increase in temperature from room to intermediate temperatures followed by rapid decrease at high temperatures. A gradual decrease in ductility to a minimum at intermediate temperatures followed by an increase at high temperatures has been observed. The fracture mode remained transgranular ductile. The steel displayed signatures of dynamic strain ageing at intermediate temperatures and dominance of recovery at high temperatures. No significant difference in the strength and ductility values was observed for varying silicon in the range 0.24–0.60% in P9 steel. P9 steel for wrapper application displayed strength and ductility values comparable to those reported in the literature

  6. Room and elevated temperature Mechanical Behavior of 9-12% Cr Steels

    Energy Technology Data Exchange (ETDEWEB)

    Dogan, Omer N.; Hawk, Jeffrey A.; Schrems, Karol K.

    2005-02-01

    The mechanical properties of medium Cr steels used in fossil fired power plants are very good because of their excellent high temperature microstructural stability. However, as the desire to increase the operating temperature (>650C) of the plant goes up, the need for steels that maintain their strength at these temperatures also increases. The mechanical properties of three medium Cr steels (0.08C-(9-12)Cr-1.2Ni-0.7Mo-3.0Cu-3.0Co-0.5Ti) were investigated through hardness, hot hardness and tensile measurements. The strength of the 9-12%Cr steels at room temperature after long-term isothermal aging (750C; 1000 hours) compares favorably with that of other power plant steels (e.g., P91). In addition, the elevated temperature strength and hot hardness also behave similarly. The mechanical behavior will be discussed in terms of the strength, elongation and tensile fracture characteristics.

  7. 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

  8. Microstructure-based assessment of creep rupture strength in 9Cr steels

    International Nuclear Information System (INIS)

    Spigarelli, S.

    2013-01-01

    A microstructure-based model to assess the long-term creep strength in 9Cr steels is proposed. The model takes into account a number of different key issues, including the presence and evolution of the most important families of precipitates (M 23 C 6 , MX, Laves and Z phases), the subgrain recovery process, the different strengthening mechanisms (solid solution strengthening and particle strengthening), and is able to give realistic values of the long-term creep strength in P9, P91 and P911 steels. If properly tuned to describe the mid/long-term precipitation of the Z-phase, and the concurrent dissolution of MX precipitates, the model can also predict the sigmoidal behaviour which leads to the early rupture of single heats of P91 steel. Highlights: ► Creep response at 600 °C of 9% Cr steels. ► Important effect of the different families of precipitates. ► The effect is described by introducing the grain size term in a previously developed model. ► Degradation of particle strengthening effect is considered by calculating the coarsening of the particles.

  9. The co-evolution of microstructure features in self-ion irradiated HT9 at very high damage levels

    Energy Technology Data Exchange (ETDEWEB)

    Getto, E., E-mail: getto@usna.edu [Department of Mechanical Engineering, United States Naval Academy, Annapolis, MD, 21402 (United States); Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI, 48109 (United States); Vancoevering, G.; Was, G.S. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI, 48109 (United States)

    2017-02-15

    Understanding the void swelling and phase evolution of reactor structural materials at very high damage levels is essential to maintaining safety and longevity of components in Gen IV fast reactors. A combination of ion irradiation and modeling was utilized to understand the microstructure evolution of ferritic-martensitic alloy HT9 at high dpa. Self-ion irradiation experiments were performed on alloy HT9 to determine the co-evolution of voids, dislocations and precipitates up to 650 dpa at 460 °C. Modeling of microstructure evolution was conducted using the modified Radiation Induced Microstructure Evolution (RIME) model, which utilizes a mean field rate theory approach with grouped cluster dynamics. Irradiations were performed with 5 MeV raster-scanned Fe{sup 2+} ions on samples pre-implanted with 10 atom parts per million He. The swelling, dislocation and precipitate evolution at very high dpa was determined using Analytical Electron Microscopy in Scanning Transmission Electron Microscopy (STEM) mode. Experimental results were then interpreted using the RIME model. A microstructure consisting only of dislocations and voids is insufficient to account for the swelling evolution observed experimentally at high damage levels in a complicated microstructure such as irradiated alloy HT9. G phase was found to have a minimal effect on either void or dislocation evolution. M{sub 2}X played two roles; a variable biased sink for defects, and as a vehicle for removal of carbon from solution, thus promoting void growth. When accounting for all microstructure interactions, swelling at high damage levels is a dynamic process that continues to respond to other changes in the microstructure as long as they occur.

  10. SEM and TEM characterization of microstructure of stainless steel composites reinforced with TiB2

    International Nuclear Information System (INIS)

    Sulima, Iwona; Boczkal, Sonia; Jaworska, Lucyna

    2016-01-01

    Steel-8TiB 2 composites were produced by two new sintering techniques, i.e. Spark Plasma Sintering (SPS) and High Pressure-High Temperature (HP-HT) sintering. This study discusses the impact of these sintering methods on the microstructure of steel composites reinforced with TiB 2 particles. Scanning electron microscopy (SEM), wavelength dispersive spectroscopy (WDS), X-ray diffraction, electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) were used to analyze the microstructure evolution in steel matrix composites. The results of microscopic examinations revealed a close relationship between the composite microstructure and the methods and conditions of sintering. Substantial differences were observed in the grain size of materials sintered by HP-HT and SPS. It has been demonstrated that the composites sintered by HP-HT tend to form a chromium-iron-nickel phase in the steel matrix. In contrast, the microstructure of the composites sintered by SPS is characterized by the presence of complex borides and chromium-iron phase. - Highlights: •The steel-8TiB 2 composites were fabricated by Spark Plasma Sintering (SPS) and High Pressure-High Temperature (HP-HT). •Sintering techniques has an important effect on changes in the microstructure of steel-8TiB 2 composites. •New phases of different size and morphology were identified.

  11. Accelerated development of advanced steels for nuclear applications

    International Nuclear Information System (INIS)

    Ghoniem, N.; Zinkle, S.

    2009-01-01

    Significant progress has been achieved in the operational performance and radiation resistance of ferritic-martensitic steels during the past few decades. Conventional high temperature steels, such as HT-9 and 2 1/4 Cr-1Mo have evolved into super Oxide Dispersion Strengthened (ODS) steels through successive optimization to meet strict performance and radiation-resistance constraints. Such evolution was possible through a combination of experimentation, modeling and empirical information. Further development and optimization of structural steels in nuclear applications will require full utilization of the available array of sophisticated experimental techniques and multiscale computational modeling, in addition to empirical data. We present here a systematic approach to the process of optimum steel development, by linking material fabrication to thermo-mechanical properties through a physical understanding of microstructure evolution. The optimization process is based on the application of design constraints (e.g. low activation, low DBTT, low swelling, creep resistance, and weldability) to describe the required microstructures, which in turn, can be controlled through material processing techniques. Prospects for future design of optimum structural steels in nuclear applications by utilization of the hierarchy of multiscale experimental and computational strategies will be described. (author)

  12. 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

  13. Creep strength and ductility of 9 to 12% chromium steels

    DEFF Research Database (Denmark)

    Hald, John

    2004-01-01

    The present paper focuses in on long-term creep properties of parent material of the new 9-12%Cr creep resistant steels, P91, E911 and P92 developed for use in advanced ultrasupercritical power plants. These steels have been at the center of activities in the ECCC Working Group 3A (WG3A) "Ferriti...

  14. Recent improvements in size effects correlations for DBTT and upper shelf energy of ferritic steels

    International Nuclear Information System (INIS)

    Kumar, A.S.; Louden, B.S.; Garner, F.A.; Hamilton, M.L.

    1992-01-01

    Currently available correlations for the effects of specimen size on the USE were developed for relatively ductile steels and will not serve as well when the steels become embrittled. Size effects correlations were developed recently for the impact properties of less ductile HT9 to be applied to other initially more ductile steels as they lose their ductility during irradiation. These new correlations successfully predict the ductile brittle transition temperature (DBTT) and the upper shelf energy (USE) of full size Charpy specimens based on subsize specimen data. The new DBTT and the USE correlations were tested against published experimental data on other ferritic steels and shown to perform successfully at lower USE particularly when both precracked and notched only specimens were employed

  15. Impact behavior of 9-Cr and 12-Cr ferritic steels after low-temperature irradiation

    International Nuclear Information System (INIS)

    Klueh, R.L.; Vitek, J.M.; Corwin, W.R.; Alexander, D.J.

    1987-01-01

    Miniature Charpy impact specimens of 9Cr-1MoVNb and 12Cr-1MoVW steels and these steels with 1 and 2% Ni were irradiated in the High-Flux Isotope Reactor (HFIR) at 50 0 C to displacement damage levels of up to 9 dpa. Nickel was added to study the effect of transmutation helium. Irradiation caused an increase in the ductile-brittle transition temperature (DBTT). The 9Cr-1MoVNb steels, with and without nickel, showed a larger shift than the 12Cr-1MoVW steels, with and without nickel. The results indicated that helium also increased the DBTT. The same steels were previously irradiated at higher temperatures. From the present and past tests, the effect of irradiation temperature on the DBTT behavior can be evaluated. For the 9Cr-1MoVNb steel, there is a continuous decrease in the magnitude of the DBTT increase up to an irradiation temperature of about 400 0 C, after which the shift drops rapidly to zero at about 450 0 C. The DBTT of the 12Cr-1MoVW steel shows a maximum increase at an irradiation temperature of about 400 0 C and less of an increase at either higher or lower irradiation temperatures

  16. Conversion of MX Nitrides to Modified Z-Phase in 9-12%Cr Ferritic Steels

    DEFF Research Database (Denmark)

    Cipolla, Leonardo

    for Z-phase formation was highlighted during the studies. Several 9-12%Cr commercial steels with prolonged high-temperature exposures have been investigated, too. The same mechanism of Z-phase formation observed in 12%Cr model alloys was identified in industrial 9-12%Cr steels after thousands of hours......The 9-12%Cr ferritic steels are extensively used in modern steam power plants at service temperature up to 620°C. Currently the best perform ing ferritic creep resistance steel is the ASTM Grade 92, whose high temperature strength has recently been assessed by European Creep Collaborative Committee...... in 2005 as 600°C/113MPa/10 5h. All previous attempts made in the last twenty years to develop ferritic steels for 650°C applications have failed due to the incapacity to combine the superior oxidation resistance, given by 12%Cr content, with excellent creep resistance of high-alloyed ferritic steels...

  17. A study in the surface treatment of the barrier of a nuclear fuel protector

    Energy Technology Data Exchange (ETDEWEB)

    Song, Yo Seung; Chang, Si Young; Lee, Du Hyung; Noh, Bong Hyun; Kim, Ye Na [Korea Aerospace University, Goyang (Korea, Republic of)

    2009-06-15

    Materials used in the nuclear power plant, such as pipe, are needed to endure severe corrosion because they could expose the high temperature coolant under radiation. Up to now, the HT9 steel(12Cr-1MoVW) which is one of Ferritic Martensite Stainless steels has been applied because of its high swelling resistance. However, its applications are limited to the temperature of approximately 500 .deg. C. Therefore, it has been strongly demanded that the materials have excellent corrosion resistance concurrent with high mechanical properties such as fracture toughness and irradiation resistance at higher temperatures of more than 500 .dec. C for high efficiency of operating reactor. In order to overcome the corrosion problem of irradiated HT9 steel causing severe environmental problem, particularly, the ceramic coating methods could be applied. Recently, plasma electrolytic oxidation (PEO) emerged as a novel technique being capable of thick, dense and hard oxide ceramic coatings on the surface of light materials. In this study, we focused on applying the newly developed coating method, Plasma Electrolytic Oxidation (PEO) which was mainly developed for non-ferrous materials such as Al, Mg and Ti, for the HT9 steel. And then, we investigated and evaluated the possibility of application of PEO method for HT9 steel treated with/without aluminum cladding based on the microstructure observation of coatings formed under various processing parameters such as current ratio, electrolyte and time. Plasma Electrolytic Oxidation (PEO) treatment, which is an advancement of the conventional electrochemical anodizing treatment and leads to the local formation of a plasma by a spark on the metal surface, is expected to be a promising surface treatment that can overcome the drawbacks of HT9 steel. We applied PEO treatment for HT9 steel. We tried to find the effect of processing parameters, such as coating time, current ratio and electrolyte, on PEO coatings of HT9 steel, and also studied

  18. Cognitive Impairment Induced by Delta9-tetrahydrocannabinol Occurs through Heteromers between Cannabinoid CB1 and Serotonin 5-HT2A Receptors.

    Directory of Open Access Journals (Sweden)

    Xavier Viñals

    2015-07-01

    Full Text Available Activation of cannabinoid CB1 receptors (CB1R by delta9-tetrahydrocannabinol (THC produces a variety of negative effects with major consequences in cannabis users that constitute important drawbacks for the use of cannabinoids as therapeutic agents. For this reason, there is a tremendous medical interest in harnessing the beneficial effects of THC. Behavioral studies carried out in mice lacking 5-HT2A receptors (5-HT2AR revealed a remarkable 5-HT2AR-dependent dissociation in the beneficial antinociceptive effects of THC and its detrimental amnesic properties. We found that specific effects of THC such as memory deficits, anxiolytic-like effects, and social interaction are under the control of 5-HT2AR, but its acute hypolocomotor, hypothermic, anxiogenic, and antinociceptive effects are not. In biochemical studies, we show that CB1R and 5-HT2AR form heteromers that are expressed and functionally active in specific brain regions involved in memory impairment. Remarkably, our functional data shows that costimulation of both receptors by agonists reduces cell signaling, antagonist binding to one receptor blocks signaling of the interacting receptor, and heteromer formation leads to a switch in G-protein coupling for 5-HT2AR from Gq to Gi proteins. Synthetic peptides with the sequence of transmembrane helices 5 and 6 of CB1R, fused to a cell-penetrating peptide, were able to disrupt receptor heteromerization in vivo, leading to a selective abrogation of memory impairments caused by exposure to THC. These data reveal a novel molecular mechanism for the functional interaction between CB1R and 5-HT2AR mediating cognitive impairment. CB1R-5-HT2AR heteromers are thus good targets to dissociate the cognitive deficits induced by THC from its beneficial antinociceptive properties.

  19. Cognitive Impairment Induced by Delta9-tetrahydrocannabinol Occurs through Heteromers between Cannabinoid CB1 and Serotonin 5-HT2A Receptors.

    Science.gov (United States)

    Viñals, Xavier; Moreno, Estefanía; Lanfumey, Laurence; Cordomí, Arnau; Pastor, Antoni; de La Torre, Rafael; Gasperini, Paola; Navarro, Gemma; Howell, Lesley A; Pardo, Leonardo; Lluís, Carmen; Canela, Enric I; McCormick, Peter J; Maldonado, Rafael; Robledo, Patricia

    2015-07-01

    Activation of cannabinoid CB1 receptors (CB1R) by delta9-tetrahydrocannabinol (THC) produces a variety of negative effects with major consequences in cannabis users that constitute important drawbacks for the use of cannabinoids as therapeutic agents. For this reason, there is a tremendous medical interest in harnessing the beneficial effects of THC. Behavioral studies carried out in mice lacking 5-HT2A receptors (5-HT2AR) revealed a remarkable 5-HT2AR-dependent dissociation in the beneficial antinociceptive effects of THC and its detrimental amnesic properties. We found that specific effects of THC such as memory deficits, anxiolytic-like effects, and social interaction are under the control of 5-HT2AR, but its acute hypolocomotor, hypothermic, anxiogenic, and antinociceptive effects are not. In biochemical studies, we show that CB1R and 5-HT2AR form heteromers that are expressed and functionally active in specific brain regions involved in memory impairment. Remarkably, our functional data shows that costimulation of both receptors by agonists reduces cell signaling, antagonist binding to one receptor blocks signaling of the interacting receptor, and heteromer formation leads to a switch in G-protein coupling for 5-HT2AR from Gq to Gi proteins. Synthetic peptides with the sequence of transmembrane helices 5 and 6 of CB1R, fused to a cell-penetrating peptide, were able to disrupt receptor heteromerization in vivo, leading to a selective abrogation of memory impairments caused by exposure to THC. These data reveal a novel molecular mechanism for the functional interaction between CB1R and 5-HT2AR mediating cognitive impairment. CB1R-5-HT2AR heteromers are thus good targets to dissociate the cognitive deficits induced by THC from its beneficial antinociceptive properties.

  20. Effects of lithium environment on the fatigue properties of ferritic and austenitic steels

    International Nuclear Information System (INIS)

    Chopra, O.K.; Smith, D.L.

    1982-01-01

    Low-cycle fatigue data have been obtained on HT-9 alloy and Type 304 stainless steel at 755 K in a flowing lithium environment of controlled purity. The results show that the fatigue properties of these materials are strongly influenced by the concentration of nitrogen in lithium. For HT-9 alloy, the fatigue life in lithium containing 1000-1500 wppm nitrogen is a factor of 2 to 5 lower than that in lithium with 100-200 wppm nitrogen. The reduction in fatigue life in high-nitrogen lithium can be attributed to internal corrosive attack of the material. The specimens tested in high-nitrogen lithium show considerable surface corrosion, internal corrosive attack, secondary cracks, and partial intergranular fracture mode. This behavior is not observed in specimens tested either in low-nitrogen lithium or a sodium environment. (orig.)

  1. Creep-fatigue-environment interaction of 9Cr-1Mo-V-Nb steel

    International Nuclear Information System (INIS)

    Shibata, Hiroyuki; Ishikawa, Akiyoshi; Asada, Yasuhide

    1996-01-01

    An extension of the creep-fatigue damage model has been conducted in the present study. The original damage model has been developed to the predict the creep-fatigue life of 9Cr-1Mo-V-Nb steel (Modified 9Cr-1Mo steel) in a very high vacuum environment. The present study is to extend an applicability of the model to the creep-fatigue damage accumulation in the air environment. (orig.)

  2. Microstructure and elevated temperature stability of 9-12% Cr steels

    Energy Technology Data Exchange (ETDEWEB)

    Dogan, Omer N.; Hawk, Jeffrey A.

    2005-02-01

    Medium Cr steels have been used in fossil fired power plants for many years because of their excellent high temperature stability and mechanical properties. As the desire to increase the efficiency of power plants continues, the operating temperature (>650C) continues to go up. Currently available low and medium Cr containing steels will not withstand the new operating temperature and must be reassessed in terms of their solid-solution and precipitation strengthening schemes. Three medium Cr steels were developed to investigate high temperature alloy strengthening strategies: 0.08C-(9-12)Cr-1.2Ni-0.7Mo-3.0Cu-3.0Co-0.5Ti. The microstructure of the alloy will be described in the as-cast and thermo-mechanically worked states. In addition, the effect on microstructure from long-term high temperature exposure will also be discussed. Finally, the overall stability of these steels will be compared against currently available power plant steels.

  3. Design of the Cryostat for HT-7U Superconducting Tokamak

    Science.gov (United States)

    Yu, Jie; Wu, Song-tao; Song, Yun-tao; Weng, Pei-de

    2002-06-01

    The cryostat of HT-7U tokamak is a large vacuum vessel surrounding the entire basic machine with a cylindrical shell, a dished top and a flat bottom. The main function of HT-7U cryostat is to provide a thermal barrier between an ambient temperature test hall and a liquid helium-cooled superconducting magnet. The loads applied to the cryostat are from sources of vacuum pressure, dead weight, seismic events and electromagnetic forces originated by eddy currents. It also provides feed-through penetrations for all the connecting elements inside and outside the cryostat. The main material selected for the cryostat is stainless steel 304L. The structural analyses including buckling for the cryostat vessel under the plasma operation condition have been carried out by using a finite element code. Stress analysis results show that the maximum stress intensity was below the allowable value. In this paper, the structural analyses and design of HT-7U cryostat are emphasized.

  4. Microstructure refinement and strengthening mechanisms of a 9Cr oxide dispersion strengthened steel by zirconium addition

    International Nuclear Information System (INIS)

    Xu, Hai Jian; Lu, Zheng; Wang, Dong Mei; Liu, Chunming

    2017-01-01

    To study the effects of zirconium (Zr) addition on the microstructure, hardness and the tensile properties of oxide dispersion strengthened (ODS) ferritic-martensitic steels, two kinds of 9Cr-ODS ferritic-martensitic steels with nominal compositions (wt.%) of Fe-9Cr-2W-0.3Y_2O-3 and Fe-9Cr-2W-0.3Zr-0.3Y_2O_3 were fabricated by the mechanical alloying (MA) of premixed powders and then consolidated by hot isostatic pressing (HIP) techniques. The experimental results showed that the average grain size decreases with Zr addition. The trigonal δ-phase Y_4Zr_3O_1_2 oxides and body-centered cubic Y_2O_3 oxides are formed in the 9Cr-Zr-ODS steel and 9Cr non-Zr ODS steel, respectively, and the average size of Y_4Zr_3O_1_2 particles is much smaller than that of Y_2O_3. The dispersion morphology of the oxide particles in 9Cr-Zr-ODS steel is significantly improved and the number density is 1.1 x 10"2"3/m"3 with Zr addition. The 9Cr-Zr-ODS steel shows much higher tensile ductility, ultimate tensile strength and Vickers hardness at the same time

  5. Influence of Normalizing Temperature on the Microstructure and Hardness of 9Cr-1Mo ODS Steel

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Ki Nam; Kim, Tae Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Kyu Tae [Dongguk University, Gyeongju (Korea, Republic of)

    2016-10-15

    Oxide dispersion strengthened(ODS) steel has superior high-temperature strength and creep properties because fine oxide particles having an excellent stability at high temperatures are uniformly distributed in the matrix. ODS steel has being developed for structure materials of sodium fast cooled reactor(SFR) because of its excellent irradiation resistance and mechanical properties. 9Cr-1Mo ODS steel has better high temperature strength and irradiation resistance than common 9Cr-1Mo steel because Y{sub 2}O{sub 3} nano-sized particles which interrupt dislocation movement and grain boundary slip are uniformly dispersed in the martensite matrix. The mechanical properties of the ODS steels are mainly determined by their microstructures, and the microstructure is considerably decided by the heat-treatment conditions. This study focused on the effect of normalizing temperature on microstructure and hardness of 9Cr-1Mo martensitic ODS steel so as to optimize the heat-treatment condition. In this study, the effect of normalizing temperature on mechanical property and microstructures of 9Cr-1Mo martensitic ODS steel was investigated. It was shown that the microhardness was steadily increased with increasing of the normalizing temperature. According to TEM observation, mechanical property of 9Cr-1Mo ODS steel was significantly affected by lath width. These observations, could be useful to understand the relationship between normalizing temperature and microstructure.

  6. Construction of in-situ creep strain test facility for the SFR fuel cladding

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sang Gyu; Heo, Hyeong Min; Kim, Jun Hwan; Kim, Sung Ho [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    In this study, in-situ laser inspection creep test machine was developed for the measuring the creep strain of SFR fuel cladding materials. Ferritic-martensitic steels are being considered as an attractive candidate material for a fuel cladding of a SFR due to their low expansion coefficients, high thermal conductivities and excellent irradiation resistances to a void swelling. HT9 steel (12CrMoVW) is initially developed as a material for power plants in Europe in the 1960. This steel has experienced to expose up to 200dpa in FFTE and EBR-II. Ferritic-Martensitic steel's maximum creep strength in existence is 180Mpa for 106 hour 600 .deg., but HT9 steel is 60Mpa. Because SFR is difficult to secure in developing and applying materials, HT9 steel has accumulated validated data and is suitable for SFR component. And also, because of its superior dimensional stability against fast neutron irradiation, Ferritic-martensitic steel of 9Cr and 12Cr steels, such as HT9 and FC92(12Cr-2W) are preferable to utilize in the fuel cladding of an SFR in KAERI. The pressurized thermal creep test of HT9 and FC92 claddings are being conducted in KAERI, but the change of creep strain in cladding is not easy to measure during the creep test due to its pressurized and closed conditions. In this paper, in-situ laser inspection pressurized creep test machine developed for SFR fuel cladding specimens is described. Moreover, the creep strain rate of HT9 at 650 .deg. C was examined from the in-situ laser inspection pressurized creep test machine.

  7. Development of martensitic steels for high neutron damage applications

    International Nuclear Information System (INIS)

    Gelles, D.S.

    1998-01-01

    Martensitic stainless steels have been developed for both in-core applications in advanced liquid metal fast breeder reactors (LMFBR) and for first wall and structural materials applications for commercial fusion reactors. It can now be shown that these steels can be expected to maintain properties to levels as high as 175 or 200 dpa, respectively. The 12Cr-1Mo-0.5W-0.2C alloy HT-9 has been extensively tested for LMFBR applications and shown to resist radiation damage, providing a creep and swelling resistant alternative to austenitic steels. Degradation of fracture toughness and Charpy impact properties have been observed, but properties are sufficient to provide reliable service. In comparison, alloys with lower chromium contents are found to decarburize in contact with liquid sodium and are therefore not recommended. Tungsten stabilized martensitic stainless steels have appropriate properties for fusion applications. Radioactivity levels are being less than 500 years after service, radiation damage resistance is excellent, including impact properties, and swelling is modest. This report describes the history of the development effort. (author)

  8. Development of martensitic steels for high neutron damage applications

    Science.gov (United States)

    Gelles, D. S.

    1996-12-01

    Martensitic stainless steels have been developed for both in-core applications in advanced liquid metal fast breeder reactors (LMFBR) and for first wall and structural materials applications for commercial fusion reactors. It can now be shown that these steels can be expected to maintain properties to levels as high as 175 or 200 dpa, respectively. The 12Cr1Mo0.5W0.2C alloy HT-9 has been extensively tested for LMFBR applications and shown to resist radiation damage, providing a creep and swelling resistant alternative to austenitic steels. Degradation of fracture toughness and Charpy impact properties have been observed, but properties are sufficient to provide reliable service. In comparison, alloys with lower chromium contents are found to decarburize in contact with liquid sodium and are therefore not recommended. Tungsten stabilized martensitic stainless steels have appropriate properties for fusion applications. Radioactivity levels are benign less than 500 years after service, radiation damage resistance is excellent, including impact properties, and swelling is modest. This report describes the history of the development effort.

  9. Helium-induced weld cracking in austenitic and martensitic steels

    International Nuclear Information System (INIS)

    Lin, H.T.; Chin, B.A.

    1991-01-01

    Helium was uniformly implanted into type 316 stainless steel and Sandvik HT-9 (12Cr-1MoVW) to levels of 0.18 to 256 and 0.3 to 1 a.p.p.m., respectively, using the ''tritium trick'' technique. Autogenous bead-on-plate, full penetration, welds were then produced under fully constrained conditions using the gas tungsten arc welding (GTAW) process. The control and hydrogen-charged plates of both alloys were sound and free of any weld defects. For the 316 stainless steel, catastrophic intergranular fracture occurred in the heat-affected zone (HAZ) of welds with helium levels ≥ 2.5 a.p.p.m. In addition to the HAZ cracking, brittle fracture along the centreline of the fusion zone was also observed for the welds containing greater than 100 a.p.p.m. He. For HT-9, intergranular cracking occurred in the HAZ along prior-austenite grain boundaries of welds containing 1 a.p.p.m. He. Electron microscopy observations showed that the cracking in the HAZ originated from the growth and coalescence of grain-boundary helium bubbles and that the fusion-zone cracking resulted from the growth of helium bubbles at dendrite boundaries. The bubble growth kinetics in the HAZ is dominated by stress-induced diffusion of vacancies into bubbles. Results of this study indicate that the use of conventional GTAW techniques to repair irradiation-degraded materials containing even small amounts of helium may be difficult. (author)

  10. High-Temperature Confocal Laser Scanning Microscopy Studies of Ferrite Formation in Inclusion-Engineered Steels: A Review

    Science.gov (United States)

    Mu, Wangzhong; Hedström, Peter; Shibata, Hiroyuki; Jönsson, Pär G.; Nakajima, Keiji

    2018-05-01

    The concepts of oxide metallurgy and inclusion engineering can be utilized to improve the properties of low-alloy steels. These concepts aim at controlling the formation of intragranular ferrite (IGF), often a desirable microstructure providing good mechanical properties without the need for expensive alloying elements. IGF formation is stimulated to occur at non-metallic inclusions and form an arrangement of fine, interlocking ferrite grains. A method that has contributed significantly to investigations in this field lately is high-temperature confocal laser scanning microscopy (HT-CLSM). HT-CLSM is suited for in situ studies of inclusion behavior in liquid steel and phase transformations in solid-state steel, where in particular, displacive phase transformations can be studied, since they provide sufficient topographic contrast. The purpose of the present report is to provide a brief review of the state of the art of HT-CLSM and its application for in situ observations of ferrite formation in inclusion-engineered steels. The scientific literature in this field is surveyed and supplemented by new work to reveal the capability of HT-CLSM as well as to discuss the effect of factors such as cooling rate and parent grain size on IGF formation and growth kinetics. The report concludes with an outlook on the opportunities and challenges of HT-CLSM for applications in oxide metallurgy.

  11. Microstructure refinement and strengthening mechanisms of a 9Cr oxide dispersion strengthened steel by zirconium addition

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Hai Jian; Lu, Zheng; Wang, Dong Mei; Liu, Chunming [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials Science and Engineering, Northeastern University, Shenyang (China)

    2017-02-15

    To study the effects of zirconium (Zr) addition on the microstructure, hardness and the tensile properties of oxide dispersion strengthened (ODS) ferritic-martensitic steels, two kinds of 9Cr-ODS ferritic-martensitic steels with nominal compositions (wt.%) of Fe-9Cr-2W-0.3Y{sub 2}O-3 and Fe-9Cr-2W-0.3Zr-0.3Y{sub 2}O{sub 3} were fabricated by the mechanical alloying (MA) of premixed powders and then consolidated by hot isostatic pressing (HIP) techniques. The experimental results showed that the average grain size decreases with Zr addition. The trigonal δ-phase Y{sub 4}Zr{sub 3}O{sub 12} oxides and body-centered cubic Y{sub 2}O{sub 3} oxides are formed in the 9Cr-Zr-ODS steel and 9Cr non-Zr ODS steel, respectively, and the average size of Y{sub 4}Zr{sub 3}O{sub 12} particles is much smaller than that of Y{sub 2}O{sub 3}. The dispersion morphology of the oxide particles in 9Cr-Zr-ODS steel is significantly improved and the number density is 1.1 x 10{sup 23}/m{sup 3} with Zr addition. The 9Cr-Zr-ODS steel shows much higher tensile ductility, ultimate tensile strength and Vickers hardness at the same time.

  12. Precipitation process of Z-phase in 9-12%CR steels

    DEFF Research Database (Denmark)

    Danielsen, Hilmar Kjartansson

    2014-01-01

    Precipitation of Z-phase, Cr(V,Nb)N, is known to negatively affect creep properties of 9-12%Cr steels for power plant applications as it dissolves finely distributed MX particles, (V,Nb)N, especially in high Cr steels. As the Z-phase precipitates slowly as large particles, this causes a net drop ...... and crystallographically into Z-phase CrTaN particles. Copyright © 2014 Electric Power Research Institute, Inc. Distributed by ASM International®. All rights reserved....

  13. Radiation induced microstructural evolution in ferritic/martensitic steels

    International Nuclear Information System (INIS)

    Kohno, Y.; Kohyama, A.; Asakura, K.; Gelles, D.S.

    1993-01-01

    R and D of ferritic/martensitic steels as structural materials for fusion reactor is one of the most important issues of fusion technology. The efforts to characterize microstructural evolution under irradiation in the conventional Fe-Cr-Mo steels as well as newly developed Fe-Cr-Mn or Fe-Cr-W low activation ferritic/ martensitic steels have been continued. This paper provides some of the recent results of heavy irradiation effects on the microstructural evolution of ferritic/martensitic steels neutron irradiated in the FFTF/MOTA (Fast Flux Test Facility/Materials Open Test Assembly). Materials examined are Fe-10Cr-2Mo dual phase steel (JFMS: Japanese Ferritic/Martensitic Steel), Fe-12Cr-XMn-1Mo manganese stabilized martensitic steels and Fe-8Cr-2W Tungsten stabilized low activation martensitic steel (F82H). JFMS showed excellent void swelling resistance similar to 12Cr martensitic steel such as HT-9, while the manganese stabilized steels and F82H showed less void swelling resistance with small amount of void swelling at 640-700 K (F82H: 0.14% at 678 K). As for irradiation response of precipitate behavior, significant formation of intermetallic χ phase was observed in the manganese stabilized steels along grain boundaries which is though to cause mechanical property degradation. On the other hand, precipitates identified were the same type as those in unirradiated condition in F82H with no recognition of irradiation induced precipitates, which suggested satisfactory mechanical properties of F82H after the irradiation. (author)

  14. Starting of H9ANFNb(P91) steel tubing production for energetics in domestic steel-works; Uruchomienie w krajowych hutach produkcji rur ze stali H9AMFNb(P91) przeznaczonych dla energetyki

    Energy Technology Data Exchange (ETDEWEB)

    Wiedermann, J. [Instytut Metalurgii Zelaza, Gliwice (Poland); Bieniek, K. [Huta Jednosc, Siemianowice Slaskie (Poland); Pogoda, K. [Huta Batory, Chorzow (Poland)

    1996-12-31

    The results of primary investigations and attempt of ferritic steel H9AMFNb production in domestic steel-works have been reported. The prototype series of tubes for energetic boilers have been tested and their mechanical properties determined. It has been found the applicability of the material for use in energetics. 9 refs, 4 figs, 3 tabs.

  15. Interdiffusion between U-Pu-Zr fuel and HT9 cladding

    International Nuclear Information System (INIS)

    Keiser, D.D. Jr.; Petri, M.C.

    1994-01-01

    As part of systematic interdiffusion studies of fuel-cladding compatibility in the integral Fast Reactor, a solid-solid diffusion couple was assembled with U-22Pu-23 1 Zr fuel and HT9 2 cladding and annealed at 650 degrees C for 100 hours. The couple was examined for diffusion structure development using a scanning electron microscope equipped with an energy dispersive x-ray analyzer (SEM-EDX). Point-by-point and linescan analysis was used to generate composition profiles and diffusion paths. From the composition profiles, average effective interdiffusion coefficients were calculated for individual components on both sides of the Matano plane. Results from this investigation indicate that the same types of phases as would be expected from binary U-Fe, Pu-Fe, and Zr-Fe phase diagrams develop in this couple; and U and Pu are the fastest diffusing fuel components and Fe is the fastest diffusing cladding component. Compared with diffusion couples with binary (U-Zr) fuel, the addition of Pu greatly enhanced the extent of diffusion and affected the types of phases observed

  16. Thermal creep properties of alloy D9 stainless steel and 316 stainless steel fuel clad tubes

    International Nuclear Information System (INIS)

    Latha, S.; Mathew, M.D.; Parameswaran, P.; Bhanu Sankara Rao, K.; Mannan, S.L.

    2008-01-01

    Uniaxial thermal creep rupture properties of 20% cold worked alloy D9 stainless steel (alloy D9 SS) fuel clad tubes for fast breeder reactors have been evaluated at 973 K in the stress range 125-250 MPa. The rupture lives were in the range 90-8100 h. The results are compared with the properties of 20% cold worked type 316 stainless steel (316 SS) clad tubes. Alloy D9 SS were found to have higher creep rupture strengths, lower creep rates and lower rupture ductility than 316 SS. The deformation and damage processes were related through Monkman Grant relationship and modified Monkman Grant relationship. The creep damage tolerance parameter indicates that creep fracture takes place by intergranular cavitation. Precipitation of titanium carbides in the matrix and chromium carbides on the grain boundaries, dislocation substructure and twins were observed in transmission electron microscopic investigations of alloy D9 SS. The improvement in strength is attributed to the precipitation of fine titanium carbides in the matrix which prevents the recovery and recrystallisation of the cold worked microstructure

  17. Effect of specimen size on the upper shelf energy of ferritic steels

    International Nuclear Information System (INIS)

    Kumar, A.S.

    1990-01-01

    A methodology is proposed that can be used to predict the upper shelf energy (USE) of ferritic steels based on subsize specimen data. The proposed methodology utilizes the partitioning of the USE into energies required for crack initiation and crack propagation. Notched-only Charpy specimens are used in conjunction with precracked specimens to separate the two components. An unirradiated ferritic steel, HT-9, was used to demonstrate the validity of the methodology. Unlike previous correlations that were limited in their applicability to either highly ductile or brittle material, the proposed methodology is expected to be applicable over a wide range of ductility and to be particularly useful for materials that harden significantly during irradiation

  18. On-line Measurement of Boiler Tube Corrosion Rates using Dedicated EMAT (HT-EMAT) Phase 1

    Energy Technology Data Exchange (ETDEWEB)

    Borggreen, Kjeld (SydTek AB, Malmoe (Sweden))

    2009-06-15

    The project includes development of prototype HT-EMAT (High Temperature Electro Magnetic Acoustic Transducer) probes and testing of these in laboratory environment at high temperatures. The following results were obtained: Standard Alnico (Al-Ni-Co-Fe) magnets are sufficiently strong to drive a HT-EMAT probe in the magnetostrictive mode at temperatures up to 550 deg C. With a standard (diam)20 x 40 mm Alnico magnet, the number of turns in the coil using a 0.25 mm wire should be 25 - 30 to give optimum response and highest accuracy. The velocity of shear type sound waves in metals varies linearly with temperature in the interval considered. The prototype HT-EMAT only needs to be calibrated at room temperature, which is a simple procedure. If the temperature dependence of the velocity of the sound waves in steels is taking into account, the prototype probe gives excellent results at temperatures up to 550 deg C. The coil and the connection wire should preferably have a high electric conductivity to minimize damping, skin effects, and impedance mismatch, and also a high oxidation resistance. Pure copper and fine silver are the candidate materials for the HT-EMAT. Deposition of magnetostrictive layers on steel surfaces has been resolved. Magnetite seems as the only useful material until further. Thin layers of natural grown magnetite can be made by long term heat treatments. Thicker layers of artificial magnetite can be made by thermal spraying. Most of the reduction in efficiency of the HT-EMAT probe at high temperatures may be explained by the thermal dependence of the magnetostrictive constant for magnetite. Because the magnetostriction of magnetite disappears at its Curie temperature, the theoretical temperature limit for the HT-EMAT probe is foreseen to be 575 deg C. The prototype HT-EMAT performed well up to 550 deg C both during long time testing and at dynamic testing. The electronic and mechanical stabilities were excellent

  19. Characteristics of Modified 9Cr-1Mo Steel for Reactor Pressure Vessel of Very High Temperature Gas Cooled Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Ho; Ryu, W. S.; Han, Chang Hee; Yoon, J. H.; Chang, Jong Hwa

    2004-11-15

    Many researches and developments have been progressed for the construction of VHTR by 2020 in Korea. Modified 9Cr-1Mo steel has been receiving attention for the application to the reactor pressure vessel material of VHTR. We collected and analyzed the research data for modified 9Cr-1Mo steel in order to understand the characteristics of modified 9Cr-1Mo steel. The modified 9Cr-1Mo steel is a modified alloy system similar to conventional 9Cr-1Mo grade ferritic steel. Modifications include additions of vanadium, niobium, and nitrogen, as well as lower carbon content. In this report, we summarized the change of microstructure and mechanical properties after tempering, thermal aging, and irradiation. Modified 9Cr-1Mo steel has high strength and thermal conductivity, low thermal expansion, and good resistance to corrosion. But the irradiation embrittlement behavior of modified 9Cr-1Mo steel should be evaluated and the evaluation methodology also should be developed. At the same time, the characteristics of weldment which is the weak part in pressure vessel should be evaluated.

  20. Microstructural Stability and Oxidation Resistance of 9-12 Chromium Steels at Elevated Temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Dogan, O.N.; Alman, D.E.; Jablonski, P.D.; Hawk, J.A.

    2006-05-01

    Various martensitic 9-12 Cr steels are utilized currently in fossil fuel powered energy plants for their good elevated temperature properties such as creep strength, steam side oxidation resistance, fire side corrosion resistance, and thermal fatigue resistance. Need for further improvements on the properties of 9-12 Cr steels for higher temperature (>600oC) use is driven by the environmental concerns (i.e., improve efficiency to reduce emissions and fossil fuel consumption). In this paper, we will discuss the results of the research done to explore new subsitutional solute solution and precipitate hardening mechanisms for improved strength of 9-12 Cr martensitic steels. Stability of the phases present in the steels will be evaluated for various temperature and time exposures. A comparison of microstructural properties of the experimental steels and commercial steels will also be presented.

    The influence of a Ce surface treatment on oxidation behavior of a commercial (P91) and several experimental steels containing 9 to 12 weight percent Cr was examined at 650ºC in flowing dry and moist air. The oxidation behavior of all the alloys without the Ce modification was significantly degraded by the presence of moisture in the air during testing. For instance the weight gain for P91 was two orders of magnitude greater in moist air than in dry air. This was accompanied by a change in oxide scale from the formation of Cr-based scales in dry air to the formation of Fe-based scales in moist air. The Ce surface treatment was very effective in improving the oxidation resistance of the experimental steels in both moist and dry air. For instance, after exposure to moist air at 650ºC for 2000 hours, an experimental alloy with the cerium surface modification had a weight gain three orders of magnitude lower than the alloy without the Ce modification and two orders of magnitude lower than P91. The Ce surface treatment suppressed the formation of Fe-based scales and

  1. Creep Strength of Dissimilar Welded Joints Using High B-9Cr Steel for Advanced USC Boiler

    Science.gov (United States)

    Tabuchi, Masaaki; Hongo, Hiromichi; Abe, Fujio

    2014-10-01

    The commercialization of a 973 K (700 °C) class pulverized coal power system, advanced ultra-supercritical (A-USC) pressure power generation, is the target of an ongoing research project initiated in Japan in 2008. In the A-USC boiler, Ni or Ni-Fe base alloys are used for high-temperature parts at 923 K to 973 K (650 °C to 700 °C), and advanced high-Cr ferritic steels are planned to be used at temperatures lower than 923 K (650 °C). In the dissimilar welds between Ni base alloys and high-Cr ferritic steels, Type IV failure in the heat-affected zone (HAZ) is a concern. Thus, the high B-9Cr steel developed at the National Institute for Materials Science, which has improved creep strength in weldments, is a candidate material for the Japanese A-USC boiler. In the present study, creep tests were conducted on the dissimilar welded joints between Ni base alloys and high B-9Cr steels. Microstructures and creep damage in the dissimilar welded joints were investigated. In the HAZ of the high B-9Cr steels, fine-grained microstructures were not formed and the grain size of the base metal was retained. Consequently, the creep rupture life of the dissimilar welded joints using high B-9Cr steel was 5 to 10 times longer than that of the conventional 9Cr steel welded joints at 923 K (650 °C).

  2. An assessment of magnetic effects in ferromagnetic martensitic steels for use in fusion machines

    International Nuclear Information System (INIS)

    Lechtenberg, T.; Dahms, C.; Attaya, H.

    1984-01-01

    Interest in the 9-12%Cr class of martensitic stainless steels has accelerated since these materials were included in the U.S. Alloy Development for Irradiation Performance (ADIP) task funded by the Office of Fusion Energy in 1979. This program is focused on developing structural materials for fusion reactor first wall/breeding blanket components where the neutron damage is most severe. This area of a fusion reactor will be required to tolerate damage levels on the order of 110 dpa( 1 ). As a part of ADIP, study of the martensitic steels is focused on establishing the feasibility of using these materials. The interest in martensitic steels stems from their potential to tolerate high levels of radiation damage without significant degradation of material properties. Martensitic steels have a body-centered-cubic crystal structure that, unlike face-centered-cubic structure of austenitic steels, exhibits very little swelling under neutron irradiation( 2 ). One of the outstanding issues with martensitic steels is the possible parasitic stresses associated with ferromagnetic interaction with the magnetic fields. This paper is divided into two parts, the first reviews previous work on magnetic effects to the structure and plasma; the second presents new calculations of stresses on a coolant pipe in a Starfire model assumed to be made of 12Cr-1Mo steel(HT-9)

  3. Characterisation of 5-HT3C, 5-HT3D and 5-HT3E receptor subunits: evolution, distribution and function.

    Science.gov (United States)

    Holbrook, Joanna D; Gill, Catherine H; Zebda, Noureddine; Spencer, Jon P; Leyland, Rebecca; Rance, Kim H; Trinh, Han; Balmer, Gemma; Kelly, Fiona M; Yusaf, Shahnaz P; Courtenay, Nicola; Luck, Jane; Rhodes, Andrew; Modha, Sundip; Moore, Stephen E; Sanger, Gareth J; Gunthorpe, Martin J

    2009-01-01

    The 5-HT(3) receptor is a member of the 'Cys-loop' family of ligand-gated ion channels that mediate fast excitatory and inhibitory transmission in the nervous system. Current evidence points towards native 5-HT(3) receptors originating from homomeric assemblies of 5-HT(3A) or heteromeric assembly of 5-HT(3A) and 5-HT(3B). Novel genes encoding 5-HT(3C), 5-HT(3D), and 5-HT(3E) have recently been described but the functional importance of these proteins is unknown. In the present study, in silico analysis (confirmed by partial cloning) indicated that 5-HT(3C), 5-HT(3D), and 5-HT(3E) are not human-specific as previously reported: they are conserved in multiple mammalian species but are absent in rodents. Expression profiles of the novel human genes indicated high levels in the gastrointestinal tract but also in the brain, Dorsal Root Ganglion (DRG) and other tissues. Following the demonstration that these subunits are expressed at the cell membrane, the functional properties of the recombinant human subunits were investigated using patch clamp electrophysiology. 5-HT(3C), 5-HT(3D), and 5-HT(3E) were all non-functional when expressed alone. Co-transfection studies to determine potential novel heteromeric receptor interactions with 5-HT(3A) demonstrated that the expression or function of the receptor was modified by 5-HT(3C) and 5-HT(3E), but not 5-HT(3D). The lack of distinct effects on current rectification, kinetics or pharmacology of 5-HT(3A) receptors does not however provide unequivocal evidence to support a direct contribution of 5-HT(3C) or 5-HT(3E) to the lining of the ion channel pore of novel heteromeric receptors. The functional and pharmacological contributions of these novel subunits to human biology and diseases such as irritable bowel syndrome for which 5-HT(3) receptor antagonists have major clinical usage, therefore remains to be fully determined.

  4. Characteristics of centrifugally cast GX25CrNiSi18-9 steel

    Directory of Open Access Journals (Sweden)

    R. Zapała

    2011-07-01

    Full Text Available The paper presents the results of microstructural examinations of the industrial heat-resistant centrifugally cast GX25CrNiSi18-9 steel characterised by increased content of Cu. The study included changes in the microstructure of base cast steel respective of the steel held at a temperature of 900 and 950°C for 48 hours. Based on the results obtained, an increase in microhardness of the examined cast steel matrix with increasing temperature was stated, which was probably caused by fine precipitates enriched in Cr, Mo, and C forming inside the matrix grains.The layer of scale formed on the tested cast steel oxidised in the atmosphere of air at 900 and 950°C was characterised by an increased tendency to degradation with increasing temperature of the conducted tests.

  5. Microstructure and mechanical properties of friction stir welded 9Cr ODS steel

    International Nuclear Information System (INIS)

    Min, Hyoung Kee; Kang, Suk Hoon; Noh, Sanghoon; Lee, Jung Gu; Jang, Jinsung; Kim, Tae Kyu

    2013-01-01

    It is well known that the welding of ODS steel with a conventional melting.solidification process is not adequate to reserve nano-oxide particles in the matrix homogeneously. To reserve nano-oxide particles in the matrix homogeneously, friction stir welding (FSW) is the most promising technique to join ODS alloys. In this study, the effects of FSW on the microstructure and mechanical properties of a ODS steel were studied to apply the FSW process to 9Cr ODS steels. Microstructures were observed by means of optical microscopy, electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). A tensile test and hardness test were carried out to the investigate mechanical properties. FSW could successfully produce defect-free welds on ODS plates. FSW produced a fine grain structure consisting of ferrite and martensite. Tensile strengths and elongations of the SZs were excellent at 298 K, compared to those of the BM. This study suggests that FSW might be an appropriate welding method of ODS steels. Oxide dispersion strengthened (ODS) ferritic-martensitic (FM) steel containing 9 wt%Cr is a promising candidate material for high temperature components operating in aggressive environments such as nuclear fusion and fission systems because of the excellent elevated temperature strength, corrosion and radiation resistance. These characteristics come from microstructures consisting of fine grains and nano-oxide particles dispersed in high number density. However, for more applications of ODS steel in nuclear systems, its weldability is the one of the barrier to be solved

  6. Microstructures and mechanical properties of 9Cr oxide dispersion strengthened steel produced by spark plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Rui [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials Science and Engineering, Northeastern University, Shenyang 110819 (China); School of Metallurgy, Northeastern University, Shenyang 110819 (China); Lu, Zheng, E-mail: luz@atm.neu.edu.cn [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials Science and Engineering, Northeastern University, Shenyang 110819 (China); Lu, Chenyang; Li, Zhengyuan [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials Science and Engineering, Northeastern University, Shenyang 110819 (China); Ding, Xueyong [School of Metallurgy, Northeastern University, Shenyang 110819 (China); Liu, Chunming [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials Science and Engineering, Northeastern University, Shenyang 110819 (China)

    2017-02-15

    Highlights: • A 9Cr-ODS steel was produced by mechanical alloying and spark plasma sintering. • Bimodal grain size distribution was observed. • Formation mechanism of bimodal grain size distribution was discussed. • The size and number density of nanoscale particles were obtained by SAXS and HRTEM. • The contribution of nano-sized particles to yield strength is dominating. - Abstract: 9Cr oxide dispersion strengthened (ODS) steel was fabricated by mechanical alloying (MA) and spark plasma sintering (SPS). The nano-sized particles, grain size distribution and mechanical properties of 9Cr-ODS steel sintered at 950 °C were studied by synchrotron radiation small angle X-ray scattering (SAXS), high-resolution transmission electron microscopy (HRTEM), electron backscatter diffraction (EBSD) and tensile experiment. The results showed that bimodal grain size distribution in the matrix is observed, which is attributed to the heterogeneous recrystallization process during the SPS. High-density nano-sized Y{sub 2}Ti{sub 2}O{sub 7} and some large oxides of Cr{sub 2}Mn(Ti)O{sub 4} are formed in 9Cr-ODS steel. The number density and average size of Y{sub 2}Ti{sub 2}O{sub 7} obtained from SAXS are 4.72 × 10{sup 22}/m{sup 3} and 4.4 nm, respectively. The yield strengths of 9Cr-ODS steel fabricated by SPS are compared with the typical 9Cr-ODS steel produced by HIP.

  7. Stress-controlled inelastic behavior of modified 9 Cr-1 Mo steel at elevated temperatures

    International Nuclear Information System (INIS)

    Taguchi, Kosei.

    1989-01-01

    Interest in the ferritic steels of higher chromium concentration has increased recently because of an economical combination of mechanical and corrosion properties at elevated temperatures. A modified 9 Cr-1 Mo ferritic steel, developed in the United States, has been expected as an alternative structural material for fast breeder reactor components, in which Type 304 stainless steel or 2.25 Cr-1 Mo steel is currently used. For application of this material to the structural components, a lot of work has been done to develop evaluation methods for the deformation behavior and strength properties. The authors have studied the inelastic behavior and the creep-fatigue properties of modified 9 Cr-1 Mo steel at elevated temperatures, and proposed a constitutive equation and a creep-fatigue damage equation based on the overstress concept. In this paper, the applicability is discussed of the constitutive equation to stress-controlled inelastic behavior, such as creep strain hardening and stress cycling

  8. Tritiated Water Interaction with Stainless Steel

    International Nuclear Information System (INIS)

    Glen R. Longhurst

    2007-01-01

    Experiments conducted to study tritium permeation of stainless steel at ambient and elevated temperatures revealed that HT converts relatively quickly to HTO. Further, the HTO partial pressure contributes essentially equally with elemental tritium gas in driving permeation through the stainless steel. Such permeation appears to be due to dissociation of the water molecule on the hot stainless steel surface. There is an equilibrium concentration of HTO vapor above adsorbed gas on the walls of the experimental apparatus evident from freezing transients. The uptake process of tritium from the carrier gas involves both surface adsorption and isotopic exchange with surface bound water

  9. Influence of Z-phase on long-term creep stability of martensitic 9-12% Cr steels

    Energy Technology Data Exchange (ETDEWEB)

    Danielsen, Hilmar K. [Technical Univ. of Denmark, Lyngby (Denmark). Dept. of Mechanical Engineering; Hald, John [DONG Energy A/S (Denmark); Vattenfall (Denmark)

    2010-07-01

    The long-term creep strength of the new generation of martensitic creep resistant 9-12%Cr steels since the well-known steel Grade 91 relies strongly on particle strengthening by fine Mn nitrides based on V and Nb. During long-term high-temperature exposures the Mn nitrides may be replaced by the thermodynamically more stable Z-phases (Cr(V,Nb)N) causing a breakdown in creep strength. Cr contents above 10.5% strongly accelerate Z-phase precipitation, which explains the lack of success for all attempts to develop martensitic creep resistant steels with high Cr content for oxidation protection. However 9%Cr steels do not seem to be affected by the Z-phase. Careful control of the Z-phase precipitation process has led to the design of experimental 12%Cr martensitic steels strengthened by fine Z-phase nitrides based on Nb or Ta. Such steels may again enable the combination of high strength and oxidation resistance in the same alloy. This opens a new pathway for further alloy development of the heat resistant martensitic steels. (orig.)

  10. Development of ferritic-martensitic P9 steel for wrapper application in future SFRs

    International Nuclear Information System (INIS)

    Choudhary, B.K.; Mathew, M.D.; Isaac Samuel, E.; Moitra, A.

    2011-01-01

    The paper deals with the outcome of the research and development efforts directed towards the development of ferritic-martensitic P9 steel for wrapper application in future sodium cooled fast reactors with an objective to achieve high fuel burnup and more economical nuclear energy. The important and critical issues involved for the development of P9 wrappers such as optimisation of chemical composition in terms of trace elements like sulphur and phosphorous and appropriate thermo-mechanical treatments along with thermal ageing and irradiation effects on fracture properties have been discussed. Tensile properties evaluated at temperatures ranging from 300 to 873 K on the experimental three heats of P9 steel with different silicon contents and made using primary vacuum induction melting followed by secondary electro slag refining route, have been presented. Fracture behaviour examined mainly in terms of ductile to brittle transition temperature and upper shelf energy provided encouraging results. Based on these investigations, a roadmap has been drawn to make experimental P9 steel wrappers for tests in fast breeder test reactor and prototype fast breeder reactor. (author)

  11. Analysis of High Temperature Deformed Structure and Dynamic Precipitation in W9Mo3Cr4V Steel

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    With TEM、SEM, various high-temperature deformed structures inW9Mo3Cr4V steel were investigated. The sub-structures,recrystallized nuclei, as well as the dynamic precipitation were also studied and analyzed. The relationship between recrystallized structures and dynamic precipitation was discussed. The results showed that the deformed structures in W9Mo3Cr4V steel are more complicated than those in low alloy steels. Because W9Mo3Cr4V steel is a high-speed steel, there are a large number of residual carbides on the matrix. Also, much dynamic precipitating carbides will precipitate during deformation at high temperature.

  12. Review of Z phase precipitation in 9–12 wt-%Cr steels

    DEFF Research Database (Denmark)

    Danielsen, Hilmar Kjartansson

    2016-01-01

    For high temperature applications, 9–12 wt-%Cr steels in fossil fired power plants rely upon precipitate strengthening from (V,Nb)N MX nitrides for long term creep strength. During prolonged exposure at service temperature, another nitride precipitates: Cr(V,Nb)NZ phase. The Z phases lowly replace......MX, eventually causing a breakdown in creep strength. The present paper reviews the Z phase and its behaviour in 9–12 wt-%Cr steels including thermodynamic modelling, crystal structure, nucleation process and precipitation rate as a function of chemical composition. The influence of Z phase precipitation upon...

  13. Gas Gap Conductance between HT9 and SS316

    OpenAIRE

    Scoggins, Michael; Martinez, Chris; Song, Zhuorui

    2016-01-01

    inside a nuclear reactor, it is important to understand in detail the heat transfer between surfaces. This research aims to ensure the safety of new fuel experiments in the Idaho National Laboratory test reactor by studying the thermal properties of stainless steel and high temperature steel surfaces with a microscopic gas gap between them. The complex behavior of the gas requires a combination of experimental and theoretical modeling. A technique called laser flash analysis is being applied ...

  14. Diffusion bonding of 9Cr ODS ferritic/martensitic steel with a phase transformation

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Sanghoon, E-mail: shnoh@kaeri.re.kr [Nuclear Materials Division, Korea Atomic Energy Research Institute, Yuseong-gu, Daejeon (Korea, Republic of); Kimura, Akihiko [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto (Japan); Kim, Tae Kyu [Nuclear Materials Division, Korea Atomic Energy Research Institute, Yuseong-gu, Daejeon (Korea, Republic of)

    2014-10-15

    Highlights: • Diffusion bonding was employed to join 9Cr oxide dispersion strengthened ferritic/martensitic steel under uniaxial hydrostatic pressure, and the microstructure and tensile properties of the joints were investigated. • ODS steel was successfully diffusion bonded at an austenization temperature to migrate a residual diffusion bonding interface. • The tensile properties of the joint region were comparable with that of the base metal with a ductile fracture occurred far from the bonding interface. • It is considered that diffusion bonding with a phase transformation can be a very useful joining method for fabricating components in next-generation nuclear systems using 9Cr ODS ferritic/martensitic steel. - Abstract: Diffusion bonding was employed to join oxide-dispersion-strengthened ferritic/martensitic steel under uniaxial hydrostatic pressure using a high vacuum hot press, and the microstructure and tensile properties of the joints were investigated. 9Cr oxide dispersion strengthened (ODS) steel was successfully diffusion bonded at 1150 °C for 1 h to migrate a residual bonding interface. Following heat treatment, including normalising at 1050 °C and tempering at 800 °C for 1 h, comparable results without inclusions or micro-voids at the bonding interface, or degradation in the base metal were achieved. Transmission electron microscopy (TEM) observation revealed that the nano-oxide particles in the bonding region were uniformly distributed in the matrix. At room temperature, the joint had nearly the same tensile properties with that of the base metal. The tensile strength of the joint region at elevated temperatures was comparable with that of the base metal. The total elongation of the joint region decreased slightly, but reached 80% of the base metal at 700 °C, and a ductile fracture occurred far from the bonding interface. Therefore, it is considered that diffusion bonding with a phase transformation can be a very useful joining method for

  15. Effect of Isothermal Bainitic Quenching on Rail Steel Impact Strength and Wear Resistance

    Science.gov (United States)

    Çakir, Fatih Hayati; Çelik, Osman Nuri

    2017-09-01

    The effect of heat treatment regimes on hardness, impact strength, and wear resistance of rail steel for high-speed tracks (rail quality category R350HT) is studied. Analysis of steel properties with a different structure is compared: pearlitic, and upper and lower bainite. It is shown that the steel with bainitic structure has the best impact strength, but wear resistance is better for steel with a lower bainite structure.

  16. Consideration of the oxide particle-dislocation interaction in 9Cr-ODS steel

    Science.gov (United States)

    Ijiri, Yuta; Oono, N.; Ukai, S.; Yu, Hao; Ohtsuka, S.; Abe, Y.; Matsukawa, Y.

    2017-05-01

    The interaction between oxide particles and dislocations in a 9Cr-ODS ferritic steel is investigated by both static and in situ TEM observation under dynamic straining conditions and room temperature. The measured obstacle strength (?) of the oxide particles was no greater than 0.80 and the average was 0.63. The dislocation loops around some coarsened particles were also observed. The calculated obstacle strength by a stress formula of the Orowan interaction is nearly equaled to the average experimental value. Not only cross-slip system but also the Orowan interaction should be considered as the main interaction mechanism between oxide particles and dislocation in 9CrODS ferritic steel.

  17. Evaluation of dynamic fracture toughness of cold worked 9Cr-1Mo steel

    International Nuclear Information System (INIS)

    Sathyanarayanan, S.; Sasikala, G.; Ray, S.K.

    2004-01-01

    Dynamic J-R curves for cold worked 9Cr-1Mo steel have been estimated from instrumented impact test data at ambient temperature on pre-cracked Charpy specimens using three methods of analysis, namely those by Ray et al., Schindler, and Sreenivasan and Mannan. It is concluded that of these three, Schindler's method is the best suited for the purpose since it gives consistent variations with cold work of dynamic J-R curves and dynamic fracture toughness. Cold work results in substantial degradation in dynamic fracture toughness of 9Cr-1Mo steel

  18. Effect of laser absorption on picosecond laser ablation of Cr12MoV mold steel, 9Cr18 stainless steel and H13A cemented carbide

    Science.gov (United States)

    Wu, Baoye; Liu, Peng; Wang, Xizhao; Zhang, Fei; Deng, Leimin; Duan, Jun; Zeng, Xiaoyan

    2018-05-01

    Due to excellent properties, Cr12MoV mold steel, 9Cr18 stainless steel and H13A cemented carbide are widely used in industry. In this paper, the effect of absorption of laser light on ablation efficiency and roughness have been studied using a picosecond pulse Nd:YVO4 laser. The experimental results reveal that laser wavelength, original surface roughness and chemical composition play an important role in controlling ablation efficiency and roughness. Firstly, higher ablation efficiency with lower surface roughness is achieved on the ablation of 9Cr18 at 532, comparing with 1064 nm. Secondly, the ablation efficiency increases while the Ra of the ablated region decreases with the decrease of original surface roughness on ablation of Cr12MoV mold steel at 532 nm. Thirdly, the ablation efficiency of H13A cemented carbide is much higher than 9Cr18 stainless steel and Cr12MoV mold steel at 1064 nm. Scanning electron microscopy images reveals the formation of pores on the surface of 9Cr18 stainless steel and Cr12MoV mold steel at 532 nm while no pores are formed at 1064 nm. As to H13A cemented carbide, worm-like structure is formed at 1064 nm. The synergetic effects of the heat accumulation, plasma shielding and ablation threshold on laser ablation efficiency and machining quality were analyzed and discussed systematically in this paper.

  19. Fundamental flow and fracture studies of HT-9

    International Nuclear Information System (INIS)

    Odette, G.R.; Lucas, G.E.; Maiti, R.; Sheckherd, J.W.

    1984-01-01

    Results of electron microscopy studies of cleavage crack formation and propagation in HT-9 are consistent with a model for stress-controlled cleavage in which the critical stress sigma/sub f//sup */ is related to the lath packet size. Moreover, sigma/sub f//sup */ appears to undergo a sharp transition at low temperatures and high strain rates; this is probably a result of a change in mechanism from slip- to twinning-nucleated cleavage. This change in sigma/sub f//sup */ effects corresponding changes in lower shelf fracture toughness. A simple two-parameter approach is shown to be a reasonable basis for predicting fracture loads for various size and crack-geometry bend specimens. These results indicated that cleavage fracture will occur near plastic collapse loads for thin wall structures containing shallow surface cracks. Results of an initial study of ductility in the cleavage regime indicate deflectional displacements on the order of 1-2 cm/m will be the limit for such shallow surface cracks in thin walls. The effects of dissolved hydrogen and stress state variations induced by side grooving were investigated. Hydrogen charges resulted in an average reduction in measured K/sub O/ values of about 17% and 5% in the ratio of maximum load fracture-to-collapse stress ratios. No significant effect of hydrogen on ductility was observed. Side grooving resulted in increases in both apparent K/sub O/ toughness levels and fracture-to-collapse stress ratios. Side grooving decreased ductility for shallow cracks and increased it for deep cracks. In general these effects are judged to be relatively modest compared to uncertainties in the measurements and the effects of significant variations in size and strength levels

  20. An Experimental Investigation on Hardness and Microstructure of Heat Treated EN 9 Steel

    Science.gov (United States)

    Biswas, Palash; Kundu, Arnab; Mondal, Dhiraj

    2017-08-01

    In the modern engineering world, extensive research has led to the development of some special grades of steel, often suited for enhanced functions. EN 9 steel is one such grade, having major applications in power plants, automobile and aerospace industry. Different heat treatment processes are employed to achieve high hardness and high wear resistance, but machinability subsequently decreases. Existing literature is not sufficient to achieve a balance between hardness and machinability. The aim of this experimental work is to determine the hardness values and observe microstructural changes in EN9 steel, when it is subjected to annealing, normalizing and quenching. Finally, the effects of tempering after each of these heat treatments on hardness and microstructure have also been shown. It is seen that the tempering after normalizing the specimen achieved satisfactory results. The microstructure was also observed to be consisting of fine grains.

  1. Hydrogen degradation of 21-6-9 and medium carbon steel by disc pressure test

    International Nuclear Information System (INIS)

    Zhou, D.H.; Zhou, W.X.; Xu, Z.L.

    1986-01-01

    This paper reports the method of disc pressure test and the results for 21-6-9 stainless steel and medium carbon steel in hydrogen gas with different pressures and time of storage. The results show the hydrogen induced degradation of these two kinds of steel. An attempt was made to establish an index which uses variation of area of deformed disc to determine the degradation of ductility in a hydrogen environment. (orig.)

  2. Magnetic forces on a ferromagnetic HT-9 first wall/blanket and coolant pipe

    International Nuclear Information System (INIS)

    Lechtenberg, T.A.; Dahms, C.; Attaya, H.; Univ. of Wisconsin, Madison)

    1984-01-01

    The GFUN 3D code was used to model the toroidal fields and determine the magnetic body forces on the STARFIRE design for coolant pipes exiting the first wall sector and first wall/blanket modules. The HT-9 coolant pipes were modeled on the basis of a square bar having the same length and material volume as the coolant pipes. The stress analysis was performed using these magnetic forces applied to a pipe of 4 meters length, 8.25 cm O.D., and 0.75 cm thickness by the MODSAP stress analysis code. For the first wall/blanket module, GFUN 3D does not allow full modeling of the complex thin-walled structure or numerous small tubes because of the element aspect ratio limitations. Therefore, to obtain three dimensional loads, a solid homogeneous equivalent structure was used

  3. Creep-fatigue evaluation method for modified 9Cr-1Mo steel

    International Nuclear Information System (INIS)

    Wada, Y.; Aoto, K.

    1997-01-01

    As creep-fatigue evaluation methods on normalized and tempered Modified 9Cr-1Mo steel for design use, the time fraction rule and the simplified conventional ductility exhaustion rule are investigated for the prediction of tension strain hold creep-fatigue damage of this material. For the above investigation, stress relaxation behaviour during strain hold has to be analyzed using stress-strain-time relation. The initial value of stress relaxation was determined by cyclic stress-strain curves in continuous cycling fatigue tests. Cyclic stress-strain behaviour of Mod.9Cr-1Mo(NT) steel is different from that of austenitic stainless steels, so this effect was considered. Stress relaxation analysis was performed using static creep strain-time relation and conventional hardening rule. The time fraction by using the above stress relaxation analysis results can give good prediction for creep-fatigue life of Mod.9Cr-1Mo(NT) steel. For design use it is practical to be able to estimate creep damages conservatively by both strain behaviour of cyclic plastic (in continuous cycling fatigue tests) and monotonic creep (in standard creep tests). The life reduction by strain hold at the minimum peak of compressive stress in creep-fatigue tests was examined, and this effects can be evaluated by the relationship between the location of oxidation and the effective deformation at crack tip. In an accelerated oxidation environment, for example in high temperature and high pressure steam, a different approach for life reduction should be developed based on the mechanism of growth of oxide and crack growth with oxidation. However, in the creep damage dominant region, its effect is saturated and the effect of cavity growth along grain boundary becomes dominant for long-term strain hold in the high temperature conditions. (author). 6 refs, 6 figs

  4. Microstructure and long-term creep properties of 9–12% Cr steels

    DEFF Research Database (Denmark)

    Hald, John

    2008-01-01

    Advanced microstructure characterisation and microstructure modelling has demonstrated that long-term microstructure stability in 9–12% Cr steels under technical loading conditions is equivalent to precipitate stability. Mo and W can have a positive influence on long-term creep strength of 9–12% Cr...

  5. Changes of Serotonin (5-HT), 5-HT2A Receptor, and 5-HT Transporter in the Sprague-Dawley Rats of Depression,Myocardial Infarction and Myocardial Infarction Co-exist with Depression

    Institute of Scientific and Technical Information of China (English)

    Mei-Yan Liu; Yah-Ping Ren; Wan-Lin Wei; Guo-Xiang Tian; Guo Li

    2015-01-01

    Background:To evaluate whether serotonin (5-HT),5-HT2A receptor (5-HT2AR),and 5-HT transporter (serotonin transporter [SERT]) are associated with different disease states of depression,myocardial infarction (MI) and MI co-exist with depression in Sprague-Dawley rats.Methods:After established the animal model of four groups include control,depression,MI and MI with depression,we measured 5-HT,5-HT2AR and SERT from serum and platelet lysate.Results:The serum concentration of 5-HT in depression rats decreased significantly compared with the control group (303.25 ± 9.99 vs.352.98 ± 13.73;P =0.000),while that in MI group increased (381.78 ± 14.17 vs.352.98 ± 13.73;P =0.000).However,the depression + MI group had no change compared with control group (360.62 ± 11.40 vs.352.98 ± 13.73;P =0.036).The changes of the platelet concentration of 5-HT in the depression,MI,and depression + MI group were different from that of serum.The levels of 5-HT in above three groups were lower than that in the control group (380.40 ± 17.90,387.75 ± 22.28,246.40 ± 18.99 vs.500.29 ± 20.91;P =0.000).The platelet lysate concentration of 5-HT2AR increased in depression group,MI group,and depression + MI group compared with the control group (370.75 ± 14.75,393.47 ± 15.73,446.66 ± 18.86 vs.273.66 ± 16.90;P =0.000).The serum and platelet concentration of SERT in the depression group,MI group and depression + MI group were all increased compared with the control group (527.51 ± 28.32,602.02 ± 23.32,734.76 ± 29.59 vs.490.56 ± 16.90;P =0.047,P =0.000,P =0.000 in each and 906.38 ± 51.84,897.33 ± 60.34,1030.17 ± 58.73 vs.708.62 ± 51.15;P =0.000 in each).Conclusions:The concentration of 5-HT2AR in platelet lysate and SERT in serum and platelet may be involved in the pathway of MI with depression.Further studies should examine whether elevated 5-HT2AR and SERT may contribute to the biomarker in MI patients with depression.

  6. Long-term strength and allowable stresses of grade 10Kh9MFB and X10CrMoVNb9-1 (T91/P91) chromium heat-resistant steels

    Science.gov (United States)

    Skorobogatykh, V. N.; Danyushevskiy, I. A.; Schenkova, I. A.; Prudnikov, D. A.

    2015-04-01

    Currently, grade X10CrMoVNb9-1 (T91, P91) and 10Kh9MFB (10Kh9MFB-Sh) chromium steels are widely applied in equipment manufacturing for thermal power plants in Russia and abroad. Compilation and comparison of tensile, impact, and long-term strength tests results accumulated for many years of investigations of foreign grade X10CrMoVNb9-1, T91, P91, and domestic grade 10Kh9MFB (10Kh9MFB-Sh) steels is carried out. The property identity of metals investigated is established. High strength and plastic properties of steels, from which pipes and other products are made, for operation under creep conditions are confirmed. Design characteristics of long-term strength on the basis of tests with more than one million of hour-samples are determined ( and at temperatures of 500-650°C). The table of recommended allowable stresses for grade 10Kh9MFB, 10Kh9MFB-SH, X10CrMoVNb9-1, T91, and P91 steels is developed. The long-time properties of pipe welded joints of grade 10Kh9MFB+10Kh9MFB, 10Kh9MFB-Sh+10Kh9MFB-Sh, X10CrMoVNb9-1+X10CrMoVNb9-1, P91+P91, T91+T91, 10Kh9MFB (10Kh9MFB-Sh)+X10CrMoVNb9-1(T/P91) steels is researched. The welded joint reduction factor is experimentally determined.

  7. Conservation of 5-HT1A receptor-mediated autoinhibition of serotonin (5-HT neurons in mice with altered 5-HT homeostasis

    Directory of Open Access Journals (Sweden)

    Naozumi eAraragi

    2013-08-01

    Full Text Available Firing activity of serotonin (5-HT neurons in the dorsal raphe nucleus (DRN is controlled by inhibitory somatodendritic 5-HT1A autoreceptors. This autoinhibitory mechanism is implicated in the etiology of disorders of emotion regulation, such as anxiety disorders and depression, as well as in the mechanism of antidepressant action. Here, we investigated how persistent alterations in brain 5-HT availability affect autoinhibition in two genetically modified mouse models lacking critical mediators of serotonergic transmission: 5-HT transporter knockout (Sert -/- and tryptophan hydroxylase-2 knockout (Tph2 -/- mice. The degree of autoinhibition was assessed by loose-seal cell-attached recording in DRN slices. First, application of the 5-HT1A-selective agonist R(+-8-hydroxy-2-(di-n-propylaminotetralin showed mild sensitization and marked desensitization of 5-HT1A receptors in Tph2 -/- mice and Sert -/- mice, respectively. While 5-HT neurons from Tph2 -/- mice did not display autoinhibition in response to L-tryptophan, autoinhibition of these neurons was unaltered in Sert -/- mice despite marked desensitization of their 5-HT1A autoreceptors. When the Tph2-dependent 5-HT synthesis step was bypassed by application of 5-hydroxy-L-tryptophan (5-HTP, neurons from both Tph2 -/- and Sert -/- mice decreased their firing rates at significantly lower concentrations of 5-HTP compared to wildtype controls. Our findings demonstrate that, as opposed to the prevalent view, sensitivity of somatodendritic 5-HT1A receptors does not predict the magnitude of 5-HT neuron autoinhibition. Changes in 5-HT1A receptor sensitivity may rather be seen as an adaptive mechanism to keep autoinhibition functioning in response to extremely altered levels of extracellular 5-HT resulting from targeted inactivation of mediators of serotonergic signaling.

  8. The recovery of 5-HT transporter and 5-HT immunoreactivity in injured rat spinal cord.

    Science.gov (United States)

    Saruhashi, Yasuo; Matsusue, Yoshitaka; Fujimiya, Mineko

    2009-09-01

    Experimental spinal cord injury. To determine the role of serotonin (5-HT) and 5-HT transporter in recovery from spinal cord injury. We examined 5-HT and 5-HT transporter of spinal cord immunohistologically and assessed locomotor recovery after extradural compression at the thoracic (T8) spinal cord in 21 rats. Eighteen rats had laminectomy and spinal cord injury, while the remaining three rats received laminectomy only. All rats were evaluated every other day for 4 weeks, using a 0-14 point scale open field test. Extradural compression markedly reduced mean hindlimbs scores from 14 to 1.5 +/- 2.0 (mean +/- standard error of mean). The rats recovered apparently normal walking by 4 weeks. The animals were perfused with fixative 1-3 days, 1, 2 and 4 weeks (three rats in each) after a spinal cord injury. The 5-HT transporter immunohistological study revealed a marked reduction of 5-HT transporter-containing terminals by 1 day after injury. By 4 weeks after injury, 5-HT transporter immunoreactive terminals returned to the control level. The 5-HT immunohistological study revealed a reduction of 5-HT-containing terminals by 1 week after injury. By 4 weeks after injury, 5-HT immunoreactive fibers and terminals returned to the control level. We estimated the recovery of 5-HT transporter and 5-HT neural elements in lumbosacral ventral horn by ranking 5-HT transporter and 5-HT staining intensity and counting 5-HT and 5-HT transporter terminals. The return of 5-HT transporter and 5-HT immunoreactivity of the lumbosacral ventral horn correlated with locomotor recovery, while 5-HT transporter showed closer relationship with locomotor recovery than 5-HT. The presence of 5-HT transporter indicates that the 5-HT fibers certainly function. This study shows that return of the function of 5-HT fibers predict the time course and extent of locomotory recovery after thoracic spinal cord injury.

  9. Control of Amygdala Circuits by 5-HT Neurons via 5-HT and Glutamate Cotransmission.

    Science.gov (United States)

    Sengupta, Ayesha; Bocchio, Marco; Bannerman, David M; Sharp, Trevor; Capogna, Marco

    2017-02-15

    The serotonin (5-HT) system and the amygdala are key regulators of emotional behavior. Several lines of evidence suggest that 5-HT transmission in the amygdala is implicated in the susceptibility and drug treatment of mood disorders. Therefore, elucidating the physiological mechanisms through which midbrain 5-HT neurons modulate amygdala circuits could be pivotal in understanding emotional regulation in health and disease. To shed light on these mechanisms, we performed patch-clamp recordings from basal amygdala (BA) neurons in brain slices from mice with channelrhodopsin genetically targeted to 5-HT neurons. Optical stimulation of 5-HT terminals at low frequencies (≤1 Hz) evoked a short-latency excitation of BA interneurons (INs) that was depressed at higher frequencies. Pharmacological analysis revealed that this effect was mediated by glutamate and not 5-HT because it was abolished by ionotropic glutamate receptor antagonists. Optical stimulation of 5-HT terminals at higher frequencies (10-20 Hz) evoked both slow excitation and slow inhibition of INs. These effects were mediated by 5-HT because they were blocked by antagonists of 5-HT 2A and 5-HT 1A receptors, respectively. These fast glutamate- and slow 5-HT-mediated responses often coexisted in the same neuron. Interestingly, fast-spiking and non-fast-spiking INs displayed differential modulation by glutamate and 5-HT. Furthermore, optical stimulation of 5-HT terminals did not evoke glutamate release onto BA principal neurons, but inhibited these cells directly via activation of 5-HT 1A receptors and indirectly via enhanced GABA release. Collectively, these findings suggest that 5-HT neurons exert a frequency-dependent, cell-type-specific control over BA circuitry via 5-HT and glutamate co-release to inhibit the BA output. SIGNIFICANCE STATEMENT The modulation of the amygdala by serotonin (5-HT) is important for emotional regulation and is implicated in the pathogenesis and treatment of affective disorders

  10. Controlling the ductile to brittle transition in Fe–9%Cr ODS steels

    Energy Technology Data Exchange (ETDEWEB)

    Di Martino, S.F., E-mail: s.f.di-martino@lboro.ac.uk; Riddle, N.B.; Faulkner, R.G.

    2013-11-15

    Probably the most important range of materials for consideration as the blanket material for the tokamak design for fusion reactors ITER and DEMO is the high alloy Fe–9Cr oxide dispersion strengthened ferritic steels. Ferritic steels possess exceptional thermal conductivity and low thermal expansion and are resistant to void swelling. Their main drawback is high ductile to brittle transition temperatures, particularly in the oxide dispersion strengthened versions. This paper describes attempts to reduce the DBTT in an un-irradiated ferritic steel by a novel heat treatment procedure. New batches of high alloy Fe–9Cr oxide dispersion strengthened (Eurofer) ferritic steel have been produced by a powder metallurgy route, and relatively homogeneous material has been produced by hot isostatic pressing (HIP). Mini-Charpy test specimens were made from materials which had been subjected to a matrix of heat treatments with varying solution treatment temperature (ST), cooling rate from the ST temperature, and tempering treatment. The initial DBTT was in the range of 150–200 °C (423–473 K). Downward shifts of up to approximately 200 °C (473 K) have been observed after solution treatment at 1300 °C (1573 K) followed by slow cooling. This paper describes the microstructure of this material, and discussion is made of the likely microstructural factors needed to produce these DBTT downward shifts.

  11. Evaluation of mechanical properties and nano-meso structures of 9–11%Cr ODS steels

    Energy Technology Data Exchange (ETDEWEB)

    Tanno, Takashi, E-mail: tanno.takashi@jaea.go.jp [Japan Atomic Energy Agency, Oarai, Ibaraki 311-1393 (Japan); Ohtsuka, Satoshi; Yano, Yasuhide; Kaito, Takeji [Japan Atomic Energy Agency, Oarai, Ibaraki 311-1393 (Japan); Oba, Yojiro; Ohnuma, Masato [National Institute for Materials Science, Tsukuba 305-1195 (Japan); Koyama, Shinichi; Tanaka, Kenya [Japan Atomic Energy Agency, Oarai, Ibaraki 311-1393 (Japan)

    2013-09-15

    Highlights: • We successfully manufactured 11Cr-ODS steels with residual α-ferrite controlled. • Dispersion conditions of nano oxide particles were quantitatively characterized. • Tungsten solid solution could improve only tensile strength of ODS steels at 973 K. • Oxide dispersion strengthening was dominant in creep strength of ODS steels at 973 K. -- Abstract: This study carried out mechanical tests and microstructural characterizations of several 9Cr and 11Cr-ODS tempered martensitic steels. From those results, the appropriate chemical composition range of 11Cr-ODS tempered martensitic steel was discussed from the viewpoint of high temperature strength improvement. It was shown that the residual α-ferrite fraction in 11Cr-ODS steel was successfully controlled to the same level as the 9Cr-ODS steel, which has excellent high temperature strength, by selecting the chemical compositions on the basis of the multi-component phase diagram. The tensile strength decreased with decreasing W content from 2.0 to 1.4 wt%. On the other hand, creep strength at 973 K did not degrade by the decreasing W content. Both tensile strength and creep strength increased with increasing population of the nano-sized oxide particles. Small angle X-ray scattering analysis revealed that titanium and excess oxygen contents were key parameters in order to improve the dispersion conditions of nano-sized oxide particles.

  12. Silicon coating treatment to improve high temperature corrosion resistance of 9%Cr steels

    International Nuclear Information System (INIS)

    Hill, M.P.

    1989-01-01

    A silicon coating process is described which confers good protection on 9%Cr steels and alloys in CO 2 based atmospheres at high temperatures and pressures. The coatings are formed by decomposition of silane at temperatures above 720 K. Protective layers are typically up to 1 μm thick. The optimum coating conditions are discussed. The chemical state of the coatings has been investigated by X-ray photoelectron spectroscopy and has demonstrated the importance of avoiding silicon oxide formation during processing. Corrosion testing has been carried out for extended periods, up to 20 000 h, at temperatures between 753 and 853 K, in a simulated advanced gas cooled reactor gas at 4 MPa pressure. Benefit factors of up to 60 times have been measured for 9%Cr steels. Even higher values have been measured for 9Cr-Fe binary alloy on which a 1 μm coating was sufficient to eliminate significant oxidation over 19 000 h except at the specimen edges. The mechanism of protection is discussed. It is suggested that a silicon surface coating for protecting steels from high temperature corrosion has some advantages over adding silicon to the bulk metal. (author)

  13. Haliotis tuberculata hemocyanin (HtH): analysis of oligomeric stability of HtH1 and HtH2, and comparison with keyhole limpet hemocyanin KLH1 and KLH2.

    Science.gov (United States)

    Harris, J R; Scheffler, D; Gebauer, W; Lehnert, R; Markl, J

    2000-12-01

    The multimeric/higher oligomeric states of the two isoforms of Haliotis tuberculata hemocyanin (HtH1 and HtH2) have been assessed by transmission electron microscopy (TEM) of negatively stained specimens, for comparison with previously published structural data from keyhole limpet hemocyanin (KLH1 and KLH2) [see Harris, J.R., Gebauer, W., Guderian, F.U., Markl, J., 1997a. Keyhole limpet hemocyanin (KLH), I: Reassociation from Immucothel followed by separation of KLH1 and KLH2. Micron, 28, 31-41; Harris, J.R., Gebauer, W., Söhngen, S.M., Nermut, M.V., Markl, J., 1997b. Keyhole limpet hemocyanin (KLH). II: Characteristic reassociation properties of purified KLH1 and KLH2. Micron, 28, 43-56; Harris, J.R., Gebauer, W., Adrian, M., Markl, J., 1998. Keyhole limpet hemocyanin (KLH): Slow in vitro reassociation of KLH1 and KLH2 from Immucothel. Micron, 29, 329-339]. In purified samples of both HtH isoforms, the hollow cylindrical ca 8MDa didecamer predominates together with a small number of decamers, but tri- and longer multidecamers are detectable only in the HtH2. The stability of the two HtH isoforms under varying ionic conditions have been monitored, thereby enabling conditions for the production of stable decamers to be established. The ability of these decamers to reform multimers in the presence of 10 and 100mM concentrations of calcium and magnesium ions in Tris-HCl buffer (pH 7.4), and also of individual HtH1 and HtH2 subunits (produced by pH 9.6 dissociation in glycine-NaOH buffer), to reassociate in the presence of calcium and magnesium ions, has been assessed. For the HtH1 decamers, the predominant multimeric product is the didecamer at 10 and 100mM calcium and magnesium concentrations, whereas for the HtH2 decamers, large numbers of multidecamers are produced, with the reaction proceeding more completely at the higher calcium and magnesium concentration. With the HtH1 subunit, reassociation in the presence of 10 and 100mM calcium and magnesium ions yielded

  14. Dysfunctional attitudes and 5-HT2 receptors during depression and self-harm.

    Science.gov (United States)

    Meyer, Jeffrey H; McMain, Shelley; Kennedy, Sidney H; Korman, Lorne; Brown, Gregory M; DaSilva, Jean N; Wilson, Alan A; Blak, Thomas; Eynan-Harvey, Rahel; Goulding, Verdell S; Houle, Sylvain; Links, Paul

    2003-01-01

    Dysfunctional attitudes are negatively biased assumptions and beliefs regarding oneself, the world, and the future. In healthy subjects, increasing serotonin (5-HT) agonism with a single dose of d-fenfluramine lowered dysfunctional attitudes. To investigate whether the converse, a low level of 5-HT agonism, could account for the higher levels of dysfunctional attitudes observed in patients with major depression or with self-injurious behavior, cortex 5-HT(2) receptor binding potential and dysfunctional attitudes were measured in patients with major depressive disorder, patients with a history of self-injurious behavior, and healthy comparison subjects (5-HT(2) receptor density increases during 5-HT depletion). Twenty-nine healthy subjects were recruited to evaluate the effect of d-fenfluramine or of clonidine (control condition) on dysfunctional attitudes. Dysfunctional attitudes were assessed with the Dysfunctional Attitude Scale 1 hour before and 1 hour after drug administration. In a second experiment, dysfunctional attitudes and 5-HT(2) binding potential were measured in 22 patients with a major depressive episode secondary to major depressive disorder, 18 patients with a history of self-injurious behavior occurring outside of a depressive episode, and another 29 age-matched healthy subjects. Cortex 5-HT(2) binding potential was measured with [(18)F]setoperone positron emission tomography. In the first experiment, dysfunctional attitudes decreased after administration of d-fenfluramine. In the second experiment, in the depressed group, dysfunctional attitudes were positively associated with cortex 5-HT(2) binding potential, especially in Brodmann's area 9 (after adjustment for age). Depressed subjects with extremely dysfunctional attitudes had higher 5-HT(2) binding potential, compared to healthy subjects, particularly in Brodmann's area 9. Low levels of 5-HT agonism in the brain cortex may explain the severely pessimistic, dysfunctional attitudes associated

  15. Heat treated 9 Cr-1 Mo steel material for high temperature application

    Science.gov (United States)

    Jablonski, Paul D.; Alman, David; Dogan, Omer; Holcomb, Gordon; Cowen, Christopher

    2012-08-21

    The invention relates to a composition and heat treatment for a high-temperature, titanium alloyed, 9 Cr-1 Mo steel exhibiting improved creep strength and oxidation resistance at service temperatures up to 650.degree. C. The novel combination of composition and heat treatment produces a heat treated material containing both large primary titanium carbides and small secondary titanium carbides. The primary titanium carbides contribute to creep strength while the secondary titanium carbides act to maintain a higher level of chromium in the finished steel for increased oxidation resistance, and strengthen the steel by impeding the movement of dislocations through the crystal structure. The heat treated material provides improved performance at comparable cost to commonly used high-temperature steels such as ASTM P91 and ASTM P92, and requires heat treatment consisting solely of austenization, rapid cooling, tempering, and final cooling, avoiding the need for any hot-working in the austenite temperature range.

  16. Fracture Resistances of Y_2O_3 Particle Dispersion Strengthened 9Cr Steel at Room Temperature and High Temperatures

    International Nuclear Information System (INIS)

    Yoon, Ji Hyun; Kang, Suk Hoon; Lee, Yongbok; Kim, Sung Soo

    2012-01-01

    The fracture resistance and tensile properties of Y_2O_3 oxide dispersion strengthened steel containing 9 wt% Cr (9Cr-ODS) were measured at various temperatures up to 700°C. The fracture characteristics were compared with those of commercial E911 ferritic/martensitic steel. The strength of 9Cr-ODS was at least 30% higher than that of E911 steel at the test temperatures below 500°C. The strength difference between the two materials was almost diminished at 700°C. 9Cr-ODS showed cleavage fracture behavior at room temperature and unstable crack growth behaviors at 300°C and 500°C. The J-R fracture resistance of 9Cr-ODS was much lower than that of E911 steel at all temperatures. It was deduced that the coarse Cr_2O_3 particles that were formed during the alloying process provided the crack initiation sites of cleavage fracture in 9Cr-ODS.

  17. Creep behaviour of modified 9Cr-1Mo ferritic steel

    International Nuclear Information System (INIS)

    Choudhary, B.K.; Isaac Samuel, E.

    2011-01-01

    Creep deformation and fracture behaviour of indigenously developed modified 9Cr-1Mo steel for steam generator (SG) tube application has been examined at 823, 848 and 873 K. Creep tests were performed on flat creep specimens machined from normalised and tempered SG tubes at stresses ranging from 125 to 275 MPa. The stress dependence of minimum creep rate obeyed Norton's power law. Similarly, the rupture life dependence on stress obeyed a power law. The fracture mode remained transgranular at all test conditions examined. The analysis of creep data indicated that the steel obey Monkman-Grant and modified Monkman-Grant relationships and display high creep damage tolerance factor. The tertiary creep was examined in terms of the variations of time to onset of tertiary creep with rupture life, and a recently proposed concept of time to reach Monkman-Grant ductility, and its relationship with rupture life that depends only on damage tolerance factor. SG tube steel exhibited creep-rupture strength comparable to those reported in literature and specified in the nuclear design code RCC-MR.

  18. Thermal fatigue crack growth tests and analyses of thick wall cylinder made of Mod.9Cr–1Mo steel

    Energy Technology Data Exchange (ETDEWEB)

    Wakai, Takashi, E-mail: wakai.takashi@jaea.go.jp [Japan Atomic Energy Agency, 4002 Narita-cho Oarai, Ibaraki 3111393 (Japan); Inoue, Osamu [IX Knowledge Inc., 3-22-23 MSC Center Bldg, Kaigan Minato-ku, Tokyo 1080022 Japan (Japan); Ando, Masanori; Kobayashi, Sumio [Japan Atomic Energy Agency, 4002 Narita-cho Oarai, Ibaraki 3111393 (Japan)

    2015-12-15

    Highlights: • A thermal fatigue crack growth test was performed using Mod.9Cr–1Mo steel cylinder. • Axial/circumferential notches were machined on the inner surface of the cylinder. • Simplified analytical results were compared to the test data. • Crack length could not be predicted by the analyses because of crack conjunctions. • If there are no surface cracks, the calculations might agree with the observations. - Abstract: In Japan, the basic designing works for a demonstration plant of Japan Sodium cooled Fast Reactor (JSFR) are now conducted. JSFR is an advanced loop type reactor concept. To enhance the safety and the economic competitiveness, JSFR employs modified 9% chromium–1% molybdenum (Mod.9Cr–1Mo) steel as a material for coolant pipes and components, because the steel has both excellent high temperature strength and thermal properties. The steel has been standardized as a nuclear material in Japan Society of Mechanical Engineers (JSME) code in 2012. In JSFR pipes, demonstration of Leak Before Break (LBB) aspect is strongly expected because the safety assessment may be performed on the premise of leak rate where the LBB aspect is assured. Although the authors have already performed a series of thermal fatigue crack growth tests of austenitic stainless steel cylinders (Wakai et al., 2005), crack growth behavior in the structures made of Mod.9Cr–1Mo steel has not been investigated yet. Especially for the welded joints of Mod.9Cr–1Mo steel, “Type-IV” cracking may occur at heat affected zone (HAZ). Therefore, this study performed a series of thermal fatigue crack growth tests of thick wall cylinders made of Mod.9Cr–1Mo steel including welds, to obtain the crack growth data under cyclic thermal transients. The test results were compared to the analytical results obtained from JAEA's simplified methods (Wakai et al., 2005).

  19. An examination of the potential for 9%Cr1%Mo steel as thick section tubeplates in fast reactors

    International Nuclear Information System (INIS)

    Orr, J.; Sanderson, S.J.

    1984-01-01

    The steam generator units of future commercial demonstration fast reactors are likely to have a requirement for heavy section tubeplates (up to 500mm thick) with good elevated temperature strength and creep-fatigue resistance. A comparison of the mechanical properties available for ferritic steels has suggested that 9%Cr1%Mo steel would be a strong candidate material for this application. Although this steel is covered in some national specifications for tubes, pipes, plates and forgings and is also well established in the UK nuclear industry, international experience to date is confined to sections less than ca 150mm. The potential of 9%Cr1%Mo steel for use in thick sections has therefore been assessed in the present study by using simulation heat treatments. The work reported here involved the laboratory-scale cooling of bar samples to simulate water-quenching rates in cylindrical sections up to 720mm diameter (ie: equivalent to 500mm thick plate). The tensile properties at ambient and 525 0 C and impact fracture appearance transition temperatures were determined for material tempered after cooling at simulated thick section rates; the transformation characteristics as influenced by the net chromium equivalent were also established. The results of this work show that 9%Cr1%Mo steel may be fully hardened in the equivalent of the section sizes examined,and the mechanical properties of tempered material show only a small reduction from those of thin section normalised and tempered 9%Cr1%Mo steel. These findings support the potential usage of heavy section 9%Cr1%Mo steel envisaged for fast reactor steam generator tubeplates

  20. Boundary and sub-boundary hardening in tempered martensitic 9Cr steel during long-term creep at 650 C

    Energy Technology Data Exchange (ETDEWEB)

    Abe, Fujio [National Institute for Materials Science, Sengen, Tsukuba (Japan)

    2010-07-01

    The boundary and sub-boundary hardening is shown to be the most important strengthening mechanism in creep of the 9% Cr steel base metal and welded joints. The addition of boron reduces the coarsening rate of M{sub 23}C{sub 6} carbides along boundaries near prior austenite grain boundaries during creep, enhancing the boundary and sub-boundary hardening. This improves long-term creep strength of base metal. The enhancement of boundary and sub-boundary hardening is significantly reduced in fine-grained region of Ac{sub 3} HAZ simulated specimens of conventional steel P92. In NIMS 9Cr boron steel welded joints, the grain size and distribution of carbonitrides are substantially the same between the HAZ and base metal, where fine carbonitrides are distributed along the lath and block boundaries as well as along prior austenite grain boundaries. This is essential for the suppression of Type IV fracture in NIMS 9% Cr boron steel welded joints. Newly alloy-designed 9Cr steel with 160 ppm boron and 85 ppm nitrogen exhibits much higher creep rupture strength of base metal than P92 and also no Tpe-IV fracture in welded joints at 650 C. (orig.)

  1. 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.)

  2. Plaque deposition dependent decrease in 5-HT2A serotonin receptor in AbetaPPswe/PS1dE9 amyloid overexpressing mice

    DEFF Research Database (Denmark)

    Holm, Peter; Ettrup, Anders; Klein, Anders B

    2010-01-01

    -HT2A receptor regulation in double transgenic AbetaPPswe/PS1dE9 mice which display excess production of Abeta and age-dependent increase in amyloid plaques. Three different age-groups, 4-month-old, 8- month-old, and 11-month-old were included in the study. [3H]-MDL100907, [3H]-escitalopram, and [11C...

  3. Mechanical properties of martensitic alloy AISI 422

    International Nuclear Information System (INIS)

    Huang, F.H.; Hu, W.L.; Hamilton, M.L.

    1992-09-01

    HT9 is a martensitic stainless steel that has been considered for structural applications in liquid metal reactors (LMRs) as well as in fusion reactors. AISI 422 is a commercially available martensitic stainless steel that closely resembles HT9, and was studied briefly under the auspices of the US LMR program. Previously unpublished tensile, fracture toughness and charpy impact data on AISI 422 were reexamined for potential insights into the consequences of the compositional differences between the two alloys, particularly with respect to current questions concerning the origin of the radiation-induced embrittlement observed in HT9. 8 refs, 8 figs

  4. Forced swimming test and fluoxetine treatment: in vivo evidence that peripheral 5-HT in rat platelet-rich plasma mirrors cerebral extracellular 5-HT levels, whilst 5-HT in isolated platelets mirrors neuronal 5-HT changes.

    Science.gov (United States)

    Bianchi, M; Moser, C; Lazzarini, C; Vecchiato, E; Crespi, F

    2002-03-01

    Low levels of central serotonin (5-HT) have been related to the state of depression, and 5-HT is the major target of the newer antidepressant drugs such as selective serotonin reuptake inhibitors (SSRIs). Neurons and platelets display structural and functional similarities, so that the latter have been proposed as a peripheral model of central functions. In particular, in blood more than 99% of 5-HT is contained in platelets, so that one could consider changes in 5-HT levels in platelets as a mirror of changes in central 5-HT. Here, this hypothesis has been studied via the analysis of the influence of: (1) the forced swimming test (FST, which has been proved to be of utility to predict the clinical efficacy of antidepressants in rodents) and (2) treatment with the SSRI fluoxetine upon 5-HT levels monitored in brain regions and in peripheral platelets by means of electrochemical in vivo and ex vivo measurements. The results obtained confirm that the FST increases immobility; furthermore they show a parallel and significant decrease in cerebral (brain homogenate) and peripheral (in platelet-rich plasma, PRP) voltammetric 5-HT levels following the FST in naive rats. In addition, subchronic treatment with fluoxetine was followed by a significant increase in 5-HT levels in PRP, while the same SSRI treatment performed within the FST resulted in a decrease in the 5-HT levels in PRP. However, this decrease was inferior to that observed without SSRI treatment. These data suggest that there is an inverse relationship between immobility and the levels of 5-HT in PRP and that these peripheral 5-HT levels are sensitive to: (1) the FST, (2) the treatment with fluoxetine and (3) the combination of both treatments, i.e. SSRI + FST. It has been reported that SSRI treatment at first inhibits the 5-HT transporter in brain, resulting in increased extracellular 5-HT, while following sustained SSRI treatments decreased intracellular levels of central 5-HT were observed. Accordingly, the

  5. 5-HT3 and 5-HT4 antagonists inhibit peristaltic contractions in guinea-pig distal colon by mechanisms independent of endogenous 5-HT

    Directory of Open Access Journals (Sweden)

    Tiong Cheng Sia

    2013-08-01

    Full Text Available Recent studies have shown that endogenous serotonin is not required for colonic peristalsis in vitro, nor gastrointestinal (GI transit in vivo. However, antagonists of 5-Hydroxytryptamine (5-HT receptors can inhibit peristalsis and GI-transit in mammals, including humans. This raises the question of how these antagonists inhibit GI-motility and transit, if depletion of endogenous 5-HT does not cause any significant inhibitory changes to either GI-motility or transit ? We investigated the mechanism by which 5-HT3 and 5-HT4 antagonists inhibit distension-evoked peristaltic contractions in guinea-pig distal colon. In control animals, repetitive peristaltic contractions of the circular muscle were evoked in response to fixed fecal pellet distension. Distension-evoked peristaltic contractions were unaffected in animals with mucosa and submucosal plexus removed, that were also treated with reserpine (to deplete neuronal 5-HT. In control animals, peristaltic contractions were blocked temporarily by ondansetron (1-10µM and SDZ-205-557 (1-10µM in many animals. Interestingly, after this temporary blockade, and whilst in the continued presence of these antagonists, peristaltic contractions recovered, with characteristics no different from controls. Surprisingly, similar effects were seen in mucosa-free preparations, which had no detectable 5-HT, as detected by mass spectrometry. In summary, distension-evoked peristaltic reflex contractions of the circular muscle layer of the guinea-pig colon can be inhibited temporarily, or permanently, in the same preparation by selective 5-HT3 and 5-HT4 antagonists, depending on the concentration of the antagonists applied. These effects also occur in preparations that lack any detectable 5-HT. We suggest caution should be exercised when interpreting the effects of 5-HT3 and 5-HT4 antagonists; and the role of endogenous 5-HT, in the generation of distension-evoked colonic peristalsis.

  6. Galangin and kaempferol suppress phorbol-12-myristate-13-acetate-induced matrix metalloproteinase-9 expression in human fibrosarcoma HT-1080 cells.

    Science.gov (United States)

    Choi, Yu Jung; Lee, Young Hun; Lee, Seung-Taek

    2015-01-01

    Matrix metalloproteinase (MMP)-9 degrades type IV collagen in the basement membrane and plays crucial roles in several pathological implications, including tumorigenesis and inflammation. In this study, we analyzed the effect of flavonols on MMP-9 expression in phorbol-12-myristate-13-acetate (PMA)-induced human fibrosarcoma HT-1080 cells. Galangin and kaempferol efficiently decreased MMP-9 secretion, whereas fisetin only weakly decreased its secretion. Galangin and kaempferol did not affect cell viability at concentrations up to 30 μM. Luciferase reporter assays showed that galangin and kaempferol decrease transcription of MMP-9 mRNA. Moreover, galangin and kaempferol strongly reduce IκBα phosphorylation and significantly decrease JNK phosphorylation. These results indicate that galangin and kaempferol suppress PMA-induced MMP-9 expression by blocking activation of NF-κB and AP-1. Therefore, these flavonols could be used as chemopreventive agents to lower the risk of diseases involving MMP-9.

  7. Effects of welding on toughness of Mod. 9Cr-1Mo steel

    International Nuclear Information System (INIS)

    Ryu, W. S.; Kim, S. H.; Yoon, J. H.

    2008-01-01

    Nuclear energy is being seriously considered to meet the increasing demand for a world-wide energy supply without environmental effects. Generation IV reactors are being developed to produce a reliable energy safely and with an economic benefit. Since these new reactors require an elevated temperature, ferritic/martensitic steels are attracting attention as candidate materials for the reactor vessel of a very high temperature reactor (VHTR) and the cladding of a sodium fast reactor (SFR,) due to their high strength and thermal conductivity, low thermal expansion, and good resistance to corrosion. in recent years, new ferritic/martensitic steels have been developed for ultra supercritical fossil power plants. Advanced technologies for a steel fabrication have improved the elevated temperature properties of ferritic/martensitic steels to make them comparable with austenitic stainless steels. The microstructural stability of the pressure vessel, cladding and core structural materials of the VHTR and SCWR is very important. Welding process affects the microstructure and residual stress, so the toughness of ferritic/martensitic steels decreases in general. In this paper; Mod. 9Cr-1Mo steel is welded by SMAW with V-groove, and the effects of welding on tensile and impact properties are evaluated. The upper self energy of the weldment was only 57% of that of the base metal, and the DBTT T 41J and T 68J index temperatures of the weldment were higher than those of the base metal by 17 deg. C, 38 deg. C and 37 deg. C, respectively. (authors)

  8. Influences mass concentration of P3HT and PCBM to application of organic solar cells

    International Nuclear Information System (INIS)

    Supriyanto, A.; Maya; Iriani, Y.; Ramelan, A. H.; Nurosyid, F; Rosa, E. S.

    2016-01-01

    Poly (3-hexylthiophene) (P3HT) and [6, 6] -phenyl-C61-butyric acid methyl ester (PCBM) are used for the organic solar cell applications. P3HT and PCBM act as donors and acceptors, respectively. In this study the efficiency of the P3HT: PCBM organic solar cells as function of the mass concentration of the blend P3HT: PCBM with 1, 2, 8, 16 mg/ml. Deposition P3HT:PCBM film using spin coating with a rotary speed of 2500 rpm for 10 seconds. Optical properties of absorption spectra characteristic using a UV-Visible Spectrometer Lambda 25 and electrical properties of I-V characteristic using Keithley 2602 instrument. The results of absoption spectra for P3HT:PCBM within different mass concentration obtained 500-600 nm wavelengths. The Energy-gap obtained about 1.9eV. The organic solar cells device performance were investigated using I-V cahractyeristic. For mass concentration of 1, 2, 8 and 16 mg/ml P3HT:PCBM were obtained 0.5×10 -3 %, 2.2×10 -3 %, 5.9×10 -3 %, and 6.1×10 -3 % efficiency of organics solar cells respectively. (paper)

  9. Effect of normalization heat treatment on creep and tensile properties of modified 9Cr-1Mo steel

    International Nuclear Information System (INIS)

    Panneer Selvi, S.; Sakthivel, T.; Parameswaran, P.; Laha, K.

    2016-01-01

    Creep and tensile properties have been investigated on modified 9Cr-1Mo steel subjected to single and double normalization heat treatments. Optical, scanning and transmission electron microscopic investigation revealed the presence of refined prior austenite grain size and fine M 23 C 6 precipitates in the double normalized steel compared to the steel subjected to single normalization heat treatment. Increased creep strain and significant reduction in creep rupture life were observed with the double normalized steel in comparison with single normalized steel. Increased tensile ductility coupled with marginal decrease in tensile strength at higher test temperature was observed with double normalized steel compared to single normalized steel. It has been attributed to the presence of refined prior austenite grain size and coarsening of Nb rich MX precipitates in double normalized steel. (author)

  10. Strength behaviour of 10CrMo9.10 steel in nonsteady-state applications

    International Nuclear Information System (INIS)

    Seidel, C.

    2 testing runs with cyclic temperature increase were conducted on steel 10CrMo9.10 samples, i.e., at 500 degC and cyclic increase by 10, 25 and 50 degC, and at 550 degC and cyclic increase by 50 degC. Long-term strength was studied under a strain of 6.1 to 25.6 kp/mm 2 for 22,000 hours and the effect of periodical unloading was investigated on long-term strength at 550 degC. Sample loading and unloading proceeded within the range of 8.8 to 24.7 kp/mm 2 at an unloading rate of 8 to 100 %/min. Steel lifetime was not affected by the number of cycles. The effect of the changing load and of constant temperature without load on the long-term strength of the steel at 550 degC is shown graphically. The results showed a clear dependence of steel life on dwell time at the given temperature without load. (J.P.)

  11. 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.

  12. Fabrication of P3HT/gold nanoparticle LB films by P3HT templating Langmuir monolayer

    International Nuclear Information System (INIS)

    Chen, Liang-Huei; Hsu, Wen-Ping; Chan, Han-Wen; Lee, Yuh-Lang

    2014-01-01

    Highlights: • Addition of ODA into the P3HT monolayer can significantly improve the dispersion ability of P3HT molecules. • The adsorption ability of the P3HT monolayer to the dispersed AuNPs can also be enhanced by the presence of ODA. - Abstract: Regioregular poly(3-hexyl thiophene) (rr-P3HT) and mixed P3HT/octadecyl amine (ODA) were used as template monolayers to adsorb the gold nanoparticles (AuNPs) dispersed in subphase. The behaviors of P3HT and P3HT/ODA monolayers were investigated by surface pressure area per molecule (π–A) isotherms, transmission electron microscopy (TEM) and atomic force microscopy (AFM). The experimental results show that P3HT does not form a homogeneous film and tends to aggregate at the air/water interface. Meanwhile, the amount of AuNPs adsorbed by the P3HT monolayers is low, attributable to the weak interaction between AuNPs and P3HT. By introduction of ODA molecules into the P3HT monolayer, the spreading of P3HT molecules at the air/water interface is improved and the aggregation of P3HT is significantly inhibited. A nearly uniform and homogeneously mixed P3HT/ODA monolayer can be obtained when 50% of ODA is introduced. It is also found that the introduction of ODA can significantly increase the adsorption of AuNPs. For the mixed monolayer with low ratio of ODA (P3HT/ODA = 1/0.2), a higher concentration of adsorbed AuNPs was observed on the corresponding monolayer. However, when the ODA/P3HT ratio increases to 1/1, the AuNPs tend to form three-dimensional (3D) aggregates and the AuNPs cannot distribute well as a homogeneous monolayer. This result is ascribed to the increasing hydrophobicity of the adsorbed AuNPs because of capping of more ODA molecules

  13. Improved creep and oxidation behavior of a martensitic 9Cr steel by the controlled addition of boron and nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Mayr, Peter [Massachusetts Institute of Technology, Cambridge, MA (United States). Dept. of Materials Science; Graz Univ. of Technology (Austria). Inst. of Material Science and Welding; Holzer, Ivan; Mendez-Martin, Francisca [Graz Univ. of Technology (Austria). Inst. of Material Science and Welding; Albu, Mihaela; Mitsche, Stefan [Graz Univ. of Technology (Austria). Inst. for Electron Microscopy; Gonzalez, Vanessa; Agueero, Alina [Instituto Nacional de Tecnica Aeroespacial, Torrejon de Ardoz (Spain)

    2010-07-01

    This manuscript gives an overview on recent developments of a martensitic steel grade based on 9Cr3W3CoVNb with controlled additions of boron and nitrogen. Alloy design by thermodynamic equilibrium calculations and calculation of boron-nitrogen solubility is discussed. Out of this alloy design process, two melts of a 9Cr3W3CoVNbBN steel were produced. The investigation focused on microstructural evolution during high temperature exposure, creep properties and oxidation resistance in steam at 650 C. Microstructural characterization of ''as-received'' and creep exposed material was carried out using conventional optical as well as advanced electron microscopic methods. Creep data at 650 was obtained at various stress levels. Longest-running specimens have reached more than 20,000 hours of testing time. In parallel, long-term oxidation resistance has been studied at 650 C in steam atmosphere up to 5,000 hours. Preliminary results of the extensive testing program on a 9Cr3W3CoVNbBN steel show significant improvement in respect to creep strength and oxidation resistance compared to the state-of-the-art 9 wt. % Cr martensitic steel grades. Up to current testing times, the creep strength is significantly beyond the +20% scatterband of standard grade P92 material. Despite the chromium content of 9 wt % the material exhibits excellent oxidation resistance. Steam exposed plain base material shows comparable oxidation behavior to coated material, and the corrosion rate of the boron-nitrogen controlled steel is much lower compared to standard 9 wt % Cr steel grades, P91 and P92. (orig.)

  14. Creep strength and microstructural evolution of 9-12% Cr heat resistant steels during creep exposure at 600 C and 650 C

    Energy Technology Data Exchange (ETDEWEB)

    Mendez Martin, Francisca [Graz Univ. of Technology (Austria). Inst. for Materials Science and Welding; Panait, Clara Gabriela [MINES ParisTech, UMR CNRS, Evry (France). Centre des Materiaux; V et M France CEV, Aulnoye-Aymeries (France); Bendick, Walter [Salzgitter Mannesmann Forschung GmbH (SZMF), Duisburg (DE)] (and others)

    2010-07-01

    9-12% Cr heat resistant steels are used for applications at high temperatures and pressures in steam power plants. 12% Cr steels show higher creep strength and higher corrosion resistance compared to 9% Cr steels for short term creep exposure. However, the higher creep strength of 12 %Cr steels drops increasingly after 10,000-20,000 h of creep. This is probably due to a microstructural instability such as the precipitation of new phases (e.g. Laves phases and Z-phases), the growth of the precipitates and the recovery of the matrix. 9% Cr and 12% Cr tempered martensitic steels that have been creep tested for times up to 50,000 h at 600 C and 650 C were investigated using Transmission Electron Microscopy (TEM) on extractive replicas and thin foils together with Backscatter Scanning Electron Microscopy (BSE-SEM) to better understand the different creep behaviour of the two different steels. A significant precipitation of Laves phase and low amounts of Z-phase was observed in the 9% Cr steels after long-term creep exposure. The size distribution of Laves phases was measured by image analysis of SEM-BSE images. In the 12% Cr steel two new phases were identified, Laves phase and Z-phase after almost 30,000 h of creep test. The quantification of the different precipitated phases was studied. (orig.)

  15. Effect of Welding Processes on the Microstructure, Mechanical Properties and Residual Stresses of Plain 9Cr-1Mo Steel Weld Joints

    Science.gov (United States)

    Nagaraju, S.; Vasantharaja, P.; Brahadees, G.; Vasudevan, M.; Mahadevan, S.

    2017-12-01

    9Cr-1Mo steel designated as P9 is widely used in the construction of power plants and high-temperature applications. It is chosen for fabricating hexcan fuel subassembly wrapper components of fast breeder reactors. Arc welding processes are generally used for fabricating 9Cr-1Mo steel weld joints. A-TIG welding process is increasingly being adopted by the industries. In the present study, shielded metal arc (SMA), tungsten inert gas (TIG) and A-TIG welding processes are used for fabricating the 9Cr-1Mo steel weld joints of 10 mm thickness. Effect of the above welding processes on the microstructure evolution, mechanical properties and residual stresses of the weld joints has been studied in detail. All the three weld joints exhibited comparable strength and ductility values. 9Cr-1Mo steel weld joint fabricated by SMAW process exhibited lower impact toughness values caused by coarser grain size and inclusions. 9Cr-1Mo steel weld joint fabricated by TIG welding exhibited higher toughness due to finer grain size, while the weld joint fabricated by A-TIG welding process exhibited adequate toughness values. SMA steel weld joint exhibited compressive residual stresses in the weld metal and HAZ, while TIG and A-TIG weld joint exhibited tensile residual stresses in the weld metal and HAZ.

  16. Getost võrsunud täht kingib lootuse / Triin Oppi

    Index Scriptorium Estoniae

    Oppi, Triin

    2007-01-01

    Vt. ka Postimees : na russkom jazõke 9. jaan., lk. 9. USA miljardärist meediatäht Oprah Winfrey avas alanud aasta teisel päeval sadadele viletsates tingimustes elanud 11-13-aastastele tüdrukutele omanimelise kooli Lõuna-Aafrikas

  17. The effects of manipulation of presynaptic 5-HT nerve terminals of postsynaptic 5-HT1 and 5-HT2 binding sites of the rat brain

    International Nuclear Information System (INIS)

    Hall, H.; Wedel, I.

    1985-01-01

    The effects of long-term treatment of rats with alaproclate and amiflamine on the number and kinetics of 5-HT 1 and 5-HT 2 binding sites were investigated using in vitro receptor binding techniques. Some other studies have reported down-regulatory effects of alaproclate and amiflamine on 5-HT 2 binding sites in certain regions of the rat forebrain, but no such effects could be detected in the present study. Induction of a high-affinity binding site for 3 H-5-HT after long-term antidepressant treatment, as has been reported elsewhere, was not obtained in the present study. The results are compared to the effects obtained by treatment of rats with para-chloroamphetamine (PCA), which depletes the presynaptic neurons of monoamines. These different types of treatment do not cause any change in the binding properties of the specific 5-HT binding sites. It is thus concluded that such manipulations of the presynaptic 5-HT neurons do not affect the postsynaptic 5-HT 1 and 5-HT 2 binding sites. (Author)

  18. HTO/HT discriminating samplers constructed for the french experiment on the environmental behaviour of HT

    International Nuclear Information System (INIS)

    Ogram, G.L.

    1988-12-01

    The French Experiment on Environmental Tritium Behaviour was a field experiment carried out to determine the rate of formation of atmospheric HTO from a release of HT to the natural environment. The Canadian Fusion Fuels Technology Project and Ontario Hydro contributed to the project by supplying HTO/HT-discriminating, atmospheric tritium samplers. Each sampler consisted of a molecular-sieve trap to capture HTO followed by a Pd-impregnated molecular-sieve trap to oxidise and collect HT from the same air stream. This method was selected as it provided high sensitivity over short sampling periods and was convenient for field use. Laboratory tests indicated that this system measured HT concentrations reliably, but only achieved limited discrimination between HT and HTO at HTO/HT concentration ratios below 10 -2 to 10 -3 . Small cold traps were therefore operated during the French experiment in addition to the molecular-sieve samplers exhibited much improved discrimination in the field (approaching 10 4 ), possibly due to higher sampling flow rates than used in the laboratory. These results demonstrate that care should be taken in using desiccant-based, HTO/HT-discriminating samplers when the HT concentration is much higher than HTO concentration, and suggest the need to systematically characterize and perhaps improve the performance of discriminating samplers at low HTO/HT ratios

  19. Development of oxide dispersion strengthened 9Cr ferritic-martensitic steel clad tube for fast reactor

    International Nuclear Information System (INIS)

    Laha, K.; Saroja, S.; Mathew, M.D.; Jayakumar, T.; Vijay, R.; Venugopal Reddy, A.; Lakshminarayana, B.; Kapoor, Komal; Jha, S.K.; Tonpe, S.S.

    2012-01-01

    One of the key issues in the economical operation of FBR is to achieve high burn-up of fuel (200-250 GWd/t) which considerably reduces the fuel cycle cost. This imposes stringent requirements of void swelling resistance upto 200 dpa for the core structural materials. Presently used alloy 09 (a modified austenitic stainless steel, 15Cr-15Ni-Ti) for PFBR has void swelling limit less than 150 dpa. Because of the inherent void swelling resistance, 9-12Cr steels ferritic/martensitic steels are qualified for irradiation upto 200 dpa but their low creep strength at temperatures above 600 deg C restricts their application as a clad material. Oxide dispersion strengthening is found to be promising means of extending the creep resistance of ferritic/martensitic steels beyond 650 deg C without sacrificing the inherent advantages of high thermal conductivity and low swelling of ferritic steels

  20. Impression creep behaviour of Mod. 9Cr-1Mo steel weld joints

    International Nuclear Information System (INIS)

    Ridhin Raj, V.R.; Kottda, Ravi Sankar; Kamaraj, M.; Maduraimuthu, V.M.; Vasudevan, M.

    2016-01-01

    P91 steel (9Cr-1Mo) steel is extensively used in power plants for super heater coils, headers and steam piping. The aim of the present work is to study the creep behaviour of different zones of A-TIG weld joint using impression creep technique and compare it with that of the TIG weld joint. P91 steel weld joints were made by A-TIG welding without using any filler material and multi-pass TIG welding is done using ER90S-B9 filler rods. Welds were subjected to post-weld heat treatment (PWHT). Impression creep tests were carried out at 650 °C on the base metal, weld metal and HAZ regions. Optical Microscope and TEM were used to correlate microstructures with observed creep rates. The FGHAZ showed significantly higher impression creep rate compared to that of the base metal and weld metal. Fine grain size and relatively coarser M 23 C 6 carbide particles are responsible for higher creep rate. The impression creep rate of A-TIG weld metal and coarse grain HAZ was found to be lower than that of base metal. This is attributed to the higher grain size in weld metal and coarse HAZ attributed to the higher grain size in weld metal and to the higher peak temperature observed during A-TIG welding. (author)

  1. Hydrothermal Valorization of Steel Slags—Part I: Coupled H2 Production and CO2 Mineral Sequestration

    Directory of Open Access Journals (Sweden)

    Camille Crouzet

    2017-10-01

    Full Text Available A new process route for the valorization of BOF steel slags combining H2 production and CO2 mineral sequestration is investigated at 300°C (HT under hydrothermal conditions. A BOF steel slag stored several weeks outdoor on the production site was used as starting material. To serve as a reference, room temperature (RT carbonation of the same BOF steel slag has been monitored with in situ Raman spectroscopy and by measuring pH and PCO2 on a time-resolved basis. CO2 uptake under RT and HT are, respectively, 243 and 327 kg CO2/t of fresh steel slag, which add up with the 63 kg of atmospheric CO2 per ton already uptaken by the starting steel slag on the storage site. The CO2 gained by the sample at HT is bounded to the carbonation of brownmillerite. H2 yield decreased by about 30% in comparison to the same experiment performed without added CO2, due to sequestration of ferrous iron in a Mg-rich siderite phase. Ferric iron, initially present in brownmillerite, is partitioned between an Fe-rich clay mineral of saponite type and metastable hematite. Saponite is likely stabilized by the presence of Al, whereas hematite may represent a metastable product of brownmillerite carbonation. Mg-rich wüstite is involved in at least two competing reactions, i.e., oxidation into magnetite and carbonation into siderite. Results of both water-slag and water-CO2-slag experiments after 72 h are consistent with a kinetics enhancement of the former reaction when a CO2 partial pressure imposes a pH between 5 and 6. Three possible valorization routes, (1 RT carbonation prior to hydrothermal oxidation, (2 RT carbonation after hydrothermal treatment, and (3 combined HT carbonation and oxidation are discussed in light of the present results and literature data.

  2. Irradiation performance of 9--12 Cr ferritic/martensitic stainless steels and their potential for in-core application in LWRs

    International Nuclear Information System (INIS)

    Jones, R.H.; Gelles, D.S.

    1993-08-01

    Ferritic-martensitic stainless steels exhibit radiation stability and stress corrosion resistance that make them attractive replacement materials for austenitic stainless steels for in-core applications. Recent radiation studies have demonstrated that 9% Cr ferritic/martensitic stainless steel had less than a 30C shift in ductile-to-brittle transition temperature (DBTT) following irradiation at 365C to a dose of 14 dpa. These steels also exhibit very low swelling rates, a result of the microstructural stability of these alloys during radiation. The 9 to 12% Cr alloys to also exhibit excellent corrosion and stress corrosion resistance in out-of-core applications. Demonstration of the applicability of ferritic/martensitic stainless steels for in-core LWR application will require verification of the irradiation assisted stress corrosion cracking behavior, measurement of DBTT following irradiation at 288C, and corrosion rates measurements for in-core water chemistry

  3. Kinetics of Z-Phase Precipitation in 9 to 12 pct Cr Steels

    DEFF Research Database (Denmark)

    Danielsen, Hilmar Kjartansson; Nunzio, Paolo Emilio di; Hald, John

    2013-01-01

    precipitated Z-phase 20 to 50 times faster than the 9 pct Cr steel. Transmission electron microscopy (TEM) was applied to follow the Z-phase precipitation, using energy-dispersive X-ray spectroscopy (EDS) line scans and atomic resolution imaging. © The Minerals, Metals & Materials Society and ASM International...

  4. Mechanical behavior of 9Cr-1Mo-1V steel due to creep fatigue deformation

    International Nuclear Information System (INIS)

    Kim, Sang Tae; Kim, Jae Kyoung; Lee, Hak Sun; Oh, Sang Hyun; Kwun, Sook In; Kim, Chung Seok

    2005-01-01

    Creep-fatigue tests with trapezoid load wave were performed on a 9Cr-1Mo-1V steel at high temperature(550 .deg. C). Trapezoid load wave is considering about hold time for creep effects. we could find out some information in the relationship between number of cycles to failure and hold time. The number of cycles to failure depended on hold time. The cyclic behavior of 9Cr-1Mo-1V steel was characterized by cyclic softening with increasing number of cycles in high temperature. Also we could observe some cavity in the specimens. The size of cavity was different from each hold time

  5. Preliminary results of effect of environment on the low cycle fatigue behaviour of type 316 stainless steel and 9% Cr ferritic steel

    International Nuclear Information System (INIS)

    Wood, D.S.; Slattery, G.F.; Wynn, J.; Connaughton, M.D.; Lambert, M.E.

    1976-06-01

    Strain controlled fatigue tests on Type 316 steel at 625 0 C and 9% Cr steel at 525 0 C have been performed in air and in helium containing 200 μ atm H 2 and 1 μ atm H 2 O. In rapid cycling the endurance of Type 316 steel in this helium mixture was found to be about five times longer than in air. When a hold time was introduced into the tension part of the cycle however the endurance in the two environments was found to be virtually identical. Fractomicrographic examinations have been performed which have helped to explain some of these findings which are attributed to differences in oxidation behaviour at the crack tip. In the case of the 90% Cr steel the endurance in the helium mixture was found to be only slightly better than in air. The implications of these results are considered in relation to thermal shock effects on sodium cooled fast reactor components. (author)

  6. Optimum tungsten content in high strength 9 to 12% chromium containing creep resistant steels

    International Nuclear Information System (INIS)

    Hasegawa, Y.; Muraki, T.; Mimura, H.

    2000-01-01

    Tungsten containing ferritic creep resistant steels are the candidate materials for ultra-super-critical fossil power plant because of their high creep rupture strength. But the strengthening mechanisms by tungsten addition have not yet been completely studied. In this report, creep rupture time and creep strain rate measurement decided the optimum tungsten content in 9 to 12% chromium ferritic steels. The precipitation behavior of Laves phase and the precise discussion of creep strain rate analyses explain the contribution of Laves phase at the lath boundary and the contribution of tungsten in solid solution. P92 contains the optimum amount of tungsten and chromium, 1.8 mass% and 9 mass% respectively judging from the creep rupture strength point of view. (orig.)

  7. Irradiation hardening of Mod.9Cr-1Mo steel

    International Nuclear Information System (INIS)

    Ryu, Woo-Seog; Kim, Sung-Ho; Choo, Kee-Nam; Kim, Do-Sik

    2009-01-01

    An irradiation test of Mod.9Cr-1Mo steel was carried out in the OR5 test hole of HANARO of a 30 MW thermal power at 390±10degC up to a fast neutron fluence of 4.4x10 19 (n/cm 2 ) (E > 1.0 MeV). The dpa of the irradiated specimens was evaluated to be 0.034 - 0.07. Tensile and impact tests of the irradiated Mod.9Cr-1Mo were done in the hot cell of the IMEF. The change of the tensile strength by irradiation was similar to the change of the yield strength. The increase of the yield and tensile strengths was up to 18% and 10% respectively. The elongation reduction of the weldment was up to 65%. (author)

  8. Thermal Aging Evaluation of Mod. 9Cr-1Mo Steel using Nonlinear Rayleigh Waves

    Energy Technology Data Exchange (ETDEWEB)

    Joo, Young-Sang; Kim, Hoe-Woong; Kim, Jong-Bum [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Marino, Daniel; Kim, Jin-Yeon; Jacobs, L.J [Georgia Institute of Technology, Atlanta (United States); Ruiz, Alberto [UMSNH, Morelia (Mexico)

    2014-10-15

    Thermal aging can pose a high risk to decreases in the mechanical properties such as strength or creep resistance. This can lead to an unexpected failure during long term operation. Nonlinear NDE techniques are preferred over conventional NDE techniques (linear ultrasonic measurements) because nonlinear ultrasonic techniques have shown their capability to detect a microstructural damage in the structures undergoing fatigue and creep. These nonlinear ultrasonic techniques make use of the fact that the dislocation density increases, which will create a nonlinear distortion of an ultrasonic wave; this damage causes the generation of measurable higher harmonic components in an initially mono-chromatic ultrasonic signal. This study investigates the recently developed non-contact nonlinear ultrasonic technique to detect the microstructural damage of mod. 9Cr-1Mo steel based on nonlinear Rayleigh wave with varying propagation distances. Nonlinear Rayleigh surface wave measurements using a non-contact, air-coupled ultrasonic transducer have been applied for the thermal aging evaluation of modified 9Cr-1Mo ferritic-martensitic steel. Thermal aging for various heat treatment times of mod.. 9Cr-1Mo steel specimens is performed to obtain the nucleation and growth of precipitated particles in specimens. The amplitudes of the first and second harmonics are measured along the propagation distance and the relative nonlinearity parameter is obtained from these amplitudes. The relative nonlinearity parameter shows a similar trend with the Rockwell C hardness.

  9. Characterizing microstructural changes in ferritic steels by positron annihilation spectroscopy: Studies on modified 9Cr-1Mo steel

    Energy Technology Data Exchange (ETDEWEB)

    Hari Babu, S., E-mail: shb@igcar.gov.in [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, TN (India); Rajkumar, K.V. [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, TN (India); Hussain, S. [UGC-DAE CSR, Kokilamedu 603 104, TN (India); Amarendra, G.; Sundar, C.S. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, TN (India); Jayakumar, T. [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, TN (India)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer Positron lifetime technique probing microstructure of ferritic/martensitic steels. Black-Right-Pointing-Pointer Correlation between positron lifetime, ultrasonic and hardness. Black-Right-Pointing-Pointer Complementary nature of positron annihilation spectroscopy in probing defects. Black-Right-Pointing-Pointer Distinguishing precipitation stages by positron annihilation spectroscopy. - Abstract: Applicability of positron annihilation spectroscopy in probing the microstructural changes in ferritic steels has been investigated with thermal treatment studies on modified 9Cr-1Mo steel, during 300-1273 K. Positron lifetime results are compared with those of ultrasonic velocity and hardness techniques with two initial microstructural conditions i.e., normalized and tempered condition as well as only normalized condition. In first case, positron lifetime is found to be sensitive to small changes in metal carbide precipitation which could not be probed by other two techniques. In later case, positron lifetime is found to be sensitive to defect annealing until 673 K and in distinguishing the growth and coarsening of metal carbide precipitation stages during 773-1073 K. The present study suggests that by combining positron lifetime, ultrasonic velocity and hardness measurements, it is possible to distinguish distinct microstructures occurring at different stages.

  10. Effect of silicon contents on the microstructures and mechanical properties of heat affected zones for 9Cr2WVTa steels

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jian [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Science, 110016, Shenyang (China); Key Laboratory of Nuclear Materials and Safety Assessment, Institute of Metal Research, Chinese Academy of Science, 110016, Shenyang (China); Lu, Shanping, E-mail: shplu@imr.ac.cn [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Science, 110016, Shenyang (China); Rong, Lijian [Key Laboratory of Nuclear Materials and Safety Assessment, Institute of Metal Research, Chinese Academy of Science, 110016, Shenyang (China); Li, Dianzhong [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Science, 110016, Shenyang (China)

    2016-03-15

    The weldability of 9Cr2WVTa steels with silicon content varying from 0.30 wt.% to 1.36 wt.% was studied to meet the requirement of Generation-Ⅳ nuclear reactor. Samples of enlarged HAZs were fabricated by a thermal-mechanical simulator based on the simulation and measurement of non-equilibrium phase transformation. The content of δ-ferrite in the HAZs increased with the silicon content and the peak temperature of welding thermal cycle. The impact toughness in the HAZs decreased in different degrees when the δ-ferrite exhibits stripe (lower than 4.82%) or blocky types (higher than 4.82%). Post weld heat treatment (PWHT) has a significant role on improving the toughness. Adding silicon content increased the volume of δ-ferrite and therefore, decreased the tensile strength of the HAZs for 9Cr2WVTa steels. Silicon also as solid solution strengthening element increased the tensile strength. The 9Cr2WVTa steel has good weldability when the silicon content is lower than 0.60 wt.%. - Highlights: • The weldability of 9Cr2WVTa steel with different silicon contents was studied. • The impact toughness decreased in different degrees owing to the δ-ferrite. • PWHT has a significant role on improving the impact toughness. • The 9Cr2WVTa steel with silicon content not exceeding 0.60 wt.% has good weldability.

  11. The rate(time)- dependent mechanical behavior modified 9Cr-1Mo steel, 3

    International Nuclear Information System (INIS)

    Moosbrugger, J.C.

    1991-01-01

    In this paper, constitutive equations are presented for the nonisothermal small strain behavior of modified 9Cr-1Mo steel between 25degC - 600degC. The basic framework uses the superposition of nonlinear kinematic hardening rules as proposed by Chaboche and coworkes. A framework for accounting for isotropic softening is presented wherein this softening can be included in a drag stress, in a yield stress or as a decrease in the saturation level of kinematic hardening or some combination of these; a single isotropic softening equation is used as determined from experiments. The behavior of modified 9Cr-1Mo steel between 25degC - 600degC has been investigated by Swindeman, and Majors et. al. and many important features have been discussed. Here, model parameters are determined from available isothermal uniaxial data and some correlations with isothermal and nonisothermal tests are presented. (J.P.N.)

  12. Influence of Z-phase on long-term creep stability of martensitic 9-12%Cr steels

    Energy Technology Data Exchange (ETDEWEB)

    Hald, J. [DONG Energy (Denmark)]|[Vattenfall Europe AG, Berlin (Germany)]|[DTU Mechanical Engineering (Denmark); Danielsen, H.K. [DTU Mechanical Engineering (Denmark)

    2008-07-01

    The long-term creep strength of the new generation of martensitic creep resistant 9- 12% Cr steels since the well-known steel Grade 91 relies strongly on particle strengthening by fine MN nitrides based on V and Nb. During long-term hightemperature exposures the MN nitrides may be replaced by the thermodynamically more stable Z-phases (Cr(V,Nb)N) causing a breakdown in creep strength. Cr contents above 10.5% strongly accelerate Z-phase precipitation, which explains the lack of success for all attempts to develop martensitic creep resistant steels with high Cr content for oxidation protection. The Z-phase nucleation process by Cr-diffusion into pre-existing MN nitrides is rate controlling for the Z-phase transformation. More work is needed before effects of chemical composition on the nucleation process can be reliably modeled. Careful control of the Z-phase precipitation process has led to the design of experimental 12%Cr martensitic steels strengthened by Z-phase. Such steels may again enable the combination of high strength and oxidation resistance in the same alloy. This opens a new pathway for further alloy development of the heat resistant martensitic steels. (orig.)

  13. Effects of iron spallation products Ti, P and S on the physical metallurgy of 9Cr martensitic steels

    International Nuclear Information System (INIS)

    Danylova, O.; Carlan, Y. de; Hamon, D.; Brachet, J.C.; Alamo, A.

    2002-01-01

    The design of an Accelerator Driven System (ADS) requires that the 'window', which separates the proton accelerator from the spallation target, be able to withstand very severe irradiation conditions. Fe-9/12Cr martensitic steels are good candidates for the window material due to their intrinsic stability under neutron irradiation, but the influence of iron spallation elements on their behaviour is not known. To elucidate the effects of the spallation elements titanium, phosphorus and sulphur on the behaviour of martensitic steels, it was decides to obtain different castings of 9Cr 1Mo steels doped with these elements. The aim of this paper is to present the data obtained on the physical metallurgy of these steels and to show the possible methods of obtaining titanium, phosphorus and sulphur in solid solution for subsequent study of the evolution of the microstructure and mechanical properties. (authors)

  14. Fireside corrosion and steamside oxidation of 9-12% Cr martensitic steels exposed for long term testing

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Jensen, S. A.; Rasmussen, F.

    2009-01-01

    MoV121 and HCM12 for the 12% Cr steels. The test tubes were welded in as part of the existing final superheaters in actual plants and exposure has been conducted over a ten year period (1994-2005). Compared to the older steel types, T92 and HCM12 utilise tungsten to improve their creep strength. From......To obtain long term corrosion and steam oxidation data for the 9-12%Cr ferritic steels, test tube sections have been exposed in Amager 3 and Avedore 1 coal fired power plants in Denmark (formerly run by ENERGI E2). Thus direct comparisons can be made for T91 and T92 for the 9% Cr steels and X20Cr...... Avedore I testing, T91 and T92 can be compared for exposure times up to similar to 48 000 h exposure. From Amager 3 testing, X20, HCM12 and T92 were tested; T92 has been exposed for up to 31 000 h and X20 and HCM12 have had 84 500 h exposure. Tube sections were removed for various exposure durations...

  15. Tensile properties of modified 9Cr-1Mo steel by shear punch testing and correlation with microstructures

    Energy Technology Data Exchange (ETDEWEB)

    Karthik, V., E-mail: karthik@igcar.gov.in [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu 603102 (India); Laha, K.; Parameswaran, P.; Chandravathi, K.S.; Kasiviswanathan, K.V.; Jayakumar, T.; Raj, Baldev [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu 603102 (India)

    2011-10-15

    Modified 9Cr-1Mo ferritic steel (P91) is subjected to a series of heat treatments consisting of soaking for 5 min at the selected temperatures in the range 973 K-1623 K (below Ac{sub 1} to above Ac{sub 4}) followed by oil quenching and tempering at 1033 K for 1 h to obtain different microstructural conditions. The tensile properties of the different microstructural conditions are evaluated from small volumes of material by shear punch test technique. A new methodology for evaluating yield strength, ultimate tensile strength and strain hardening exponent from shear punch test by using correlation equations without employing empirical constants is presented and validated. The changes in the tensile properties are related to the microstructural changes of the steel investigated by electron microscopic studies. The steel exhibits minimum strength and hardness when soaked between Ac{sub 1} and Ac{sub 3} (intercritical range) temperatures due to the replacement of original lath martensitic structure with subgrains. The finer martensitic microstructure produced in the steel after soaking at temperatures above Ac{sub 3} leads to a monotonic increase in hardness and strength with decreasing strain hardening exponent. For soaking temperatures above Ac{sub 4}, the hardness and strength of the steel increases marginally due to the formation of soft {delta} ferrite. - Highlights: > A methodology presented for computing tensile properties from shear punch test. > UTS and strain hardening estimated using extended analysis of blanking models. > The analysis methodology validated for different heat treated 9Cr-1Mo steel. > Changes in tensile properties of steel correlated with microstructures.

  16. Hydrothermal Valorization of Steel Slags—Part I: Coupled H{sub 2} Production and CO{sub 2} Mineral Sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Crouzet, Camille [University Grenoble Alpes, University Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre, Grenoble (France); LRCS and RS2E, CNRS-UMR7314, University Picardie Jules Verne, Amiens (France); Aix Marseille University, CNRS, Centrale Marseille, M2P2, Marseille (France); Brunet, Fabrice, E-mail: fabrice.brunet@univ-grenoble-alpes.fr; Montes-Hernandez, German [University Grenoble Alpes, University Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre, Grenoble (France); Recham, Nadir [LRCS and RS2E, CNRS-UMR7314, University Picardie Jules Verne, Amiens (France); Findling, Nathaniel [University Grenoble Alpes, University Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre, Grenoble (France); Ferrasse, Jean-Henry [Aix Marseille University, CNRS, Centrale Marseille, M2P2, Marseille (France); Goffé, Bruno [Aix-Marseille University, CNRS, IRD, Coll. de France, CEREGE, Aix-en-Provence (France)

    2017-10-30

    A new process route for the valorization of BOF steel slags combining H{sub 2} production and CO{sub 2} mineral sequestration is investigated at 300°C (HT) under hydrothermal conditions. A BOF steel slag stored several weeks outdoor on the production site was used as starting material. To serve as a reference, room temperature (RT) carbonation of the same BOF steel slag has been monitored with in situ Raman spectroscopy and by measuring pH and P{sub CO2} on a time-resolved basis. CO{sub 2} uptake under RT and HT are, respectively, 243 and 327 kg CO{sub 2}/t of fresh steel slag, which add up with the 63 kg of atmospheric CO{sub 2} per ton already uptaken by the starting steel slag on the storage site. The CO{sub 2} gained by the sample at HT is bounded to the carbonation of brownmillerite. H{sub 2} yield decreased by about 30% in comparison to the same experiment performed without added CO{sub 2}, due to sequestration of ferrous iron in a Mg-rich siderite phase. Ferric iron, initially present in brownmillerite, is partitioned between an Fe-rich clay mineral of saponite type and metastable hematite. Saponite is likely stabilized by the presence of Al, whereas hematite may represent a metastable product of brownmillerite carbonation. Mg-rich wüstite is involved in at least two competing reactions, i.e., oxidation into magnetite and carbonation into siderite. Results of both water-slag and water-CO{sub 2}-slag experiments after 72 h are consistent with a kinetics enhancement of the former reaction when a CO{sub 2} partial pressure imposes a pH between 5 and 6. Three possible valorization routes, (1) RT carbonation prior to hydrothermal oxidation, (2) RT carbonation after hydrothermal treatment, and (3) combined HT carbonation and oxidation are discussed in light of the present results and literature data.

  17. Tianeptine: 5-HT uptake sites and 5-HT(1-7) receptors modulate memory formation in an autoshaping Pavlovian/instrumental task.

    Science.gov (United States)

    Meneses, Alfredo

    2002-05-01

    Recent studies using invertebrate and mammal species have revealed that, endogenous serotonin (5-hydroxytryptamine, 5-HT) modulates cognitive processes, particularly learning and memory, though, at present, it is unclear the manner, where, and how long 5-HT systems are involved. Hence in this work, an attempt was made to study the effects of 5-HT endogenous on memory formation, using a 5-HT uptake facilitator (tianeptine) and, selective 5-HT(1-7) receptor antagonists to determine whether 5-HT uptake sites and which 5-HT receptors are involved, respectively. Results showed that post-training tianeptine injection enhanced memory consolidation in an autoshaping Pavlovian/instrumental learning task, which has been useful to detect changes on memory formation elicited by drugs or aging. On interaction experiments, ketanserin (5-HT(1D/2A/2C) antagonist) slightly enhanced tianeptine effects, while WAY 100635 (5-HT(1A) antagonist), SB-224289 (5-HT(1B) inverse agonist), SB-200646 (5-HT(2B/2C) antagonist), ondansetron (5-HT(3) antagonist), GR 127487 (5-HT(4) antagonist), Ro 04-6790 (5-HT(6) antagonist), DR 4004 (5-HT(7) antagonist), or fluoxetine (an inhibitor of 5-HT reuptake) blocked the facilitatory tianeptine effect. Notably, together tianeptine and Ro 04-6790 impaired learning consolidation. Moreover, 5-HT depletion completely reversed the tianeptine effect. Tianeptine also normalized an impaired memory elicited by scopolamine (an antimuscarinic) or dizocilpine (non-competitive glutamatergic antagonist), while partially reversed that induced by TFMPP (5-HT(1B/1D/2A-2C/7) agonist/antagonist). Finally, tianeptine-fluoxetine coadministration had no effect on learning consolidation; nevertheless, administration of an acetylcholinesterase inhibitor, phenserine, potentiated subeffective tianeptine or fluoxetine doses. Collectively, these data confirmed that endogenously 5-HT modulates, via uptake sites and 5-HT(1-7) receptors, memory consolidation, and are consistent with the

  18. The inhibition of cholera toxin-induced 5-HT release by the 5-HT3 receptor antagonist, granisetron, in the rat

    Science.gov (United States)

    Turvill, J L; Connor, P; Farthing, M J G

    2000-01-01

    The secretagogue 5-hydroxytryptamine (5-HT) is implicated in the pathophysiology of cholera. 5-HT released from enterochromaffin cells after cholera toxin exposure is thought to activate non-neuronally (5-HT2 dependent) and neuronally (5-HT3 dependent) mediated water and electrolyte secretion. CT-secretion can be reduced by preventing the release of 5-HT. Enterochromaffin cells possess numerous receptors that, under basal conditions, modulate 5-HT release. These include basolateral 5-HT3 receptors, the activation of which is known to enhance 5-HT release. Until now, 5-HT3 receptor antagonists (e.g. granisetron) have been thought to inhibit cholera toxin-induced fluid secretion by blockading 5-HT3 receptors on secretory enteric neurones. Instead we postulated that they act by inhibiting cholera toxin-induced enterochromaffin cell degranulation. Isolated intestinal segments in anaesthetized male Wistar rats, pre-treated with granisetron 75 μg kg−1, lidoocaine 6 mg kg−1 or saline, were instilled with a supramaximal dose of cholera toxin or saline. Net fluid movement was determined by small intestinal perfusion or gravimetry and small intestinal and luminal fluid 5-HT levels were determined by HPLC with fluorimetric detection. Intraluminal 5-HT release was proportional to the reduction in tissue 5-HT levels and to the onset of water and electrolyte secretion, suggesting that luminal 5-HT levels reflect enterochromaffin cell activity. Both lidocaine and granisetron inhibited fluid secretion. However, granisetron alone, and proportionately, reduced 5-HT release. The simultaneous inhibition of 5-HT release and fluid secretion by granisetron suggests that 5-HT release from enterochromaffin cells is potentiated by endogenous 5-HT3 receptors. The accentuated 5-HT release promotes cholera toxin-induced fluid secretion. PMID:10882387

  19. A comparison of implantation-driven permeation characteristics of fusion reactor structural materials

    Science.gov (United States)

    Longhurst, G. R.; Anderl, R. A.; Struttmann, D. A.

    1986-11-01

    Implantation-driven permeation experiments have been conducted on samples of the ferritic steel HT-9, the austenitic Primary Candidate Alloy (PCA) and the vanadium alloy V-15Cr-5Ti using D 3+ ions under conditions that simulate charge-exchange neutral loading on a fusion reactor first wall. The steels all exhibited an initially intense permeation "spike" followed by an exponential decrease to low steady-state values. That spike was not evident in the V-15Cr-5Ti experiments. Steady-state permeation was highest in the vanadium alloy and lowest in the austenitic steel. Though permeation rates in the HT-9 were lower than those in V-15Cr-5Ti, permeation transients were much faster in HT-9 than in other materials tested. Sputtering of the steel surface resulted in enhanced reemission, whereas in the vanadium tests, recombination and diffusivity both appeared to diminish as the deuterium concentration rose. We conclude that for conditions comparable to those of these experiments, tritium retention and permeation loss in first wall structures made of steels will be less than in structures made of V-15Cr-5Ti.

  20. Comparison on implantation-driven permeation characteristics of fusion reactor structural materials

    Energy Technology Data Exchange (ETDEWEB)

    Longhurst, G.R.; Anderl, R.A.; Struttmann, D.A. (Idaho National Engineering Lab., Idaho Falls)

    Implantation-driven permeation experiments have been conducted on samples of the ferritic steel HT-9, the austenitic Primary Candidate Alloy (PCA) and the vanadium alloy V-15Cr-5Ti using D{sub 3}{sup +} ions under conditions that simulate charge-exchange neutral loading on a fusion reactor first wall. The steels all exhibited an initially intense permeation spike followed by an exponential decrease to low steady-state values. That spike was not evident in the V-15Cr-5Ti experiments. Steady-state permeation was highest in the vanadium alloy and lowest in the austenitic steel. Though permeation rates in the HT-9 were lower than those in V-15Cr-5Ti, permeation transients were much faster in HT-9 than in other materials tested. Sputtering of the steel surface resulted in enhanced reemission, whereas in the vanadium tests, recombination and diffusivity both appeared to diminish as the deuterium concentration rose. We conclude that for conditions comparable to those of these experiments, tritium retention and permeation loss in first wall structures made of steels will be less than in structures made of V-15Cr-5Ti.

  1. Overview of 9Cr steels properties for structural application in sodium fast reactors

    International Nuclear Information System (INIS)

    Cabet, Celine; Courouau, Jean-Louis; Dalle, France; Desgranges, Clara; Forest, Laurent; Martinelli, Laure; Sauzay, Maxime

    2015-01-01

    A research and development programme has been launched by CEA, EDF and AREVA for the choice and qualification of material for sodium fast reactor (SFR) structural components. The requirements on steam generator (SG) are demanding, with operating temperatures ranging from 240 deg. C to 530 deg. C in water/steam and in sodium for an extended design life of several decades. The selection of the SG materials is based on many characteristics: fabrication, welding, thermal properties, mechanical strength at low and high temperature, environmental resistance. 9%Cr steels which are relevant candidate alloys for different designs of SGs have been extensively studied in the past decade. The objective of this paper is to review some advances made at CEA on determining properties of the X10CrMoVNb9-1 steel (hereafter named 'grade 91'): welding, modelling of cyclic softening, modelling of long-term creep, compatibility with liquid sodium, corrosion in steam. (authors)

  2. Microstructure and Mechanical Properties of 21-6-9 Stainless Steel Electron Beam Welds

    Science.gov (United States)

    Elmer, John W.; Ellsworth, G. Fred; Florando, Jeffrey N.; Golosker, Ilya V.; Mulay, Rupalee P.

    2017-04-01

    Welds can either be stronger or weaker than the base metals that they join depending on the microstructures that form in the fusion and heat-affected zones of the weld. In this paper, weld strengthening in the fusion zone of annealed 21-6-9 stainless steel is investigated using cross-weld tensile samples, hardness testing, and microstructural characterization. Due to the stronger nature of the weld, the cross-weld tensile tests failed in the base metal and were not able to generate true fusion zone mechanical properties. Nanoindentation with a spherical indenter was instead used to predict the tensile behavior for the weld metal. Extrapolation of the nanoindentation results to higher strains was performed using the Steinberg-Guinan and Johnson-Cook strength models, and the results can be used for weld strength modeling purposes. The results illustrate how microstructural refinement and residual ferrite formation in the weld fusion zone can be an effective strengthener for 21-6-9 stainless steel.

  3. Psychopharmacology of 5-HT1A receptors

    International Nuclear Information System (INIS)

    Cowen, Philip J.

    2000-01-01

    Serotonin 1A (5-HT 1A ) receptors are located on both 5-HT cell bodies where they act as inhibitory autoreceptors and at postsynaptic sites where they mediate the effects of 5-HT released from nerve terminals. The sensitivity of 5-HT 1A receptors in humans can be measured using the technique of pharmacological challenge. For example, acute administration of a selective 5-HT 1A receptor agonist, such as ipsapirone, decreases body temperature and increases plasma cortisol through activation of pre- and postsynaptic 5-HT 1A receptors, respectively. Use of this technique has demonstrated that unmedicated patients with major depression have decreased sensitivity of both pre- and postsynaptic 5-HT 1A receptors. Treatment with selective serotonin reuptake inhibitors further down-regulates 5-HT 1A receptor activity. Due to the hypotheses linking decreased sensitivity of 5-HT 1A autoreceptors with the onset of antidepressant activity, there is current interest in the therapeutic efficacy of combined treatment with selective serotonin reuptake inhibitors and 5-HT 1A receptor antagonists

  4. Structure-activity relationships of constrained phenylethylamine ligands for the serotonin 5-ht2 receptors

    DEFF Research Database (Denmark)

    Isberg, Vignir; Paine, James; Leth-Petersen, Sebastian

    2013-01-01

    Serotonergic ligands have proven effective drugs in the treatment of migraine, pain, obesity, and a wide range of psychiatric and neurological disorders. There is a clinical need for more highly 5-HT2 receptor subtype-selective ligands and the most attention has been given to the phenethylamine...... about the bioactive conformation of the amine functionality. However, combined 1,2-constriction by cyclization has only been tested with one compound. Here, we present three new 1,2-cyclized phenylethylamines, 9-11, and describe their synthetic routes. Ligand docking in the 5-HT2B crystal structure...... but shift the placement of the core scaffold. The constraints in 9-11 resulted in docking poses with the 4-bromine in closer vicinity to 5.46, which is polar only in the human 5-HT2A subtype, for which 9-11 have the lowest affinity. The new ligands, conformational analysis and docking expand the structure...

  5. Both exogenous 5-HT and endogenous 5-HT, released by fluoxetine, enhance distension evoked propulsion in guinea-pig ileum in vitro

    Directory of Open Access Journals (Sweden)

    Rachel M Gwynne

    2014-09-01

    Full Text Available The roles of 5-HT3 and 5-HT4 receptors in the modulation of intestinal propulsion by luminal application of 5-HT and augmentation of endogenous 5-HT effects were studied in segments of guinea-pig ileum in vitro. Persistent propulsive contractions evoked by saline distension were examined using a modified Trendelenburg method. When 5-HT (30 nM, fluoxetine (selective serotonin reuptake inhibitor; 1 nM, 2-methyl-5-HT (5-HT3 receptor agonist; 1 mM or RS 67506 (5-HT4 receptor agonist, 1 µM was infused into the lumen, the pressure needed to initiate persistent propulsive activity fell significantly. A specific 5-HT4 receptor antagonist, SB 207266 (10 nM in lumen, abolished the effects of 5-HT, fluoxetine, and RS 67506, but not those of 2-methyl-5-HT. Granisetron (5-HT3 receptor antagonist; 1 µM in lumen abolished the effect of 5-HT, fluoxetine, RS 67506 and 2-methyl-5-HT. The NK3 receptor antagonist SR 142801 (100 nM in lumen blocked the effects of 5-HT, fluoxetine and 2-methyl-5-HT. SB 207266, granisetron and SR 142801 had no effect by themselves. Higher concentrations of fluoxetine (100 nM and 300 nM and RS 67506 (3 µM and 10 µM had no effect on the distension threshold for propulsive contractions. These results indicate that luminal application of exogenous 5-HT, or increased release of endogenous mucosal 5-HT above basal levels, acts to lower the threshold for propulsive contractions in the guinea-pig ileum via activation of 5-HT3 and 5-HT4 receptors and the release of tachykinins. The results further indicate that basal release of 5-HT is insufficient to alter the threshold for propulsive motor activity.

  6. What would 5-HT do? Regional diversity of 5-HT1 receptor modulation of primary afferent neurotransmission

    OpenAIRE

    Connor, Mark

    2012-01-01

    5-HT (serotonin) is a significant modulator of sensory input to the CNS, but the only analgesics that selectively target G-protein-coupled 5-HT receptors are highly specific for treatment of headache. Two recent papers in BJP shed light on this puzzling situation by showing that primary afferent neurotransmission to the superficial layers of the spinal and trigeminal dorsal is inhibited by different subtypes of the 5-HT1 receptor – 5-HT1B(and 1D) in the trigeminal dorsal horn and 5-HT1A in th...

  7. 5-HT2A and 5-HT2C receptors as hypothalamic targets of developmental programming in male rats

    Directory of Open Access Journals (Sweden)

    Malgorzata S. Martin-Gronert

    2016-04-01

    Full Text Available Although obesity is a global epidemic, the physiological mechanisms involved are not well understood. Recent advances reveal that susceptibility to obesity can be programmed by maternal and neonatal nutrition. Specifically, a maternal low-protein diet during pregnancy causes decreased intrauterine growth, rapid postnatal catch-up growth and an increased risk for diet-induced obesity. Given that the synthesis of the neurotransmitter 5-hydroxytryptamine (5-HT is nutritionally regulated and 5-HT is a trophic factor, we hypothesised that maternal diet influences fetal 5-HT exposure, which then influences development of the central appetite network and the subsequent efficacy of 5-HT to control energy balance in later life. Consistent with our hypothesis, pregnant rats fed a low-protein diet exhibited elevated serum levels of 5-HT, which was also evident in the placenta and fetal brains at embryonic day 16.5. This increase was associated with reduced levels of 5-HT2CR, the primary 5-HT receptor influencing appetite, in the fetal, neonatal and adult hypothalamus. As expected, a reduction of 5-HT2CR was associated with impaired sensitivity to 5-HT-mediated appetite suppression in adulthood. 5-HT primarily achieves effects on appetite by 5-HT2CR stimulation of pro-opiomelanocortin (POMC peptides within the arcuate nucleus of the hypothalamus (ARC. We show that 5-HT2ARs are also anatomically positioned to influence the activity of ARC POMC neurons and that mRNA encoding 5-HT2AR is increased in the hypothalamus of in utero growth-restricted offspring that underwent rapid postnatal catch-up growth. Furthermore, these animals at 3 months of age are more sensitive to appetite suppression induced by 5-HT2AR agonists. These findings not only reveal a 5-HT-mediated mechanism underlying the programming of susceptibility to obesity, but also provide a promising means to correct it, by treatment with a 5-HT2AR agonist.

  8. 5-HT2A and 5-HT2C receptors as hypothalamic targets of developmental programming in male rats.

    Science.gov (United States)

    Martin-Gronert, Malgorzata S; Stocker, Claire J; Wargent, Edward T; Cripps, Roselle L; Garfield, Alastair S; Jovanovic, Zorica; D'Agostino, Giuseppe; Yeo, Giles S H; Cawthorne, Michael A; Arch, Jonathan R S; Heisler, Lora K; Ozanne, Susan E

    2016-04-01

    Although obesity is a global epidemic, the physiological mechanisms involved are not well understood. Recent advances reveal that susceptibility to obesity can be programmed by maternal and neonatal nutrition. Specifically, a maternal low-protein diet during pregnancy causes decreased intrauterine growth, rapid postnatal catch-up growth and an increased risk for diet-induced obesity. Given that the synthesis of the neurotransmitter 5-hydroxytryptamine (5-HT) is nutritionally regulated and 5-HT is a trophic factor, we hypothesised that maternal diet influences fetal 5-HT exposure, which then influences development of the central appetite network and the subsequent efficacy of 5-HT to control energy balance in later life. Consistent with our hypothesis, pregnant rats fed a low-protein diet exhibited elevated serum levels of 5-HT, which was also evident in the placenta and fetal brains at embryonic day 16.5. This increase was associated with reduced levels of 5-HT2CR, the primary 5-HT receptor influencing appetite, in the fetal, neonatal and adult hypothalamus. As expected, a reduction of 5-HT2CR was associated with impaired sensitivity to 5-HT-mediated appetite suppression in adulthood. 5-HT primarily achieves effects on appetite by 5-HT2CR stimulation of pro-opiomelanocortin (POMC) peptides within the arcuate nucleus of the hypothalamus (ARC). We show that 5-HT2ARs are also anatomically positioned to influence the activity of ARC POMC neurons and that mRNA encoding 5-HT2AR is increased in the hypothalamus ofin uterogrowth-restricted offspring that underwent rapid postnatal catch-up growth. Furthermore, these animals at 3 months of age are more sensitive to appetite suppression induced by 5-HT2AR agonists. These findings not only reveal a 5-HT-mediated mechanism underlying the programming of susceptibility to obesity, but also provide a promising means to correct it, by treatment with a 5-HT2AR agonist. © 2016. Published by The Company of Biologists Ltd.

  9. Investigation of the relationships between mechanical properties and microstructure in a Fe-9%Cr ODS steel

    OpenAIRE

    Hary Benjamin; Guilbert Thomas; Wident Pierre; Baudin Thierry; Logé Roland; de Carlan Yann

    2016-01-01

    Ferritic-martensitic Oxide Dispersion Strengthened (ODS) steels are potential materials for fuel pin cladding in Sodium Fast Reactor (SFR) and their optimisation is essential for future industrial applications. In this paper, a feasibility study concerning the generation of tensile specimens using a quenching dilatometer is presented. The ODS steel investigated contains 9%Cr and exhibits a phase transformation between ferrite and austenite around 870 °C. The purpose was to generate different ...

  10. Influence of cooling rates on the transformation behaviour of 9Cr-1Mo-0.07C steel

    International Nuclear Information System (INIS)

    Saroja, S.; Vijayalakshmi, M.; Raghunathan, V.S.

    1992-01-01

    The choice of various decomposition mechanisms of austenite in a 9Cr-1 Mo-0.07C steel under different rates of cooling has been studied. The techniques employed were electron probe micro-analysis, X-ray diffraction and electron microscopy. The observed morphological features may be explained based on the predominance of the two types of transformation, austenite → martensite and austenite → ferrite during cooling. In the steel used in this study, decomposition of austenite to proeutectoid ferrite was favoured at cooling rates less than about 2 Ks -1 . The mechanism by which the supersaturated proeutectoid ferrite relieves its excess solute concentration was also studied. A ''microstructural map'' has been proposed to predict the constitution at the end of any given cooling rate for 9Cr-1 Mo-0.07C steel. The choice of commercial treatment has been rationalized with respect to the resultant microstructural constituents. (Author)

  11. Segmentation of 9Cr Steel Samples based on Composition and Mechanical Property

    Science.gov (United States)

    Krishnamurthy, Narayanan; Maddali, Siddharth; Vyacheslav, Romanov; Hawk, Jeffrey

    Data mining approaches were used to look at composition-process-property linkage in 9Cr steel. We present results of cluster identification using 7 principal composition elements and analyze its significance with respect to mechanical tensile properties. Data set comprises 82 compositional variants of 9Cr steel whose Cr weight fraction ranges 8-13%. The alloys underwent heat treatments (homogenization, normalization, and 1 to 3 tempering cycles) and were tested for tensile and creep properties at room temperature and elevated temperatures (427/800 oC median/max). In this study, alloys were partitioned into groups, and their mechanical properties were analyzed for significant differences across groups. Normalized weight fractions were used to delineate groups of alloys. Partitioning Around Medoids (PAM) clustering was used, with dissimilarities instead of distance metrics. Dataset of 21 chemical components, with Fe being the majority component, followed by Cr and C. Major contributors of composition to PAM clustering were obtained from PCA scores. Mean ultimate tensile strength of segmented groups of alloys was analyzed with ANOVA & Tukey HSD tests to identify the final 3 groups based on composition and mechanical property.

  12. TEM characterization of irradiated microstructure of Fe-9%Cr ODS and ferritic-martensitic alloys

    Science.gov (United States)

    Swenson, M. J.; Wharry, J. P.

    2018-04-01

    The objective of this study is to evaluate the effects of irradiation dose and dose rate on defect cluster (i.e. dislocation loops and voids) evolution in a model Fe-9%Cr oxide dispersion strengthened steel and commercial ferritic-martensitic steels HCM12A and HT9. Complimentary irradiations using Fe2+ ions, protons, or neutrons to doses ranging from 1 to 100 displacements per atom (dpa) at 500 °C are conducted on each alloy. The irradiated microstructures are characterized using transmission electron microscopy (TEM). Dislocation loops exhibit limited growth after 1 dpa upon Fe2+ and proton irradiation, while any voids observed are small and sparse. The average size and number density of loops are statistically invariant between Fe2+, proton, and neutron irradiated specimens at otherwise fixed irradiation conditions of ∼3 dpa, 500 °C. Therefore, we conclude that higher dose rate charged particle irradiations can reproduce the neutron irradiated loop microstructure with temperature shift governed by the invariance theory; this temperature shift is ∼0 °C for the high sink strength alloys studied herein.

  13. 9% Cr steel high temperature oxidation. Solutions investigated for improving corrosion resistance of the steel

    Energy Technology Data Exchange (ETDEWEB)

    Evin, Harold Nicolas; Heintz, Olivier; Chevalier, Sebastien [UMR 5209 CNRS-Bourgogne Univ. (France). Lab. Interdisciplinaire Carnot de Bourgogne; Foejer, Cecilia; Jakani, Saad; Dhont, Annick; Claessens, Serge [OCAS N.V. ArcelorMittal Global R and D, Gent (Belgium)

    2010-07-01

    The improvement of high temperature oxidation resistance of low chromium content steels, such as T/P91, is of great interest in regards with their application in thermal power generating plants. Indeed, they possess good creep properties, but are facing their limits of use at temperature higher than 600 C, due to accelerated corrosion phenomena. Good knowledge of the mechanisms involved during their oxidation process is needed to prevent the degradation of the materials and to extend life time of the power plants components. Oxide layers thermally grown, on 9% Cr steels (provided by OCAS N.V), during isothermal tests between 600 C and 750 C in laboratory air under atmospheric pressure were investigated, by Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD). The oxidation behaviour appeared very limited at 750 C, due to the presence of a breakaway, which can be linked to iron porous oxide grown over the surface of the samples. ''In situ'' X-ray Photoelectron spectroscopy (XPS) analyses were performed in air at 600 C after short exposures (between 5 min and 25 h). A complex mixture of iron oxide, Cr{sub 2}O{sub 3} and Cr (VI) species were characterized in the scales. The in-situ analyses were compared and related to XPS analyses performed on thick oxide scales formed on samples oxidized in air at 600 C for 100h. An oxidation mechanism is then proposed to understand the oxide scale growth in the temperature range 600 - 750 C. The second step of this study consists in improving the high temperature corrosion resistance of these steels without modifying their mechanical properties. Thus several solutions were investigated such as MOCVD coatings, pack cementation coatings, and tested in cycle conditions prior. (orig.)

  14. High trait aggression in men is associated with low 5-HT levels, as indexed by 5-HT4 receptor binding

    Science.gov (United States)

    Mc Mahon, Brenda; MacDonald Fisher, Patrick; Jensen, Peter Steen; Svarer, Claus; Moos Knudsen, Gitte

    2016-01-01

    Impulsive aggression has commonly been associated with a dysfunction of the serotonin (5-HT) system: many, but not all, studies point to an inverse relationship between 5-HT and aggression. As cerebral 5-HT4 receptor (5-HT4R) binding has recently been recognized as a proxy for stable brain levels of 5-HT, we here test the hypothesis in healthy men and women that brain 5-HT levels, as indexed by cerebral 5-HT4R, are inversely correlated with trait aggression and impulsivity. Sixty-one individuals (47 men) underwent positron emission tomography scanning with the radioligand [11C]SB207145 for quantification of brain 5-HT4R binding. The Buss–Perry Aggression Questionnaire (BPAQ) and the Barratt Impulsiveness Scale were used for assessment of trait aggression and trait impulsivity. Among male subjects, there was a positive correlation between global 5-HT4R and BPAQ total score (P = 0.037) as well as BPAQ physical aggression (P = 0.025). No main effect of global 5-HT4R on trait aggression or impulsivity was found in the mixed gender sample, but there was evidence for sex interaction effects in the relationship between global 5-HT4R and BPAQ physical aggression. In conclusion we found that low cerebral 5-HT levels, as indexed by 5-HT4R binding were associated with high trait aggression in males, but not in females. PMID:26772668

  15. In vitro assessment of the agonist properties of the novel 5-HT1A receptor ligand, CUMI-101 (MMP), in rat brain tissue

    International Nuclear Information System (INIS)

    Hendry, Nicola; Christie, Isabel; Rabiner, Eugenii Alfredovich; Laruelle, Marc; Watson, Jeannette

    2011-01-01

    Introduction: Development of agonist positron emission tomography (PET) radioligands for the 5-HT neurotransmitter system is an important target to enable the understanding of human 5-HT function in vivo. [ 11 C]CUMI-101, proposed as the first 5-HT 1A receptor agonist PET ligand, has been reported to behave as a potent 5-HT 1A agonist in a cellular system stably expressing human recombinant 5-HT 1A receptors. In this study, we investigate the agonist properties of CUMI-101 in rat brain tissue. Methods: [ 35 S]-GTPγS binding studies were used to determine receptor function in HEK (human embryonic kidney) 293 cells transfected with human recombinant 5-HT 1A receptors and in rat cortex and rat hippocampal tissue, following administration of CUMI-101 and standard 5-HT1A antagonists (5-HT, 5-CT and 8-OH-DPAT). Results: CUMI-101 behaved as an agonist at human recombinant 5-HT 1A receptors (pEC 50 9.2). However, CUMI-101 did not show agonist activity in either rat cortex or hippocampus at concentrations up to 10 μM. In these tissues, CUMI-behaved as an antagonist with pK B s of 9.2 and 9.3, respectively. Conclusions: Our studies demonstrate that as opposed to its behavior in human recombinant system, in rat brain tissue CUMI-101 behaves as a potent 5-HT 1A receptor antagonist.

  16. Influence of cold work on the diffusion of ion-implanted nitrogen in D9 steel using nuclear reaction analysis

    International Nuclear Information System (INIS)

    Arunkumar, J.; David, C.; Panigrahi, B.K.; Nair, K.G.M.

    2014-01-01

    D9 steels and their modified versions are envisaged for use as fuel cladding and wrapper materials in the Indian fast breeder reactor (FBR) programme. The role played by interstitially dissolved nitrogen in steel matrices for the stabilization of austenitic phase, increase of strength and corrosion resistance is well known. Various factors: the role of grain boundaries and the their orientation, stress mediation, grain fragmentation and production of short circuit paths as a result of compressive stress are known to affect the diffusion of nitrogen. Basically, cold working produces plethora of defects throughout the sample as compared to its solution annealed state. Our earlier studies on 1 x10"1"5 and 5x10"1"5 N"1"5 implanted Solution Annealed D9 (SAD9) showed significant vacancy-nitrogen complexes for higher fluence. Hence, thermal diffusion behaviour of nitrogen was studied in 5 x10"1"5 -N"1"5 implanted samples in solution annealed state. In the present study, to understand the influence of cold work, similar thermal diffusion behaviour of nitrogen has been studied in Cold Worked D9 steel (CWD9) using nuclear reaction analysis

  17. Microstructure and creep properties of 9-12 % Cr-steels. The influence of Co

    Energy Technology Data Exchange (ETDEWEB)

    Kauffmann, F.; Zies, G.; Maile, K. [Stuttgart Univ. (Germany). MPA; Straub, S. [ALSTOM Power Systems, Mannheim (Germany); Mayer, K.H. [ALSTOM Power System, Nuernberg (Germany)

    2008-07-01

    The martensitic 9-12 wt. % Cr steels currently developed for the application in steam power plants are aimed for service temperatures above 600 C and steam pressures above 250 bar. The creep strength of these steels strongly depends on the microstructure and thereby on the chemical composition. In the present work, a combination of various microscopy techniques is used to study the microstructural changes of creep relevant features like subgrain-size, dislocation density, the chemical composition and crystallographic structure of the occurring precipitates as well as their density and size distribution in dependence of the addition of Co for several steels developed in the frame of the COST programs. These features are then correlated with the creep strength of the materials. The behavior of the alloy CB6 with a high Co content is compared to the low Co containing CB2 and the Co free B0 at 650 C. Similar comparisons are made for the alloy FN2, FN3 and FN 4 at 600 C. (orig.)

  18. Impact of 5-HT3 receptor antagonists on chemotherapy-induced nausea and vomiting: a retrospective cohort study.

    Science.gov (United States)

    Lin, Swu-Jane; Hatoum, Hind T; Buchner, Deborah; Cox, David; Balu, Sanjeev

    2012-07-23

    1st generation 5-hydroxytryptamine receptor antagonists (5-HT3 RAs), and palonosetron, a 2nd generation 5-HT3 RA, are indicated for the prevention of chemotherapy (CT)-induced nausea and vomiting (CINV) associated with moderately (MEC) and highly emetogenic CT agents (HEC). This study explores the impact of step therapy policies requiring use of an older 5-HT3 RA before palonosetron on risk of CINV associated with hospital or emergency department (ED) admissions. Patients who received cyclophosphamide post breast cancer (BC) surgery or who were diagnosed with lung cancer on carboplatin (LC-carboplatin) or cisplatin (LC-cisplatin) were selected from PharMetrics' (IMS LifeLink) claims dataset (2005-2008). Patients were followed for 6 months from initial CT administration for CINV events identified through ICD-9-CM codes. Patients were grouped into those initiated with older, generic 5-HT3 RAs (ondansetron, granisetron, and dolasetron) and those initiated and maintained on palonosetron throughout study follow-up. CINV events and CINV days were analyzed using multivariate regressions controlling for demographic and clinical variables. Eligible patients numbered 3,606 in BC, 4,497 in LC-carboplatin and 1,154 in LC-cisplatin cohorts, with 52%, 40%, and 34% in the palonosetron group, respectively. There was no significant difference between the two 5-HT3 RA groups in age or Charlson Comorbidity Index among the two MEC cohorts (BC and LC-carboplatin). Among the LC-cisplatin cohort, palonosetron users were older with more males than the older 5-HT3 RA group (age: 60.1 vs. 61.3; males, 66.9% vs. 56.9%). Compared to the older 5-HT3 RAs, the palonosetron groups incurred 22%-51% fewer 5-HT3 RA pharmacy claims, had fewer patients with CINV events (3.5% vs. 5.5% in BC, 9.5% vs. 12.8% in LC-carboplatin, 16.4% vs. 21.7% in LC-cisplatin), and had lower risk for CINV events (odds ratios 0.62, 0.71, or 0.71, respectively; pRAs. Further studies on impact of step therapy policy are

  19. High trait aggression in men is associated with low 5-HT levels, as indexed by 5-HT4 receptor binding

    DEFF Research Database (Denmark)

    da Cunha-Bang, Sofi; Mc Mahon, Brenda; Fisher, Patrick MacDonald

    2016-01-01

    of 5-HT, we here test the hypothesis in healthy men and women that brain 5-HT levels, as indexed by cerebral 5-HT4R, are inversely correlated with trait aggression and impulsivity. Sixty-one individuals (47 men) underwent positron emission tomography scanning with the radioligand [(11)C]SB207145......Impulsive aggression has commonly been associated with a dysfunction of the serotonin (5-HT) system: many, but not all, studies point to an inverse relationship between 5-HT and aggression. As cerebral 5-HT4 receptor (5-HT4R) binding has recently been recognized as a proxy for stable brain levels...... for quantification of brain 5-HT4R binding. The Buss-Perry Aggression Questionnaire (BPAQ) and the Barratt Impulsiveness Scale were used for assessment of trait aggression and trait impulsivity. Among male subjects, there was a positive correlation between global 5-HT4R and BPAQ total score (P = 0.037) as well...

  20. Impact of 5-HT3 receptor antagonists on chemotherapy-induced nausea and vomiting: a retrospective cohort study

    Directory of Open Access Journals (Sweden)

    Lin Swu-Jane

    2012-07-01

    Full Text Available Abstract Background 1st generation 5-hydroxytryptamine receptor antagonists (5-HT3 RAs, and palonosetron, a 2nd generation 5-HT3 RA, are indicated for the prevention of chemotherapy (CT-induced nausea and vomiting (CINV associated with moderately (MEC and highly emetogenic CT agents (HEC. This study explores the impact of step therapy policies requiring use of an older 5-HT3 RA before palonosetron on risk of CINV associated with hospital or emergency department (ED admissions. Methods Patients who received cyclophosphamide post breast cancer (BC surgery or who were diagnosed with lung cancer on carboplatin (LC-carboplatin or cisplatin (LC-cisplatin were selected from PharMetrics’ (IMS LifeLink claims dataset (2005-2008. Patients were followed for 6 months from initial CT administration for CINV events identified through ICD-9-CM codes. Patients were grouped into those initiated with older, generic 5-HT3 RAs (ondansetron, granisetron, and dolasetron and those initiated and maintained on palonosetron throughout study follow-up. CINV events and CINV days were analyzed using multivariate regressions controlling for demographic and clinical variables. Results Eligible patients numbered 3,606 in BC, 4,497 in LC-carboplatin and 1,154 in LC-cisplatin cohorts, with 52%, 40%, and 34% in the palonosetron group, respectively. There was no significant difference between the two 5-HT3 RA groups in age or Charlson Comorbidity Index among the two MEC cohorts (BC and LC-carboplatin. Among the LC-cisplatin cohort, palonosetron users were older with more males than the older 5-HT3 RA group (age: 60.1 vs. 61.3; males, 66.9% vs. 56.9%. Compared to the older 5-HT3 RAs, the palonosetron groups incurred 22%-51% fewer 5-HT3 RA pharmacy claims, had fewer patients with CINV events (3.5% vs. 5.5% in BC, 9.5% vs. 12.8% in LC-carboplatin, 16.4% vs. 21.7% in LC-cisplatin, and had lower risk for CINV events (odds ratios 0.62, 0.71, or 0.71, respectively; p 3 RA group (p

  1. Genotype-Dependent Difference in 5-HT2C Receptor-Induced Hypolocomotion: Comparison with 5-HT2A Receptor Functional Activity

    Directory of Open Access Journals (Sweden)

    Darya V. Bazovkina

    2015-01-01

    Full Text Available In the present study behavioral effects of the 5-HT2C serotonin receptor were investigated in different mouse strains. The 5-HT2C receptor agonist MK-212 applied intraperitoneally induced significant dose-dependent reduction of distance traveled in the open field test in CBA/Lac mice. This effect was receptor-specific because it was inhibited by the 5-HT2C receptor antagonist RS102221. To study the role of genotype in 5-HT2C receptor-induced hypolocomotion, locomotor activity of seven inbred mouse strains was measured after MK-212 acute treatment. We found that the 5-HT2C receptor stimulation by MK-212 decreased distance traveled in the open field test in CBA/Lac, C57Bl/6, C3H/He, and ICR mice, whereas it failed to affect locomotor activity in DBA/2J, Asn, and Balb/c mice. We also compared the interstrain differences in functional response to 5-HT2C and 5-HT2A receptors activation measured by the quantification of receptor-mediated head-twitches. These experiments revealed significant positive correlation between 5-HT2C and 5-HT2A receptors functional responses for all investigated mouse strains. Moreover, we found that 5-HT2A receptor activation with DOI did not change locomotor activity in CBA/Lac mice. Taken together, our data indicate the implication of 5-HT2C receptors in regulation of locomotor activity and suggest the shared mechanism for functional responses mediated by 5-HT2C and 5-HT2A receptors.

  2. High trait aggression in men is associated with low 5-HT levels, as indexed by 5-HT4 receptor binding.

    Science.gov (United States)

    da Cunha-Bang, Sofi; Mc Mahon, Brenda; Fisher, Patrick MacDonald; Jensen, Peter Steen; Svarer, Claus; Knudsen, Gitte Moos

    2016-04-01

    Impulsive aggression has commonly been associated with a dysfunction of the serotonin (5-HT) system: many, but not all, studies point to an inverse relationship between 5-HT and aggression. As cerebral 5-HT4 receptor (5-HT4R) binding has recently been recognized as a proxy for stable brain levels of 5-HT, we here test the hypothesis in healthy men and women that brain 5-HT levels, as indexed by cerebral 5-HT4R, are inversely correlated with trait aggression and impulsivity. Sixty-one individuals (47 men) underwent positron emission tomography scanning with the radioligand [(11)C]SB207145 for quantification of brain 5-HT4R binding. The Buss-Perry Aggression Questionnaire (BPAQ) and the Barratt Impulsiveness Scale were used for assessment of trait aggression and trait impulsivity. Among male subjects, there was a positive correlation between global 5-HT4R and BPAQ total score (P = 0.037) as well as BPAQ physical aggression (P = 0.025). No main effect of global 5-HT4R on trait aggression or impulsivity was found in the mixed gender sample, but there was evidence for sex interaction effects in the relationship between global 5-HT4R and BPAQ physical aggression. In conclusion we found that low cerebral 5-HT levels, as indexed by 5-HT4R binding were associated with high trait aggression in males, but not in females. © The Author (2016). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  3. Comparison of implantation-driven permeation characteristics of fusion reactor structural materials

    International Nuclear Information System (INIS)

    Longhurst, G.R.; Anderl, R.A.; Struttmann, D.A.

    1986-01-01

    Implantation-driven permeation experiments have been conducted on samples of the ferritic steel HT-9, the austenitic Primary Candidate Alloy (PCA) and the vanadium alloy V-15Cr-5Ti using D 3 + ions under conditions that simulate charge-exchange neutral loading on a fusion reactor first wall. The steels all exhibited an initially intense permeation ''spike'' followed by an exponential decrease to low steady-state values. That spike was not evident in the V-15Cr-5Ti experiments. Steady-state permeation was highest in the vanadium alloy and lowest in the austenitic steel. Though permeation rates in the HT-9 were lower than those in V-15Cr-5Ti, permeation transients were much faster in HT-9 than in other materials tested. Ion-beam sputtering of the surface in the steel experiments resulted in enhanced remission at the front surface, whereas in the vanadium tests, recombination and diffusivity both appeared to diminish as the deuterium concentration rose. This may be due to a phase change in the material. We conclude that for conditions comparable to those of these experiments, tritium retention and loss in first wall structures made of steels will be less than in structures made of V-15Cr-5Ti

  4. Psychopharmacology of 5-HT{sub 1A} receptors

    Energy Technology Data Exchange (ETDEWEB)

    Cowen, Philip J

    2000-07-01

    Serotonin{sub 1A} (5-HT{sub 1A}) receptors are located on both 5-HT cell bodies where they act as inhibitory autoreceptors and at postsynaptic sites where they mediate the effects of 5-HT released from nerve terminals. The sensitivity of 5-HT{sub 1A} receptors in humans can be measured using the technique of pharmacological challenge. For example, acute administration of a selective 5-HT{sub 1A} receptor agonist, such as ipsapirone, decreases body temperature and increases plasma cortisol through activation of pre- and postsynaptic 5-HT{sub 1A} receptors, respectively. Use of this technique has demonstrated that unmedicated patients with major depression have decreased sensitivity of both pre- and postsynaptic 5-HT{sub 1A} receptors. Treatment with selective serotonin reuptake inhibitors further down-regulates 5-HT{sub 1A} receptor activity. Due to the hypotheses linking decreased sensitivity of 5-HT{sub 1A} autoreceptors with the onset of antidepressant activity, there is current interest in the therapeutic efficacy of combined treatment with selective serotonin reuptake inhibitors and 5-HT{sub 1A} receptor antagonists.

  5. Alloy development for cladding and duct applications

    International Nuclear Information System (INIS)

    Straalsund, J.L.; Johnson, G.D.

    1981-01-01

    Three general classes of materials under development for cladding and ducts are listed. Solid solution strengthened, or austenitic, alloys are Type 316 stainless steel and D9. Precipitation hardened (also austenitic) alloys consist of D21, D66 and D68. These alloys are similar to such commercial alloys as M-813, Inconel 706, Inconel 718 and Nimonic PE-16. The third general class of alloys is composed of ferritic alloys, with current emphasis being placed on HT-9, a tempered martensitic alloy, and D67, a delta-ferritic steel. The program is comprised of three parallel paths. The current reference, or first generation alloy, is 20% cold worked Type 316 stainless steel. Second generation alloys for near-term applications include D9 and HT-9. Third generation materials consist of the precipitation strengthened steels and ferritic alloys, and are being considered for implementation at a later time than the first and second generation alloys. The development of second and third generation materials was initiated in 1974 with the selection of 35 alloys. This program has proceeded to today where there are six advanced alloys being evaluated. These alloys are the developmental alloys D9, D21, D57, D66 and D68, together with the commerical alloy, HT-9. The status of development of these alloys is summarized

  6. Creep and creep fatigue crack behavior of 1Cr- and 9Cr-steels

    International Nuclear Information System (INIS)

    Maile, K.; Klenk, A.; Schellenberg, G.; Granacher, J.; Tramer, M.

    2000-01-01

    A large database for creep crack initiation and propagation under constant load conditions is available on conventional power plant steels of types 1%Cr and 12%Cr. Modern plants are often used in the medium and peak load regime, thus the dominant loading situation in high temperature components is creep fatigue. For life assessment data about crack initiation and growth under creep fatigue loading are required. These characteristics can not be substituted by pure fatigue or creep crack data. Therefore, a comprehensive test programme was started to investigate the creep fatigue crack behaviour of a 1%CrMoNiV turbine rotor steel (30CrMoNiV 4 11) at 550 C and a new 9%CrMoVNb pipe steel (type P 9 1) at 600 C. DENT-specimen with 15 and 60 mm thickness as well as side grooved CT-specimen with 25 and 50 mm thickness have been tested to determine possible influences of geometry and thus to check the transferability of the data to components. The creep fatigue crack growth results of tests with dwell times between t H = 0,32h and 10 h lie in the scatterbands given by creep crack growth results. Nevertheless a higher crack growth rate under creep fatigue conditions can be stated. An increase in crack growth rate due to creep fatigue is clearly visible. Loading situations with frequencies higher than 1.10 -4 Hz should be not assessed with pure creep crack results or sufficient safety margins have to be applied. (orig.)

  7. The integrity of 9Cr-1Mo to stainless steel transition joints in AGR steam generators

    International Nuclear Information System (INIS)

    James, D.W.; Neumann, P.; Soo, J.

    1982-01-01

    The metallurgical aspects of the transition joint between 9Cr-1Mo and 316 stainless steel boiler tube sections are reviewed. A large minimum superheat margin (106 0 C) between the dryout zone and the 9Cr-1Mo to stainless steel transition joint was specified in the original design to eliminate the risk of wetting the stainless steel which is susceptible to stress corrosion cracking. However, small defects were discovered in the welds between the 9Cr-1Mo and Sanicro (72%Ni-16%Cr-10%Fe) transition piece, resulting from dilution of the weld pool by nickel from the transition piece. This led to the possibility of weld failure as a result of creep crack growth in service, and any significant reduction in operating temperature would mean that the large superheat margin could not be sustained. The creep properties of the joints, together with the transition joint temperature distribution, enabled tube failure rates to be determined as a function of operating temperature. A probabilistic model was developed so that the transition joint could be operated within a temperature 'window', the lower temperature limit being determined by stress corrosion considerations and the upper limit being set by creep rate limitations. This allows full load performance from the boilers throughout the anticipated life of the plant. (author)

  8. Adaptation of antenna profiles for control of MR guided hyperthermia (HT) in a hybrid MR-HT system

    International Nuclear Information System (INIS)

    Weihrauch, Mirko; Wust, Peter; Weiser, Martin; Nadobny, Jacek; Eisenhardt, Steffen; Budach, Volker; Gellermann, Johanna

    2007-01-01

    A combined numerical-experimental iterative procedure, based on the Gauss-Newton algorithm, has been developed for control of magnetic resonance (MR)-guided hyperthermia (HT) applications in a hybrid MR-HT system BSD 2000 3D-MRI. In this MR-HT system, composed of a 3-D HT applicator Sigma-Eye placed inside a tunnel-type MR tomograph Siemens MAGNETOM Symphony (1.5 T), the temperature rise due to the HT radiation can be measured on-line in three dimensions by use of the proton resonance frequency shift (PRFS) method. The basic idea of our iterative procedure is the improvement of the system's characterization by a step-by-step modification of the theoretical HT antenna profiles (electric fields radiated by single antennas). The adaptation of antenna profiles is efficient if the initial estimates are radiation fields calculated from a good a priori electromagnetic model. Throughout the iterative procedure, the calculated antenna fields (FDTD) are step-by-step modified by comparing the calculated and experimental data, the latter obtained using the PRFS method. The procedure has been experimentally tested on homogeneous and inhomogeneous phantoms. It is shown that only few comparison steps are necessary for obtaining a dramatic improvement of the general predictability and quality of the specific absorption rate (SAR) inside the MR-HT hybrid system

  9. Influence of dynamic sodium environment on the creep-fatigue behaviour of Modified 9Cr-1Mo ferritic-martensitic steel

    International Nuclear Information System (INIS)

    Kannan, R.; Ganesan, V.; Mariappan, K.; Sukumaran, G.; Sandhya, R.; Mathew, M.D.; Bhanu Sankara Rao, K.

    2011-01-01

    Highlights: → The effects of dynamic sodium on the CFI behaviour of Mod. 9Cr-1Mo steel has investigated. → The cyclic stress response of Mod. 9Cr-1Mo steel under flowing sodium environment is similar to that of air environment. → The creep-fatigue endurance of the alloy is found to decrease with introduction of hold time and with increase in the duration of hold time and the factor of life increase in sodium compared to air environment is reduced with increase in hold time. → In contrast to air environment, tensile holds were found to be more damaging than compression hold in sodium environment. → Design rules based on air environment can be safely applied for the components operating in sodium environment. - Abstract: The use of liquid sodium as a heat transfer medium for sodium-cooled fast reactors (SFRs) necessitates a clear understanding of the effects of dynamic sodium on low cycle fatigue (LCF), creep and creep-fatigue interaction (CFI) behaviour of reactor structural materials. Mod. 9Cr-1Mo ferritic steel is the material of current interest for the steam generator components of sodium cooled fast reactors. The steam generator has a design life of 30-40 years. The effects of dynamic sodium on the LCF and CFI behaviour of Mod. 9Cr-1Mo steel have been investigated at 823 and 873 K. The CFI life of the steel showed marginal increase under flowing sodium environment when compared to air environment. Hence, the design rules for creep-fatigue interaction based on air tests can be safely applied for components operating in sodium environment. This paper attempts to explain the observed LCF and CFI results based on the detailed metallography and fractography conducted on the failed samples.

  10. Deletion of Munc18-1 in 5-HT neurons results in rapid degeneration of the 5-HT system and early postnatal lethality.

    Directory of Open Access Journals (Sweden)

    Jacobus J Dudok

    Full Text Available The serotonin (5-HT system densely innervates many brain areas and is important for proper brain development. To specifically ablate the 5-HT system we generated mutant mice carrying a floxed Munc18-1 gene and Cre recombinase driven by the 5-HT-specific serotonin reuptake transporter (SERT promoter. The majority of mutant mice died within a few days after birth. Immunohistochemical analysis of brains of these mice showed that initially 5-HT neurons are formed and the cortex is innervated with 5-HT projections. From embryonic day 16 onwards, however, 5-HT neurons started to degenerate and at postnatal day 2 hardly any 5-HT projections were present in the cortex. The 5-HT system of mice heterozygous for the floxed Munc18-1 allele was indistinguishable from control mice. These data show that deletion of Munc18-1 in 5-HT neurons results in rapid degeneration of the 5-HT system and suggests that the 5-HT system is important for postnatal survival.

  11. Recovery and Precipitate Analysis of 9 Pct Cr-1 Pct MoVNb Steel during Creep

    NARCIS (Netherlands)

    Kabadwal, A.; Tamura, M.; Shinozuka, K.; Esaka, H.

    The effect of tempering temperature and creep exposure on the microstructure of a modified 9Cr steel was investigated. Creep-interrupted specimens, including the grip portion, were investigated precisely using mainly X-ray and inductively coupled plasma (ICP) spectroscopy. After saturation of

  12. Short communication: Antiproliferative effect of wild Lactobacillus strains isolated from fermented foods on HT-29 cells.

    Science.gov (United States)

    Tuo, Y F; Zhang, L W; Yi, H X; Zhang, Y C; Zhang, W Q; Han, X; Du, M; Jiao, Y H; Wang, S M

    2010-06-01

    In vitro studies, animal models, epidemiology, and human intervention studies provide evidence that some lactic acid bacteria can reduce the risk of certain cancers. In this study, heat-killed bacterial cells, genomic DNA, and cell wall of 7 wild Lactobacillus strains isolated from traditional fermented foods in western China were tested in vitro for cytotoxicity on colonic cancer cell line HT-29 by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The heat-killed bacterial cells, genomic DNA, and cell wall of the 7 strains exhibited direct antiproliferative activities against HT-29 cells. Among the strains, the cellular components of Lactobacillus coryniformis ssp. torquens T3L exerted marked antiproliferative activities against HT-29 cells. The maximum inhibition rates of HT-29 cells by the heat-killed bacterial cells (1x10(7) cfu/mL), cell wall (20 microg of protein/mL) and genomic DNA (100 microg/mL) of L. coryniformis ssp. torquens T3L were 30, 44.9, and 35.9%, respectively. The results indicate that the heat-killed bacterial cells, cell wall, and genomic DNA of the 7 wild Lactobacillus strains could inhibit the growth of HT-29 cells. 2010 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  13. PHP-HT (VitaResc Biotech).

    Science.gov (United States)

    Baldwin, A; Wiley, E

    2001-04-01

    VitaResc (formerly Apex) is developing PHP-HT, pyridoxalated hemoglobin polyoxyethylene conjugate, for the potential treatment of nitric oxide-induced shock (characterized by hypotension), associated with various etiologies, initially in septic shock. A phase I safety study and an initial phase I/II patient trial for NO-induced shock have been completed, and VitaResc has enrolled patients in three of five planned cohorts in a continuation of these trials to include a protocol of continuous infusion and dose escalation [330680,349187,390918]. The results from the dose escalation trials are expected to provide the basis for a randomized, controlled phase II/III pivotal trial of PHP-HT [390918]. VitaResc has licensed PHP-HT exclusively from Ajinomoto for all indications, worldwide, except Japan [275263]. Ajinomoto originally developed the human derived and chemically modified hemoglobin preparation as a blood substitute, but no development has been reported by the company since 1997 [275277,303577]. The other potential indications of PHP-HT include shock associated with burns, pancreatitis, hemodialysis and cytokine therapies [275277]. VitaResc expects the annual market potential of PHP-HT to exceed 1 billion dollars [330680].

  14. The role of the serotonin receptor subtypes 5-HT1A and 5-HT7 and its interaction in emotional learning and memory

    Directory of Open Access Journals (Sweden)

    Oliver eStiedl

    2015-08-01

    Full Text Available Serotonin (5-hydroxytryptamine, 5-HT is a multifunctional neurotransmitter innervating cortical and limbic areas involved in cognition and emotional regulation. Dysregulation of serotonergic transmission is associated with emotional and cognitive deficits in psychiatric patients and animal models. Drugs targeting the 5-HT system are widely used to treat mood disorders and anxiety-like behaviors. Among the fourteen 5-HT receptor (5-HTR subtypes, the 5-HT1AR and 5-HT7R are associated with the development of anxiety, depression and cognitive function linked to mechanisms of emotional learning and memory. In rodents fear conditioning and passive avoidance (PA are associative learning paradigms to study emotional memory. This review assesses the role of 5-HT1AR and 5-HT7R as well as their interplay at the molecular, neurochemical and behavioral level. Activation of postsynaptic 5-HT1ARs impairs emotional memory through attenuation of neuronal activity, whereas presynaptic 5-HT1AR activation reduces 5-HT release and exerts pro-cognitive effects on PA retention. Antagonism of the 5-HT1AR facilitates memory retention possibly via 5-HT7R activation and evidence is provided that 5HT7R can facilitate emotional memory upon reduced 5-HT1AR transmission. These findings highlight the differential role of these 5-HTRs in cognitive/emotional domains of behavior. Moreover, the results indicate that tonic and phasic 5-HT release can exert different and potentially opposing effects on emotional memory, depending on the states of 5-HT1ARs and 5-HT7Rs and their interaction. Consequently, individual differences due to genetic and/or epigenetic mechanisms play an essential role for the responsiveness to drug treatment, e.g., by SSRIs which increase intrasynaptic 5-HT levels thereby activating multiple pre- and postsynaptic 5-HTR subtypes.

  15. Serotonin 5-HT3 and 5-HT4 ligands: an update of medicinal chemistry research in the last few years.

    Science.gov (United States)

    Modica, M N; Pittalà, V; Romeo, G; Salerno, L; Siracusa, M A

    2010-01-01

    The biogenic amine serotonin (5-hydroxytryptamine, 5-HT) is one of the most studied neurotransmitters in the central nervous system. It acts through the activation of at least fourteen 5-HT receptor subtypes. Over the last two decades, high attention was devoted to the 5-HT(3) and 5-HT(4) receptors due to their colocalization in the gastrointestinal tract and because their ligands are useful in the treatment of intestinal serotonergic system dysfunctions. The focus of this review is to discuss the literature concerning recent advances on 5-HT(3)R and 5-HT(4)R ligands and their structure-activity relationships from a medicinal chemistry perspective. During the last few years, new and significant progresses have been made in the field of novel potent and selective ligands, mixed ligands, agonists, partial agonists, and antagonists, and a number of patents have been filed. Furthermore several ligands targeting the 5-HT(3)R and 5-HT(4)R have been proposed for novel therapeutic indications such as the treatment of various psychiatric disorders.

  16. Influence of heat treatment on microstructure and properties of GX12CrMoVNbN9-1 cast steel

    Directory of Open Access Journals (Sweden)

    G. Golański

    2010-07-01

    Full Text Available The paper presents results of research on the influence of multistage heat treatment on microstructure and properties of high-chromiummartensitic GX12CrMoVNbN9 – 1 (GP91 steel. The material under investigation were samples taken out from a test coupon. Heattreatment of GP91 cast steel was performed at the parameters of temperature and time typical of treatment for multi-ton steel casts. The research has proved that in the as-received condition (as-cast state GP91 cast steel was characterized by a coarse grain, martensitic microstructure which provided the required standard mechanical properties. The heat treatment of GP91 cast steel contributed to obtainment of a fine grain microstructure of high tempered martensite with numerous precipitations of carbides of diverse size. The GP91 cast steel structure received through heat treatment made it possible to obtain high plastic properties, particularly impact strength, maintaining strength properties on the level of the required minimum.

  17. Low-cyclic fatigue behavior of modified 9Cr–1Mo steel at elevated temperature

    Energy Technology Data Exchange (ETDEWEB)

    Guguloth, Krishna; Sivaprasad, S. [CSIR-National Metallurgical laboratory, Material Science and Technology Division, Jamshedpur 831007 (India); Chakrabarti, D. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Kharagpur 721302 (India); Tarafder, S. [CSIR-National Metallurgical laboratory, Material Science and Technology Division, Jamshedpur 831007 (India)

    2014-05-01

    The low-cycle fatigue behavior of indigenously developed modified 9Cr–1Mo steel has been evaluated using a constant strain rate (1×10{sup −3} s{sup −1}) at ambient temperature (25 °C) and at elevated temperatures (500–600 °C) over the strain amplitudes varying between ±0.7% and ±1.2%. Cyclic stress response showed a gradual softening regime that ended in a stress plateau until complete failure of the specimens. The estimated fatigue life decreased with the increase in test temperature. The effect of temperature on fatigue life was more pronounced at lower strain amplitudes. The cyclic deformation behavior at different temperatures has been analyzed from hysteresis loop and also in view of the changes taking place in dislocation structure and dislocation–precipitation interaction. Evaluation of low-cycle fatigue properties of modified 9Cr–1Mo steel over a range of test temperature can help in designing components for in-core applications in fast breeder reactors and in super heaters for nuclear power plants.

  18. Effect of heat treatment and plastic deformation on the structure and the mechanical properties of nitrogen-bearing 04N9Kh2A steel

    Science.gov (United States)

    Blinov, V. M.; Bannykh, O. A.; Lukin, E. I.; Kostina, M. V.; Blinov, E. V.

    2014-11-01

    The effect of the conditions of heat treatment and plastic deformation on the structure and the mechanical properties of low-carbon martensitic nickel steel (9 wt % Ni) with an overequilibrium nitrogen content is studied. The limiting strain to failure of 04N9Kh2A steel is found to be 40% at a rolling temperature of 20°C and 80% at a rolling temperature of 900°C. Significant strengthening of the steel (σ0.2 = 1089 MPa) is obtained after rolling at a reduction of 40% at 20°C. The start and final temperatures of the α → γ transformation on heating and those of the γ → α transformation on cooling are determined by dilatometry. The specific features of the formation of the steel structure have been revealed as functions of the annealing and tempering temperatures. Electron-microscopic studies show that, after quenching from 850°C and tempering at 600°C for 1 h, the structure contains packet martensite with thin interlayers of retained austenite between martensite crystals. The strength of the nitrogen-bearing 04N9Kh2A steel after quenching from 850 and 900°C, cooling in water, and subsequent tempering at 500°C for 1 h is significantly higher than that of carboncontaining 0H9 steel used in cryogenic engineering.

  19. Effects of autoshaping procedures on 3H-8-OH-DPAT-labeled 5-HT1a binding and 125I-LSD-labeled 5-HT2a binding in rat brain.

    Science.gov (United States)

    Tomie, Arthur; Di Poce, Jason; Aguado, Allison; Janes, Amy; Benjamin, Daniel; Pohorecky, Larissa

    2003-06-13

    Effects of experience with Pavlovian autoshaping procedures on lever-press autoshaping conditioned response (CR) performance and 3H-8-OH-DPAT-labeled binding of 5-HT(1a) receptors as well as 125I-LSD-labeled binding of 5-HT(2a) receptors were evaluated in four groups of male Long-Evans hooded rats. Two groups of rats (Group Paired High CR and Group Paired Low CR) received Pavlovian autoshaping procedures wherein the presentation of a lever (conditioned stimulus, CS) was followed by the response-independent presentation of food (unconditioned stimulus, US). Rats in Group Paired High CR (n=12) showed more rapid CR acquisition and higher asymptotic levels of lever-press autoshaping CR performance relative to rats in Group Low CR (n=12). Group Omission (n=9) received autoshaping with an omission contingency, such that performing the lever-press autoshaping CR resulted in the cancellation the food US, while Group Random (n=9) received presentations of lever CS and food US randomly with respect to one another. Though Groups Omission and Random did not differ in lever-press autoshaping CR performance, Group Omission showed significantly lower levels of 3H-8-OH-DPAT-labeled 5-HT(1a) binding in post-synaptic areas (frontal cortex, septum, caudate putamen), as well as significantly higher plasma corticosterone levels than Group Random. In addition, Group Random showed higher levels of 3H-8-OH-DPAT-labeled 5-HT(1a) binding in pre-synaptic somatodendritic autoreceptors on dorsal raphe nucleus relative to each of the other three groups. Autoradiographic analysis of 125I-LSD-labeled 5-HT(2a) receptor binding revealed no significant differences between Groups Paired High CR and Paired Low CR or between Groups Omission and Random in any brain regions.

  20. Quantification by image analysis of grain size of the high temperature phase (austenite) of martensitic steels 9Cr-1Mo

    International Nuclear Information System (INIS)

    Barcelo, F.; Brachet, J.C.

    1993-01-01

    In martensitic steels, the austenitic grain size before transformation may influence mechanical properties. 9Cr-1Mo steel (EM10) is used in hexagonal pipes fabrication in fast neutrons reactors. Image analysis allows to quantify the older grain size in function of the austenization heat treatment conditions. (A.B.). 2 figs

  1. Oxide fuel fabrication technology development of the FaCT project (5). Current status on 9Cr-ODS steel cladding development for high burn-up fast reactor fuel

    International Nuclear Information System (INIS)

    Ohtsuka, Satoshi; Kaito, Takeji; Yano, Yasuhide; Yamashita, Shinichiro; Ogawa, Ryuichiro; Uwaba, Tomoyuki; Koyama, Shinichi; Tanaka, Kenya

    2011-01-01

    This paper describes evaluation results of in-reactor integrity of 9Cr and 12Cr-ODS steel cladding tubes and the plan for reliability improvement in homogeneous tube production, both of which are key points for the commercialized use of ODS steels as long-life fuel cladding tubes. A fuel assembly in the BOR-60 irradiation test including 9Cr and 12Cr-ODS fuel pins has achieved the highest burn-up, i.e. peak burn-up of 11.9at% and peak neutron dose of 51dpa, without any fuel pin rupture and microstructure instability. In another fuel assembly containing 9Cr and 12Cr-ODS steel fuel pins whose peak burn-up was 10.5at%, one 9Cr-ODS steel fuel pin failed near the upper end of the fuel column. A peculiar microstructure change occurred in the vicinity of the ruptured area. The primary cause of this fuel pin rupture and microstructure change was shown to be the presence of metallic Cr inclusions in the 9Cr-ODS steel tube, which had passed an ultrasonic inspection test for defects. In the next stage from 2011 to 2013, the fabrication technology of full pre-alloy 9Cr-ODS steel cladding tube will be developed, where the handling of elemental powder is prohibited in the process. (author)

  2. Fabrication and characterization of reference 9Cr and 12Cr-ODS low activation ferritic/martensitic steels

    Energy Technology Data Exchange (ETDEWEB)

    Muroga, T., E-mail: muroga@nifs.ac.jp [National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292 (Japan); Nagasaka, T. [National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292 (Japan); Li, Y.; Abe, H. [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Ukai, S. [Graduate School of Engineering, Hokkaido University, N13, W8, Kita-ku, Sapporo 060-8628 (Japan); Kimura, A. [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Okuda, T. [Kobelco Research Institute, 1-5-5 Takatsukadai, Nishi-ku, Kobe, Hyogo 651-2271 (Japan)

    2014-10-15

    For the purpose of arranging reference alloys available for various characterization efforts by Japanese fusion research groups, fabrication of reference 9Cr and 12Cr-ODS steels have been carried out with similar manufacturing processes followed by various characterizations. The fabrication proceeded with powder mixing, MA, encapsulation into mild steel cases, hot extrusion and hot forging, followed by final heat treatments. Each alloy was extruded into three bars. The characterization included chemical composition analysis, SEM and TEM microstructural observations, hardness tests, tensile tests at RT and 973 K, and relatively short-term thermal creep tests at 973 K. Room temperature hardness for 9Cr-ODS was larger than 12Cr-ODS, the former showing large increase when annealing temperature exceeded 1200 K and the latter showing no significant change with annealing temperature. Tensile strength of 9Cr-ODS was significantly larger than that of 12Cr-ODS at RT but comparable at 973 K. 9Cr-ODS showed longer and shorter creep rupture time than 12Cr-ODS at high and low stress levels, respectively. The mechanism of the difference in creep properties of the two alloys was discussed.

  3. Alloy Design of Martensitic 9Cr-Boron Steel for A-USC Boiler at 650 °C — Beyond Grades 91, 92 and 122

    Science.gov (United States)

    Abe, Fujio; Tabuchi, M.; Tsukamoto, S.

    Boundary hardening is shown to be the most important strengthening mechanism in creep of tempered martensitic 9% Cr steel base metal and welded joints at 650 °C. The enrichment of soluble boron near prior austenite grain boundaries (PAGBs) by the GB segregation is essential for the reduction of coarsening rate of M23C6 carbides near PAGBs, enhancing the boundary and sub-boundary hardening near PAGBs, and also for the change in α/γ transformation behavior in heat-affected-zone (HAZ) of welded joints during heating of welding, producing the same microstructure in HAZ as in the base metal. Excess addition of nitrogen to the 9Cr-boron steel promotes the formation of boron nitrides during normalizing heat treatment, which consumes most of soluble boron and degrades the creep strength. A NIMS 9Cr steel (MARBN; Martensitic 9Cr steel strengthened by boron and MX nitrides) with 120-150 ppm boron and 60-90 ppm nitrogen, where no boron nitride forms during normalizing heat treatment, exhibits not only much higher creep strength of base metal than Grades 91, 92 and 122 but also substantially no degradation in creep strength due to Type IV fracture in HAZ of welded joints at 650°C. The protective Cr2O3-rich scale forms on the surface of 9Cr steel by pre-oxidation treatment in Ar gas, which significantly improves the oxidation resistance in steam at 650°C.

  4. Some elevated temperature tensile and strain-controlled fatigue properties for a 9%Cr1Mo steel heat treated to simulate thick section material

    International Nuclear Information System (INIS)

    Sanderson, S.J.; Jacques, S.

    Current interest has been expressed in the usage of thick section 9%Cr1%Mo steel, particularly for UK Commercial Demonstration Fast Reactor (CDFR) steam generator tubeplates. This paper presents the results of some preliminary mechanical property test work on a single cast of the steel, heat treated to simulate heavy ruling sections encompassing thicknesses likely to be met in the CDFR context. The microstructures of the simulated thick section material were found to remain predominantly as tempered martensite even at the slowest transformation cooling rates used (50 deg. C/h). The effect of microstructure is reflected in the elevated temperature proof stress, tensile strength and strain-controlled fatigue endurance which were found to be comparable with the properties established for thin section normalised and tempered 9%Cr1%Mo steel. These results are extremely encouraging and, taken in conjunction with the results from other simulation work on this material, further demonstrate the potential of thick section 9%Cr1%Mo steel. (author)

  5. 5-HT1A and 5-HT7 receptor crosstalk in the regulation of emotional memory: implications for effects of selective serotonin reuptake inhibitors.

    Science.gov (United States)

    Eriksson, Therese M; Holst, Sarah; Stan, Tiberiu L; Hager, Torben; Sjögren, Benita; Ogren, Sven Öve; Svenningsson, Per; Stiedl, Oliver

    2012-11-01

    This study utilized pharmacological manipulations to analyze the role of direct and indirect activation of 5-HT(7) receptors (5-HT(7)Rs) in passive avoidance learning by assessing emotional memory in male C57BL/6J mice. Additionally, 5-HT(7)R binding affinity and 5-HT(7)R-mediated protein phosphorylation of downstream signaling targets were determined. Elevation of 5-HT by the selective serotonin reuptake inhibitor (SSRI) fluoxetine had no effect by itself, but facilitated emotional memory performance when combined with the 5-HT(1A)R antagonist NAD-299. This facilitation was blocked by the selective 5-HT(7)R antagonist SB269970, revealing excitatory effects of the SSRI via 5-HT(7)Rs. The enhanced memory retention by NAD-299 was blocked by SB269970, indicating that reduced activation of 5-HT(1A)Rs results in enhanced 5-HT stimulation of 5-HT(7)Rs. The putative 5-HT(7)R agonists LP-44 when administered systemically and AS19 when administered both systemically and into the dorsal hippocampus failed to facilitate memory. This finding is consistent with the low efficacy of LP-44 and AS19 to stimulate protein phosphorylation of 5-HT(7)R-activated signaling cascades. In contrast, increasing doses of the dual 5-HT(1A)R/5-HT(7)R agonist 8-OH-DPAT impaired memory, while co-administration with NAD-299 facilitated of emotional memory in a dose-dependent manner. This facilitation was blocked by SB269970 indicating 5-HT(7)R activation by 8-OH-DPAT. Dorsohippocampal infusion of 8-OH-DPAT impaired passive avoidance retention through hippocampal 5-HT(1A)R activation, while 5-HT(7)Rs appear to facilitate memory processes in a broader cortico-limbic network and not the hippocampus alone. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Molecular and pharmacological characterization of serotonin 5-HT2α and 5-HT7 receptors in the salivary glands of the blowfly Calliphora vicina.

    Science.gov (United States)

    Röser, Claudia; Jordan, Nadine; Balfanz, Sabine; Baumann, Arnd; Walz, Bernd; Baumann, Otto; Blenau, Wolfgang

    2012-01-01

    Secretion in blowfly (Calliphora vicina) salivary glands is stimulated by the biogenic amine serotonin (5-hydroxytryptamine, 5-HT), which activates both inositol 1,4,5-trisphosphate (InsP(3))/Ca(2+) and cyclic adenosine 3',5'-monophosphate (cAMP) signalling pathways in the secretory cells. In order to characterize the signal-inducing 5-HT receptors, we cloned two cDNAs (Cv5-ht2α, Cv5-ht7) that share high similarity with mammalian 5-HT(2) and 5-HT(7) receptor genes, respectively. RT-PCR demonstrated that both receptors are expressed in the salivary glands and brain. Stimulation of Cv5-ht2α-transfected mammalian cells with 5-HT elevates cytosolic [Ca(2+)] in a dose-dependent manner (EC(50) = 24 nM). In Cv5-ht7-transfected cells, 5-HT produces a dose-dependent increase in [cAMP](i) (EC(50) = 4 nM). We studied the pharmacological profile for both receptors. Substances that appear to act as specific ligands of either Cv5-HT(2α) or Cv5-HT(7) in the heterologous expression system were also tested in intact blowfly salivary gland preparations. We observed that 5-methoxytryptamine (100 nM) activates only the Cv5-HT(2α) receptor, 5-carboxamidotryptamine (300 nM) activates only the Cv5-HT(7) receptor, and clozapine (1 µM) antagonizes the effects of 5-HT via Cv5-HT(7) in blowfly salivary glands, providing means for the selective activation of each of the two 5-HT receptor subtypes. This study represents the first comprehensive molecular and pharmacological characterization of two 5-HT receptors in the blowfly and permits the analysis of the physiological role of these receptors, even when co-expressed in cells, and of the modes of interaction between the Ca(2+)- and cAMP-signalling cascades.

  7. Molecular and pharmacological characterization of serotonin 5-HT2α and 5-HT7 receptors in the salivary glands of the blowfly Calliphora vicina.

    Directory of Open Access Journals (Sweden)

    Claudia Röser

    Full Text Available Secretion in blowfly (Calliphora vicina salivary glands is stimulated by the biogenic amine serotonin (5-hydroxytryptamine, 5-HT, which activates both inositol 1,4,5-trisphosphate (InsP(3/Ca(2+ and cyclic adenosine 3',5'-monophosphate (cAMP signalling pathways in the secretory cells. In order to characterize the signal-inducing 5-HT receptors, we cloned two cDNAs (Cv5-ht2α, Cv5-ht7 that share high similarity with mammalian 5-HT(2 and 5-HT(7 receptor genes, respectively. RT-PCR demonstrated that both receptors are expressed in the salivary glands and brain. Stimulation of Cv5-ht2α-transfected mammalian cells with 5-HT elevates cytosolic [Ca(2+] in a dose-dependent manner (EC(50 = 24 nM. In Cv5-ht7-transfected cells, 5-HT produces a dose-dependent increase in [cAMP](i (EC(50 = 4 nM. We studied the pharmacological profile for both receptors. Substances that appear to act as specific ligands of either Cv5-HT(2α or Cv5-HT(7 in the heterologous expression system were also tested in intact blowfly salivary gland preparations. We observed that 5-methoxytryptamine (100 nM activates only the Cv5-HT(2α receptor, 5-carboxamidotryptamine (300 nM activates only the Cv5-HT(7 receptor, and clozapine (1 µM antagonizes the effects of 5-HT via Cv5-HT(7 in blowfly salivary glands, providing means for the selective activation of each of the two 5-HT receptor subtypes. This study represents the first comprehensive molecular and pharmacological characterization of two 5-HT receptors in the blowfly and permits the analysis of the physiological role of these receptors, even when co-expressed in cells, and of the modes of interaction between the Ca(2+- and cAMP-signalling cascades.

  8. Prediction and Monitoring Systems of Creep-Fracture Behavior of 9Cr-1Mo Steels for Reactor Pressure Vessels

    International Nuclear Information System (INIS)

    Potirniche, Gabriel; Barlow, Fred D.; Charit, Indrajit; Rink, Karl

    2013-01-01

    A recent workshop on next-generation nuclear plant (NGNP) topics underscored the need for research studies on the creep fracture behavior of two materials under consideration for reactor pressure vessel (RPV) applications: 9Cr-1Mo and SA-5XX steels. This research project will provide a fundamental understanding of creep fracture behavior of modified 9Cr-1Mo steel welds for through modeling and experimentation and will recommend a design for an RPV structural health monitoring system. Following are the specific objectives of this research project: Characterize metallurgical degradation in welded modified 9Cr-1Mo steel resulting from aging processes and creep service conditions; Perform creep tests and characterize the mechanisms of creep fracture process; Quantify how the microstructure degradation controls the creep strength of welded steel specimens; Perform finite element (FE) simulations using polycrystal plasticity to understand how grain texture affects the creep fracture properties of welds; Develop a microstructure-based creep fracture model to estimate RPVs service life; Manufacture small, prototypic, cylindrical pressure vessels, subject them to degradation by aging, and measure their leak rates; Simulate damage evolution in creep specimens by FE analyses; Develop a model that correlates gas leak rates from welded pressure vessels with the amount of microstructural damage; Perform large-scale FE simulations with a realistic microstructure to evaluate RPV performance at elevated temperatures and creep strength; Develop a fracture model for the structural integrity of RPVs subjected to creep loads; and Develop a plan for a non-destructive structural health monitoring technique and damage detection device for RPVs.

  9. Prediction and Monitoring Systems of Creep-Fracture Behavior of 9Cr-1Mo Steels for Teactor Pressure Vessels

    Energy Technology Data Exchange (ETDEWEB)

    Potirniche, Gabriel [Univ. of Idaho, Moscow, ID (United States); Barlow, Fred D. [Univ. of Idaho, Moscow, ID (United States); Charit, Indrajit [Univ. of Idaho, Moscow, ID (United States); Rink, Karl [Univ. of Idaho, Moscow, ID (United States)

    2013-11-26

    A recent workshop on next-generation nuclear plant (NGNP) topics underscored the need for research studies on the creep fracture behavior of two materials under consideration for reactor pressure vessel (RPV) applications: 9Cr-1Mo and SA-5XX steels. This research project will provide a fundamental understanding of creep fracture behavior of modified 9Cr-1Mo steel welds for through modeling and experimentation and will recommend a design for an RPV structural health monitoring system. Following are the specific objectives of this research project: Characterize metallurgical degradation in welded modified 9Cr-1Mo steel resulting from aging processes and creep service conditions; Perform creep tests and characterize the mechanisms of creep fracture process; Quantify how the microstructure degradation controls the creep strength of welded steel specimens; Perform finite element (FE) simulations using polycrystal plasticity to understand how grain texture affects the creep fracture properties of welds; Develop a microstructure-based creep fracture model to estimate RPVs service life; Manufacture small, prototypic, cylindrical pressure vessels, subject them to degradation by aging, and measure their leak rates; Simulate damage evolution in creep specimens by FE analyses; Develop a model that correlates gas leak rates from welded pressure vessels with the amount of microstructural damage; Perform large-scale FE simulations with a realistic microstructure to evaluate RPV performance at elevated temperatures and creep strength; Develop a fracture model for the structural integrity of RPVs subjected to creep loads; and Develop a plan for a non-destructive structural health monitoring technique and damage detection device for RPVs.

  10. Standard practice for evaluation of disbonding of bimetallic stainless alloy/steel plate for use in high-pressure, high-temperature refinery hydrogen service

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2001-01-01

    1.1 This practice covers a procedure for the evaluation of disbonding of bimetallic stainless alloy/steel plate for use in refinery high-pressure/high-temperature (HP/HT) gaseous hydrogen service. It includes procedures to (1) produce suitable laboratory test specimens, (2) obtain hydrogen charging conditions in the laboratory that are similar to those found in refinery HP/HT hydrogen gas service for evaluation of bimetallic specimens exposed to these environments, and (3) perform analysis of the test data. The purpose of this practice is to allow for comparison of data among test laboratories on the resistance of bimetallic stainless alloy/steels to hydrogen-induced disbonding (HID). 1.2 This practice applies primarily to bimetallic products fabricated by weld overlay of stainless alloy onto a steel substrate. Most of the information developed using this practice has been obtained for such materials. The procedures described herein, may also be appropriate for evaluation of hot roll bonded, explosive bonded...

  11. Experimental study on kinematic hardening of 1Cr18Ni9Ti stainless steel under low cycle fatigue

    International Nuclear Information System (INIS)

    Shao Er; Yang Xianjie; Mao Jianghui; Sun Yafang

    2006-01-01

    To study the effect of the monotonic loading on subsequent cyclic plastic hardening and flow properties of 1Cr18Ni9Ti steel, an experimental study of the low cycle fatigue tests with mean strains for 1Cr18Ni9Ti stainless steel was carried out. An analysis on the evolutions of the yield surface radius and the back stresses under symmetric and asymmetric cyclic strain loading with different strain amplitudes was made. The dependence of the evolutions of the material kinematic hardening and isotropic hardening on the strain amplitude and mean strain was observed. These results provide the experimental foundation for the constitutive model of the material under combined monotonic and cyclic complicated loads. (authors)

  12. Changes in 5-HT2A-mediated behavior and 5-HT2A- and 5-HT1A receptor binding and expression in conditional brain-derived neurotrophic factor knock-out mice

    DEFF Research Database (Denmark)

    Klein, A B; Santini, M A; Aznar, S

    2010-01-01

    Changes in brain-derived neurotrophic factor (BDNF) expression have been implicated in the etiology of psychiatric disorders. To investigate pathological mechanisms elicited by perturbed BDNF signaling, we examined mutant mice with central depletion of BDNF (BDNF(2L/2LCk-cre)). A severe impairment...... specific for the serotonin 2A receptor (5-HT(2A)R) in prefrontal cortex was described previously in these mice. This is of much interest, as 5-HT(2A)Rs have been linked to neuropsychiatric disorders and anxiety-related behavior. Here we further characterized the serotonin receptor alterations triggered...... was decreased in hippocampus of BDNF mutants, but unchanged in frontal cortex. Molecular analysis indicated corresponding changes in 5-HT(2A) and 5-HT(1A) mRNA expression but normal 5-HT(2C) content in these brain regions in BDNF(2L/2LCk-cre) mice. We investigated whether the reduction in frontal 5-HT(2A...

  13. Notch and hydrogen effects on sensitized 21-6-9 stainless steel

    International Nuclear Information System (INIS)

    Caskey, C.R. Jr.

    1979-01-01

    Type 21-6-9 stainless steel alloy is slightly notch sensitive in the solution annealed condition, a behavior that is aggravated by sensitization anneal at 920 0 K. The lower toughness of the sensitized alloy is a measure of microstructural embrittlement associated with carbide precipitation in grain boundaries. The tendency toward grain boundary fracture in the sensitized alloy is accentuated by stress concentration at the notch. Also, there is an increase in notch sensitivity when the alloy is tested in a high pressure (69 MPa) hydrogen environment, due to susceptibility of the grain boundaries to hydrogen embrittlement

  14. Catabolism of neurotensin by neural (neuroblastoma clone N1E115) and extraneural (HT29) cell lines

    International Nuclear Information System (INIS)

    Checler, F.; Amar, S.; Kitabgi, P.; Vincent, J.P.

    1986-01-01

    The mechanisms by which neurotensin (NT) was inactivated by differentiated neuroblastoma and HT29 cells were characterized. In both cell lines, the sites of primary cleavages of NT were Pro7-Arg8, Arg8-Arg9 and Pro10-Tyr11 bonds. The cleavage at the Pro7-Arg8 bond was totally inhibited by N-benzyloxycarbonyl-Prolyl-Prolinal and therefore resulted from the action of proline endopeptidase. This peptidase also contributed in a major way to the cleavage at the Pro10-Tyr11 bond. However the latter breakdown was partly due to an NT-degrading neutral metallopeptidase. Finally, we demonstrated the involvement of a recently purified rat brain soluble metalloendopeptidase at the Arg8-Arg9 site by the use of its specific inhibitor N-[1(R,S)-carboxy-2-Phenylethyl]-alanylalanylphenylalanine-p-amino benzoate. The secondary processing of NT degradation products revealed differences between HT29 and N1E115 cells. Angiotensin converting enzyme was shown to degrade NT1-10 and NT1-7 in N1E115 cells but was not detected in HT29 cells. A post-proline dipeptidyl aminopeptidase activity converted NT9-13 into NT11-13 in HT29 cells but not in N1E115 cells. Finally, bestatin-sensitive aminopeptidases rapidly broke down NT11-13 to Tyr in both cell lines. Models for the inactivation of NT in HT29 and N1E115 cells are proposed and compared to that previously described for purified rat brain synaptic membranes

  15. Vortioxetine, but not escitalopram or duloxetine, reverses memory impairment induced by central 5-HT depletion in rats: evidence for direct 5-HT receptor modulation

    DEFF Research Database (Denmark)

    Jensen, Jesper Bornø; du Jardin, Kristian Gaarn; Song, Dekun

    2014-01-01

    Depressed patients suffer from cognitive dysfunction, including memory deficits. Acute serotonin (5-HT) depletion impairs memory and mood in vulnerable patients. The investigational multimodal acting antidepressant vortioxetine is a 5-HT3, 5-HT7 and 5-HT1D receptor antagonist, 5-HT1B receptor...... depletion impaired memory performance in rats through one or more of its receptor activities....... partial agonist, 5-HT1A receptor agonist and 5-HT transporter (SERT) inhibitor that enhances memory in normal rats in novel object recognition (NOR) and conditioned fear (Mørk et al., 2013). We hypothesized that vortioxetine's 5-HT receptor mechanisms are involved in its memory effects, and therefore...

  16. Nondestructive testing for microstructural characterization in 9Cr-1Mo ferritic steel towards assessment of fabrication quality and in-service degradation

    Energy Technology Data Exchange (ETDEWEB)

    Jayakumar, T.; Rao, K.B.S.; Raj, Baldev [Indira Gandhi Centre for Atomic Research, Kalpakkam (India)

    1999-07-01

    The paper discusses the usefulness of non destructive testing for microstructural characterization in 9Cr-1Mo ferritic steel. Ultrasonic velocity and attenuation measurements and spectral analysis have been used in a complementary way for characterizing Ac{sub 1} and Ac{sub 3} temperatures, amount of martensite and ferrite, dissolution of V{sub 4}C{sub 3} and NbC and formation of {delta}-ferrite. The microstructural degradation occurring due to thermal ageing and creep has also been studied by ultrasonic velocity measurements. Magnetic Barkhausen noise technique has been used for estimating the extent of various regions in heat affected zone (HAZ) of 9Cr-1Mo ferritic steel weldment. The same technique has been used for the assessment of low cycle fatigue damage in 9Cr-1Mo steel. The study establishes that non destructive methods can be used for the assessment of fabrication quality and in service degradation of the components. (author)

  17. The co-evolution of microstructure features in self-ion irradiated HT9 at very high damage levels

    Science.gov (United States)

    Getto, Elizabeth Margaret

    The objective of this study was to understand the co-evolution of microstructure features in self-ion irradiated HT9 at very high damage levels. HT9 (heat 84425) was pre-implanted with 10 atom parts per million helium and then irradiated with 5 MeV Fe++ in the temperature range of 440-480°C to 188 dpa. A damage dependence study from 75 to 650 dpa was performed at the peak swelling temperature of 460°C. The swelling, dislocation and precipitate evolution was determined using Analytic Electron Microscopes in both Conventional Transmission electron microscopy (CTEM) and Scanning Transmission Electron Microscopy (STEM) modes. Void swelling reached a nominally linear rate of 0.03%/dpa from 188 to 650 dpa at 460°C. G phase precipitates were observed by 75 dpa and grew linearly up to 650 dpa. M 2X was observed by 250 dpa and peaked in volume fraction at 450 dpa. Dislocation loop evolution was observed up to 650 dpa including a step change in diameter between 375 and 450 dpa; which correlated with nucleation and growth of M2X. The experimental results were interpreted using a rate theory model, the Radiation Induced Microstructure Evolution (RIME), in the damage range from 188 to 650 dpa. A simple system of voids and dislocations was modeled in which the dislocations measured from experiment were used as input, or the dislocations were allowed to evolve dynamically, resulting in swelling that was overestimated by 63% relative to that observed experimentally. G phase had limited effect on the void or dislocation behavior. The behavior of M2X within the microstructure was characterized as a direct effect as a coherent sink, and as an indirect effect in consuming carbon from the matrix, which had the largest impact on both void and dislocation behavior. A slowly monotonically increasing swelling rate was observed both experimentally and computationally, with swelling rates of ˜0.025%/dpa and ˜0.036%/dpa before and after 450 dpa. The agreement in void behavior between

  18. Fusion reactor materials research in China

    International Nuclear Information System (INIS)

    Qian Jiapu

    1994-10-01

    The fusion materials research in China is introduced. Many kinds of structural materials (such as Ti-modified stainless steel, ferritic steel, HT-9, HT-7, oxide dispersion strengthening ferritic steel), tritium breeders (lithium, Li 2 O, γ-LiAlO 2 ) and plasma facing materials (PFMs) (graphite with TiC and SiC coatings) have been developed or being developed. A systematic research activities on irradiation effects, compatibility, plasma materials interaction, thermal shock during disruption, tritium production, release and permeation, neutron multiplication in Be and Pb, etc. have been performed. The research activities are summarized and some experimental results are also given

  19. A study on the proton irradiation effect of reactor materials using cyclotron

    International Nuclear Information System (INIS)

    Chi, Se Hwan; Park, Jong Man; Park, Deuk Keun; Lee, Bong Sang; Oh, Jong Myung

    1993-02-01

    Understanding on radiation damage of important structural materials is important for safe operation and radiation damage evaluation of new reactor structural materials. This study was performed to simulate and evaluate 14 MeV neutron irradiation effects on mechanical properties of candidate structural materials (HT-9/SS316) of next generation reactors (FBR, Fusion) irradiated by Cyclotron(MC-50) using SP test technique. After qualification of SP test techniques from J IC and ε qf correlation, SP tests were performed to evaluate 16MeV proton irradiation effects on mechanical properties of irradiated and unirradiated HT-9/SS316 steels. Test results were evaluated for ε qf , energy and displacement up to failure and J IC change. In addition, damaged zone and dpa upon depth after irradiation were calculated using TRIM code and Doppler broadening line shapes were measured to evaluate defects for 15% cold worked HT-9 steel using PAS. (Author)

  20. In-situ Raman and X-ray photoelectron spectroscopic studies on the pitting corrosion of modified 9Cr-1Mo steel in neutral chloride solution

    Science.gov (United States)

    Ramya, S.; Nanda Gopala Krishna, D.; Mudali, U. Kamachi

    2018-01-01

    In-situ Raman and X-ray photoelectron spectroscopic studies were performed for the identification of native and corroded surface oxide layers of modified 9Cr-1Mo steel. The Raman data obtained for native oxide layer of modified 9Cr-1Mo steel revealed that it was mainly composed of oxides of Fe and Cr. The presence of alloying element Mo was found to be less significant in the native oxide film. The oxides of Cr were dominant at the surface and were found to be decreasing closer to metal/oxide layer interface. The changes in the chemical composition of the native films upon in-situ pitting during potentiostatic polarization experiment were characterized by in-situ Raman analysis. The corrosion products of potentiostatically polarized modified 9Cr-1Mo steel was composed of dominant Fe (III) phases viz., γ- Fe2O3, α and γ - FeOOH along with the oxides of chromium. The results from Raman analysis were corroborated with the XPS experiments on as received and pitted samples of modified 9Cr-1Mo steel specimens. It was observed that the oxides of Cr and Mo contributed for the stability of the surface layer by forming Cr2O3 and MoO3. Also, the study attempted to find out the intermediate corrosion products inside the metastable pits to account for the pseudo passive behavior of modified 9Cr-1Mo steel in 0.1 M NaCl solution.

  1. Corrosion stability of ferritic stainless steels for solid oxide electrolyser cell interconnects

    DEFF Research Database (Denmark)

    Palcut, Marián; Mikkelsen, Lars; Neufeld, Kai

    2010-01-01

    Long-term oxidation behaviour of eight ferritic steels with 20–29 wt.% chromium (F 20 T, TUS 220 M, AL 453, Crofer 22 APU, Crofer 22 H, Sanergy HT, E-Brite and AL 29-4C) has been studied. The samples were cut into square coupons, ground and annealed for 140–1000 h at 1173 K in flowing, wet hydrogen...

  2. Implication of 5-HT(2B) receptors in the serotonin syndrome.

    Science.gov (United States)

    Diaz, Silvina Laura; Maroteaux, Luc

    2011-09-01

    The serotonin (5-HT) syndrome occurs in humans after antidepressant overdose or combination of drugs inducing a massive increase in extracellular 5-HT. Several 5-HT receptors are known to participate in this syndrome in humans and animal models. The 5-HT(2B) receptor has been proposed as a positive modulator of serotonergic activity, but whether it is involved in 5-HT syndrome has not yet been studied. We analyzed here, a putative role of 5-HT(2B) receptors in this disorder by forced swimming test (FST) and behavioral assessment in the open field. In FST, genetic (5-HT(2B)(-/-) mice) or pharmacological (antagonist RS127445 at 0.5 mg/kg) ablation of 5-HT(2B) receptors facilitated selective 5-HT reuptake inhibitors (SSRI)-induced increase of immobility time as well as expression of other symptoms related to 5-HT syndrome like hind limb abduction and Straub tail. Increase in immobility was also developed in FST by both wild type (WT) and 5-HT(2B)(-/-) mice after the administration of 5-HT(1A), 5-HT(2A) or 5-HT(2C) receptor agonists, 8-OH-DPAT (5 mg/kg), DOI (1 mg/kg), or WAY161503 (5 mg/kg), respectively. In contrast, the 5-HT(2B) receptor agonist BW723C86 (3 mg/kg) or 5-HT(1B) receptor agonist CGS12066A (2 mg/kg) decreased immobility time in both genotypes. The 5-HT syndrome induced by fluoxetine at high doses was blocked in WT and 5-HT(2B)(-/-) mice by administration of 5-HT(1A) and 5-HT(2C) receptor antagonists (WAY100635 0.5 mg/kg and SB242084 0.5 mg/kg) but not by the 5-HT(2A) receptor antagonist MDL100907 (1 mg/kg). By behavioral assessment, we confirmed that 5-HT(2B)(-/-) mice were more prone to develop 5-HT syndrome symptoms after administration of high dose of SSRIs or the 5-HT precursor 5-Hydroxytryptophan, 5-HTP, even if increases in 5-HT plasma levels were similar in both genotypes. This evidence suggests that the presence of 5-HT(2B) receptors hinders acute 5-HT toxicity once high levels of 5-HT are attained. Therefore, differential agonism

  3. (+)Lysergic acid diethylamide, but not its nonhallucinogenic congeners, is a potent serotonin 5HT1C receptor agonist

    International Nuclear Information System (INIS)

    Burris, K.D.; Breeding, M.; Sanders-Bush, E.

    1991-01-01

    Activation of central serotonin 5HT2 receptors is believed to be the primary mechanism whereby lysergic acid diethylamide (LSD) and other hallucinogens induce psychoactive effects. This hypothesis is based on extensive radioligand binding and electrophysiological and behavioral studies in laboratory animals. However, the pharmacological profiles of 5HT2 and 5HT1C receptors are similar, making it difficult to distinguish between effects due to activation of one or the other receptor. For this reason, it was of interest to investigate the interaction of LSD with 5HT1C receptors. Agonist-stimulated phosphoinositide hydrolysis in rat choroid plexus was used as a direct measure of 5HT1C receptor activation. (+)LSD potently stimulated phosphoinositide hydrolysis in intact choroid plexus and in cultures of choroid plexus epithelial cells, with EC50 values of 9 and 26 nM, respectively. The effect of (+)LSD in both systems was blocked by 5HT receptor antagonists with an order of activity consistent with interaction at 5HT1C receptors. Neither (+)-2-bromo-LSD nor lisuride, two nonhallucinogenic congeners of LSD, were able to stimulate 5HT1C receptors in cultured cells or intact choroid plexus. In contrast, lisuride, like (+)LSD, is a partial agonist at 5HT2 receptors in cerebral cortex slices and in NIH 3T3 cells transfected with 5HT2 receptor cDNA. The present finding that (+)LSD, but not its nonhallucinogenic congeners, is a 5HT1C receptor agonist suggests a possible role for these receptors in mediating the psychoactive effects of LSD

  4. Precipitation behavior of Laves phase and its effect on toughness of 9Cr-2Mo ferritic-martensitic steel

    International Nuclear Information System (INIS)

    Hosoi, Y.; Wade, N.; Kunimitsu, S.; Urita, T.

    1986-01-01

    This study clarified the relationship between the toughness of a 9Cr-2Mo dual phase steel and precipitates formed during aging, with special attention to the Laves phase (Fe 2 Mo). The ductile-brittle transition temperature (DBTT) is increased and the upper shelf energy decreased when the Laves phase begins to precipitate during aging. Electron microscopy and X-ray diffraction indicate that elimination of Si in the steel reduces the precipitation of the Laves phase and results in maintaining good toughness. It is also noted that the toughness of the steel is controlled by the total amount of precipitates (Laves + carbides) in the aging at 873 K for more than 3.6x10 3 ks. A time-temperature-precipitation diagram for the Laves phase is established and it clearly shows that the precipitation of the Laves phase is markedly retarded by the decrease of Si content. In Si-free steel, no Laves phase is observed in the temperature and time range investigated. (orig.)

  5. Receptor⁻Receptor Interactions in Multiple 5-HT1A Heteroreceptor Complexes in Raphe-Hippocampal 5-HT Transmission and Their Relevance for Depression and Its Treatment.

    Science.gov (United States)

    Borroto-Escuela, Dasiel O; Narváez, Manuel; Ambrogini, Patrizia; Ferraro, Luca; Brito, Ismel; Romero-Fernandez, Wilber; Andrade-Talavera, Yuniesky; Flores-Burgess, Antonio; Millon, Carmelo; Gago, Belen; Narvaez, Jose Angel; Odagaki, Yuji; Palkovits, Miklos; Diaz-Cabiale, Zaida; Fuxe, Kjell

    2018-06-03

    Due to the binding to a number of proteins to the receptor protomers in receptor heteromers in the brain, the term "heteroreceptor complexes" was introduced. A number of serotonin 5-HT1A heteroreceptor complexes were recently found to be linked to the ascending 5-HT pathways known to have a significant role in depression. The 5-HT1A⁻FGFR1 heteroreceptor complexes were involved in synergistically enhancing neuroplasticity in the hippocampus and in the dorsal raphe 5-HT nerve cells. The 5-HT1A protomer significantly increased FGFR1 protomer signaling in wild-type rats. Disturbances in the 5-HT1A⁻FGFR1 heteroreceptor complexes in the raphe-hippocampal 5-HT system were found in a genetic rat model of depression (Flinders sensitive line (FSL) rats). Deficits in FSL rats were observed in the ability of combined FGFR1 and 5-HT1A agonist cotreatment to produce antidepressant-like effects. It may in part reflect a failure of FGFR1 treatment to uncouple the 5-HT1A postjunctional receptors and autoreceptors from the hippocampal and dorsal raphe GIRK channels, respectively. This may result in maintained inhibition of hippocampal pyramidal nerve cell and dorsal raphe 5-HT nerve cell firing. Also, 5-HT1A⁻5-HT2A isoreceptor complexes were recently demonstrated to exist in the hippocampus and limbic cortex. They may play a role in depression through an ability of 5-HT2A protomer signaling to inhibit the 5-HT1A protomer recognition and signaling. Finally, galanin (1⁻15) was reported to enhance the antidepressant effects of fluoxetine through the putative formation of GalR1⁻GalR2⁻5-HT1A heteroreceptor complexes. Taken together, these novel 5-HT1A receptor complexes offer new targets for treatment of depression.

  6. Receptor–Receptor Interactions in Multiple 5-HT1A Heteroreceptor Complexes in Raphe-Hippocampal 5-HT Transmission and Their Relevance for Depression and Its Treatment

    Directory of Open Access Journals (Sweden)

    Dasiel O. Borroto-Escuela

    2018-06-01

    Full Text Available Due to the binding to a number of proteins to the receptor protomers in receptor heteromers in the brain, the term “heteroreceptor complexes” was introduced. A number of serotonin 5-HT1A heteroreceptor complexes were recently found to be linked to the ascending 5-HT pathways known to have a significant role in depression. The 5-HT1A–FGFR1 heteroreceptor complexes were involved in synergistically enhancing neuroplasticity in the hippocampus and in the dorsal raphe 5-HT nerve cells. The 5-HT1A protomer significantly increased FGFR1 protomer signaling in wild-type rats. Disturbances in the 5-HT1A–FGFR1 heteroreceptor complexes in the raphe-hippocampal 5-HT system were found in a genetic rat model of depression (Flinders sensitive line (FSL rats. Deficits in FSL rats were observed in the ability of combined FGFR1 and 5-HT1A agonist cotreatment to produce antidepressant-like effects. It may in part reflect a failure of FGFR1 treatment to uncouple the 5-HT1A postjunctional receptors and autoreceptors from the hippocampal and dorsal raphe GIRK channels, respectively. This may result in maintained inhibition of hippocampal pyramidal nerve cell and dorsal raphe 5-HT nerve cell firing. Also, 5-HT1A–5-HT2A isoreceptor complexes were recently demonstrated to exist in the hippocampus and limbic cortex. They may play a role in depression through an ability of 5-HT2A protomer signaling to inhibit the 5-HT1A protomer recognition and signaling. Finally, galanin (1–15 was reported to enhance the antidepressant effects of fluoxetine through the putative formation of GalR1–GalR2–5-HT1A heteroreceptor complexes. Taken together, these novel 5-HT1A receptor complexes offer new targets for treatment of depression.

  7. Investigation of Creep Processes and Microdamages in 10Kh9V2MFBR-Sh High-Chromium Steel

    Science.gov (United States)

    Grin', E. A.; Pchelintsev, A. V.

    2018-01-01

    During the modernization and the new construction of power units at TPPs in Russia, high-chromium martensitic steels with higher heat-resistant properties than the traditional perlite steels are increasingly used as structural materials. High-chromium steels have a necessary regulatory support for their use in domestic power engineering. However, up to the present time, the issue of assessing the quality of these steels at the analysis of their state during long-term operation remains open. The article proposed is one of the first attempts to create a system of quality criteria for martensitic steels based on their microdamage parameters. Tests were carried out on the long-term strength and creep of samples from 10Kh9V2MFBR-Sh steel at high temperatures with the construction of creep curves in relative coordinates "deformation related to the deformation of fracture, current time related to time to failure." For some samples, the tests were interrupted and the metal was subjected to metallographic studies consisting of the analysis of microdamage with reference to the accumulated creep strain. It has been shown experimentally that the deformation curve of high-chromium steel differs from the analogous curve of pearlitic steel by a longer and flat section of steady creep and by a sharper transition to the third accelerated creep stage, which has a very short time period (approximately 10% of the total durability). The tendency to the increase in the microdamage of the structure of steel as the accumulated creep strain increases with time was confirmed. The beginning of transition to the final creep phase is characterized by the formation of contours of future pore chains and by the appearance of individual large pores of up to 6 μm in size, the presence of which in the microstructure of the martensitic steel indicates a very significant accumulation of creep strain, and corresponds to the predestruction stage of metal. It is necessary to continue the research to

  8. An immunocapture/scintillation proximity analysis of G alpha q/11 activation by native serotonin (5-HT)2A receptors in rat cortex: blockade by clozapine and mirtazapine.

    Science.gov (United States)

    Mannoury La Cour, C; Chaput, C; Touzard, M; Millan, M J

    2009-02-01

    Though transduction mechanisms recruited by heterologously expressed 5-HT(2A) receptors have been extensively studied, their interaction with specific subtypes of G-protein remains to be directly evaluated in cerebral tissue. Herein, as shown by an immunocapture/scintillation proximity analysis, 5-HT, the prototypical 5-HT(2A) agonist, DOI, and Ro60,0175 all enhanced [(35)S]GTPgammaS binding to G alpha q/11 in rat cortex with pEC(50) values of 6.22, 7.24 and 6.35, respectively. No activation of G o or G s/olf was seen at equivalent concentrations of DOI. Stimulation of G alpha q/11 by 5-HT (30 microM) and DOI (30 microM) was abolished by the selective 5-HT(2A) vs. 5-HT(2C)/5-HT(2B) antagonists, ketanserin (pK(B) values of 9.11 and 8.88, respectively) and MDL100,907 (9.82 and 9.68). By contrast, 5-HT-induced [(35)S]GTPgammaS binding to G alpha q/11 was only weakly inhibited by the preferential 5-HT(2C) receptor antagonists, RS102,221 (6.94) and SB242,084 (7.39), and the preferential 5-HT(2B) receptor antagonist, LY266,097 (6.66). The antipsychotic, clozapine, which had marked affinity for 5-HT(2A) receptors, blocked the recruitment of G alpha q/11 by 5-HT and DOI with pK(B) values of 8.54 and 8.14, respectively. Its actions were mimicked by the "atypical" antidepressant and 5-HT(2A) receptor antagonist, mirtazapine, which likewise blocked 5-HT and DOI-induced G alpha q/11 protein activation with pK(B) values of 7.90 and 7.76, respectively. In conclusion, by use of an immunocapture/scintillation proximity strategy, this study shows that native 5-HT(2A) receptors in rat frontal cortex specifically recruit G alpha q/11 and that this action is blocked by clozapine and mirtazapine. Quantification of 5-HT(2A) receptor-mediated G alpha q/11 activation in frontal cortex should prove instructive in characterizing the actions of diverse classes of psychotropic agent. 2008 Wiley-Liss, Inc.

  9. VOPcPhO:P3HT composite micro-structures with nano-porous surface morphology

    Energy Technology Data Exchange (ETDEWEB)

    Azmer, Mohamad Izzat [Low Dimensional Materials Research Centre (LDMRC), Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Ahmad, Zubair, E-mail: zubairtarar@qu.edu.qa [Center for Advanced Materials (CAM), Qatar University, P. O. Box 2713, Doha (Qatar); Sulaiman, Khaulah, E-mail: khaulah@um.edu.my [Low Dimensional Materials Research Centre (LDMRC), Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Touati, Farid [Department of Electrical Engineering, College of Engineering, Qatar University, P. O. Box 2713, Doha (Qatar); Bawazeer, Tahani M. [Department of Chemistry, Faculty of Applied Science, Umm Al-Qura University, Makkah (Saudi Arabia); Alsoufi, Mohammad S. [Mechanical Engineering Department, College of Engineering and Islamic Architecture, Umm Al-Qura University, Makkah (Saudi Arabia)

    2017-03-31

    Highlights: • VOPcPhO:P3HT micro-structures with nano-porous surface morphology have been formed. • Multidimensional structures have been formed by electro-spraying technique. • The electro-sprayed films are very promising for the humidity sensors. - Abstract: In this paper, composite micro-structures of Vanadyl 2,9,16,23-tetraphenoxy-29H,31H-phthalocyanine) (VOPcPhO) and Poly (3-hexylthiophene-2,5-diyl) (P3HT) complex with nano-porous surface morphology have been developed by electro-spraying technique. The structural and morphological characteristics of the VOPcPhO:P3HT composite films have been studied by field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The multidimensional VOPcPhO:P3HT micro-structures formed by electro-spraying with nano-porous surface morphology are very promising for the humidity sensors due to the pore sizes in the range of micro to nano-meters scale. The performance of the VOPcPhO:P3HT electro-sprayed sensor is superior in term of sensitivity, hysteresis and response/recovery times as compared to the spin-coated one. The electro-sprayed humidity sensor exhibits ∼3 times and 0.19 times lower hysteresis in capacitive and resistive mode, respectively, as compared to the spin-coated humidity sensor.

  10. Phase Transformations of an Fe-0.85 C-17.9 Mn-7.1 Al Austenitic Steel After Quenching and Annealing

    Science.gov (United States)

    Cheng, Wei-Chun

    2014-09-01

    Low-density Mn-Al steels could potentially be substitutes for commercial Ni-Cr stainless steels. However, the development of the Mn-Al stainless steels requires knowledge of the phase transformations that occur during the steel making processes. Phase transformations of an Fe-0.85 C-17.9 Mn-7.1 Al (wt.%) austenitic steel, which include spinodal decomposition, precipitation transformations, and cellular transformations, have been studied after quenching and annealing. The results show that spinodal decomposition occurs prior to the precipitation transformation in the steel after quenching and annealing at temperatures below 1023 K and that coherent fine particles of L12-type carbide precipitate homogeneously in the austenite. The cellular transformation occurs during the transformation of high-temperature austenite into lamellae of austenite, ferrite, and kappa carbide at temperatures below 1048 K. During annealing at temperatures below 923 K, the austenite decomposes into lamellar austenite, ferrite, κ-carbide, and M23C6 carbide grains for another cellular transformation. Last, when annealing at temperatures below 873 K, lamellae of ferrite and κ-carbide appear in the austenite.

  11. Computer modelling of HT gas metabolism in humans

    International Nuclear Information System (INIS)

    Peterman, B.F.

    1982-01-01

    A mathematical model was developed to simulate the metabolism of HT gas in humans. The rate constants of the model were estimated by fitting the calculated curves to the experimental data by Pinson and Langham in 1957. The calculations suggest that the oxidation of HT gas (which probably occurs as a result of the enzymatic action of hydrogenase present in bacteria of human gut) occurs at a relatively low rate with a half-time of 10-12 hours. The inclusion of the dose due to the production of the HT oxidation product (HTO) in the soft tissues lowers the value of derived air concentration by about 50%. Furthermore the relationship between the concentration of HTO in urine and the dose to the lung from HT in the air in lungs is linear after short HT exposures, and hence HTO concentrations in urine can be used to estimate the upper limits on the lung dose from HT exposures. (author)

  12. Electron-beam welding of 21-6-9 (Cr--Ni--Mn) stainless steel: effect of machine parameters on weldability

    International Nuclear Information System (INIS)

    Casey, H.

    1975-04-01

    The high-manganese, nitrogen-strengthened 21-6-9 (Cr--Ni--Mn) austenitic stainless steel has a weldability rating similar to that of more common austenitic stainless steels in terms of cracking, porosity, etc. However, weld pool disruption problems may occur with this alloy that can be related to instability within the molten weld pool. Selection of machine parameters is critical to achieving weld pool quiescence as this report confirms from recent tests. Test samples came from heats of air-melted, vacuum-arc remelted, and electroslag remelted material. Low- and high-voltage machine parameters are discussed, and effects of parameter variation on weld pool behavior are given. Data relate weld pool behavior to weld fusion-zone geometry. Various weld parameters are recommended for the 21-6-9 alloy, regardless of its source or chemistry. (auth)

  13. Fatigue Resistance of GX12CrMoVNbN9-1 Cast Steel after Ageing Process

    Directory of Open Access Journals (Sweden)

    Stanisław MROZIŃSKI

    2014-12-01

    Full Text Available In the present paper, low cycle fatigue behaviour of GX12CrMoVNbN9-1 (GP91 cast steel is presented. Fatigue tests were performed under isothermal conditions at room temperature and at 550 and 600oC, on five levels of total strain amplitude value ɛac = 0.25÷0.60%. The cast steel subject to investigation was in the as-received condition (after heat treatment and after 8000 hours of ageing at the temperature of 600oC. Performed research has shown an insignificant influence of the ageing process on mechanical properties of GP91 cast steel, determined with the static test of tension. Analysis of the performed tests has proved that GP91 cast steel in the as-received condition and after ageing process was characterized by strong cyclic softening without a clear period of stabilization of the hysteresis loop parameters. The fatigue lifetime curves at each temperature were obtained based on Basquin and Coffin – Manson equations. The process of ageing of GP91 cast steel contributed to a decrease in its fatigue life Nf from a few to a few dozen percent, and the level of fatigue life was dependent on the value of strain amplitude ɛac. It has also been stated that the fatigue life Nf of GP91 cast steel is determined by its plastic properties, and the degree of changes in fatigue life Nf was dependent not only on the temperature of testing, but also on the value of strain amplitude ɛac. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6077

  14. Microstructure of HIPed and SPSed 9Cr-ODS steel and its effect on helium bubble formation

    International Nuclear Information System (INIS)

    Lu, Chenyang; Lu, Zheng; Xie, Rui; Liu, Chunming; Wang, Lumin

    2016-01-01

    Two 9Cr-ODS steels with the same nominal composition were consolidated by hot isostatic pressing (HIP, named COS-1) and spark plasma sintering (SPS, named COS-2). Helium ions were implanted into COS-1, COS-2 and non-ODS Eurofer 97 steels up at 673 K. Microstructures before and after helium ion implantations were carefully characterized. The results show a bimodal grain size distribution in COS-2 and a more uniform grain size distribution in COS-1. Nanoscale clusters of GP-zone type Y–Ti–O and Y_2Ti_2O_7 pyrochlore as well as large spinel Mn(Ti)Cr_2O_4 particles are all observed in the two ODS steels. The Y–Ti-enriched nano-oxides in COS-1 exhibit higher number density and smaller size than in COS-2. The Y–Ti-enriched nano-oxides in fine grains of COS-2 show higher number density and smaller size than that in coarse grains of COS-2. Nano-oxides effectively trap helium atoms and lead to the formation of high density and ultra-fine helium bubbles. - Highlights: • The microstructure changes of two ODS steels before and after helium ion implantation have been elucidated. • The mechanism of the microstructures of ODS steels under varied thermal mechanical processing paths have been explored. • The dependence of the size, density and distribution of helium bubbles on the specific microstructure features are explored.

  15. Microstructure of HIPed and SPSed 9Cr-ODS steel and its effect on helium bubble formation

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Chenyang [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Material Science and Engineering, Northeastern University, Shenyang 110819, Liaoning (China); Department of Nuclear Engineering and Radiological Science, University of Michigan, Ann Arbor, MI, 48109 (United States); Lu, Zheng, E-mail: luz@atm.neu.edu.cn [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Material Science and Engineering, Northeastern University, Shenyang 110819, Liaoning (China); Xie, Rui; Liu, Chunming [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Material Science and Engineering, Northeastern University, Shenyang 110819, Liaoning (China); Wang, Lumin, E-mail: lmwang@umich.edu [Department of Nuclear Engineering and Radiological Science, University of Michigan, Ann Arbor, MI, 48109 (United States)

    2016-06-15

    Two 9Cr-ODS steels with the same nominal composition were consolidated by hot isostatic pressing (HIP, named COS-1) and spark plasma sintering (SPS, named COS-2). Helium ions were implanted into COS-1, COS-2 and non-ODS Eurofer 97 steels up at 673 K. Microstructures before and after helium ion implantations were carefully characterized. The results show a bimodal grain size distribution in COS-2 and a more uniform grain size distribution in COS-1. Nanoscale clusters of GP-zone type Y–Ti–O and Y{sub 2}Ti{sub 2}O{sub 7} pyrochlore as well as large spinel Mn(Ti)Cr{sub 2}O{sub 4} particles are all observed in the two ODS steels. The Y–Ti-enriched nano-oxides in COS-1 exhibit higher number density and smaller size than in COS-2. The Y–Ti-enriched nano-oxides in fine grains of COS-2 show higher number density and smaller size than that in coarse grains of COS-2. Nano-oxides effectively trap helium atoms and lead to the formation of high density and ultra-fine helium bubbles. - Highlights: • The microstructure changes of two ODS steels before and after helium ion implantation have been elucidated. • The mechanism of the microstructures of ODS steels under varied thermal mechanical processing paths have been explored. • The dependence of the size, density and distribution of helium bubbles on the specific microstructure features are explored.

  16. Increased hypothalamic 5-HT2A receptor gene expression and effects of pharmacologic 5-HT2A receptor inactivation in obese Ay mice

    International Nuclear Information System (INIS)

    Nonogaki, Katsunori; Nozue, Kana; Oka, Yoshitomo

    2006-01-01

    Serotonin (5-hydroxytryptamine; 5-HT) 2A receptors contribute to the effects of 5-HT on platelet aggregation and vascular smooth muscle cell proliferation, and are reportedly involved in decreases in plasma levels of adiponectin, an adipokine, in diabetic subjects. Here, we report that systemic administration of sarpogrelate, a 5-HT2A receptor antagonist, suppressed appetite and increased hypothalamic pro-opiomelanocortin and cocaine- and amphetamine-regulated transcript, corticotropin releasing hormone, 5-HT2C, and 5-HT1B receptor gene expression. A y mice, which have ectopic expression of the agouti protein, significantly increased hypothalamic 5-HT2A receptor gene expression in association with obesity compared with wild-type mice matched for age. Systemic administration of sarpogrelate suppressed overfeeding, body weight gain, and hyperglycemia in obese A y mice, whereas it did not increase plasma adiponectin levels. These results suggest that obesity increases hypothalamic 5-HT2A receptor gene expression, and pharmacologic inactivation of 5-HT2A receptors inhibits overfeeding and obesity in A y mice, but did not increase plasma adiponectin levels

  17. High - speed steel for precise cased tools

    International Nuclear Information System (INIS)

    Karwiarz, J.; Mazur, A.

    2001-01-01

    The test results of high-vanadium high - speed steel (SWV9) for precise casted tools are presented. The face -milling cutters of NFCa80A type have been tested in industrial operating conditions. An average life - time of SWV9 steel tools was 3-10 times longer compare to the conventional high - speed milling cutters. Metallography of SWB9 precise casted steel revealed beneficial for tool properties distribution of primary vanadium carbides in the steel matrix. Presented results should be a good argument for wide application of high - vanadium high - speed steel for precise casted tools. (author)

  18. MDMA self-administration fails to alter the behavioral response to 5-HT(1A) and 5-HT(1B) agonists.

    Science.gov (United States)

    Aronsen, Dane; Schenk, Susan

    2016-04-01

    Regular use of the street drug, ecstasy, produces a number of cognitive and behavioral deficits. One possible mechanism for these deficits is functional changes in serotonin (5-HT) receptors as a consequence of prolonged 3,4 methylenedioxymethamphetamine (MDMA)-produced 5-HT release. Of particular interest are the 5-HT(1A) and 5-HT(1B) receptor subtypes since they have been implicated in several of the behaviors that have been shown to be impacted in ecstasy users and in animals exposed to MDMA. This study aimed to determine the effect of extensive MDMA self-administration on behavioral responses to the 5-HT(1A) agonist, 8-hydroxy-2-(n-dipropylamino)tetralin (8-OH-DPAT), and the 5-HT(1B/1A) agonist, RU 24969. Male Sprague-Dawley rats self-administered a total of 350 mg/kg MDMA, or vehicle, over 20-58 daily self-administration sessions. Two days after the last self-administration session, the hyperactive response to 8-OH-DPAT (0.03-1.0 mg/kg) or the adipsic response to RU 24969 (0.3-3.0 mg/kg) were assessed. 8-OH-DPAT dose dependently increased horizontal activity, but this response was not altered by MDMA self-administration. The dose-response curve for RU 24969-produced adipsia was also not altered by MDMA self-administration. Cognitive and behavioral deficits produced by repeated exposure to MDMA self-administration are not likely due to alterations in 5-HT(1A) or 5-HT(1B) receptor mechanisms.

  19. Changes In Properties and Microstructure of High-Chromium 9-12%Cr Steels Due to Long-Term Exposure at Elevated Temperature

    Directory of Open Access Journals (Sweden)

    Zieliński A.

    2016-06-01

    Full Text Available This paper presents the characteristics of the performance of P91 (X10CrMoVNb9-1, P92 (X10CrWMoVNb9-2 and VM12 (X12CrCoWVNb12-2-2 steels used for condition assessment of the pressure components of boilers with supercritical steam parameters. Studies on the mechanical properties, microstructure tests using scanning and transmission electron microscopy, and X-ray analysis of the phase composition of precipitates were performed for selected steels in the as-received condition and after long-term annealing. These steel characteristics are used for the evaluation of the microstructural changes and mechanical properties of the material of components after long-term service. The result of this study is the database of material characteristics representing the mechanical properties related to the microstructure analysis and it can be used for diagnosis of the components of pressure parts of power boilers.

  20. Experimental Setup with Transient Behavior of Fuel Cladding of SFR

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Sang Hun; Kim, Jun Hwan; Kim, June-Hyung; Ryu, Woo Seog; Park, Sang Gyu; Kim, Sung Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    Nowadays, in Korea, advanced cladding such as FC92 is developed and its transient behaviors are required for the safety analysis of SFR. Design and safety analyses of sodium-cooled fast reactor (SFR) require understanding fuel pin responses to a wide range of off-normal events. In a loss-of-flow (LOF) or transient over-power (TOP), the temperature of the cladding is rapidly increased above its steady-state service temperature. Transient tests have been performed in sections of fuel pin cladding and a large data base has been established for austenitic stainless steel such as 20% cold-worked 316 SS and ferritic/martensitic steels such as HT9. This paper summarizes the technical status of transient testing facilities and their results. Previous researches showed the transient behaviors of HT9 cladding. For the safety analyses in SFR in Korea, simulated transient tests with newly developed FC92 as well as HT9 cladding are being carried out.

  1. Unified inelastic constitutive equations incorporating dynamic strain aging for Mod. 9Cr-1Mo steel

    International Nuclear Information System (INIS)

    Yaguchi, Masatsugu; Takahashi, Yukio

    1998-01-01

    A unified constitutive model considering dynamic strain aging effect was developed in order to describe inelastic deformation behavior of the Mod. 9Cr-1Mo steel precisely. The inelastic behavior of the steel was summarized as follows. A rate dependent deformation was observed above 500degC, and there was no rate dependency under 400degC. However, stress relaxation behavior was observed even at rate independent temperature region. Further, a stress after relaxation depended on prior loading strain rate, and it showed a higher value as the strain rate was slow. A feature of the proposed constitutive model was that an applied stress consists of three stress components: a back stress, an overstress and an aging stress which corresponds to dynamics strain aging and shows a negative strain rate dependency. The aging stress was measured by strain rate change tests, and it showed larger values as the strain rates were slow and the temperatures were low. The backstress and the overstress were measured by strain dip tests. The backstress was approximately rate independent under 400degC, however it showed rate dependency above 500degC. The overstress showed larger values as the strain rates were fast and the temperatures were high. The material constants were determined systematically based on the measured values of each internal variable. In order to evaluate the validity of the constitutive model, numerical simulations were done for various inelastic deformation behavior of Mod. 9Cr-1Mo steel. The simulations agreed with experimental results very well in all cases. (author)

  2. Down-regulation of 5-HT1B and 5-HT1D receptors inhibits proliferation, clonogenicity and invasion of human pancreatic cancer cells.

    Directory of Open Access Journals (Sweden)

    Nilgun Gurbuz

    Full Text Available Pancreatic ductal adenocarcinoma is characterized by extensive local tumor invasion, metastasis and early systemic dissemination. The vast majority of pancreatic cancer (PaCa patients already have metastatic complications at the time of diagnosis, and the death rate of this lethal type of cancer has increased over the past decades. Thus, efforts at identifying novel molecularly targeted therapies are priorities. Recent studies have suggested that serotonin (5-HT contributes to the tumor growth in a variety of cancers including prostate, colon, bladder and liver cancer. However, there is lack of evidence about the impact of 5-HT receptors on promoting pancreatic cancer. Having considered the role of 5-HT-1 receptors, especially 5-HT1B and 5-HT1D subtypes in different types of malignancies, the aim of this study was to investigate the role of 5-HT1B and 5-HT1D receptors in PaCa growth and progression and analyze their potential as cytotoxic targets. We found that knockdown of 5-HT1B and 5-HT1D receptors expression, using specific small interfering RNA (siRNA, induced significant inhibition of proliferation and clonogenicity of PaCa cells. Also, it significantly suppressed PaCa cells invasion and reduced the activity of uPAR/MMP-2 signaling and Integrin/Src/Fak-mediated signaling, as integral tumor cell pathways associated with invasion, migration, adhesion, and proliferation. Moreover, targeting 5-HT1B and 5-HT1D receptors down-regulates zinc finger ZEB1 and Snail proteins, the hallmarks transcription factors regulating epithelial-mesenchymal transition (EMT, concomitantly with up-regulating of claudin-1 and E-Cadherin. In conclusion, our data suggests that 5-HT1B- and 5-HT1D-mediated signaling play an important role in the regulation of the proliferative and invasive phenotype of PaCa. It also highlights the therapeutic potential of targeting of 5-HT1B/1D receptors in the treatment of PaCa, and opens a new avenue for biomarkers identification

  3. Down-regulation of 5-HT1B and 5-HT1D receptors inhibits proliferation, clonogenicity and invasion of human pancreatic cancer cells.

    Directory of Open Access Journals (Sweden)

    Nilgun Gurbuz

    Full Text Available Pancreatic ductal adenocarcinoma is characterized by extensive local tumor invasion, metastasis and early systemic dissemination. The vast majority of pancreatic cancer (PaCa patients already have metastatic complications at the time of diagnosis, and the death rate of this lethal type of cancer has increased over the past decades. Thus, efforts at identifying novel molecularly targeted therapies are priorities. Recent studies have suggested that serotonin (5-HT contributes to the tumor growth in a variety of cancers including prostate, colon, bladder and liver cancer. However, there is lack of evidence about the impact of 5-HT receptors on promoting pancreatic cancer. Having considered the role of 5-HT-1 receptors, especially 5-HT1B and 5-HT1D subtypes in different types of malignancies, the aim of this study was to investigate the role of 5-HT1B and 5-HT1D receptors in PaCa growth and progression and analyze their potential as cytotoxic targets. We found that knockdown of 5-HT1B and 5-HT1D receptors expression, using specific small interfering RNA (siRNA, induced significant inhibition of proliferation and clonogenicity of PaCa cells. Also, it significantly suppressed PaCa cells invasion and reduced the activity of uPAR/MMP-2 signaling and Integrin/Src/Fak-mediated signaling, as integral tumor cell pathways associated with invasion, migration, adhesion, and proliferation. Moreover, targeting 5-HT1B and 5-HT1D receptors down-regulates zinc finger ZEB1 and Snail proteins, the hallmarks transcription factors regulating epithelial-mesenchymal transition (EMT, concomitantly with up-regulating of claudin-1 and E-Cadherin. In conclusion, our data suggests that 5-HT1B- and 5-HT1D- mediated signaling play an important role in the regulation of the proliferative and invasive phenotype of PaCa. It also highlights the therapeutic potential of targeting of 5-HT1B/1D receptors in the treatment of PaCa, and opens a new avenue for biomarkers identification

  4. Do dorsal raphe 5-HT neurons encode "beneficialness"?

    Science.gov (United States)

    Luo, Minmin; Li, Yi; Zhong, Weixin

    2016-11-01

    The neurotransmitter serotonin (5-hydroxytryptamine; 5-HT) affects numerous behavioral and physiological processes. Drugs that alter 5-HT signaling treat several major psychiatric disorders and may lead to widespread abuse. The dorsal raphe nucleus (DRN) in the midbrain provides a majority of 5-HT for the forebrain. The importance of 5-HT signaling propels the search for a general theoretical framework under which the diverse functions of the DRN 5-HT neurons can be interpreted and additional therapeutic solutions may be developed. However, experimental data so far support several seeming irreconcilable theories, suggesting that 5-HT neurons mediate behavioral inhibition, aversive processing, or reward signaling. Here, we review recent progresses and propose that DRN 5-HT neurons encode "beneficialness" - how beneficial the current environmental context represents for an individual. Specifically, we speculate that the activity of these neurons reflects the possible net benefit of the current context as determined by p·R-C, in which p indicates reward probability, R the reward value, and C the cost. Through the widespread projections of these neurons to the forebrain, the beneficialness signal may reconfigure neural circuits to bias perception, boost positive emotions, and switch behavioral choices. The "beneficialness" hypothesis can explain many conflicting observations, and at the same time raises new questions. We suggest additional experiments that will help elucidate the exact computational functions of the DRN 5-HT neurons. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Differential actions of antiparkinson agents at multiple classes of monoaminergic receptor. III. Agonist and antagonist properties at serotonin, 5-HT(1) and 5-HT(2), receptor subtypes.

    Science.gov (United States)

    Newman-Tancredi, Adrian; Cussac, Didier; Quentric, Yann; Touzard, Manuelle; Verrièle, Laurence; Carpentier, Nathalie; Millan, Mark J

    2002-11-01

    Although certain antiparkinson agents interact with serotonin (5-HT) receptors, little information is available concerning functional actions. Herein, we characterized efficacies of apomorphine, bromocriptine, cabergoline, lisuride, piribedil, pergolide, roxindole, and terguride at human (h)5-HT(1A), h5-HT(1B), and h5-HT(1D) receptors [guanosine 5'-O-(3-[(35)S]thio)triphosphate ([(35)S]GTPgammaS) binding], and at h5-HT(2A), h5-HT(2B), and h5-HT(2C) receptors (depletion of membrane-bound [(3)H]phosphatydilinositol). All drugs stimulated h5-HT(1A) receptors with efficacies (compared with 5-HT, 100%) ranging from modest (apomorphine, 35%) to high (cabergoline, 93%). At h5-HT(1B) receptors, efficacies varied from mild (terguride, 37%) to marked (cabergoline, 102%) and potencies were modest (pEC(50) values of 5.8-7.6): h5-HT(1D) sites were activated with a similar range of efficacies and greater potency (7.1-8.5). Piribedil and apomorphine were inactive at h5-HT(1B) and h5-HT(1D) receptors. At h5-HT(2A) receptors, terguride, lisuride, bromocriptine, cabergoline, and pergolide displayed potent (7.6-8.8) agonist properties (49-103%), whereas apomorphine and roxindole were antagonists and piribedil was inactive. Only pergolide (113%/8.2) and cabergoline (123%/8.6) displayed pronounced agonist properties at h5-HT(2B) receptors. At 5-HT(2C) receptors, lisuride, bromocriptine, pergolide, and cabergoline were efficacious (75-96%) agonists, apomorphine and terguride were antagonists, and piribedil was inactive. MDL100,907 and SB242,084, selective antagonists at 5-HT(2A) and 5-HT(2C) receptors, respectively, abolished these actions of pergolide, cabergoline, and bromocriptine. In conclusion, antiparkinson agents display markedly different patterns of agonist and antagonist properties at multiple 5-HT receptor subtypes. Although all show modest (agonist) activity at 5-HT(1A) sites, their contrasting actions at 5-HT(2A) and 5-HT(2C) sites may be of particular significance to their

  6. The pharmacology of TD-8954, a potent and selective 5-HT4 receptor agonist with gastrointestinal prokinetic properties

    Directory of Open Access Journals (Sweden)

    David T Beattie

    2011-05-01

    Full Text Available This study evaluated the in vitro and in vivo pharmacological properties of TD-8954, a potent and selective 5-HT4 receptor agonist. TD-8954 had high affinity (pKi = 9.4 for human recombinant 5-HT4(c (h5-HT4(c receptors, and selectivity (> 2,000-fold over all other 5-HT receptors and non-5-HT receptors, ion channels, enzymes and transporters tested (n = 78. TD-8954 produced an elevation of cAMP in HEK-293 cells expressing the h5-HT4(c receptor (pEC50 = 9.3, and contracted the guinea pig colonic longitudinal muscle/myenteric plexus (LMMP preparation (pEC50 = 8.6. TD-8954 had moderate intrinsic activity (IA in the in vitro assays. In conscious guinea pigs, subcutaneous (s.c. administration of TD 8954 (0.03 - 3 mg/kg increased the colonic transit of carmine red dye, reducing the time taken for its excretion. Following intraduodenal (i.d. dosing to anesthetized rats, TD 8954 (0.03 - 10 mg/kg evoked a dose-dependent relaxation of the esophagus. Following oral administration to conscious dogs, TD 8954 (10 and 30 µg/kg produced an increase in contractility of the antrum, duodenum and jejunum. In a single ascending oral dose study in healthy human subjects, TD-8954 (0.1 - 20 mg increased bowel movement frequency and reduced the time to first stool. It is concluded that TD-8954 is a potent and selective 5-HT4 receptor agonist in vitro, with robust in vivo stimulatory activity in the gastrointestinal (GI tract of guinea pigs, rats, dogs and humans. TD-8954 may have clinical utility in patients with disorders of reduced GI motility.

  7. The binding characteristics and orientation of a novel radioligand with distinct properties at 5-HT3A and 5-HT3AB receptors

    NARCIS (Netherlands)

    Thompson, Andrew J; Verheij, Mark H P; Verbeek, Joost; Windhorst, Albert D; de Esch, Iwan J P; Lummis, Sarah C R

    2014-01-01

    VUF10166 (2-chloro-3-(4-methyl piperazin-1-yl)quinoxaline) is a ligand that binds with high affinity to 5-HT3 receptors. Here we synthesise [(3)H]VUF10166 and characterise its binding properties at 5-HT3A and 5-HT3AB receptors. At 5-HT3A receptors [(3)H]VUF10166 displayed saturable binding with a Kd

  8. Carbide precipitation in the heat affected zone of a GTA weld in 21-6-9 stainless steel

    International Nuclear Information System (INIS)

    Carr, M.J.; Thorvaldson, W.G.

    1979-01-01

    Grain boundary precipitation was observed in a multipass GTA weld in 21-6-9 stainless steel. The precipitate was identified by electron diffraction as M 23 C 6 -type carbide. The presence of these carbide particles did not cause intergranular attack in standard corrosion tests

  9. Effects of Constant Flickering Light on Refractive Status, 5-HT and 5-HT2A Receptor in Guinea Pigs.

    Science.gov (United States)

    Li, Bing; Luo, Xiumei; Li, Tao; Zheng, Changyue; Ji, Shunmei; Ma, Yuanyuan; Zhang, Shuangshuang; Zhou, Xiaodong

    2016-01-01

    To investigate the effects of constant flickering light on refractive development, the role of serotonin (i.e.5-hydroxytryptamine, 5-HT)and 5-HT2A receptor in myopia induced by flickering light in guinea pigs. Forty-five guinea pigs were randomly divided into three groups: control, form deprivation myopia (FDM) and flickering light induced myopia (FLM) groups(n = 15 for each group). The right eyes of the FDM group were covered with semitransparent hemispherical plastic shells serving as eye diffusers. Guinea pigs in FLM group were raised with illumination of a duty cycle of 50% at a flash frequency of 0.5Hz. The refractive status, axial length (AL), corneal radius of curvature(CRC) were measured by streak retinoscope, A-scan ultrasonography and keratometer, respectively. Ultramicroscopy images were taken by electron microscopy. The concentrations of 5-HTin the retina, vitreous body and retinal pigment epithelium (RPE) were assessed by high performance liquid chromatography, the retinal 5-HT2A receptor expression was evaluated by immunohistofluorescence and western blot. The refraction of FDM and FLM eyes became myopic from some time point (the 4th week and the 6th week, respectively) in the course of the experiment, which was indicated by significantly decreased refraction and longer AL when compared with the controls (plight could cause progressive myopia in guinea pigs. 5-HT and 5-HT2A receptor increased both in form deprivation myopia and flickering light induced myopia, indicating that 5-HT possibly involved in myopic development via binding to5-HT2A receptor.

  10. Nanocluster irradiation evolution in Fe-9%Cr ODS and ferritic-martensitic alloys

    Science.gov (United States)

    Swenson, M. J.; Wharry, J. P.

    2017-12-01

    The objective of this study is to evaluate the influence of dose rate and cascade morphology on nanocluster evolution in a model Fe-9%Cr oxide dispersion strengthened steel and the commercial ferritic/martensitic (F/M) alloys HCM12A and HT9. We present a large, systematic data set spanning the three alloys, three irradiating particle types, four orders of magnitude in dose rate, and doses ranging 1-100 displacements per atom over 400-500 °C. Nanoclusters are characterized using atom probe tomography. ODS oxide nanoclusters experience partial dissolution after irradiation due to inverse Ostwald ripening, while F/M nanoclusters undergo Ostwald ripening. Damage cascade morphology is indicative of nanocluster number density evolution. Finally, the effects of dose rate on nanocluster morphology provide evidence for a temperature dilation theory, which purports that a negative temperature shift is necessary for higher dose rate irradiations to emulate nanocluster evolution in lower dose rate irradiations.

  11. 5HT(1A) and 5HT(1B) receptors of medial prefrontal cortex modulate anxiogenic-like behaviors in rats.

    Science.gov (United States)

    Solati, Jalal; Salari, Ali-Akbar; Bakhtiari, Amir

    2011-10-31

    Medial prefrontal cortex (MPFC) is one of the brain regions which play an important role in emotional behaviors. The purpose of the present study was to evaluate the role of 5HT(1A) and 5HT(1B) receptors of the MPFC in modulation of anxiety behaviors in rats. The elevated plus maze (EPM) which is a useful test to investigate the effects of anxiogenic or anxiolytic drugs in rodents, was used. Bilateral intra-MPFC administration of 5HT(1A) receptor agonist, 8-OH-DPAT (5, 10, and 50 ng/rat) decreased the percentages of open arm time (OAT%) and open arm entries (OAE%), indicating an anxiogenic response. Moreover, administration of 5HT(1A) receptor antagonist, NAN-190 (0.25, 0.5, and 1 μg/rat) significantly increased OAT% and OAE%. Pre-treatment administration of NAN-190 (0.5 μg/rat), which was injected into the MPFC, reversed the anxiogenic effects of 8-OH-DPAT (5, 10, and 50 ng/rat). Intra-MPFC microinjection of 5HT(1B) receptor agonist, CGS-12066A (0.25, 0.5, and 1 μg/rat) significantly decreased OAT% and OAE%, without any change in locomotor activity, indicating an anxiogenic effect. However, injection of 5HT(1B) receptor antagonist, SB-224289 (0.5, 1, and 2 μg/rat) into the MPFC showed no significant effect. In conclusion, these findings suggest that 5HT(1A) and 5HT(1B) receptors of the MPFC region modulate anxiogenic-like behaviors in rats. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  12. Effect of Alloy 625 Buffer Layer on Hardfacing of Modified 9Cr-1Mo Steel Using Nickel Base Hardfacing Alloy

    Science.gov (United States)

    Chakraborty, Gopa; Das, C. R.; Albert, S. K.; Bhaduri, A. K.; Murugesan, S.; Dasgupta, Arup

    2016-04-01

    Dashpot piston, made up of modified 9Cr-1Mo steel, is a part of diverse safety rod used for safe shutdown of a nuclear reactor. This component was hardfaced using nickel base AWS ER NiCr-B alloy and extensive cracking was experienced during direct deposition of this alloy on dashpot piston. Cracking reduced considerably and the component was successfully hardfaced by application of Inconel 625 as buffer layer prior to hardface deposition. Hence, a separate study was undertaken to investigate the role of buffer layer in reducing the cracking and on the microstructure of the hardfaced deposit. Results indicate that in the direct deposition of hardfacing alloy on modified 9Cr-1Mo steel, both heat-affected zone (HAZ) formed and the deposit layer are hard making the thickness of the hard layer formed equal to combined thickness of both HAZ and deposit. This hard layer is unable to absorb thermal stresses resulting in the cracking of the deposit. By providing a buffer layer of Alloy 625 followed by a post-weld heat treatment, HAZ formed in the modified 9Cr-1Mo steel is effectively tempered, and HAZ formed during the subsequent deposition of the hardfacing alloy over the Alloy 625 buffer layer is almost completely confined to Alloy 625, which does not harden. This reduces the cracking susceptibility of the deposit. Further, unlike in the case of direct deposition on modified 9Cr-1Mo steel, dilution of the deposit by Ni-base buffer layer does not alter the hardness of the deposit and desired hardness on the deposit surface could be achieved even with lower thickness of the deposit. This gives an option for reducing the recommended thickness of the deposit, which can also reduce the risk of cracking.

  13. Cell Free DNA of Tumor Origin Induces a 'Metastatic' Expression Profile in HT-29 Cancer Cell Line.

    Directory of Open Access Journals (Sweden)

    István Fűri

    Full Text Available Epithelial cells in malignant conditions release DNA into the extracellular compartment. Cell free DNA of tumor origin may act as a ligand of DNA sensing mechanisms and mediate changes in epithelial-stromal interactions.To evaluate and compare the potential autocrine and paracrine regulatory effect of normal and malignant epithelial cell-related DNA on TLR9 and STING mediated pathways in HT-29 human colorectal adenocarcinoma cells and normal fibroblasts.DNA isolated from normal and tumorous colonic epithelia of fresh frozen surgically removed tissue samples was used for 24 and 6 hour treatment of HT-29 colon carcinoma and HDF-α fibroblast cells. Whole genome mRNA expression analysis and qRT-PCR was performed for the elements/members of TLR9 signaling pathway. Immunocytochemistry was performed for epithelial markers (i.e. CK20 and E-cadherin, DNA methyltransferase 3a (DNMT3a and NFκB (for treated HDFα cells.Administration of tumor derived DNA on HT29 cells resulted in significant (p<0.05 mRNA level alteration in 118 genes (logFc≥1, p≤0.05, including overexpression of metallothionein genes (i.e. MT1H, MT1X, MT1P2, MT2A, metastasis-associated genes (i.e. TACSTD2, MACC1, MALAT1, tumor biomarker (CEACAM5, metabolic genes (i.e. INSIG1, LIPG, messenger molecule genes (i.e. DAPP, CREB3L2. Increased protein levels of CK20, E-cadherin, and DNMT3a was observed after tumor DNA treatment in HT-29 cells. Healthy DNA treatment affected mRNA expression of 613 genes (logFc≥1, p≤0.05, including increased expression of key adaptor molecules of TLR9 pathway (e.g. MYD88, IRAK2, NFκB, IL8, IL-1β, STING pathway (ADAR, IRF7, CXCL10, CASP1 and the FGF2 gene.DNA from tumorous colon epithelium, but not from the normal epithelial cells acts as a pro-metastatic factor to HT-29 cells through the overexpression of pro-metastatic genes through TLR9/MYD88 independent pathway. In contrast, DNA derived from healthy colonic epithelium induced TLR9 and STING signaling

  14. The oxidation behaviour of Fe-9Cr-1Mo steels

    International Nuclear Information System (INIS)

    Rowlands, P.C.; Holmes, D.R.; Whittaker, A.; Brierley, R.A.; Garrett, J.C.P.

    1983-01-01

    The oxidation behaviour of Fe9Cr1Mo steels over a wide range of conditions covering likely operating environments has been determined. In particular the effects of temperature, gas composition and materials variables on production materials have been investigated. From this work the mechanisms of protective and breakaway corrosion have broadly been elucidated. The vital role of carbon deposition in the oxide and carburisation of the metal has been determined. Aspects of the breakaway and protective oxidation mechanisms have been incorporated into a statistical model for predicting breakaway initiation and boiler component life. The results obtained from the tube life calculations indicate very low probabilities of component failure for coolant gas compositions containing up to the equivalent of 825 vppm H 2 O and 1%CO. For a more aggressive gas at the upper limit of CO concentration (2%CO) there is a small probability of failure within 25 years for finned boiler tubes. Current work may in time allow these constraints composition to be relaxed. The information gained has been used in the design of Heysham II/Torness to reduce the probabilities of 9Cr component failure to insignificant levels. (author)

  15. Hyperthyroidism enhances 5-HT-induced contraction of the rat pulmonary artery: role of calcium-activated chloride channel activation.

    Science.gov (United States)

    Oriowo, Mabayoje A; Oommen, Elsie; Khan, Islam

    2011-11-01

    Experimentally-induced hyperthyroidism in rodents is associated with signs and symptoms of pulmonary hypertension. The main objective of the present study was to investigate the effect of thyroxine-induced pulmonary hypertension on the contractile response of the pulmonary artery to 5-HT and the possible underlying signaling pathway. 5-HT concentration-dependently contracted artery segments from control and thyroxine-treated rats with pD(2) values of 5.04 ± 0.19 and 5.34 ± 0.14, respectively. The maximum response was significantly greater in artery segments from thyroxine-treated rats. Neither BW 723C86 (5-HT(2B)-receptor agonist) nor CP 93129 (5-HT(1B)-receptor agonist) contracted ring segments of the pulmonary artery from control and thyroxine-treated rats at concentrations up to 10(-4)M. There was no significant difference in the level of expression of 5-HT(2A)-receptor protein between the two groups. Ketanserin (3 × 10(-8)M) produced a rightward shift of the concentration-response curve to 5-HT in both groups with equal potency (-logK(B) values were 8.1 ± 0.2 and 7.9 ± 0.1 in control and thyroxine-treated rats, respectively). Nifedipine (10(-6)M) inhibited 5-HT-induced contractions in artery segments from control and thyroxine-treated rats and was more effective against 5-HT-induced contraction in artery segments for thyroxine-treated rats. The calcium-activated chloride channel blocker, niflumic acid (10(-4)M) also inhibited 5-HT-induced contractions in artery segments from control and thyroxine-treated rats and was more effective against 5-HT-induced contraction in artery segments for thyroxine-treated rats. It was concluded that hyperthyroidism enhanced 5-HT-induced contractions of the rat pulmonary artery by a mechanism involving increased activity of calcium-activated chloride channels. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Deletion of Munc18-1 in 5-HT Neurons Results in Rapid Degeneration of the 5-HT System and Early Postnatal Lethality

    NARCIS (Netherlands)

    Dudok, J.J.; Groffen, A.J.A.; Toonen, R.F.G.; Verhage, M.

    2011-01-01

    The serotonin (5-HT) system densely innervates many brain areas and is important for proper brain development. To specifically ablate the 5-HT system we generated mutant mice carrying a floxed Munc18-1 gene and Cre recombinase driven by the 5-HT-specific serotonin reuptake transporter (SERT)

  17. On the microstructural basis of creep strength and creep-fatigue interaction in 9-12 % Cr steels for application in power plants

    Energy Technology Data Exchange (ETDEWEB)

    Chilukuru, H

    2007-03-06

    As part of the efforts of preserving the environment it is necessary to reduce of the CO2 emissions from power plants. This can be done by increasing the plant efficiency. Research groups around the world are engaged in developing new steels capable of sustaining higher stresses and temperatures envisaged for high-efficiency power plants. Research carried out in Europe is organized within the COST Programme (Co-Operation in Science and Technology) aiming at replacing the conventional steels of type X20CrMoV121 by the new class of 9-12% Cr-steels with modified composition. The resistance of materials against deformation at elevated temperatures depends on their microstructure. Frequently in 9-12% Cr-steels improved short-term creep properties do not persist in the long-term service [1, 2, 3, 4, 5, 6]. This is related with insufficient microstructural stability. Hardening contributions in 9-12% Cr-steels come from solute atoms of the ferritic matrix, from dislocations, and from precipitates of foreign phases within the matrix. The term ''carbide stabilized substructure hardening'' of 9-12% Cr steels [7, 8] indicates that the hardening contributions are interdependent. The dislocations are the carriers of plastic deformation. They interact with each other, with solute atoms and with precipitates. The dislocation-dislocation interaction leads to formation of planar dislocation networks constituting low-angle boundaries. They form a subgrain structure within the grains. At present, a full and detailed understanding of the effects exerted by the different components of microstructure on creep strength is still lacking. The present work makes a contribution to the efforts of understanding the microstructural basis of creep strength and of creep-fatigue interaction by transmission electron microscopic structure investigations coupled with creep tests. Investigations by transmission electron microscopy (TEM) were carried out with regard to hardening by subgrain boundaries

  18. On the microstructural basis of creep strength and creep-fatigue interaction in 9-12 % Cr steels for application in power plants

    Energy Technology Data Exchange (ETDEWEB)

    Chilukuru, H.

    2007-03-06

    As part of the efforts of preserving the environment it is necessary to reduce of the CO2 emissions from power plants. This can be done by increasing the plant efficiency. Research groups around the world are engaged in developing new steels capable of sustaining higher stresses and temperatures envisaged for high-efficiency power plants. Research carried out in Europe is organized within the COST Programme (Co-Operation in Science and Technology) aiming at replacing the conventional steels of type X20CrMoV121 by the new class of 9-12% Cr-steels with modified composition. The resistance of materials against deformation at elevated temperatures depends on their microstructure. Frequently in 9-12% Cr-steels improved short-term creep properties do not persist in the long-term service [1, 2, 3, 4, 5, 6]. This is related with insufficient microstructural stability. Hardening contributions in 9-12% Cr-steels come from solute atoms of the ferritic matrix, from dislocations, and from precipitates of foreign phases within the matrix. The term ''carbide stabilized substructure hardening'' of 9-12% Cr steels [7, 8] indicates that the hardening contributions are interdependent. The dislocations are the carriers of plastic deformation. They interact with each other, with solute atoms and with precipitates. The dislocation-dislocation interaction leads to formation of planar dislocation networks constituting low-angle boundaries. They form a subgrain structure within the grains. At present, a full and detailed understanding of the effects exerted by the different components of microstructure on creep strength is still lacking. The present work makes a contribution to the efforts of understanding the microstructural basis of creep strength and of creep-fatigue interaction by transmission electron microscopic structure investigations coupled with creep tests. Investigations by transmission electron microscopy (TEM) were carried out with regard to hardening by

  19. Resistivity, hysteresis, and magnetization of 9% Cr stainless steel as a function of temperature and its electromagnetic shielding effects in cylindrical structures

    International Nuclear Information System (INIS)

    Praeg, W.F.

    1979-01-01

    Ferromagnetic stainless steels may offer significantly greater wall life-times for first wall/blanket and vacuum vessel structures than commonly used non-magnetic stainless steels. One steel under consideration has the following composition, in wt %, Fe(86.24), Cr(9), Mo(2), Mn(1), Si(0.75), Nb(0.50), V(0.30), C(0.15), P(0.3), S(0.30). There appears to be no literature on the electromagnetic properties of this material. Therefore, the resistivity, the hysteresis loops, and magnetization were measured as a function of temperature up to the Curie point

  20. Microstructure and elevated-temperature erosion-oxidation behaviour of aluminized 9Cr-1Mo Steel

    OpenAIRE

    Huttunen, E.; Honkanen, M.; Tsipas, Sophia Alexandra; Omar, H.; Tsipas, D.

    2012-01-01

    Degradation of materials by a combination of erosive wear and atmospheric oxidation at elevated temperatures constitutes a problem in some power generation processes, such as fluidized-bed combustion. In this work, 9Cr-1Mo steel, a common tube material in combustion chambers, is coated by a pack cementation method from an Al-containing pack in order to improve the resistance to erosion-oxidation at elevated temperatures. The resulting coating is studied in terms of microstructure and microhar...

  1. A Pharmacological Analysis of an Associative Learning Task: 5-HT1 to 5-HT7 Receptor Subtypes Function on a Pavlovian/Instrumental Autoshaped Memory

    Science.gov (United States)

    Meneses, Alfredo

    2003-01-01

    Recent studies using both invertebrates and mammals have revealed that endogenous serotonin (5-hydroxytryptamine [5-HT]) modulates plasticity processes, including learning and memory. However, little is currently known about the mechanisms, loci, or time window of the actions of 5-HT. The aim of this review is to discuss some recent results on the effects of systemic administration of selective agonists and antagonists of 5-HT on associative learning in a Pavlovian/instrumental autoshaping (P/I-A) task in rats. The results indicate that pharmacological manipulation of 5-HT1-7 receptors or 5-HT reuptake sites might modulate memory consolidation, which is consistent with the emerging notion that 5-HT plays a key role in memory formation. PMID:14557609

  2. Impingement wastage experiments with 9Cr 1Mo steel

    Energy Technology Data Exchange (ETDEWEB)

    Kishore, S., E-mail: skishore@igcar.gov.in [IGCAR (India); Beauchamp, François; Allou, Alexandre [CEA (France); Kumar, A. Ashok; Chandramouli, S.; Rajan, K.K. [IGCAR (India)

    2016-02-15

    Highlights: • Sodium heated steam generators are crucial components of fast breeder reactors. • A leak in steam generator tube will cause sodium water reaction that damages the tubes. • A collaborative study by CEA and IGCAR was conducted to quantify the extent of damage on 9Cr 1Mo tube due to a steam/water leak. • It was compared against the predictions of PROPANA code. - Abstract: Steam Generator (SG) is one of the vital components of sodium cooled fast reactor (SFR). The main safety concern with SG is a probable sodium–water reaction. In case, one of its water/steam carrying tubes leaks, water/steam gets into contact with sodium causing sodium-water reaction, which is highly exothermic and producing corrosive NaOH and hydrogen. The ejecting reaction products at high temperature, impinges upon adjacent tubes by a process called impingement wastage. It could damage one of the neighboring tubes in a short time, if the detection and protection systems are failing. IGCAR and CEA carried out a collaborative study on impingement wastage of 9Cr 1Mo steel, which is one of the candidate materials for SFR SG tubes. The studies comprise of experimental works at IGCAR and simulation works with PROPANA code at CEA. This paper brings out the data and experience gained through this cooperative work.

  3. The structure of the alphinizing coat on alloy steels

    Directory of Open Access Journals (Sweden)

    S. Pietrowski

    2008-12-01

    Full Text Available In this paper results of the structure of the coat alphinizing in AlSi5 silumin on alloy steels: acid-proof 1H18N9T (X6CrNiTi18-10 and high speed SW18 (HS18-0-1 were presented. The temperature of the alphinizing bath was amounts to750±5°C, and immersion time of the element τ = 180s. It was shown, that there is the different “g” coat thickness on testing steels. On the 1H18N9T steel it amounts to g = 52μm, and on the SW18 steel – g = 203μm. Regardless of a grade of testing alloy steels the coat consist of three layers with diversified phasic structure. There is different chemical composition of coat layers on testing steels. The first layer from the base consist of AlFe phase containing alloy addictions of steels: Cr and Ni (1H18N9T and W, V and Cr (SW18. On this layer crystallize the second layer of intermetallic phases. It is the phase containing the main alloy addiction of steels: AlFeCr (1H18N9T and AlFeW (SW18. The last, outside layer consist of silumin containing AlFeNi intermetallic phases on the 1H18N9T steel and AlFeW on the SW18 steel. Regardless of the grade of testing steels there is Si element in all layers of the coat. There are morphological differences in tested layers. The second layer (AlFeW phase inside the coat on the SW18 steel consist of faced crystals growing into in outside silumin layer. On the 1H18N9T steel a boundary between transient and outside layer is more uniform. Free separations of intermetallic phases inside silumin layer on the 1H18N9T steel have lamellar and on the SW18 steel – faced form.

  4. The permeation behavior of deuterium through 1Cr18Ni9Ti stainless steel with TiN+TiC-TiN multiple films

    International Nuclear Information System (INIS)

    Xiong, Y.; Song, J.; Luo, D.; Lei, Q.; Chen, C.

    2015-01-01

    The prevention of tritium losses via permeation through structure components is an important issue in fusion technology. The production of thin layers on materials with low diffusivity and/or low surface recombination constants (so-called permeation barriers) seems to be the most practical method to reduce or hinder the permeation of tritium through materials. TiN+TiC+TiN multiple films are deposited on the surface of 1Cr18Ni9Ti stainless steel by ion-beam assisted deposition technology. The characteristics of films are tested by XPS ASEM and XRD, which shows that the film are compact and uniform with a thickness of about 15 μm, and have a good adherence with the substrate below 773 K. The diffraction peaks in the XRD patterns for TiC and TiN are broadened, implying that the multiple films are deposited on the surface of 1Cr18Ni9Ti stainless steel. Meanwhile, the C-H bonded CH 4 -appears in the infrared spectra of multiple films, suggesting that the CH 4 - is in a static state, so hydrogen atom cannot migrate from the site bonded with carbon to a neighboring site. The measured deuterium permeability in 1Cr18Ni9Ti stainless steel coated with multiple films is 2-3 orders of magnitude lower than that of pure 1Cr18Ni9Ti stainless steel substrate from 473 K to 773 K. However, this barrier is partly destroyed above 773 K

  5. Influence of temperature and lithium purity on corrosion of ferrous alloys in a flowing lithium environment

    International Nuclear Information System (INIS)

    Chopra, O.K.; Smith, D.L.

    1986-03-01

    Corrosion data have been obtained on ferritic HT-9 and Fe-9Cr-1Mo steel and austenitic Type 316 stainless steel in a flowing lithium environment at temperatures between 372 and 538 0 C. The corrosion behavior is evaluated by measurements of weight loss as a function of time and temperature. A metallographic characterization of materials exposed to a flowing lithium environment is presented

  6. Development of Creep-Resistant and Oxidation-Resistant Austenitic Stainless Steels for High Temperature Applications

    Science.gov (United States)

    Maziasz, Philip J.

    2018-01-01

    Austenitic stainless steels are cost-effective materials for high-temperature applications if they have the oxidation and creep resistance to withstand prolonged exposure at such conditions. Since 1990, Oak Ridge National Laboratory (ORNL) has developed advanced austenitic stainless steels with creep resistance comparable to Ni-based superalloy 617 at 800-900°C based on specially designed "engineered microstructures" utilizing a microstructure/composition database derived from about 20 years of radiation effect data on steels. The wrought high temperature-ultrafine precipitate strengthened (HT-UPS) steels with outstanding creep resistance at 700-800°C were developed for supercritical boiler and superheater tubing for fossil power plants in the early 1990s, the cast CF8C-Plus steels were developed in 1999-2001 for land-based gas turbine casing and diesel engine exhaust manifold and turbocharger applications at 700-900°C, and, in 2015-2017, new Al-modified cast stainless steels with oxidation and creep resistance capabilities up to 950-1000°C were developed for automotive exhaust manifold and turbocharger applications. This article reviews and summarizes their development and their properties and applications.

  7. Characterization of the 5-HT1A receptor of the honeybee (Apis mellifera) and involvement of serotonin in phototactic behavior.

    Science.gov (United States)

    Thamm, Markus; Balfanz, Sabine; Scheiner, Ricarda; Baumann, Arnd; Blenau, Wolfgang

    2010-07-01

    Serotonin plays a key role in modulating various physiological and behavioral processes in both protostomes and deuterostomes. The vast majority of serotonin receptors belong to the superfamily of G-protein-coupled receptors. We report the cloning of a cDNA from the honeybee (Am5-ht1A) sharing high similarity with members of the 5-HT(1) receptor class. Activation of Am5-HT(1A) by serotonin inhibited the production of cAMP in a dose-dependent manner (EC(50) = 16.9 nM). Am5-HT(1A) was highly expressed in brain regions known to be involved in visual information processing. Using in vivo pharmacology, we could demonstrate that Am5-HT(1A) receptor ligands had a strong impact on the phototactic behavior of individual bees. The data presented here mark the first comprehensive study-from gene to behavior-of a 5-HT(1A) receptor in the honeybee, paving the way for the eventual elucidation of additional roles of this receptor subtype in the physiology and behavior of this social insect.

  8. Development of ferritic steels for fusion reactor applications

    Energy Technology Data Exchange (ETDEWEB)

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

    1988-08-01

    Chromium-molybdenum ferritic (martensitic) steels are leading candidates for the structural components for future fusion reactors. However, irradiation of such steels in a fusion environment will produce long-lived radioactive isotopes that will lead to difficult waste-disposal problems. Such problems could be reduced by replacing the elements in the steels (i.e., Mo, Nb, Ni, N, and Cu) that lead to long-lived radioactive isotopes. We have proposed the development of ferritic steels analogous to conventional Cr-Mo steels, which contain molybdenum and niobium. It is proposed that molybdenum be replaced by tungsten and niobium be replaced by tantalum. Eight experimental steels were produced. Chromium concentrations of 2.25, 5, 9, and 12% were used (all concentrations are in wt %). Steels with these chromium compositions, each containing 2% W and 0.25% V, were produced. To determine the effect of tungsten and vanadium, 2.25 Cr steels were produced with 2% W and no vanadium and with 0.25% V and O and 1% W. A 9Cr steel containing 2% W, 0.25 V, and 0.07% Ta was also studied. For all alloys, carbon was maintained at 0.1%. Tempering studies on the normalized steels indicated that the tempering behavior of the new Cr-W steels was similar to that of the analogous Cr-Mo steels. Microscopy studies indicated that 2% tungsten was required in the 2.25 Cr steels to produce 100% bainite in 15.9-mm-thick plate during normalization. The 5Cr and 9Cr steels were 100% martensite, but the 12 Cr steel contained about 75% martensite with the balance delta-ferrite. 33 refs., 35 figs., 5 tabs.

  9. Development of ferritic steels for fusion reactor applications

    International Nuclear Information System (INIS)

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

    1988-08-01

    Chromium-molybdenum ferritic (martensitic) steels are leading candidates for the structural components for future fusion reactors. However, irradiation of such steels in a fusion environment will produce long-lived radioactive isotopes that will lead to difficult waste-disposal problems. Such problems could be reduced by replacing the elements in the steels (i.e., Mo, Nb, Ni, N, and Cu) that lead to long-lived radioactive isotopes. We have proposed the development of ferritic steels analogous to conventional Cr-Mo steels, which contain molybdenum and niobium. It is proposed that molybdenum be replaced by tungsten and niobium be replaced by tantalum. Eight experimental steels were produced. Chromium concentrations of 2.25, 5, 9, and 12% were used (all concentrations are in wt %). Steels with these chromium compositions, each containing 2% W and 0.25% V, were produced. To determine the effect of tungsten and vanadium, 2.25 Cr steels were produced with 2% W and no vanadium and with 0.25% V and O and 1% W. A 9Cr steel containing 2% W, 0.25 V, and 0.07% Ta was also studied. For all alloys, carbon was maintained at 0.1%. Tempering studies on the normalized steels indicated that the tempering behavior of the new Cr-W steels was similar to that of the analogous Cr-Mo steels. Microscopy studies indicated that 2% tungsten was required in the 2.25 Cr steels to produce 100% bainite in 15.9-mm-thick plate during normalization. The 5Cr and 9Cr steels were 100% martensite, but the 12 Cr steel contained about 75% martensite with the balance delta-ferrite. 33 refs., 35 figs., 5 tabs

  10. The love of a lifetime: 5-HT in the cardiovascular system.

    Science.gov (United States)

    Watts, Stephanie W

    2009-02-01

    Serotonin [5-hydroxytryptamine (5-HT)] is an amine made from the essential amino acid tryptophan. 5-HT serves numerous functions in the body, including mood, satiety, and gastrointestinal function. Less understood is the role 5-HT plays in the cardiovascular system, although 5-HT receptors have been localized to every important cardiovascular organ and 5-HT-induced changes in physiological function attributed to activation of these receptors. This manuscript relates a few scientific stories that test the idea that 5-HT is important to the control of normal vascular tone, more so in the hypertensive condition. Currently, our laboratory is faced with two different lines of experimentation from which one could draw vastly different conclusions as to the ability of 5-HT to modify endogenous vascular tone and blood pressure. Studies point to 5-HT being important in maintaining high blood pressure, but other studies solidly support the ability of 5-HT to reduce elevated blood pressure. This work underscores that our knowledge of the functions of 5-HT in the cardiovascular system is significantly incomplete. As such, this field is an exciting one in which to be, because there are superb questions to be asked.

  11. Environmental HTO/HT sampler development

    International Nuclear Information System (INIS)

    Workman, W.J.G.; Brown, R.M.; Wood, M.J.

    1992-12-01

    Tests of retention by several drying agents of HTO from an air stream containing HT have been performed. Two batches of Molecular Sieve (MS) 4A retained up to 1.3% of HT passed through them in contrast to material tested in 1986, when retention was -4 . Retention of 10 -5 to 10 -6 was observed for DRIERITE (anhydrous calcium sulphate) and Silica Gel. DRIERITE is preferred over Silica Gel as a desiccant in an air sampler for environmental HTO/HT, because it is much easier to decontaminate for reuse. An improved air sampler has been designed, 2 units constructed and components procured for 3 more. The air sampler may be line or battery operated, accommodates up to four 120 g drier or oxidizer traps, and will pump up to 4 L/min for up to 24 hours on battery power. It is build into a rugged aluminum case and weighs approximately 11 kg overall, facilitating deployment in the field

  12. Environmental HTO/HT sampler development

    International Nuclear Information System (INIS)

    Workman, W.J.G.; Brown, R.M.; Wood, M.J.

    1994-01-01

    Tests of retention by several drying agents of HTO from an air stream containing HT have been performed. Two batches of Molecular Sieve (MS) 4A retained up to 1.3% of HT passed through them, in contrast to material tested in 1986, when retention was -4 . Retention of 10 -5 to 10 -6 was observed for DRIERITE (anhydrous calcium sulphate) and Silica Gel. DRIERITE is preferred over Silica Gel as a desiccant in an air sampler for environmental HTO/HT, because it is much easier to decontaminate for reuse. An improved air sampler has been designed, 2 units constructed and components procured for 3 more. The air sampler may be line or battery operated, accommodates up to four 120 g drier or oxidizer traps, and will pump up to 4 L/min for up to 24 hours on battery power. It is built into a rugged aluminum case and weighs approximately 11 kg overall, facilitating deployment in the field. (author). 5 refs., 2 tabs., 4 figs

  13. The reconstruction of HT-7 superconducting tokamak and the present status of HT-7U project

    International Nuclear Information System (INIS)

    Weng, P.D.

    2000-01-01

    The first Chinese superconducting tokamak HT-7 was reconstructed from T-7. The main purposes of reconstruction are to improve the accessibility of the device and to provide a possibility of long pulse operation with high performance. The reconstruction has been done successfully. The HT-7U project has been approved and funded as a National Project, the engineering design and R and D are on the way. (author)

  14. High temperature oxidation of 9% and 12% Cr steel: effect of water vapour; Oxidation haute temperature d'un acier 9% et 12% de teneur Cr. Effet de la vapeur d'eau

    Energy Technology Data Exchange (ETDEWEB)

    Evin, H.; Heritier, D.; Chevalier, S. [Universite de Bourgogne, Institut Carnot de Bourgogne UMR 5209 CNRS, 21 - Dijon (France); Fojer, C. [OCAS N.V. ArcelorMittal Research Industry Gent, Zelzate (Belgium)

    2008-07-01

    Isothermal tests were performed on commercial 9%Cr and 12%Cr steels between 600 and 750 deg C in air under atmospheric pressure. The same steels were also tested in oxidizing atmosphere enriched with 12% H{sub 2}O at 700 deg C for 24 hours. Kinetics data were registered and the corrosion products were analyzed using different characterization tools such as scanning electron microscope, x-ray diffraction and secondary ions mass spectrometry. 9%Cr steels showed very limited high temperature corrosion behavior in air, because a breakaway appeared after less than 80 hours at 750 deg C. Spinel oxides composed of iron, chromium and manganese (Mn{sub 1.5}Cr{sub 1.5}O{sub 4} and MnFe{sub 2}O{sub 4}) were identified over the surfaces of both steel grades after oxidation. (Cr,Fe){sub 2}O{sub 3} was also identified especially at 700 deg C and 750 deg C, whereas Fe{sub 2}O{sub 3} mainly grew at 600 and 650 deg C. Differences in oxide morphology and composition were noticed between the samples oxidized under air and air + 12 % water vapor. (authors)

  15. Rapid desensitization and resensitization of 5-HT2 receptor mediated phosphatidyl inositol hydrolysis by serotonin agonists in quiescent calf aortic smooth muscle cells

    International Nuclear Information System (INIS)

    Pauwels, P.J.; Van Gompel, P.; Leysen, J.E.

    1990-01-01

    Agonist regulation of 5-hydroxytryptamine 2 (5-HT 2 ) receptors was studied in calf aortic smooth muscle cultures incubated in a quiescent, defined synthetic medium that does not stimulate cell proliferation, but that provides cells with supplements that maintain cell viability. In these cells, 5-hydroxytryptamine (5-HT)-induced [ 3 H]inositol phosphates accumulation showed the characteristics of a 5-HT 2 receptor coupled transducing system according to the inhibition of the response by 5-HT 2 antagonists at nanomolar concentrations. The 5-HT 2 receptor coupled response became rapidly desensitized during continued incubation with 5-HT and 1-(2,5-dimethoxy-4-methylphenyl)-2-aminopropane (DOM); nearly full desensitization was obtained in two hours with 10 μM 5-HT and DOM pretreatment. The recovery of the response had a half-live of 5 hours after 2 hours pretreatment and of 9.5 to 12.5 hours after 24 to 96 hours agonist pretreatment. The DOM-induced desensitization of the 5-HT 2 receptor coupled response was fully blocked by 0.1 μM cinanserin. Cinanserin alone did not induce desensitization or up-regulation of the 5-HT 2 receptor coupled response at 0.1 μM

  16. Effect of thermo-mechanical treatments on creep and fatigue properties of 9% Cr martensitic steels

    International Nuclear Information System (INIS)

    Hollner, S.; Fournier, B.; Le Pendu, J.; Caes, C.; Tournie, I.; Pineau, A.

    2011-01-01

    In the framework of the development of Generation IV nuclear reactors and fusion nuclear reactors, materials with high mechanical properties up to 550 C are required. In service the materials will be subjected to high-temperature creep and cyclic loadings. 9-12%Cr martensitic steels are candidate materials for these applications; however, they show a pronounced cyclic softening effect under cyclic loadings. This softening effect is linked to the coarsening of the martensitic microstructure. In order to refine its microstructure and its precipitation state, the commercial P91 steel has been submitted to a thermo-mechanical treatment including warm-rolling at 600 C and a tempering stage at 700 C. Microstructural observations confirm that this thermo-mechanical treatment led to a finer martensite with smaller MX-type precipitates. This evolution has an effect on the high-temperature mechanical properties: the optimized P91 steel is 100 Hv harder than the as-received P91, and its yield strength is 430 MPa higher at 20 C and 220 MPa higher at 550 C. Its lifetime under creep (at 650 C under 120 MPa) is at least 14 times longer; and the fatigue test at 650 C under 0.7% strain shows a slightly slower cyclic softening effect for the optimized P91. (authors)

  17. Martensite transformation kinetics in 9Cr–1.7W–0.4Mo–Co ferritic steel

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Qiuzhi, E-mail: neuqgao@163.com [School of Resources and Materials, Northeastern University at Qinhuangdao, Qinhuangdao, Hebei 066000 (China); Wang, Cong; Qu, Fu; Wang, Yingling [School of Resources and Materials, Northeastern University at Qinhuangdao, Qinhuangdao, Hebei 066000 (China); Qiao, Zhixia [School of Mechanical Engineering, Tianjin University of Commerce, Tianjin 300134 (China)

    2014-10-15

    Highlights: • The obtained M{sub s} temperatures of samples austenitized at 1150 °C are higher than at 900 °C. • Martensite-start transformation is slower for austenitizing at 1150 °C than at 900 °C. • Martensite transformation was controlled by nucleation rate. • Growth of martensite plates was controlled by thermal activation of atoms. - Abstract: Martensite transformation features in the 9Cr–1.7W–0.4Mo–Co ferritic steel, was conducted on a Netzsch Differential Thermal Analysis (DTA), after austenitized at 900 °C and 1150 °C followed by cooling at various rates to room temperature were studied. A martensite transformation kinetics model based on assumption of continuous nucleation and consideration of impingement was introduced to investigate the influence of austenitizing temperature and cooling rate on the martensite transformation behaviors. The obtained interface velocity and the activation energy for interface-controlling growth are lower than 10{sup −5} m/s and 40 kJ/mol, respectively, according to the fitted data. Both indicated that martensite transformation in the 9Cr–1.7W–0.4Mo–Co ferritic steel was controlled by nucleation rate, and that growth of plates was controlled by thermal activation of atoms.

  18. Martensite transformation kinetics in 9Cr–1.7W–0.4Mo–Co ferritic steel

    International Nuclear Information System (INIS)

    Gao, Qiuzhi; Wang, Cong; Qu, Fu; Wang, Yingling; Qiao, Zhixia

    2014-01-01

    Highlights: • The obtained M s temperatures of samples austenitized at 1150 °C are higher than at 900 °C. • Martensite-start transformation is slower for austenitizing at 1150 °C than at 900 °C. • Martensite transformation was controlled by nucleation rate. • Growth of martensite plates was controlled by thermal activation of atoms. - Abstract: Martensite transformation features in the 9Cr–1.7W–0.4Mo–Co ferritic steel, was conducted on a Netzsch Differential Thermal Analysis (DTA), after austenitized at 900 °C and 1150 °C followed by cooling at various rates to room temperature were studied. A martensite transformation kinetics model based on assumption of continuous nucleation and consideration of impingement was introduced to investigate the influence of austenitizing temperature and cooling rate on the martensite transformation behaviors. The obtained interface velocity and the activation energy for interface-controlling growth are lower than 10 −5 m/s and 40 kJ/mol, respectively, according to the fitted data. Both indicated that martensite transformation in the 9Cr–1.7W–0.4Mo–Co ferritic steel was controlled by nucleation rate, and that growth of plates was controlled by thermal activation of atoms

  19. The use of nanofibers of P3HT in bulk heterojunction solar cells: the effect of order and morphology on the performance of P3HT:PCBM blends

    Science.gov (United States)

    Vanderzande, Dirk J. M.; Oosterbaan, Wibren D.; Vrindts, Veerle; Bertho, Sabine; Bolsée, Jean Christophe; Gadisa, Abay; Vandewal, Koen; Manca, Jean; Lutsen, Laurence; Cleij, Thomas J.; D'Haen, Jan; Zhao, Jun; Van Assche, Guy; Van Mele, Bruno

    2009-08-01

    Poly-3-AlkylThiophenes (P3ATs) with an n-alkyl chain length varying from C3 till C9 were synthesized by using the Rieke method. Subsequently, these materials were used to make P3AT/PCBM blends which were investigated in bulk heterojunction (BHJ) solar cells. The phase diagram of a P3H(exyl)T:PCBM blend was measured by means of standard and modulated temperature differential scanning calorimetry (DSC and MTDSC). A single glass transition is observed for all compositions. The glass transition temperature (Tg) increases with increasing PCBM concentration: from 12 °C for pure P3HT to 131 °C for pure PCBM. The observed range of Tg's defines the operating window for thermal annealing and explains the long-term instability of both morphology and photovoltaic performance of P3HT:PCBM solar cells. All regioregular P3ATs allow for efficient fiber formation in several solvents. The fibers formed are typically 15 to 25 nm wide and 0.5 to >4 μm long and mainly crystalline. By means of temperature control the fiber content in the casting solution for P3AT:PCBM BHJ solar cells is controlled while keeping the overall molecular weight of the polymer in the blend constant. In this way, fiber isolation and the use of solvent mixtures are avoided and with P3HT nanofibers, a power conversion efficiency of 3.2 % was achieved. P3AT:PCBM BHJ solar cells were also prepared from P3B(utyl)T, P3P(entyl)T and P3HT using the good solvent o-dichlorobenzene and a combination of slow drying and thermal annealing. In this way, power conversion efficiencies of 3.2, 4.3, and 4.6 % were obtained, respectively. P3PT is proved to be a potentially competitive material compared to P3HT.

  20. Interfacial failure in dissimilar weld joint of high boron 9% chromium steel and nickel-based alloy under high-temperature creep condition

    Energy Technology Data Exchange (ETDEWEB)

    Matsunaga, Tetsuya, E-mail: MATSUNAGA.Tetsuya@nims.go.jp; Hongo, Hiromichi, E-mail: HONGO.Hiromichi@nims.go.jp; Tabuchi, Masaaki, E-mail: TABUCHI.Masaaki@nims.go.jp

    2017-05-17

    The advanced ultra-supercritical (A-USC) power generation system is expected to become the next-generation base-load power station in Japan. Dissimilar weld joints between high-Cr heat-resistant steels and nickel-based alloys with a nickel-based filler metal (Alloy 82) will need to be adopted for this purpose. However, interfacial failure between the steels and weld metal has been observed under high-temperature creep conditions. Fractography and microstructure observations showed the failure initiated in a brittle manner by an oxide notch at the bottom of the U-groove. The fracture then proceeded along the bond line in a ductile manner with shallow dimples, where micro-Vickers hardness tests showed remarkable softening in the steel next to the bond line. In addition, the steel showed a much larger total elongation and reduction of area than the weld metal at low stresses under long-term creep conditions, leading to mismatch deformation at the interface. According to the results, it can be concluded that the interfacial failure between the 9Cr steels and Alloy 82 weld metal is initiated by an oxide notch and promoted by softening and the difference in the plasticity of the steels and weld metal.

  1. Experimental study and modelling of high temperature creep flow and damage behaviour of 9Cr1Mo-NbV steel weldments

    International Nuclear Information System (INIS)

    Gaffard, V.

    2004-12-01

    Chromium martensitic stainless steels are under development since the 70's with the prospect of using them as structural components in thermal and nuclear power plants. The modified 9Cr1Mo-NbV steel is already used, especially in England and Japan, as a material for structural components in thermal power plants where welding is a commonly used joining technique. New generations of chromium martensitic stainless steels with improved mechanical properties for high pressure and temperature use are currently under development. However, observations of several in-service premature failures of welded components in 9Cr1Mo-NbV steel, outline a strong need for understanding the high temperature creep flow and damage behaviour of 9Cr1Mo-NbV steels and weldments. The present study aimed at experimentally determining and then modelling the high temperature creep flow and damage behaviour of both 9Cr1Mo-NbV steels and weldments (typically in the temperature range from 450 C to 650 C). The base metal was first studied as the reference material. It was especially evidenced that tempered chromium martensitic steels exhibit a change in both creep flow and damage behaviour for long term creep exposure. As a consequence, the classically performed extrapolation of 1,000 hours creep data to 100,000 hours creep lifetime predictions might be very hazardous. Based on experimental observations, a new model, integrating and coupling multiple creep flow and damage mechanisms, was developed in the framework of the mechanics of porous media. It was then successfully used to represent creep flow and damage behaviour of the base metal from high to low stress levels even for complex multiaxial loading conditions. Although the high temperature creep properties of the base metal are quite good, the occurrence of premature failure in weldments in high temperature creep conditions largely focused the attention of the scientific community. The lower creep strength of the weld component was also

  2. Analysis of the 5-HT receptor in rabbit saphenous vein exemplifies the problems of using exclusion criteria for receptor classification.

    Science.gov (United States)

    Martin, G R; MacLennan, S J

    1990-08-01

    5-Hydroxytryptamine (5-HT) contracts ring preparations of rabbit saphenous vein via direct and indirect components, the latter being compatible with a "tyramine-like" action at sympathetic nerve terminals. Here an attempt was made to establish the identity of the receptor mediating contraction directly, in terms of the currently accepted proposals (Bradley et al. 1986). Results with agonists suggested 5-HT1-like receptor activation: methylsergide behaved as a partial agonist with microcolar affinity and 5-HT effects were mimicked by 5-carboxamidotryptamine (5-CT) and GR43175. The agonist potency order was 5-CT greater than 5-HT greater than methysergide greater than or equal to GR43175, the same as that reported at the 5-HT1-like receptor in dog saphenous vein (Feniuk et al. 1985; Humphrey et al. 1988). Consistent with this, 5-HT effects were resistant to blockade by the selective 5-HT3 receptor antagonist MDL72222 (1.0 mumol/l). In contrast, methiothepin (0.01-0.3 mumol/l), ketanserin (0.3-30.0 mumol/l) and spiperone (0.3-30.0 mumol/l) each produced surmountable antagonism which, although competitive in nature only for methiothepin (pKB = 9.45 +/- 0.09, 17 d.f.), implied 5-HT2 receptor involvement. The possibility that these discrepancies resulted from mixed populations of 5-HT1-like and 5-HT2 receptors can be excluded because; 1). Ketanserin and spiperone blocked the actions of 5-HT and the selective 5-HT1-like receptor agonist GR43175 with equal facility and 2). Responses to all of the agonists studied were similarly antagonised by flesinoxan (pKB approximately 6.4), a simple competitive antagonist at the receptor in rabbit saphenous vein.(ABSTRACT TRUNCATED AT 250 WORDS)

  3. Changes of Serotonin (5-HT, 5-HT2A Receptor, and 5-HT Transporter in the Sprague-Dawley Rats of Depression, Myocardial Infarction and Myocardial Infarction Co-exist with Depression

    Directory of Open Access Journals (Sweden)

    Mei-Yan Liu

    2015-01-01

    Conclusions: The concentration of 5-HT2AR in platelet lysate and SERT in serum and platelet may be involved in the pathway of MI with depression. Further studies should examine whether elevated 5-HT2AR and SERT may contribute to the biomarker in MI patients with depression.

  4. Novel spirotetracyclic zwitterionic dual H(1)/5-HT(2A) receptor antagonists for the treatment of sleep disorders.

    Science.gov (United States)

    Gianotti, Massimo; Botta, Maurizio; Brough, Stephen; Carletti, Renzo; Castiglioni, Emiliano; Corti, Corrado; Dal-Cin, Michele; Delle Fratte, Sonia; Korajac, Denana; Lovric, Marija; Merlo, Giancarlo; Mesic, Milan; Pavone, Francesca; Piccoli, Laura; Rast, Slavko; Roscic, Maja; Sava, Anna; Smehil, Mario; Stasi, Luigi; Togninelli, Andrea; Wigglesworth, Mark J

    2010-11-11

    Histamine H(1) and serotonin 5-HT(2A) receptors mediate two different mechanisms involved in sleep regulation: H(1) antagonists are sleep inducers, while 5-HT(2A) antagonists are sleep maintainers. Starting from 9'a, a novel spirotetracyclic compound endowed with good H(1)/5-HT(2A) potency but poor selectivity, very high Cli, and a poor P450 profile, a specific optimization strategy was set up. In particular, we investigated the possibility of introducing appropriate amino acid moieties to optimize the developability profile of the series. Following this zwitterionic approach, we were able to identify several advanced leads (51, 65, and 73) with potent dual H(1)/5-HT(2A) activity and appropriate developability profiles. These compounds exhibited efficacy as hypnotic agents in a rat telemetric sleep model with minimal effective doses in the range 3-10 mg/kg po.

  5. Microstructural evolution and creep behaviour of the modified 9% Cr steel with boron and cobalt

    International Nuclear Information System (INIS)

    Nowakowski, P.; Spiradek-Hahn, K.; Brabetz, M.; Zeiler, G.

    1998-01-01

    In the present study the microstructural evolution of the new 9% Cr with boron and cobalt is shown during creep at 650 o C. The minimum creep rates of the new alloy are significantly lower than those of conventional 12 % Cr steel. This is due to the high stability of M 23 C 6 precipitates with respect to the coarsening and the preservation of high dislocation density in the course of creep exposure. (author)

  6. Tensile properties and flow behavior analysis of modified 9Cr-1Mo steel clad tube material

    Science.gov (United States)

    Singh, Kanwarjeet; Latha, S.; Nandagopal, M.; Mathew, M. D.; Laha, K.; Jayakumar, T.

    2014-11-01

    The tensile properties and flow behavior of modified 9Cr-1Mo steel clad tube have been investigated in the framework of various constitutive equations for a wide range of temperatures (300-923 K) and strain rates (3 × 10-3 s-1, 3 × 10-4 s-1 and 3 × 10-5 s-1). The tensile flow behavior of modified 9Cr-1Mo steel clad tube was most accurately described by Voce equation. The variation of instantaneous work hardening rate (θ = dσ/dε) and σθ with stress (σ) indicated two stage behavior characterized by rapid decrease at low stresses (transient stage) followed by a gradual decrease in high stresses (Stage III). The variation of work hardening parameters and work hardening rate in terms of θ vs. σ and σθ vs. σ with temperature exhibited three distinct regimes. Rapid decrease in flow stress and work hardening parameters and rapid shift of θ vs. σ and σθ vs. σ towards low stresses with increase in temperature indicated dynamic recovery at high temperatures. Tensile properties of the material have been best predicted from Voce equation.

  7. Tensile properties and flow behavior analysis of modified 9Cr–1Mo steel clad tube material

    International Nuclear Information System (INIS)

    Singh, Kanwarjeet; Latha, S.; Nandagopal, M.; Mathew, M.D.; Laha, K.; Jayakumar, T.

    2014-01-01

    The tensile properties and flow behavior of modified 9Cr–1Mo steel clad tube have been investigated in the framework of various constitutive equations for a wide range of temperatures (300–923 K) and strain rates (3 × 10 −3 s −1 , 3 × 10 −4 s −1 and 3 × 10 −5 s −1 ). The tensile flow behavior of modified 9Cr–1Mo steel clad tube was most accurately described by Voce equation. The variation of instantaneous work hardening rate (θ = dσ/dε) and σθ with stress (σ) indicated two stage behavior characterized by rapid decrease at low stresses (transient stage) followed by a gradual decrease in high stresses (Stage III). The variation of work hardening parameters and work hardening rate in terms of θ vs. σ and σθ vs. σ with temperature exhibited three distinct regimes. Rapid decrease in flow stress and work hardening parameters and rapid shift of θ vs. σ and σθ vs. σ towards low stresses with increase in temperature indicated dynamic recovery at high temperatures. Tensile properties of the material have been best predicted from Voce equation

  8. Boron effect on the microstructure of 9% Cr ferritic–martensitic steels

    International Nuclear Information System (INIS)

    Klimenkov, M.; Materna-Morris, E.; Möslang, A.

    2015-01-01

    Highlights: • Detailed TEM characterization of BN, M 23 C 6 , VN and TaC precipitates in B-alloyed EUROFER97. • Determination of B content influence on density and composition of M 23 C 6 and MX precipitates and herewith on microstructure. • α-Al 2 O 3 –BN–TaC–VN precipitation sequence of different phases during cooling was proposed. • Decreasing of thermal stability of microstructure with boron content was measured. - Abstract: The microstructure of reduces-activation 9Cr–WTaV steel alloyed with 83 and 1160 wt. ppm 10 B was detailed analysed using transmission electron microscopy. The influence of boron content on the precipitation behaviour of M 23 C 6 and MX (VN and TaC) phases and, hence, on the formation process of steel’s grain and lath structure was studied. VN precipitates, which play an important role in the stabilisation of the lath structure, exhibit most sensitive reaction on presence of boron. Their spatial density significantly reduces in the alloy with 83 ppm boron. In the steel with 1160 wt. ppm boron, no formation of VN was detected, whereas TaC particles precipitate at the lath and grain boundaries. These changes in the structure stabilisation mechanism lead to an increasing lath width and a decreasing thermal stability of laths and grains. Analytical investigations of several BN particles reveal their complex multi-phase structure and allow conclusions to be drawn with respect to their precipitation sequence

  9. Acoustic emission under biaxial stresses in unflawed 21-6-9 and 304 stainless steel

    International Nuclear Information System (INIS)

    Hamstad, M.A.; Leon, E.M.; Mukherjee, A.K.

    1980-01-01

    Acoustic emission (AE) testing has been carried out with uniaxial and biaxial (2:1 stress ratio) stressing of smooth samples of 21-6-9 and 304 stainless steel (SS). Uniaxial testing was done with simple tensile and compression samples as well as with the special biaxial specimens. Biaxial tensile stressing was accomplished with a specially designed specimen, which had been used previously to characterize AE in 7075 aluminum under biaxial stressing. Results were obtained for air-melt and for vacuum-melt samples of 21-6-9 SS. The air-melt samples contain considerably more inclusion particles than the vacuum-melt samples. For the 304 SS, as received material was examined. To allow AE correlations with microstructure, extensive characterization of the 21-6-9 microstructure was carried out. Significant differences in AE occur in biaxially stressed specimens as compared to uniaxially stressed samples. 15 figures, 3 tables

  10. Effects of chronic treatment with escitalopram or citalopram on extracellular 5-HT in the prefrontal cortex of rats: role of 5-HT1A receptors

    Science.gov (United States)

    Ceglia, I; Acconcia, S; Fracasso, C; Colovic, M; Caccia, S; Invernizzi, R W

    2004-01-01

    Microdialysis was used to study the acute and chronic effects of escitalopram (S-citalopram; ESCIT) and chronic citalopram (CIT), together with the 5-HT1A receptor antagonist WAY100,635 (N-[2-[methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl) cyclohexane carboxamide trihydrochloride) and the 5-HT1A receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), on extracellular 5-hydroxytryptamine (5-HT) levels in the rat prefrontal cortex. Extracellular 5-HT rose to 234 and 298% of basal values after subcutaneous (s.c.) acute doses of 0.15 and 0.63 mg kg−1 ESCIT. No further increase was observed at 2.5 mg kg−1 ESCIT (290%). The effect of 13-day s.c. infusion of 10 mg kg−1day−1 ESCIT on extracellular 5-HT (422% of baseline) was greater than after 2 days (257% of baseline), whereas exposure to ESCIT was similar. In contrast, the increase in extracellular 5-HT induced by the infusion of CIT for 2 (306%) and 13 days (302%) was similar. However, brain and plasma levels of S-citalopram in rats infused with CIT for 13 days were lower than after 2 days. Acute treatment with 2.5 mg kg−1 ESCIT or 5 mg kg−1 CIT raised extracellular 5-HT by 243 and 276%, respectively, in rats given chronic vehicle but had no effect in rats given ESCIT (10 mg kg−1 day−1) or CIT (20 mg kg−1 day−1) for 2 or 13 days, suggesting that the infused doses had maximally increased extracellular 5-HT. WAY100,635 (0.1 mg kg−1 s.c.) increased extracellular 5-HT levels by 168, 174 and 169% of prechallenge values in rats infused with vehicle or ESCIT for 2 or 13 days, respectively. WAY100,635 enhanced extracellular 5-HT levels to 226, 153 and 164% of prechallenge values in rats infused with vehicle or CIT for 2 and 13 days, respectively. 8-OH-DPAT (0.025 mg kg−1) reduced extracellular 5-HT by 54% in control rats, but had no effect in those given ESCIT and CIT for 13 days. This series of experiments led to the conclusion that chronic treatment with ESCIT desensitizes the 5-HT1A

  11. Nuclear reactor plant with a small gas-cooled HT reactor accommodated in a steel pressure vessel

    International Nuclear Information System (INIS)

    Schoening, J.; Elter, C.

    1986-01-01

    The plant has a small HT reactor and an He/He heat exchanger situated above this, with preferably two parallel circulating blowers connected after it. It also has at least one post-shutdown heat removal system, which is situated after the He/He heat exchanger in the direction of flow and which always has the total quantity of primary helium flowing through it. In one version of the design, the heat exchanger consists of two concentric bundles of helices connected after one another, which have primary helium flowing in one direction and secondary helium in the opposite direction. (orig./HP) [de

  12. Effect of cobalt on microstructure and creep deformation behaviour of tempered martensitic 9% Cr steel for USC power

    Energy Technology Data Exchange (ETDEWEB)

    Helis, L.; Toda, Y.; Abe, F. [NIMS, Tsukuba (Japan). Structural Metals Center; Hara, T. [NIMS, Tsukuba (Japan). Advanced Nano Characterization Center; Miyazaki, H. [NIMS, Tokyo (Japan). Materials Data Sheet Station

    2008-07-01

    Four ingots with chemical composition 9Cr-3W-0/5Co-0.2V-0.05Nb-0.08C-0.05N, varying in the amount of Co addition were studied. Creep tests were conducted at temperature of 923K. Steels with 3% and 5% Co showed creep resistance superior to those with 1% and 0% Co at stresses above 140MPa. On the other hand 5% Co steel showed a significant deterioration in long term creep properties at 80MPa. Calculation by Thermo-Calc. suggested and observation of microstructure before the creep test confirmed the presence of about 6% and 0.4% of delta-ferrite in Co free and 1% Co steel, respectively. ICP mass spectrometry measurement showed that the amount of precipitation in steels after heat treatment increased with increase in Co addition, especially significant gap was found between 1% and 3% Co steels. Distribution of precipitation was studied by SEM and TEM. Particles of M{sub 23}C{sub 6} and MX carbonitrides preferentially precipitated around prior austenitic grain boundaries. Density of precipitation around these boundaries was found to depend on prior austenitic grain size, which is affected by the presence of anti o-ferrite and precipitation at normalizing temperature. Particles of Laves phase precipitated in the microstructure during the creep tests at 923K at all stresses. Its precipitation at the early stage was also enhanced by the addition of Co. It is known that creep properties of steels with fine grain deteriorate faster than those with coarse grains, due to the faster recovering during the keep at high temperatures. Combination of larger prior austenitic grains and higher precipitation contributes to the prolonged life of steels with higher amount of Co after testing at 923K and 160MPa. Deterioration in long term creep strength of steels with high amount of Co can be attributed to the precipitation Cr(V,Nb)N particles known as Z-phase, which is associated with dissolution of MX carbonitrides. (orig.)

  13. Conduction-band valley spin splitting in single-layer H-T l2O

    Science.gov (United States)

    Ma, Yandong; Kou, Liangzhi; Du, Aijun; Huang, Baibiao; Dai, Ying; Heine, Thomas

    2018-02-01

    Despite numerous studies, coupled spin and valley physics is currently limited to two-dimensional (2D) transition-metal dichalcogenides (TMDCs). Here, we predict an exceptional 2D valleytronic material associated with the spin-valley coupling phenomena beyond 2D TMDCs—single-layer (SL) H-T l2O . It displays large valley spin splitting (VSS), significantly larger than that of 2D TMDCs, and a finite band gap, which are both critically attractive for the integration of valleytronics and spintronics. More importantly, in sharp contrast to all the experimentally confirmed 2D valleytronic materials, where the strong valence-band VSS (0.15-0.46 eV) supports the spin-valley coupling, the VSS in SL H-T l2O is pronounced in its conduction band (0.61 eV), but negligibly small in its valence band (21 meV), thus opening a way for manipulating the coupled spin and valley physics. Moreover, SL H-T l2O possesses extremely high carrier mobility, as large as 9.8 ×103c m2V-1s-1 .

  14. Recombinant HT{sub m4} gene, protein and assays

    Science.gov (United States)

    Lim, B.; Adra, C.N.; Lelias, J.M.

    1996-09-03

    The invention relates to a recombinant DNA molecule which encodes a HT{sub m4} protein, a transformed host cell which has been stably transfected with a DNA molecule which encodes a HT{sub m4} protein and a recombinant HT{sub m4} protein. The invention also relates to a method for detecting the presence of a hereditary atopy. 2 figs.

  15. Measuring endogenous 5-HT release by emission tomography: promises and pitfalls

    DEFF Research Database (Denmark)

    Paterson, Louise M; Tyacke, Robin J; Nutt, David J

    2010-01-01

    Molecular in vivo neuroimaging techniques can be used to measure regional changes in endogenous neurotransmitters, evoked by challenges that alter synaptic neurotransmitter concentration. This technique has most successfully been applied to the study of endogenous dopamine release using positron......, with reference to the dopaminergic system. Studies that aim to image acute, endogenous 5-HT release or depletion at 5-HT receptor targets are summarised, with particular attention to studies in humans. Radiotracers targeting the 5-HT(1A), 5-HT(2A), and 5-HT(4) receptors and the serotonin reuptake transporter...... have been explored for their sensitivity to 5-HT fluctuations, but with mixed outcomes; tracers for these targets cannot reliably image endogenous 5-HT in humans. Shortcomings in our basic knowledge of the mechanisms underlying changes in binding potential are addressed, and suggestions are made...

  16. P3HT-graphene bilayer electrode for Schottky junction photodetectors

    Science.gov (United States)

    Aydın, H.; Kalkan, S. B.; Varlikli, C.; Çelebi, C.

    2018-04-01

    We have investigated the effect of a poly (3-hexylthiophene-2.5-diyl)(P3HT)-graphene bilayer electrode on the photoresponsivity characteristics of Si-based Schottky photodetectors. P3HT, which is known to be an electron donor and absorb light in the visible spectrum, was placed on CVD grown graphene by dip-coating method. The results of the UV-vis and Raman spectroscopy measurements have been evaluated to confirm the optical and electronic modification of graphene by the P3HT thin film. Current-voltage measurements of graphene/Si and P3HT-graphene/Si revealed rectification behavior confirming a Schottky junction formation at the graphene/Si interface. Time-resolved photocurrent spectroscopy measurements showed the devices had excellent durability and a fast response speed. We found that the maximum spectral photoresponsivity of the P3HT-graphene/Si photodetector increased more than three orders of magnitude compared to that of the bare graphene/Si photodetector. The observed increment in the photoresponsivity of the P3HT-graphene/Si samples was attributed to the charge transfer doping from P3HT to graphene within the spectral range between near-ultraviolet and near-infrared. Furthermore, the P3HT-graphene electrode was found to improve the specific detectivity and noise equivalent power of graphene/Si photodetectors. The obtained results showed that the P3HT-graphene bilayer electrodes significantly improved the photoresponsivity characteristics of our samples and thus can be used as a functional component in Si-based optoelectronic device applications.

  17. The role of 5-HT(1A) receptors in learning and memory.

    Science.gov (United States)

    Ogren, Sven Ove; Eriksson, Therese M; Elvander-Tottie, Elin; D'Addario, Claudio; Ekström, Joanna C; Svenningsson, Per; Meister, Björn; Kehr, Jan; Stiedl, Oliver

    2008-12-16

    The ascending serotonin (5-HT) neurons innervate the cerebral cortex, hippocampus, septum and amygdala, all representing brain regions associated with various domains of cognition. The 5-HT innervation is diffuse and extensively arborized with few synaptic contacts, which indicates that 5-HT can affect a large number of neurons in a paracrine mode. Serotonin signaling is mediated by 14 receptor subtypes with different functional and transductional properties. The 5-HT(1A) subtype is of particular interest, since it is one of the main mediators of the action of 5-HT. Moreover, the 5-HT(1A) receptor regulates the activity of 5-HT neurons via autoreceptors, and it regulates the function of several neurotransmitter systems via postsynaptic receptors (heteroreceptors). This review assesses the pharmacological and genetic evidence that implicates the 5-HT(1A) receptor in learning and memory. The 5-HT(1A) receptors are in the position to influence the activity of glutamatergic, cholinergic and possibly GABAergic neurons in the cerebral cortex, hippocampus and in the septohippocampal projection, thereby affecting declarative and non-declarative memory functions. Moreover, the 5-HT(1A) receptor regulates several transduction mechanisms such as kinases and immediate early genes implicated in memory formation. Based on studies in rodents the stimulation of 5-HT(1A) receptors generally produces learning impairments by interfering with memory-encoding mechanisms. In contrast, antagonists of 5-HT(1A) receptors facilitate certain types of memory by enhancing hippocampal/cortical cholinergic and/or glutamatergic neurotransmission. Some data also support a potential role for the 5-HT(1A) receptor in memory consolidation. Available results also implicate the 5-HT(1A) receptor in the retrieval of aversive or emotional memories, supporting an involvement in reconsolidation. The contribution of 5-HT(1A) receptors in cognitive impairments in various psychiatric disorders is still

  18. An evaluation procedure of sodium environmental effects on FBR grade SUS316 (316FR) and Modified 9Cr-1Mo steel. On the basis of the studies up to the fiscal year of 1998

    International Nuclear Information System (INIS)

    1999-01-01

    Evaluation of sodium environmental effects on structural materials of fast breeder reactors (FBR's) is one of the key issues for the integrity of the plants. The Elevated Temperature Structural Design Guide for Monju (ETSDG) incorporated an evaluation procedure of sodium environmental effects in the Appendix MA.2, for the conventional steels, such as SUS304, SUS316, SUS321 and 2 1/4Cr-1Mo. Following the establishment of the ETSDG, a new material with superior elevated temperature properties, FBR grade SUS316 (316FR), has been developed, and studies on Mod.9Cr-1Mo steel (Mod.9Cr-1Mo steel) has been performed, for the application to demonstration reactors and successive large-scale reactors. These materials were shown to have, at least equal, or better compatibility with sodium compared with the conventional steels. Moreover, studies have been continued with the conventional steels, particularly with SUS304, for the further validation of the procedure in the ETSDG, especially in terms of long-term properties. Those studies provide basis for the study on 316FR. This report proposed an evaluation procedure of sodium environmental effects on 316FR and Mod.9Cr-1Mo steel, which is to be incorporated into the structural design guide for demonstration fast breeder reactors. The procedure is summarized as follows: (1) Corrosion allowance of 316FR and Mod.9Cr-1Mo can be evaluated by the equation determined in the ETSTG. (2) Strength reduction factors on design allowable values are not necessary for either steel. Strength reduction due to the transfer of carbon and nitrogen, etc does not occur with 316FR, which was the same as SUS304. Mod.9Cr-1Mo steel does not show strength reduction, contrary to 2 l/4Cr-1Mo, similar ferritic steel. (3) Corrosion allowance can be determined separately for thin-walled components. The procedure allows design without correction factors for Mod.9Cr-1Mo steel, which was not possible for 2 1/4Cr-1Mo steel in the ETSDG. (author)

  19. Investigation into the Cyclic Strength of the Bodies of Steam Shutoff Valves from 10Kh9MFB-Sh Steel

    Science.gov (United States)

    Skorobogatykh, V. N.; Kunavin, S. A.; Prudnikov, D. A.; Shchenkova, I. A.; Bazhenov, A. M.; Zadoinyi, V. A.; Starkovskii, G. L.

    2018-02-01

    Steam shutoff valves are operated under complex loading conditions at thermal and nuclear power stations. In addition to exposure to high temperature and stresses resulting in fatigue, these valves are subjected to cyclic loads in heating-up-cooling down, opening-closing, etc. cycles. The number of these cycles to be specified in designing the valves should not exceed the maximum allowable value. Hence, the problem of cyclic failure rate of steam shutoff valve bodies is critical. This paper continues the previous publications about properties of the construction material for steam shutoff valve bodies (grade 10Kh9MFB-Sh steel) produced by electroslag melting and gives the results of investigation into the cyclic strength of this material. Fatigue curves for the steal used for manufacturing steam shutoff valve bodies are presented. The experimental data are compared with the calculated fatigue curves plotted using the procedures outlined in PNAE G-002-986 and RD 10-249-98. It is confirmed that these procedures may be used in designing valve bodies from 10Kh9MFB-Sh steel. The effect of the cyclic damage after preliminary cyclic loading of the specimens according to the prescribed load conditions on the high-temperature strength of the steel is examined. The influence of cyclic failure rate on the long-term strength was investigated using cylindrical specimens with a smooth working section in the as-made conditions and after two regimes of preliminary cyclic loading (training) at a working temperature of 570°C and the number of load cycles exceeding the design value, which was 2 × 103 cycles. The experiments corroborated that the material (10Kh9MFB-Sh steel) of the body manufactured by the method of electroslag melting had high resistance to cyclic failure rate. No effect of cyclic damages in the metal of the investigated specimens on the high-temperature strength has been found.

  20. 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.

  1. Actions of 5-hydroxytryptamine and 5-HT1A receptor ligands on rat dorso-lateral septal neurones in vitro.

    Science.gov (United States)

    Van den Hooff, P; Galvan, M

    1992-08-01

    1. The actions of 5-hydroxytryptamine (5-HT) and some 5-HT1A receptor ligands on neurones in the rat dorso-lateral septal nucleus were recorded in vitro by intracellular recording techniques. 2. In the presence of tetrodotoxin (1 microM) to block any indirect effects, bath application of 5-HT (0.3-30 microM) hyperpolarized the neurones in a concentration-dependent manner and reduced membrane resistance. The hyperpolarization did not exhibit desensitization and was sometimes followed by a small depolarization. 3. The 5-HT1A receptor ligands, 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT), N,N-dipropyl-5-carboxamidotryptamine (DP-5-CT) and buspirone but not the non-selective 5-HT1 receptor agonist, 1-m-trifluoromethylphenylpiperazine (TFMPP), also hyperpolarized the neurones. 4. 5-HT, 8-OH-DPAT and DP-5-CT appeared to act as full agonists whereas buspirone behaved as a partial agonist. The estimated EC50S were: DP-5-CT 15 nM, 8-OH-DPAT 110 nM, 5-HT 3 microM and buspirone 110 nM. 5. At a concentration of 3 microM, the putative 5-HT1A receptor antagonists, spiperone, methiothepin, NAN-190 (1-(2-methoxyphenyl)-4-[4-(2-pthalimido)butyl]piperazine) and MDL 73005EF (8-[2-(2,3-dihydro-1,4-benzodioxin-2-yl-methylamino)ethyl]-8- azaspiro[4,5]decane-7,9-dione methyl sulphonate), produced a parallel rightward shift in the concentration-response curve to 5-HT with no significant reduction in the maximum response. The estimated pA2 values were: NAN-190 6.79, MDL 73005EF 6.59, spiperone 6.54 and methiothepin 6.17.6. The 5-HT2/5-HTlc receptor antagonist, ketanserin (3 microM) and the 5HT3 receptor antagonist, tropisetron (3 microM) did not antagonize the 5-HT-induced hyperpolarizations; however, ketanserin blocked the depolarization which sometimes followed the hyperpolarization.7. It is concluded that the 5-HT-induced membrane hyperpolarization of rat dorso-lateral septal neurones is mediated by 5-HTA receptors.

  2. Experiments in the HT-7 Superconducting Tokamak

    International Nuclear Information System (INIS)

    Wan Baonian

    2002-01-01

    The HT-7 tokamak experiment research has made important progress. The main efforts have dealt with quasi-steady-state operation, lower-hybrid (LH) current drive (LHCD), plasma heating with ion cyclotron range of frequencies (ICRF), ion Bernstein waves (IBWs), fueling with pellets and supersonic molecular beams, first-wall conditioning techniques, and plasma and wall interaction. Plasma parameters in the experiments were much improved; for example, n e = 6.5 x 10 19 m -3 , and a plasma pulse length of >10 s was achieved. ICRF boronization and conditioning resulted in Z eff close to unity. Steady-state full LH wave current drive has been achieved for >3 s. LHCD rampup and recharge have also been demonstrated. The best [eta] CD exp of 10 19 m -2 A/W is achieved. Quasi-steady-state H-mode-like plasmas with a density close to the Greenwald limit were obtained by LHCD, where energy confinement time was nearly five times longer than in the ohmic case. The synergy between the IBW, pellet, and LHCD was investigated. New doped graphite as limiter material and ferritic steel used to reduce the ripples have been developed. Research on the mechanism of microturbulence has been extensively carried out experimentally

  3. Characterization and Modeling of Grain Boundary Chemistry Evolution in Ferritic Steels under Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Marquis, Emmanuelle [Univ. of Michigan, Ann Arbor, MI (United States); Wirth, Brian [Univ. of Tennessee, Knoxville, TN (United States); Was, Gary [Univ. of Michigan, Ann Arbor, MI (United States)

    2016-03-28

    Ferritic/martensitic (FM) steels such as HT-9, T-91 and NF12 with chromium concentrations in the range of 9-12 at.% Cr and high Cr ferritic steels (oxide dispersion strengthened steels with 12-18% Cr) are receiving increasing attention for advanced nuclear applications, e.g. cladding and duct materials for sodium fast reactors, pressure vessels in Generation IV reactors and first wall structures in fusion reactors, thanks to their advantages over austenitic alloys. Predicting the behavior of these alloys under radiation is an essential step towards the use of these alloys. Several radiation-induced phenomena need to be taken into account, including phase separation, solute clustering, and radiation-induced segregation or depletion (RIS) to point defect sinks. RIS at grain boundaries has raised significant interest because of its role in irradiation assisted stress corrosion cracking (IASCC) and corrosion of structural materials. Numerous observations of RIS have been reported on austenitic stainless steels where it is generally found that Cr depletes at grain boundaries, consistently with Cr atoms being oversized in the fcc Fe matrix. While FM and ferritic steels are also subject to RIS at grain boundaries, unlike austenitic steels, the behavior of Cr is less clear with significant scatter and no clear dependency on irradiation condition or alloy type. In addition to the lack of conclusive experimental evidence regarding RIS in F-M alloys, there have been relatively few efforts at modeling RIS behavior in these alloys. The need for predictability of materials behavior and mitigation routes for IASCC requires elucidating the origin of the variable Cr behavior. A systematic detailed high-resolution structural and chemical characterization approach was applied to ion-implanted and neutron-irradiated model Fe-Cr alloys containing from 3 to 18 at.% Cr. Atom probe tomography analyses of the microstructures revealed slight Cr clustering and segregation to dislocations and

  4. The 5-HT(1A) receptor agonist, 8-OH-DPAT, attenuates stress-induced anorexia in conjunction with the suppression of hypothalamic serotonin release in rats.

    Science.gov (United States)

    Shimizu, N; Hori, T; Ogino, C; Kawanishi, T; Hayashi, Y

    2000-12-22

    The effect of the selective 5-HT(1A) receptor agonist 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) on stress-induced anorexia and serotonin (5-HT) release in the rat hypothalamus was studied with brain microdialysis. Subcutaneous injection of 8-OH-DPAT (1 mg/kg) significantly attenuated the immobilization-induced anorexia for 3 h, but had no effect during the following 9 h. Injection of 8-OH-DPAT itself had no effect on basal release of 5-HT, while it significantly blocked the immobilization-induced 5-HT release in the lateral hypothalamus. The results suggest that 8-OH-DPAT attenuated the stress-induced anorexia through the activation of 5-HT(1A) autoreceptors in dorsal raphe nucleus.

  5. Tensile properties and flow behavior analysis of modified 9Cr–1Mo steel clad tube material

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Kanwarjeet, E-mail: kanwar722@yahoo.com; Latha, S.; Nandagopal, M.; Mathew, M.D.; Laha, K.; Jayakumar, T.

    2014-11-15

    The tensile properties and flow behavior of modified 9Cr–1Mo steel clad tube have been investigated in the framework of various constitutive equations for a wide range of temperatures (300–923 K) and strain rates (3 × 10{sup −3} s{sup −1}, 3 × 10{sup −4} s{sup −1} and 3 × 10{sup −5} s{sup −1}). The tensile flow behavior of modified 9Cr–1Mo steel clad tube was most accurately described by Voce equation. The variation of instantaneous work hardening rate (θ = dσ/dε) and σθ with stress (σ) indicated two stage behavior characterized by rapid decrease at low stresses (transient stage) followed by a gradual decrease in high stresses (Stage III). The variation of work hardening parameters and work hardening rate in terms of θ vs. σ and σθ vs. σ with temperature exhibited three distinct regimes. Rapid decrease in flow stress and work hardening parameters and rapid shift of θ vs. σ and σθ vs. σ towards low stresses with increase in temperature indicated dynamic recovery at high temperatures. Tensile properties of the material have been best predicted from Voce equation.

  6. Distribution of serotonin 5-HT1A-binding sites in the brainstem and the hypothalamus, and their roles in 5-HT-induced sleep and ingestive behaviors in rock pigeons (Columba livia).

    Science.gov (United States)

    Dos Santos, Tiago Souza; Krüger, Jéssica; Melleu, Fernando Falkenburger; Herold, Christina; Zilles, Karl; Poli, Anicleto; Güntürkün, Onur; Marino-Neto, José

    2015-12-15

    Serotonin 1A receptors (5-HT1ARs), which are widely distributed in the mammalian brain, participate in cognitive and emotional functions. In birds, 5-HT1ARs are expressed in prosencephalic areas involved in visual and cognitive functions. Diverse evidence supports 5-HT1AR-mediated 5-HT-induced ingestive and sleep behaviors in birds. Here, we describe the distribution of 5-HT1ARs in the hypothalamus and brainstem of birds, analyze their potential roles in sleep and ingestive behaviors, and attempt to determine the involvement of auto-/hetero-5-HT1ARs in these behaviors. In 6 pigeons, the anatomical distribution of [(3)H]8-OH-DPAT binding in the rostral brainstem and hypothalamus was examined. Ingestive/sleep behaviors were recorded (1h) in 16 pigeons pretreated with MM77 (a heterosynaptic 5-HT1AR antagonist; 23 or 69 nmol) for 20 min, followed by intracerebroventricular ICV injection of 5-HT (N:8; 150 nmol), 8-OH-DPAT (DPAT, a 5-HT1A,7R agonist, 30 nmol N:8) or vehicle. 5-HT- and DPAT-induced sleep and ingestive behaviors, brainstem 5-HT neuronal density and brain 5-HT content were examined in 12 pigeons, pretreated by ICV with the 5-HT neurotoxin 5,7-dihydroxytryptamine (5,7-DHT) or vehicle (N:6/group). The distribution of brainstem and diencephalic c-Fos immunoreactivity after ICV injection of 5-HT, DPAT or vehicle (N:5/group) into birds provided with or denied access to water is also described. 5-HT1ARs are concentrated in the brainstem 5-HTergic areas and throughout the periventricular hypothalamus, preoptic nuclei and circumventricular organs. 5-HT and DPAT produced a complex c-Fos expression pattern in the 5-HT1AR-enriched preoptic hypothalamus and the circumventricular organs, which are related to drinking and sleep regulation, but modestly affected c-Fos expression in 5-HTergic neurons. The 5-HT-induced ingestivebehaviors and the 5-HT- and DPAT-induced sleep behaviors were reduced by MM77 pretreatment. 5,7-DHT increased sleep per se, decreased tryptophan

  7. Phthalate SHEDS-HT runs

    Data.gov (United States)

    U.S. Environmental Protection Agency — Inputs and outputs for SHEDS-HT runs of DiNP, DEHP, DBP. This dataset is associated with the following publication: Moreau, M., J. Leonard, K. Phillips, J. Campbell,...

  8. Comparison of various 9-12%Cr steels under fatigue and creep-fatigue loadings at high temperature

    International Nuclear Information System (INIS)

    Fournier, B.; Dalle, F.; Sauzay, M.; Longour, J.; Salvi, M.; Caes, C.; Tournie, I.; Giroux, P.F.; Kim, S.H.

    2011-01-01

    The present article compares the cyclic behaviour of various 9-12%Cr steels, both commercial grades and optimized materials (in terms of creep strength). These materials were subjected to high temperature fatigue and creep-fatigue loadings. TEM examinations of the microstructure after cyclic loadings were also carried out. It appears that all the tempered ferritic-martensitic steels suffer from a cyclic softening effect linked to the coarsening of the sub-grains and laths and to the decrease of the dislocation density. These changes of the microstructure lead to a drastic loss in creep strength for all the materials under study. However, due to a better precipitation state, several materials optimized for their creep strength still present a good creep resistance after cyclic softening. These results are discussed and compared to the literature in terms of the physical mechanisms responsible for cyclic and creep deformation at the microstructural scale. (authors)

  9. Development status und future possibilities for martensitic creep resistant steels

    Energy Technology Data Exchange (ETDEWEB)

    Hald, J. [Technical Univ. Denmark, Lyngby (Denmark). Dept. of Mechanical Engineering

    2010-07-01

    In the last four decades new stronger modified 9%Cr martensitic creep resistant steels have been introduced in power plants, which has enabled increases in maximum achievable steam conditions from the previous 250 bar and 540-560 C up to the values of 300 bar and 600-620 C currently being introduced all over the world. In order to further increase the steam parameters of steel based power plants up to a target value of 650 C/325 bar it is necessary to double the creep strength of the martensitic steels. At the same time the resistance against steam oxidation must be improved by an increase of the chromium content in the steels from 9% to 12%. However, so far all attempts to make stronger 12%Cr steels have led to breakdowns in long-term creep strength. Significant progress has been achieved in the understanding of microstructure stability of the martensitic 9-12%Cr steels: Observed microstructure instabilities in 11-12%Cr steels are explained by Z-phase precipitation, which dissolves fine MN nitrides. Improved understanding of effects of B and N on long-term creep properties has formed the basis of a series of new stronger 9%Cr test alloys with improved creep strength. In parallel 9%Cr test steels with low C content show very promising behavior in long-term tests. However, the 9%Cr steels must be surface coated to protect against steam oxidation at high temperature applications above 620%C. A possibility to use fine Z-phases for strengthening of the martensitic steels has been identified, and this opens a new pathway for development of stable strong 12%Cr steels. There are still good prospects for the realization of a 325 bar / 650 C steam power plant all based on steel. (orig.)

  10. Microstructural characterization of second phases in X10CrMoVNb9-1 and 12CrMoWCuVNb steels after long steam exposure time at 550 C

    International Nuclear Information System (INIS)

    Rodak, Kinga; Hernas, Adam; Vodarek, Vlastimil

    2015-01-01

    Microstructural changes in high alloy (9-12% Cr) creep resistant martensitic X10CrMoVNb9-1 and 12CrMoW . CuVNb steels after 100 000 h of steam exposure at 550 C have been studied using scanning transmission electron microscopy. Precipitates were identified using electron diffraction patterns and energy dispersive X-ray spectroscopy analysis. After long time exposure, a significant coarsening of M 23 C 6 carbides, and intensive precipitation of the coarse Laves phase were observed. Moreover, in the 12CrMoW . CuVNb steel, a low amount of the modified Z-phase particles was detected. The microstructures of the X10Cr . MoVNb9-1 and 12CrMoWCuVNb steels after 100 000 h of exposure differ in several aspects.

  11. Microstructural characterization of second phases in X10CrMoVNb9-1 and 12CrMoWCuVNb steels after long steam exposure time at 550 C

    Energy Technology Data Exchange (ETDEWEB)

    Rodak, Kinga; Hernas, Adam [Silesian Univ. of Technology, Inst. of Materials Science, Katowice (Poland); Vodarek, Vlastimil [VSB-Technical Univ. of Ostrava (Czech Republic)

    2015-07-15

    Microstructural changes in high alloy (9-12% Cr) creep resistant martensitic X10CrMoVNb9-1 and 12CrMoW . CuVNb steels after 100 000 h of steam exposure at 550 C have been studied using scanning transmission electron microscopy. Precipitates were identified using electron diffraction patterns and energy dispersive X-ray spectroscopy analysis. After long time exposure, a significant coarsening of M{sub 23}C{sub 6} carbides, and intensive precipitation of the coarse Laves phase were observed. Moreover, in the 12CrMoW . CuVNb steel, a low amount of the modified Z-phase particles was detected. The microstructures of the X10Cr . MoVNb9-1 and 12CrMoWCuVNb steels after 100 000 h of exposure differ in several aspects.

  12. BDNF downregulates 5-HT(2A) receptor protein levels in hippocampal cultures

    DEFF Research Database (Denmark)

    Trajkovska, V; Santini, M A; Marcussen, Anders Bue

    2009-01-01

    Both brain-derived neurotrophic factor (BDNF) and the serotonin receptor 2A (5-HT(2A)) have been related to depression pathology. Specific 5-HT(2A) receptor changes seen in BDNF conditional mutant mice suggest that BDNF regulates the 5-HT(2A) receptor level. Here we show a direct effect of BDNF...... on 5-HT(2A) receptor protein levels in primary hippocampal neuronal and mature hippocampal organotypic cultures exposed to different BDNF concentrations for either 1, 3, 5 or 7 days. In vivo effects of BDNF on hippocampal 5-HT(2A) receptor levels were further corroborated in (BDNF +/-) mice...... with reduced BDNF levels. In primary neuronal cultures, 7 days exposure to 25 and 50ng/mL BDNF resulted in downregulation of 5-HT(2A), but not of 5-HT(1A), receptor protein levels. The BDNF-associated downregulation of 5-HT(2A) receptor levels was also observed in mature hippocampal organotypic cultures...

  13. Pharmacological profile of DA-6886, a novel 5-HT4 receptor agonist to accelerate colonic motor activity in mice.

    Science.gov (United States)

    Lee, Min Jung; Cho, Kang Hun; Park, Hyun Min; Sung, Hyun Jung; Choi, Sunghak; Im, Weonbin

    2014-07-15

    DA-6886, the gastrointestinal prokinetic benzamide derivative is a novel 5-HT4 receptor agonist being developed for the treatment of constipation-predominant irritable bowel syndrome (IBS-C). The purpose of this study was to characterize in vitro and in vivo pharmacological profile of DA-6886. We used various receptor binding assay, cAMP accumulation assay, organ bath experiment and colonic transit assay in normal and chemically constipated mice. DA-6886 exhibited high affinity and selectivity to human 5-HT4 receptor splice variants, with mean pKi of 7.1, 7.5, 7.9 for the human 5-HT4a, 5-HT4b and 5-HT4d, respectively. By contrast, DA-6886 did not show significant affinity for several receptors including dopamine D2 receptor, other 5-HT receptors except for 5-HT2B receptor (pKi value of 6.2). The affinity for 5-HT4 receptor was translated into functional agonist activity in Cos-7 cells expressing 5-HT4 receptor splice variants. Furthermore, DA-6886 induced relaxation of the rat oesophagus preparation (pEC50 value of 7.4) in a 5-HT4 receptor antagonist-sensitive manner. The evaluation of DA-6886 in CHO cells expressing hERG channels revealed that it inhibited hERG channel current with an pIC50 value of 4.3, indicating that the compound was 1000-fold more selective for the 5-HT4 receptor over hERG channels. In the normal ICR mice, oral administration of DA-6886 (0.4 and 2mg/kg) resulted in marked stimulation of colonic transit. Furthermore, in the loperamide-induced constipation mouse model, 2mg/kg of DA-6886 significantly improved the delay of colonic transit, similar to 10mg/kg of tegaserod. Taken together, DA-6886 is a highly potent and selective 5-HT4 receptor agonist to accelerate colonic transit in mice, which might be therapeutic agent having a favorable safety profile in the treatment of gastrointestinal motor disorders such as IBS-C and chronic constipation. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Differential involvement of 5-HT(1A) and 5-HT(1B/1D) receptors in human interferon-alpha-induced immobility in the mouse forced swimming test.

    Science.gov (United States)

    Zhang, Hongmei; Wang, Wei; Jiang, Zhenzhou; Shang, Jing; Zhang, Luyong

    2010-01-01

    Although Interferon-alpha (IFN-alpha, CAS 9008-11-1) is a powerful drug in treating several viral infections and certain tumors, a considerable amount of neuropsychiatric side-effects such as depression and anxiety are an unavoidable consequence. Combination with the selective serotonin (5-HT) reuptake inhibitor (SSRI) fluoxetine (CAS 56296-78-7) significantly improved the situation. However, the potential 5-HT(1A) receptor- and 5-HT(1B) receptor-signals involved in the antidepressant effects are still unclear. The effects of 5-HT(1A) receptor- and 5-HT(1B) receptor signals were analyzed by using the mouse forced swimming test (FST), a predictive test of antidepressant-like action. The present results indicated that (1) fluoxetine (administrated intragastrically, 30 mg/kg; not subactive dose: 15 mg/kg) significantly reduced IFN-alpha-induced increase of the immobility time in the forced swimming test; (2) 5-HT(1A) receptor- and 5-HT(1B) receptor ligands alone or in combination had no effects on IFN-alpha-induced increase of the immobility time in the FST; (3) surprisingly, WAY 100635 (5-HT(1A) receptor antagonist, 634908-75-1) and 8-OH-DPAT(5-HT(1A) receptor agonist, CAS 78950-78-4) markedly enhanced the antidepressant effect of fluoxetine at the subactive dose (15 mg/kg, i. g.) on the IFN-alpha-treated mice in the FST. Further investigations showed that fluoxetine combined with WAY 100635 and 8-OH-DPAT failed to produce antidepressant effects in the FST. (4) Co-application of CGS 12066A (5-HT(1B) receptor agonist, CAS 109028-09-3) or GR 127935 (5-HT(1B/1D) receptor antagonist, CAS 148642-42-6) with fluoxetine had no synergistic effects on the IFN-alpha-induced increase of immobility time in FST. (5) Interestingly, co-administration of GR 127935, WAY 100635 and fluoxetine significantly reduced the IFN-alpha-induced increase in immobility time of FST, being more effective than co-administration of WAY 100635 and fluoxetine. All results suggest that (1) compared to

  15. Mechanisms underlying apoptosis-inducing effects of Kaempferol in HT-29 human colon cancer cells.

    Science.gov (United States)

    Lee, Hyun Sook; Cho, Han Jin; Yu, Rina; Lee, Ki Won; Chun, Hyang Sook; Park, Jung Han Yoon

    2014-02-17

    We previously noted that kaempferol, a flavonol present in vegetables and fruits, reduced cell cycle progression of HT-29 cells. To examine whether kaempferol induces apoptosis of HT-29 cells and to explore the underlying molecular mechanisms, cells were treated with various concentrations (0-60 μmol/L) of kaempferol and analyzed by Hoechst staining, Annexin V staining, JC-1 labeling of the mitochondria, immunoprecipitation, in vitro kinase assays, Western blot analyses, and caspase-8 assays. Kaempferol increased chromatin condensation, DNA fragmentation and the number of early apoptotic cells in HT-29 cells in a dose-dependent manner. In addition, kaempferol increased the levels of cleaved caspase-9, caspase-3 and caspase-7 as well as those of cleaved poly (ADP-ribose) polymerase. Moreover, it increased mitochondrial membrane permeability and cytosolic cytochrome c concentrations. Further, kaempferol decreased the levels of Bcl-xL proteins, but increased those of Bik. It also induced a reduction in Akt activation and Akt activity and an increase in mitochondrial Bad. Additionally, kaempferol increased the levels of membrane-bound FAS ligand, decreased those of uncleaved caspase-8 and intact Bid and increased caspase-8 activity. These results indicate that kaempferol induces the apoptosis of HT-29 cells via events associated with the activation of cell surface death receptors and the mitochondrial pathway.

  16. Processing parameters for the mechanical working of 9 Cr-1 Mo steel: processing maps approach

    Energy Technology Data Exchange (ETDEWEB)

    Sivaprasad, P.V.; Mannan, S.L.; Prasad, Y.V.R.K. [Indira Ghandi Centre for Atomic Research, Tamilnadu (India)

    2004-12-15

    Processing and instability maps using a dynamic materials model have been developed for 9Cr-1Mo steel in the temperature range 850 to 1200{sup o}C and strain rate range 0.001-100 s{sup -1} with a view to optimising its hot workability. The efficiency of power dissipation increased with increase in temperature and decrease in strain rate. The 9Cr-1Mo material exhibited two dynamic recrystallisation domains, one with a peak efficiency of 37% occurring at 950{sup o}C and 0.001 s{sup -1} and the other with a peak efficiency of 35% occurring at 1200{sup o}C and 0.1 s{sup -1}. These results are in good agreement with those found in industry. (author)

  17. Synthesis and biochemical evaluation of tritium-labeled 1-methyl-N-(8-methyl-8-azabicyclo[3.2.1]oct-3-yl)-1H-indazole-3-carboxa mide, a useful radioligand for 5HT3 receptors

    International Nuclear Information System (INIS)

    Robertson, D.W.; Bloomquist, W.; Cohen, M.L.; Reid, L.R.; Schenck, K.; Wong, D.T.

    1990-01-01

    The advent of potent, highly selective 5HT3 receptor antagonists has stimulated considerable interest in 5HT3 receptor mediated physiology and pharmacology. To permit detailed biochemical studies regarding interaction of the indazole class of serotonin (5HT) antagonists with 5HT3 receptors in multiple tissues, we synthesized 1-methyl-N-(8-methyl-8-azabicyclo[3.2.1]oct-3-yl)-1H-indazole- 3-carboxamide (LY278584, compound 9) in high specific activity, tritium-labeled form. This radioligand was selected as a synthetic target because of its potency as a 5HT3-receptor antagonist, its selectivity for this receptor viz a viz other 5HT-receptor subtypes, and the ability to readily incorporate three tritia via the indazole N-CH3 substituent. Alkylation of N-(8-methyl-8-azabicyclo[3.2.1]oct-3-yl)-1H-indazole-3-carboxamide (8) with sodium hydride and tritium-labeled iodomethane, followed by HPLC purification, resulted in [3H]-9 with a radiochemical purity of 99% and a specific activity of 80.5 Ci/mmol. This radioligand bound with high affinity to a single class of saturable recognition sites in membranes isolated from cerebral cortex of rat brain. The Kd was 0.69 nM and the Bmax was 16.9 fmol/mg of protein. The specific binding was excellent, and accounted for 83-93% of total binding at concentrations of 2 nM or less. The potencies of known 5HT3-receptor antagonists as inhibitors of [3H]-9 binding correlated well with their pharmacological receptor affinities as antagonists of 5HT-induced decreases in heart rate and contraction of guinea pig ileum, suggesting the central recognition site for this radioligand may be extremely similar to or identical with peripheral 5HT3 receptors

  18. Impurity Antimony-Induced Creep Property Deterioration and Its Suppression by Rare Earth Ceriumfor a 9Cr-1Mo Ferritic Heat-Resistant Steel

    Directory of Open Access Journals (Sweden)

    Yewei Xu

    2016-08-01

    Full Text Available The high temperature creep properties of three groups of modified 9Cr-1Mo steel samples, undoped, doped with Sb, and doped with Sb and Ce, are evaluated under the applied stresses from 150 MPa to 210 MPa and at the temperatures from 873–923 K. The creep behavior follows the temperature-compensated power law as well as the Monkman-Grant relation. The creep activation energy for the Sb-doped steel (519 kJ/mol is apparently lower than that for the undoped one (541 kJ/mol, but it is considerably higher for the Sb+Ce-doped steel (621 kJ/mol. Based on the obtained relations, both the creep lifetimes under 50 MPa, 80 MPa, and 100 MPa in the range 853–923 K and the 105 h creep rupture strengths at 853 K, 873 K, and 893 K are predicted. It is demonstrated that the creep properties of the Sb-doped steel are considerably deteriorated but those of the Sb+Ce-doped steel are significantly improved as compared with the undoped steel. Microstructural and microchemical characterizations indicate that the minor addition of Ce can stabilize the microstructure of the steel by segregating to grain boundaries and dislocations, thereby offsetting the deleterious effect of Sb by coarsening the microstructure and weakening the grain boundary.

  19. Measuring endogenous 5-HT release by emission tomography: promises and pitfalls

    Science.gov (United States)

    Paterson, Louise M; Tyacke, Robin J; Nutt, David J; Knudsen, Gitte M

    2010-01-01

    Molecular in vivo neuroimaging techniques can be used to measure regional changes in endogenous neurotransmitters, evoked by challenges that alter synaptic neurotransmitter concentration. This technique has most successfully been applied to the study of endogenous dopamine release using positron emission tomography, but has not yet been adequately extended to other neurotransmitter systems. This review focuses on how the technique has been applied to the study of the 5-hydroxytryptamine (5-HT) system. The principles behind visualising fluctuations in neurotransmitters are introduced, with reference to the dopaminergic system. Studies that aim to image acute, endogenous 5-HT release or depletion at 5-HT receptor targets are summarised, with particular attention to studies in humans. Radiotracers targeting the 5-HT1A, 5-HT2A, and 5-HT4 receptors and the serotonin reuptake transporter have been explored for their sensitivity to 5-HT fluctuations, but with mixed outcomes; tracers for these targets cannot reliably image endogenous 5-HT in humans. Shortcomings in our basic knowledge of the mechanisms underlying changes in binding potential are addressed, and suggestions are made as to how the selection of targets, radiotracers, challenge paradigms, and experimental design might be optimised to improve our chances of successfully imaging endogenous neurotransmitters in the future. PMID:20664611

  20. A Passive Diffusion Sampler for HT- and HTO-in-Air

    International Nuclear Information System (INIS)

    Surette, R.A.; Nunes, J.C.

    2005-01-01

    Fusion research and tritium removal facilities potentially handle large inventories of tritium gas (HT). If any HT is released into the workplace, a fraction may be converted to tritiated water vapour (HTO). A convenient method to determine the activity concentration of each species is necessary to assess the potential hazard since the radiological hazard of HTO is more than 10 4 that due to HT. Passive samplers for measuring tritiated water vapour (HTO) have been shown to be suitable for use indoors and outdoors. These simple samplers consist of a standard 20-mL liquid scintillation vial with a diffusion orifice that determines the sampling rate.The total tritium samplers described herein are passive or diffusion samplers that contain a small amount of AECL-proprietary wet-proofed catalyst fixed to the underside of the sampling heads to allow conversion of the HT to HTO that is subsequently collected in the sink, (HTO), in the bottom of the sampler. After an appropriate sampling time, liquid scintillation cocktail is added to the vial and the activity collected determined by liquid scintillation analysis. When used in conjunction with the conventional HTO passive sampler the difference between the total and HTO samplers can be used to determine the HT fraction ((HT+HTO) - HTO HT). The sampling rates for the modified diffusion sampler were measured to be 4.6 and 8.1 L/d for HTO and HT, respectively. For a fifteen-minute sampling period, passive samplers can be used to measure tritium activity concentrations from 37 kBq/m 3 to 115 MBq/m 3

  1. 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.)

  2. Modulatory effect of the 5-HT1A agonist buspirone and the mixed non-hallucinogenic 5-HT1A/2A agonist ergotamine on psilocybin-induced psychedelic experience.

    Science.gov (United States)

    Pokorny, Thomas; Preller, Katrin H; Kraehenmann, Rainer; Vollenweider, Franz X

    2016-04-01

    The mixed serotonin (5-HT) 1A/2A/2B/2C/6/7 receptor agonist psilocybin dose-dependently induces an altered state of consciousness (ASC) that is characterized by changes in sensory perception, mood, thought, and the sense of self. The psychological effects of psilocybin are primarily mediated by 5-HT2A receptor activation. However, accumulating evidence suggests that 5-HT1A or an interaction between 5-HT1A and 5-HT2A receptors may contribute to the overall effects of psilocybin. Therefore, we used a double-blind, counterbalanced, within-subject design to investigate the modulatory effects of the partial 5-HT1A agonist buspirone (20mg p.o.) and the non-hallucinogenic 5-HT2A/1A agonist ergotamine (3mg p.o.) on psilocybin-induced (170 µg/kg p.o.) psychological effects in two groups (n=19, n=17) of healthy human subjects. Psychological effects were assessed using the Altered State of Consciousness (5D-ASC) rating scale. Buspirone significantly reduced the 5D-ASC main scale score for Visionary Restructuralization (VR) (ppsilocybin-induced 5D-ASC main scale scores. The present finding demonstrates that buspirone exerts inhibitory effects on psilocybin-induced effects, presumably via 5-HT1A receptor activation, an interaction between 5-HT1A and 5-HT2A receptors, or both. The data suggest that the modulation of 5-HT1A receptor activity may be a useful target in the treatment of visual hallucinations in different psychiatric and neurological diseases. Copyright © 2016 Elsevier B.V. and ECNP. All rights reserved.

  3. Effect of rhenium and osmium on mechanical properties of a 9Cr-2W-0.25V-0.07Ta-0.1C steel

    International Nuclear Information System (INIS)

    Klueh, R.L.; Alexander, D.J.; Sokolov, M.A.

    2000-01-01

    The nuclear transmutation of tungsten to rhenium and osmium in a tungsten-containing steel irradiated in a fission or fusion reactor will change the chemical composition of the steel. To determine the possible consequences of such compositional changes on the mechanical properties, tensile and Charpy impact properties were measured on five 9Cr-2W-0.25V-0.07Ta-0.1C steels that contained different amounts of rhenium, osmium, and tungsten. The mechanical properties changes caused by these changes in composition were minor. Observations were also made on the effect of carbon concentration. The effect of carbon on tensile behavior was minor, but there was a large effect on Charpy properties. Several of the steels showed little effect of tempering temperature on the Charpy transition temperature, a behavior that was tentatively attributed to the low silicon and/or manganese concentration of the experimental steels

  4. Residual creep life assessment by change of martensitic lath structure in modified 9Cr-1Mo steels

    International Nuclear Information System (INIS)

    Sawada, Kota; Takeda, Masaaki; Maruyama, Kouichi; Komine, Ryuji; Nagae, Yuji

    1998-01-01

    Mod.9Cr-1Mo steel has a martensitic lath structure. Recovery of the lath structure takes place in the course of creep. Microstructural degradation due to the recovery results in the acceleration of creep rate and the subsequent failure of a specimen. Change of lath width during creep of the steel was quantitatively investigated to propose a residual life assessment methodology based on the recovery process. Since the steel was tempered at 1053 K, the lath structure is thermally stable at the testing temperatures (848 K - 923 K). However, recovery of lath structure readily takes place during creep, indicating that the recovery is induced by creep deformation. Lath width d increases with creep strain and saturates to a value d s determined by creep stress. The increase of d is faster at a higher stress and temperature. A normalized change in lath width, Δd/Δd s , was introduced to explain the variation of lath growth rate with creep stress and temperature. Δd is the change in lath width from the initial value d 0 , and Δd s is the difference between d s , and d 0 . Δd/Δd s is uniquely related to creep strain ε and the relationship is independent of creep stress as well as creep temperature. This Δd/Δd s -ε relationship obtained by an accelerated creep test at a higher temperature or stress is applicable to any creep condition including service conditions of engineering plants. Creep strain can be evaluated from the measurement of Δd/Δd s based on the Δd/Δd s -ε relationship. A creep curve under any creep condition can readily be calculated by creep data of the steel. Combining these information one can assess residual life of a structural component made of the steel. (author)

  5. Downregulation of CD147 expression by RNA interference inhibits HT29 cell proliferation, invasion and tumorigenicity in vitro and in vivo.

    Science.gov (United States)

    Li, Rui; Pan, Yuqin; He, Bangshun; Xu, Yeqiong; Gao, Tianyi; Song, Guoqi; Sun, Huiling; Deng, Qiwen; Wang, Shukui

    2013-12-01

    We investigated the effect of CD147 silencing on HT29 cell proliferation and invasion. We constructed a novel short hairpin RNA (shRNA) expression vector pYr-mir30-shRNA. The plasmid was transferred to HT29 cells. The expression of CD147, MCT1 (lactate transporters monocarboxylate transporter 1) and MCT4 (lactate transporters monocarboxylate transporter 4) were monitored by quantitative PCR and western blotting, respectively. The MMP-2 (matrix metalloproteinase-2) and MMP-9 (matrix metalloproteinase-9) activities were determined by gelatin zymography assay, while the intracellular lactate concentration was determined by the lactic acid assay kit. WST-8 assay was used to determine the HT29 cell proliferation and the chemosensitivity. Invasion assay was used to determine the invasion of HT29 cells. In addition, we established a colorectal cancer model, and detected CD147 expression in vivo. The results showed that the expression of CD147 and MCT1 was significantly reduced at both mRNA and protein levels, and also the activity of MMP-2 and MMP-9 was reduced. The proliferation and invasion were decreased, but chemosensitivity to cisplatin was increased. In vivo, the CD147 expression was also significantly decreased, and reduced the tumor growth after CD147 gene silencing. The results demonstrated that silencing of CD147 expression inhibited the proliferation and invasion, suggesting CD147 silencing might be an adjuvant gene therapy strategy to chemotherapy.

  6. The Fabrication of Bulk Heterojunction P3HT: PCBM Organic Photovoltaics

    Science.gov (United States)

    Darwis, D.; Sesa, E.; Farhamza, D.; Iqbal

    2018-05-01

    Bulk heterojunction Organic photovoltaic (OPV) devices are gaining a lot of interest due to their potential for ease of processing and lower manufacturing cost sustainable energy generation. In consequence, the number of studies into the properties and characteristics of organic solar cell devices has been increased to improving their power conversion. A further advancement over past decade has shown that improved efficiency could be obtained by mixed of poly(3 - hexylthiophene) (P3HT) and [1] – phenyl - C61-butyric acid methyl ester (PCBM) as an active layer. A series of optimizations of this P3HT: PCBM blends, such as the mixture ratio variation, the annealing treatments, and solvent treatment, have been emerged to improve the efficiency of the OPV. As a result, significant improvements were achieved. Here, we report the fabrication heterojunction devices of 2.9 % efficiency. This result has been achieved using the configuration of a typical heterojunction solar cell modules consists of layered glass/ITO/PEDOT: PSS/active layer/cathode interlayer

  7. Synthesis, radiofluorination and first evaluation of [{sup 18}F]fluorophenylsulfonyl- and [{sup 18}F]fluorophenylsulfinyl-piperidines as serotonin 5-HT{sub 2A} receptor antagonists for PET

    Energy Technology Data Exchange (ETDEWEB)

    Muehlhausen, Ute; Sihver, Wiebke [Institute of Neuroscience and Medicine, INM-5: Nuclear Chemistry, Forschungszentrum Juelich GmbH, 52425 Juelich (Germany); Ermert, Johannes, E-mail: j.ermert@fz-juelich.d [Institute of Neuroscience and Medicine, INM-5: Nuclear Chemistry, Forschungszentrum Juelich GmbH, 52425 Juelich (Germany); Coenen, Heinz H. [Institute of Neuroscience and Medicine, INM-5: Nuclear Chemistry, Forschungszentrum Juelich GmbH, 52425 Juelich (Germany)

    2010-07-15

    In psychiatric disorders, 5-HT{sub 2A} receptors play an important role. In order to study these receptors in vivo by positron emission tomography (PET), there is an increasing interest for subtype selective and high affinity radioligands. Up to now, no optimal radiotracer is available. Thus, 1-(2,4-difluorophenethyl)-4-(4-fluorophenylsulfonyl)piperidine (9), possessing high affinity and sufficient subtype selectivity for 5-HT{sub 2A} receptors, and 1-(2,4-difluorophenethyl)-4-(4-fluorophenylsulfinyl)piperidine (15) have been {sup 18}F-labelled by a nucleophilic one-step reaction. Both radiotracers could be prepared and isolated within 45 min, [{sup 18}F]9 in a radiochemical yield (RCY) of 34.5{+-}8% and [{sup 18}F]15 of 9.5{+-}2.5%. The K{sub i} values of 9 and 15 at 5-HT{sub 2A} receptors towards [{sup 3}H]ketanserin were determined to be 1.9{+-}0.6 and 198{+-}8 nM, respectively. Autoradiography with [{sup 18}F]9 and [{sup 18}F]15 on rat brain sections showed a very high nonspecific binding of >80% for [{sup 18}F]9 and 30% to 40% nonspecific binding for [{sup 18}F]15; however, it is still too high in order to compensate for its lower affinity. Even though the affinity of 9 is more promising compared with 15, the high nonspecific binding of both radiofluorinated tracers in rat brain does not recommend those as an in vivo PET imaging agent for serotonin 5-HT{sub 2A} receptors in humans.

  8. Specific labelling of serotonin 5-HT(1B) receptors in rat frontal cortex with the novel, phenylpiperazine derivative, [3H]GR125,743. A pharmacological characterization.

    Science.gov (United States)

    Millan, M J; Newman-Tancredi, A; Lochon, S; Touzard, M; Aubry, S; Audinot, V

    2002-04-01

    Although several tritiated agonists have been used for radiolabelling serotonin (5-hydroxytryptamine, 5-HT)(1B) receptors in rats, data with a selective, radiolabelled antagonist have not been presented. Inasmuch as [3H]GR125,743 specifically labels cloned, human and native guinea pig 5-HT(1B) receptors and has been employed for characterization of cerebral 5-HT(1B) receptor in the latter species [Eur. J. Pharmacol. 327 (1997) 247.], the present study evaluated its utility for characterization of native, cerebral 5-HT(1B) sites in the rat. In homogenates of frontal cortex, [3H]GR125,743 (0.8 nM) showed rapid association (t(1/2)=3.4 min), >90% specific binding and high affinity (K(d)=0.6 nM) for a homogeneous population of receptors with a density (B(max)) of 160 fmol/mg protein. In competition binding studies, affinities were determined for 15 chemically diverse 5-HT(1B) agonists, including 2-[5-[3-(4-methylsulphonylamino)benzyl-1,2,4-oxadiazol-5-yl]-1H-indole-3-yl]ethylamine (L694,247; pK(i), 10.4), 5-carboxamidotryptamine (5-CT; 9.7), 3-[3-(2-dimethylamino-ethyl)-1H-indol-6-yl]-N-(4-methoxybenzyl)acrylamide (GR46,611; 9.6), 5-methoxy-3-(1,2,5,6-tetrahydro-4-pyridinyl)-1H-indole (RU24,969; 9.5), dihydroergotamine (DHE; 8.6), 5-H-pyrrolo[3,2-b]pyridin-5-one,1,4-dihydro-3-(1,2,3,6-tetrahydro-4-pyridinyl (CP93,129; 8.4), anpirtoline (7.9), sumatriptan (7.4), 1-[2-(3-fluorophenyl)ethyl]-4-[3-[5-(1,2,4-triazol-4-yl)-1H-indol-3-yl]propyl]piperazine (L775,606; 6.4) and (minus sign)-1(S)-[2-[4-(4-methoxyphenyl)piperazin-1-yl]ethyl]-N-methyl-3,4-dihydro-1H-2-benzopyran-6-carboxamide (PNU109,291; <5.0). Similarly, affinities were established for 13 chemically diverse antagonists, including N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]-3-methyl-4-(4-pyridyl)benzamide (GR125,743; pK(i), 9.1), (-)cyanopindolol (9.0), (-)-tertatolol (8.2), N-(4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]-2'-methyl-4'-(5-methyl-1,2,4-oxadiozol-3-yl)biphenyl-4-carboxamide (GR127,935; 8.2), N-[3

  9. Tensile anisotropy and creep properties of a Fe-14CrWTi ODS ferritic steel

    Energy Technology Data Exchange (ETDEWEB)

    Steckmeyer, A., E-mail: antonin.steckmeyer@cea.fr [CEA Saclay, DEN/DANS/DMN/SRMA, 91191 Gif-sur-Yvette (France); Rodrigo, Vargas Hideroa [CEA Saclay, DEN/DANS/DMN/SRMA, 91191 Gif-sur-Yvette (France); Gentzbittel, J.M. [CEA Grenoble, DRT/LITEN/DTBH/LCTA, 38054 Grenoble Cedex 9 (France); Rabeau, V.; Fournier, B. [CEA Saclay, DEN/DANS/DMN/SRMA, 91191 Gif-sur-Yvette (France)

    2012-07-15

    A Fe-14Cr oxide dispersion strengthened (ODS) ferritic steel is studied as a potential material for cladding tube application for the next generation of fast-breeder nuclear reactors. Tensile specimens machined out from a hot extruded round bar in three different orientations are used to evaluate the mechanical anisotropy of this steel for temperatures in the range 20-750 Degree-Sign C. Its anisotropy is discussed both in terms of mechanical strength and fracture mode. At high temperatures (HTs), above 500 Degree-Sign C, the longitudinal direction appears to be the most ductile and most resistant direction. Longitudinal creep tests between 650 Degree-Sign C and 900 Degree-Sign C were also carried out. They show this ODS steel has a high HT creep lifetime and a low creep failure strain. Intergranular cracks aligned along the loading axis were observed on fractured creep specimens. They reveal a particular weakness of prior particle boundaries and suggest to modify the elaboration process through mechanical alloying and hot extrusion.

  10. Autroadiographic characterization of 125I-labeled 2,5-dimethoxy-4-iodophenylisopropylamine (DOI): A phenylisopropylamine derivative labeling both 5HT2 and 5HT1c receptors

    International Nuclear Information System (INIS)

    Appel, N.M.; Mitchell, W.M.; Garlick, R.K.; Glennon, R.A.; Titeler, M.; De Souza, E.B.

    1990-01-01

    The best-characterized 5HT 2 radioligands, such as [ 3 H]ketanserin and [ 3 H]spiperone, are antagonists that label both high- and low-affinity states of this receptor. Recently, the radiolabeled phenylisopropylamine hallucinogens DOB and DOI, which are agonists at 5HT 2 receptors, have been demonstrated to label selectively the high-affinity state of brain 5HT 2 receptors. In the present study, the authors determined optimum conditions for autoradiographic visualization of [ 125 I]DOI binding and characterized its pharmacology and guanine nucleotide sensitivity under those conditions. In slide-mounted tissue sections (rat forebrain; two 10 μm sections/slide), (±)[ 125 I]DOI binding was saturable, of high affinity (K D ∼4nM) and displayed a pharmacological profile [R(-)DOI > spiperone > DOB > (±)DOI > ketanserin > S(+)DOI > 5HT > DOM] comparable to that seen in homogenate assays. Consistent with coupling of 5HT 2 receptors to a guanine nucleotide regulatory protein, [ 125 I]DOI binding was inhibited by guanine nucleotides but not by ATP. In autoradiograms, high densities of [ 125 I]DOI binding sites were present in frontal cortex, olfactory tubercle, claustrum, caudate/putamen and mamillary nuclei with lower densities in trigeminal and solitary nuclei. The highest density of [ 125 l]DOI binding was observed in choroid plexus; these binding sites displayed a pharmacological profile characteristic of 5HT 1C receptors. These data suggest that [ 125 I]DOI labels both 5HT 2 and 5HT 1C receptors

  11. Development of metallic fuel fabrication - A study on the interdiffusion behavior between ternary metallic fuel and cladding materials

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Byung Soo; Seol, Kyung Won; Shon, In Jin [Chonbuk National University, Chonju (Korea)

    1999-04-01

    To study a new ternary metallic fuel for liquid metal reactor, various U-Zr-X alloys have been made by induction melting. The specimens were prepared for thermal stability tests at 630 deg. C upto 5000 hours in order to estimate the decomposition of the lamellar structure. Interdiffusion studies were carried out at 700 deg. C for 200 hours for the diffusion couples assembled with U-Zr-X ternary fuel versus austenitic stainless steel D9 and martensitic stainless steel HT9, respectively, to investigate the fuel-cladding compatibility. The ternary alloy, especially U-Zr-Mo and U-Zr-Nb alloys showed relatively good thermal stability as long as 5000hrs at 630 deg. C. From the composition profiles of the interdiffusion study, Fe penetrated deeper to the fuel side than other cladding elements such as Ni and Cr, whereas U did to the cladding side of fuel elements in the fuel/D9 couples. On the contrary, the reaction layers of Fuel/HT9 couple were thinner than that of Fuel/D9 couples and were less affected by cladding element, which was believed to be due to Zr rich layer between the fuel-cladding interface. HT9 is considered to be superior to D9 and a favorable choice as a cladding material in terms of fuel-cladding compatibility. 21 refs., 24 figs., 7 tabs. (Author)

  12. Hallucinogenic 5-HT2AR agonists LSD and DOI enhance dopamine D2R protomer recognition and signaling of D2-5-HT2A heteroreceptor complexes.

    Science.gov (United States)

    Borroto-Escuela, Dasiel O; Romero-Fernandez, Wilber; Narvaez, Manuel; Oflijan, Julia; Agnati, Luigi F; Fuxe, Kjell

    2014-01-03

    Dopamine D2LR-serotonin 5-HT2AR heteromers were demonstrated in HEK293 cells after cotransfection of the two receptors and shown to have bidirectional receptor-receptor interactions. In the current study the existence of D2L-5-HT2A heteroreceptor complexes was demonstrated also in discrete regions of the ventral and dorsal striatum with in situ proximity ligation assays (PLA). The hallucinogenic 5-HT2AR agonists LSD and DOI but not the standard 5-HT2AR agonist TCB2 and 5-HT significantly increased the density of D2like antagonist (3)H-raclopride binding sites and significantly reduced the pKiH values of the high affinity D2R agonist binding sites in (3)H-raclopride/DA competition experiments. Similar results were obtained in HEK293 cells and in ventral striatum. The effects of the hallucinogenic 5-HT2AR agonists on D2R density and affinity were blocked by the 5-HT2A antagonist ketanserin. In a forskolin-induced CRE-luciferase reporter gene assay using cotransfected but not D2R singly transfected HEK293 cells DOI and LSD but not TCB2 significantly enhanced the D2LR agonist quinpirole induced inhibition of CRE-luciferase activity. Haloperidol blocked the effects of both quinpirole alone and the enhancing actions of DOI and LSD while ketanserin only blocked the enhancing actions of DOI and LSD. The mechanism for the allosteric enhancement of the D2R protomer recognition and signalling observed is likely mediated by a biased agonist action of the hallucinogenic 5-HT2AR agonists at the orthosteric site of the 5-HT2AR protomer. This mechanism may contribute to the psychotic actions of LSD and DOI and the D2-5-HT2A heteroreceptor complex may thus be a target for the psychotic actions of hallunicogenic 5-HT2A agonists. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Bulk Nanostructured FCC Steels With Enhanced Radiation Tolerance

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xinghang; Hartwig, K. Ted; Allen, Todd; Yang, Yong

    2012-10-27

    The objective of this project is to increase radiation tolerance in austenitic steels through optimization of grain size and grain boundary (GB) characteristics. The focus will be on nanocrystalline austenitic Fe-Cr-Ni alloys with an fcc crystal structure. The long-term goal is to design and develop bulk nanostructured austenitic steels with enhanced void swelling resistance and substantial ductility, and to enhance their creep resistance at elevated temperatures via GB engineering. The combination of grain refinement and grain boundary engineering approaches allows us to tailor the material strength, ductility, and resistance to swelling by 1) changing the sink strength for point defects, 2) by increasing the nucleation barriers for bubble formation at GBs, and 3) by changing the precipitate distributions at boundaries. Compared to ferritic/martensitic steels, austenitic stainless steels (SS) possess good creep and fatigue resistance at elevated temperatures, and better toughness at low temperature. However, a major disadvantage of austenitic SS is that they are vulnerable to significant void swelling in nuclear reactors, especially at the temperatures and doses anticipated in the Advanced Burner Reactor. The lack of resistance to void swelling in austenitic alloys led to the switch to ferritic/martensitic steels as the preferred material for the fast reactor cladding application. Recently a type of austenitic stainless steel, HT-UPS, was developed at ORNL, and is expected to show enhanced void swelling resistance through the trapping of point defects at nanometersized carbides. Reducing the grain size and increasing the fraction of low energy grain boundaries should reduce the available radiation-produced point defects (due to the increased sink area of the grain boundaries), should make bubble nucleation at the boundaries less likely (by reducing the fraction of high-energy boundaries), and improve the strength and ductility under radiation by producing a higher

  14. Reduction factors for creep strength and fatigue life of modified 9 Cr-1 Mo steel weldments

    International Nuclear Information System (INIS)

    Blass, J.J.; Battiste, R.L.; O'Connor, D.G.

    1991-01-01

    The provisions of ASME B ampersand PV Code Case N-47 currently include reduction factors for creep strength and fatigue life of weldments. To provide experimental confirmation of such factors for modified 9 Cr-1 Mo steel, tests of tubular specimens were conducted at 538 degree C (1000 degree F). Three creep-rupture specimens with longitudinal welds were tested in tension; and, of three with circumferential welds, two were tested in tension and one in torsion. In each specimen with a circumferential weld, a nonuniform axial distribution of strain was easily visible. The test results were compared to an existing empirical model of creep-rupture life. For the torsion test, the comparison was based on a definition of equivalent normal stress recently adopted in Code Case N-47. Some 27 fatigue specimens, with longitudinal, circumferential, or no welds, were tested under axial or torsional strain control. In specimens with welds, fatigue cracking initiated at fusion lines. In axial tests cracks grew in the circumferential direction, and in torsional tests cracks grew along fusion lines. The test results were compared to empirical models of fatigue life based on two definition of equivalent normal strain range. The results have provided some needed confirmation of the reduction factors for creep strength and fatigue life of modified 9 Cr-1 Mo steel weldments currently under consideration by ASME Code committees. 8 refs., 5 figs

  15. Field studies of HT oxidation and dispersion in the environment

    International Nuclear Information System (INIS)

    Brown, R.M.; Ogram, G.L.; Spencer, F.S.; Ontario Hydro, Toronto, ON

    1988-10-01

    A tracer quantity of 3.54 TBq tritiated hydrogen (HT) was released into the atmosphere at a Chalk River, Ontario field site to determine the behaviour of HT in the environment. The primary objective was to establish the oxidation rate of HT to tritiated water (HTO) in air, soil and vegetation compartments. HTO/HT atmospheric concentration ratios observed during the release ranged from 0.14 x 10 -4 at 5 m to 7.0 x 10 -4 at 400 m distance from the release point indicating an effective oxidation rate of about 1.5% h -1 . Gas phase oxidation in the atmosphere would be less than this effective rate. Results confirm that surface soils play the dominant role in converting HT to HTO. Soil HT deposition velocities were between 2.7 x 10 -4 and 11 x 10 -4 m s -1 for an open field of varied composition, and between 3.3 x 10 -4 and 12 x 10 -4 m s -1 for a conifer forest. Soil HTO loss rates were initially 1 to 3 % h -1 averaged over the first 24 h after release. Vegetation tissue-free water tritium (TFWT) resulted from uptake of soil HTO and exchange with atmospheric HTO vapour. Upper limit HT deposition velocities to vegetation measured as TFWT in 5 species were 0.23 x 10 -7 to 6 x 10 -7 m s -1 expressed on a leaf area basis. TFWT loss rates were 5.2 to 8.1 % h -1 from about 12 to 48 h after release with low activity rain and 0.42 to 0.56 % h -1 from about 48 to 335 h. Vegetation organically-bound tritium/TFWT specific activity ratios (Bq g -1 H) were about 0.1 initially, increasing to 16 after 113 days as TFWT specific activity declined more rapidly than that of OBT. The effective HT oxidation rate, deposition velocities and HTO loss rates were in good agreement with a 1986 HT field release and previous laboratory experiments

  16. Tritium permeation in stainless-steel structures exposed to plasma ions

    International Nuclear Information System (INIS)

    Anderl, R.A.; Holland, D.F.; Struttmann, D.A.; Longhurst, G.R.; Merrill, B.J.

    1985-01-01

    This paper presents a comparison of the hydrogen permeation properties of the austenitic primary candidate alloy, PCA, and of the advanced ferritic alloy, HT-9. The comparison is based on experimental measurements of the permeation and reemission of deuterium from specimens undergoing implantation with 3-keV, D 3 + ions produced by an accelerator. Characterization of the specimen surface facing the ion beam is provided by secondary ion mass spectrometer (SIMS) analysis of the species sputtered from the surface during the implantation. Recombination and diffusivity data for PCA and HT-9 were derived from an analysis in which model calculations were applied to the reemission and permeation measurements

  17. Hydrogen transport in iron and steel

    International Nuclear Information System (INIS)

    Louthan, M.R. Jr.; Derrick, R.G.; Donovan, J.A.; Caskey, G.R. Jr.

    1975-01-01

    The permeabilities of protium, deuterium, and tritium in iron and T-1 steel at temperatures as low as 260 0 K are in agreement with the equation proposed by Gonzalez. However, the permeabilities of HP-9-4-20 and 4130 steel to hydrogen are typically lower than predicted. The present data also show that, within experimental accuracy, the isotope effect on the permeability of hydrogen in HP-9-4-20, 4130 and T-1 steel, and high purity iron can be estimated by an inverse square root of mass correction. Trapping effects prevent the development of diffusivity and solubility equations. (auth)

  18. A numerical approach to predict the long-term creep behaviour and precipitate back-stress evolution of 9-12% chromium steels

    Energy Technology Data Exchange (ETDEWEB)

    Holzer, I.; Cerjak, H. [Graz Univ. of Technology (Austria). Inst. for Materials Science and Welding; Kozeschnik, E. [Vienna Univ. of Technology (Austria). Inst. of Materials Science and Technology; Vienna Univ. of Technology (Austria). Christian Doppler Lab. ' Early Stages of Precipitation'

    2010-07-01

    The mechanical properties of modern 9-12% Cr steels are significantly influenced by the presence and stability of different precipitate populations. These secondary phases grow, coarsen and, sometimes, dissolve again during heat treatment and service, which leads to a remarkable change in the obstacle effect of these precipitates on dislocation movement. In the present work, the experimentally observed creep rupture strength of a modified 9-12% Cr steel developed in the European COST Group is compared to the calculated maximum obstacle effect (Orowan threshold stress) caused by the precipitates present in the investigated alloy for different heat treatment conditions. It is shown that the differences in creep rupture strength caused by different heat treatments disappear after long time service. This observation is discussed on the basis of the calculated evolution of the precipitate microstructure. The concept of boosting long-term creep rupture strength by maximizing the initial creep strength with optimum quality heat treatment parameters for precipitation strengthening is critically assessed. (orig.)

  19. 5-HT in the enteric nervous system: gut function and neuropharmacology.

    Science.gov (United States)

    McLean, Peter G; Borman, Richard A; Lee, Kevin

    2007-01-01

    In recent times, the perception of functional gastrointestinal disorders such as irritable bowel syndrome (IBS) has shifted fundamentally. Such disorders are now thought of as serious diseases characterized by perturbations in the neuronal regulation of gastrointestinal function. The concept of visceral hypersensitivity, the characterization of neuronal networks in the 'brain-gut axis' and the identification of several novel 5-HT-mediated mechanisms have contributed to this shift. Here, we review how some of the more promising of these new mechanisms (e.g. those involving 5-HT transporters and the 5-HT(2B), 5-HT(7) and putative 5-HT(1p) receptors) might lead to a range of second-generation therapies that could revolutionize the treatment of functional gastrointestinal disorders, particularly IBS.

  20. Boron-bearing Influences of 9Cr-0.5Mo-2W-V-Nb Ferritic/Martensitic Steels for a SFR Fuel Cladding

    International Nuclear Information System (INIS)

    Baek, Jong-Hyuk; Han, Chang-Hee; Kim, Woo-Gon; Kim, Sung-Ho; Lee, Chan-Bock

    2008-01-01

    modification, the influences of B-bearing 9Cr-0.5Mo-2W-V-Nb ferritic/ martensitic steels on the microstructural and mechanical properties were systematically investigated in order to evaluate the applicable validity as a cladding material for the Gen-IV SFR fuel

  1. 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.

  2. Wide Band-Gap 3,4-Difluorothiophene-Based Polymer with 7% Solar Cell Efficiency: an Alternative to P3HT

    KAUST Repository

    Wolf, Jannic Sebastian; Cruciani, Federico; El Labban, Abdulrahman; Beaujuge, Pierre

    2015-01-01

    We report on a wide band-gap polymer donor composed of benzo[1,2-b:4,5-b']dithiophene (BDT) and 3,4-difluorothiophene ([2F]T) units (Eopt ~2.1 eV), and show that the fluorinated analog PBDT[2F]T performs significantly better than its non-fluorinated counterpart PBDT[2H]T in BHJ solar cells with PC71BM. While control P3HT- and PBDT[2H]T-based devices yield PCEs of ca. 4% and 3% (Max.) respectively, PBDT[2F]T-based devices reach PCEs of ca. 7%, combining a large Voc of ca. 0.9 V and short-circuit current values (ca. 10.7 mA/cm2) comparable to those of the best P3HT-based control devices.

  3. Wide Band-Gap 3,4-Difluorothiophene-Based Polymer with 7% Solar Cell Efficiency: an Alternative to P3HT

    KAUST Repository

    Wolf, Jannic Sebastian

    2015-05-27

    We report on a wide band-gap polymer donor composed of benzo[1,2-b:4,5-b\\']dithiophene (BDT) and 3,4-difluorothiophene ([2F]T) units (Eopt ~2.1 eV), and show that the fluorinated analog PBDT[2F]T performs significantly better than its non-fluorinated counterpart PBDT[2H]T in BHJ solar cells with PC71BM. While control P3HT- and PBDT[2H]T-based devices yield PCEs of ca. 4% and 3% (Max.) respectively, PBDT[2F]T-based devices reach PCEs of ca. 7%, combining a large Voc of ca. 0.9 V and short-circuit current values (ca. 10.7 mA/cm2) comparable to those of the best P3HT-based control devices.

  4. 5-HT7 Receptor Antagonists with an Unprecedented Selectivity Profile.

    Science.gov (United States)

    Ates, Ali; Burssens, Pierre; Lorthioir, Olivier; Lo Brutto, Patrick; Dehon, Gwenael; Keyaerts, Jean; Coloretti, Francis; Lallemand, Bénédicte; Verbois, Valérie; Gillard, Michel; Vermeiren, Céline

    2018-04-23

    Selective leads: In this study, we generated a new series of serotonin 5-HT 7 receptor antagonists. Their synthesis, structure-activity relationships, and selectivity profiles are reported. This series includes 5-HT 7 antagonists with unprecedented high selectivity for the 5-HT 7 receptor, setting the stage for lead optimization of drugs acting on a range of neurological targets. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Comparison of fracture behavior for low-swelling ferritic and austenitic alloys irradiated in the Fast Flux Test Facility (FFTF) to 180 DPA

    International Nuclear Information System (INIS)

    Huang, F.H.

    1992-02-01

    Fracture toughness testing was conducted to investigate the radiation embrittlement of high-nickel superalloys, modified austenitic steels and ferritic steels. These materials have been experimentally proven to possess excellent resistance to void swelling after high neutron exposures. In addition to swelling resistance, post-irradiation fracture resistance is another important criterion for reactor material selection. By means of fracture mechanics techniques the fracture behavior of those highly irradiated alloys was characterized in terms of irradiation and test conditions. Precipitation-strengthened alloys failed by channel fracture with very low postirradiation ductility. The fracture toughness of titanium-modified austenitic stainless steel D9 deteriorates with increasing fluence to about 100 displacement per atom (dpa), the fluence level at which brittle fracture appears to occur. Ferritic steels such as HT9 are the most promising candidate materials for fast and fusion reactor applications. The upper-shelf fracture toughness of alloy HT9 remained adequate after irradiation to 180 dpa although its ductile- brittle transition temperature (DBTT) shift by low temperature irradiation rendered the material susceptible to brittle fracture at room temperature. Understanding the fracture characteristics under various irradiation and test conditions helps reduce the potential for brittle fracture by permitting appropriate measure to be taken

  6. Changes in 5-HT4 receptor and 5-HT transporter binding in olfactory bulbectomized and glucocorticoid receptor heterozygous mice

    DEFF Research Database (Denmark)

    Licht, Cecilie L; Kirkegaard, Lisbeth; Zueger, Maha

    2010-01-01

    . The olfactory bulbectomized mice displayed increased activity in the open field test, a characteristic depression-like feature of this model. After bulbectomy, 5-HT(4) receptor binding was increased in the ventral hippocampus (12%) but unchanged in the dorsal hippocampus, frontal and caudal caudate putamen......]citalopram in two murine models of depression-related states, olfactory bulbectomy and glucocorticoid receptor heterozygous (GR(+/-)) mice. The olfactory bulbectomy model is characterized by 5-HT system changes, while the GR(+/-) mice have a deficit in hypothalamic-pituitary-adrenal (HPA) system control....... Among post hoc analyzed regions, there was a 14% decrease in 5-HT(4) receptor binding in the olfactory tubercles. The 5-HTT binding was unchanged in the hippocampus and caudate putamen of bulbectomized mice but post hoc analysis showed small decreases in lateral septum and lateral globus pallidus...

  7. Converging evidence for central 5-HT effects in acute tryptophan depletion

    DEFF Research Database (Denmark)

    Crockett, Molly; Clark, Luke; Roiser, Jonathan

    2012-01-01

    the validity of ATD.2 Although we agree that ATD's effects on 5-HT activity at the molecular level need further clarification, van Donkelaar et al.2 goes too far in challenging whether ATD exerts its effects through serotonergic mechanisms. There is strong evidence that ATD reduces brain 5-HT and disrupts......Acute tryptophan depletion (ATD), a dietary technique for manipulating brain serotonin (5-HT) function, has advanced our understanding of 5-HT mechanisms in the etiology and treatment of depression and other affective disorders.1 A recent review article in Molecular Psychiatry questioned...

  8. The Canadian experimental HT release of June 10, 1987, US measurements

    International Nuclear Information System (INIS)

    Jalbert, R.A.; Murphy, C.E.

    1988-09-01

    In June 1987, an experiment was performed at the Chalk River Nuclear Laboratories in Ontario, Canada, to study the oxidation of elemental tritium (HT) released to the environment. The experiment involved a 30-minute release of 3.54 TBq (95.7 Ci)of HT to the atmosphere at an elevation of one meter. Scientists from six countries participated in the experiment. The air measurements showed HT concentrations downwind of the release in general agreement with classical atmospheric diffusion (Gaussian) up to the maximum distance measured (400 m). The HTO/HT ratios were shown to slowly increase downwind (∼ 4 x 10/sup /minus/5/ at 50 m to almost 10/sup /minus/3/ at 400 m) as conversion of HT took place. After the release, HTO concentrations in the atmosphere remained elevated. Vegetation samples were also taken since the vegetation and associated soil system have been implicated in the oxidation of HT. Freeze-dried water from vegetation samples was found to be low in HTO immediately after the release suggesting a low direct uptake of HTO in air by vegetation. The tritiated water concentration increased during the first day, peaking during the second day (about 15--30 kBq/L of water at 50 m from the source), and decreasing by the end of the second day. This pattern suggests oxidation in the soil followed by plant uptake through sorption of soil water. This was confirmed by measurements taken by other groups at the experiment site. The HTO in vegetation decreased with distance downwind with the same pattern as the HT measured during the release indicating that the oxidation of HT was linearly related to the HT concentration in the atmosphere during the exposure period. An adequate description of the process can be made through the observed phenomenon of HT deposition into the soil with subsequent rapid oxidation by soil bacteria. 30 refs., 10 figs., 4 tabs

  9. Simulation of Microdamage and Evaluation of Remaining Life of Steam Conduit Components from New-Generation Refractory Steel 10Kh9MF-Sh

    Science.gov (United States)

    Gladshtein, V. I.

    2018-03-01

    The effects of microdamage on the remaining life of high-temperature components of steam conduits from high-chromium steel 10Kh9MF-Sh and low-alloy steel 12Kh1M1F are compared. To simulate the microdamage, specimens with a circular notch and different relative diameters are fabricated. Specimens with a notch simulating the highest degree of microdamage and smooth specimens are tested for long-term strength. The coefficient of the remaining life of a conduit is computed for the range of relative damage presenting practical interest.

  10. Development and analysis of diffusion bonding techniques for LBE-cooled spallation targets

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, A.T., E-mail: atnelson@lanl.gov [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Hosemann, P. [University of California - Berkeley, Berkeley, CA 94720 (United States); Maloy, S.A. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2012-12-15

    Spallation sources incorporating solid targets may be driven to utilize liquid metal coolants by neutronics or temperature concerns. If tungsten is chosen as the target material, it will require cladding given its poor performance under irradiation. One option to meet this need are ferritic/martensitic stainless steel alloys. This study investigates possible diffusion bonding techniques suitable to clad tungsten targets with HT9, a high chromium stainless steel familiar to the nuclear industry. A test bonding matrix was performed to identify bonding conditions and process parameters suitable for the three material systems of interest (HT9/Ta, HT9/W, and HT9/HT9). Temperatures of 900 and 1060 Degree-Sign C were investigated along with bonding pressures of 7 and 70 MPa. A nominal soak time of 3 h was used for all tests. Three interlayers were investigated: pure nickel, Ni-6P, and vanadium. Finally, different surface preparation techniques for the tungsten were explored in order to gage their effect on the bond quality. Following joining, the bonds were characterized using an array of microscopy and micromechanical techniques to determine the resulting interface character. The nickel and NiP coatings were found to stabilize austenite at the HT9 surface during bonding, while the vanadium remained generally inert given good solubility in each of the three systems. Intermetallic formation is also a significant concern at elevated bonding temperatures as FeTa, FeW, NiTa, and NiW each rapidly form during interdiffusion. Multiple failures were observed through crack propagation parallel to the interface along the intermetallic phases. Differing contraction rates among the base materials also resulted in brittle fracture within the tungsten during cooling from bonding temperatures. Bonding performed at 900 Degree-Sign C under 70 MPa for 3 h with the inclusion of a vanadium interlayer was found to be superior of the conditions explored in this work.

  11. The Role of 5-HT3 Receptors in Signaling from Taste Buds to Nerves.

    Science.gov (United States)

    Larson, Eric D; Vandenbeuch, Aurelie; Voigt, Anja; Meyerhof, Wolfgang; Kinnamon, Sue C; Finger, Thomas E

    2015-12-02

    Activation of taste buds triggers the release of several neurotransmitters, including ATP and serotonin (5-hydroxytryptamine; 5-HT). Type III taste cells release 5-HT directly in response to acidic (sour) stimuli and indirectly in response to bitter and sweet tasting stimuli. Although ATP is necessary for activation of nerve fibers for all taste stimuli, the role of 5-HT is unclear. We investigated whether gustatory afferents express functional 5-HT3 receptors and, if so, whether these receptors play a role in transmission of taste information from taste buds to nerves. In mice expressing GFP under the control of the 5-HT(3A) promoter, a subset of cells in the geniculate ganglion and nerve fibers in taste buds are GFP-positive. RT-PCR and in situ hybridization confirmed the presence of 5-HT(3A) mRNA in the geniculate ganglion. Functional studies show that only those geniculate ganglion cells expressing 5-HT3A-driven GFP respond to 10 μM 5-HT and this response is blocked by 1 μM ondansetron, a 5-HT3 antagonist, and mimicked by application of 10 μM m-chlorophenylbiguanide, a 5-HT3 agonist. Pharmacological blockade of 5-HT3 receptors in vivo or genetic deletion of the 5-HT3 receptors reduces taste nerve responses to acids and other taste stimuli compared with controls, but only when urethane was used as the anesthetic. We find that anesthetic levels of pentobarbital reduce taste nerve responses apparently by blocking the 5-HT3 receptors. Our results suggest that 5-HT released from type III cells activates gustatory nerve fibers via 5-HT3 receptors, accounting for a significant proportion of the neural taste response. Copyright © 2015 the authors 0270-6474/15/3515984-12$15.00/0.

  12. Fatigue-creep of martensitic steels containing 9-12% Cr: behaviour and damage

    International Nuclear Information System (INIS)

    Fournier, B.

    2007-09-01

    It is in the framework of the research programs on nuclear reactors (generation IV) that the martensitic steels containing 9-12% Cr are studied by the CEA. Most of the structures for which they are considered will be solicited in fatigue-creep at high temperature (550 C). The aim of this work is to understand and model the cyclic behaviour and the damage of these materials. The proposed modelling are based on detailed observations studies (SEM, TEM, EBSD...). The cyclic softening is attributed to the growth of the microstructure. A micro-mechanical model based on the physical parameters is proposed and leads to encouraging results. The damage results of interactions between fatigue, creep and oxidation. Two main types of damage are revealed. A model of anticipation of service time is proposed and gives very satisfying results. The possible extrapolations are discussed. (O.M.)

  13. A concise review of Hashimoto thyroiditis (HT) and the importance of iodine, selenium, vitamin D and gluten on the autoimmunity and dietary management of HT patients.Points that need more investigation.

    Science.gov (United States)

    Liontiris, Michael I; Mazokopakis, Elias E

    2017-01-01

    Hashimoto's thyroiditis (HT) is a chronic autoimmune thyroid disease caused by an interaction between genetic factors and environmental conditions, both of which are yet to be fully understood. The management of HT depends on its clinical manifestations, commonly including diffuse or nodular goiter with euthyroidism, subclinical hypothyroidism and permanent hypothyroidism. However, in most cases of patients with HT, lifelong levothyroxine substitution is required. The additional role of diet for the management of HT is usually overlooked. A literature search regarding the importance and the influence of iodine, selenium, vitamin D and gluten on HT was conducted. In HT careful supplementation of possible deficiencies is recommended for the dietary management of these patients. The use of a diet low in gluten among HT patients with or without celiac disease (CD) is discussed.

  14. Basic investigation for life assessment technology of modified 9CR-1Mo steel

    Energy Technology Data Exchange (ETDEWEB)

    Okamura, Hiroyuki [Science Univ. of Tokyo (Japan); Ohtani, Ryuichi [Kyoto Univ. (Japan); Fujii, Kazuya [Japan Power Engineering and Inspection Corp., Tokyo (Japan); Kimura, Kazushige; Ishii, Ryuichi; Fujiyama, Kazunari; Hongo, Shigetada; Iseki, Takashi; Uchida, Hiroshi [Toshiba Corp., Kawasaki, Kanagawa (Japan)

    1998-11-01

    For the basic study of life assessment technologies for aged components made of mod.9Cr-1Mo steel, specimens were artificially deteriorated by aging, creep and fatigue tests at elevated temperatures. And metallurgical and mechanical properties were examined. The change in the precipitates caused the decrease in toughness. The creep damage in base metal corresponded to the decrease in hardness. The fatigue damage in base metal correlated to the maximum length of a crack among micro-cracks initiated during fatigue cycle. In the welded joint, the creep fracture occurred by the formation and growth of voids in the fine grained region of HAZ near base metal. The creep damage was associated with the increase in both number and area fraction of voids. (orig.)

  15. Pharmacological, neurochemical, and behavioral profile of JB-788, a new 5-HT1A agonist.

    Science.gov (United States)

    Picard, M; Morisset, S; Cloix, J F; Bizot, J C; Guerin, M; Beneteau, V; Guillaumet, G; Hevor, T K

    2010-09-01

    A novel pyridine derivative, 8-{4-[(6-methoxy-2,3-dihydro-[1,4]dioxino[2,3-b]pyridine-3-ylmethyl)-amino]-butyl}-8-aza-spiro[4.5]decane-7,9-dione hydrochloride, termed JB-788, was designed to selectively target 5-HT(1A) receptors. In the present study, the pharmacological profile of JB-788 was characterized in vitro using radioligands binding tests and in vivo using neurochemical and behavioural experiments. JB-788 bound tightly to human 5-HT(1A) receptor expressed in human embryonic kidney 293 (HEK-293) cells with a K(i) value of 0.8 nM. Its binding affinity is in the same range as that observed for the (+/-)8-OH-DPAT, a reference 5HT(1A) agonist compound. Notably, JB-788 only bound weakly to 5-HT(1B) or 5-HT(2A) receptors and moreover the drug displayed only weak or indetectable binding to muscarinic, alpha(2), beta(1) and beta(2) adrenergic receptors, or dopaminergic D(1) receptors. JB-788 was found to display substantial binding affinity for dopaminergic D(2) receptors and, to a lesser extend to alpha(1) adrenoreceptors. JB-788 dose-dependently decreased forskolin-induced cAMP accumulation in HEK cells expressing human 5-HT(1A), thus acting as a potent 5-HT(1A) receptor agonist (E(max.) 75%, EC(50) 3.5 nM). JB-788 did not exhibit any D(2) receptor agonism but progressively inhibited the effects of quinpirole, a D(2) receptor agonist, in the cAMP accumulation test with a K(i) value of 250 nM. JB-788 induced a weak change in cAMP levels in mouse brain but, like some antipsychotics, transiently increased glycogen contents in various brain regions. Behavioral effects were investigated in mice using the elevated plus-maze. JB-788 was found to increase the time duration spent by animals in anxiogenic situations. Locomotor hyperactivity induced by methamphetamine in mouse, a model of antipsychotic activity, was dose-dependently inhibited by JB-788. Altogether, these results suggest that JB-788 displays pharmacological properties, which could be of interest in the area

  16. HT oxidation activity of soil irradiated with gamma radiation

    International Nuclear Information System (INIS)

    Momoshima, Noriyuki; Tjahaja, P.I.; Takashima, Yoshimasa

    1992-01-01

    The HT oxidation activity was examined for soils irradiated with 60 Co γ-rays at various doses. The HT oxidation rate decreased with increase of initial H 2 concentration, indicating a similar oxidation mechanism between HT and H 2 . Irradiated soils showed decrease of oxidation activity with dose suggests that HT and H 2 oxidation activities were affected by sterilization with γ-rays. The decline of the oxidation activity with dose was analyzed by a composite of two components with different radiosensitivity and they were considered to be activities of soil microorganisms and abiotic soil enzymes. The oxidation activity due to soil microorganisms would be important at low dose range and more radioresistant abiotic soil enzymes would be responsible for the oxidation activity observed at more than several kGy. In non-irradiated soil about half of the oxidation activity was considered resulting from abiotic soil enzymes. (author)

  17. Creep-fatigue evaluation method for weld joint of Mod.9Cr-1Mo steel Part II: Plate bending test and proposal of a simplified evaluation method

    Energy Technology Data Exchange (ETDEWEB)

    Ando, Masanori, E-mail: ando.masanori@jaea.go.jp; Takaya, Shigeru, E-mail: takaya.shigeru@jaea.go.jp

    2016-12-15

    Highlights: • Creep-fatigue evaluation method for weld joint of Mod.9Cr-1Mo steel is proposed. • A simplified evaluation method is also proposed for the codification. • Both proposed evaluation method was validated by the plate bending test. • For codification, the local stress and strain behavior was analyzed. - Abstract: In the present study, to develop an evaluation procedure and design rules for Mod.9Cr-1Mo steel weld joints, a method for evaluating the creep-fatigue life of Mod.9Cr-1Mo steel weld joints was proposed based on finite element analysis (FEA) and a series of cyclic plate bending tests of longitudinal and horizontal seamed plates. The strain concentration and redistribution behaviors were evaluated and the failure cycles were estimated using FEA by considering the test conditions and metallurgical discontinuities in the weld joints. Inelastic FEA models consisting of the base metal, heat-affected zone and weld metal were employed to estimate the elastic follow-up behavior caused by the metallurgical discontinuities. The elastic follow-up factors determined by comparing the elastic and inelastic FEA results were determined to be less than 1.5. Based on the estimated elastic follow-up factors obtained via inelastic FEA, a simplified technique using elastic FEA was proposed for evaluating the creep-fatigue life in Mod.9Cr-1Mo steel weld joints. The creep-fatigue life obtained using the plate bending test was compared to those estimated from the results of inelastic FEA and by a simplified evaluation method.

  18. Creep-fatigue evaluation method for weld joint of Mod.9Cr-1Mo steel Part II: Plate bending test and proposal of a simplified evaluation method

    International Nuclear Information System (INIS)

    Ando, Masanori; Takaya, Shigeru

    2016-01-01

    Highlights: • Creep-fatigue evaluation method for weld joint of Mod.9Cr-1Mo steel is proposed. • A simplified evaluation method is also proposed for the codification. • Both proposed evaluation method was validated by the plate bending test. • For codification, the local stress and strain behavior was analyzed. - Abstract: In the present study, to develop an evaluation procedure and design rules for Mod.9Cr-1Mo steel weld joints, a method for evaluating the creep-fatigue life of Mod.9Cr-1Mo steel weld joints was proposed based on finite element analysis (FEA) and a series of cyclic plate bending tests of longitudinal and horizontal seamed plates. The strain concentration and redistribution behaviors were evaluated and the failure cycles were estimated using FEA by considering the test conditions and metallurgical discontinuities in the weld joints. Inelastic FEA models consisting of the base metal, heat-affected zone and weld metal were employed to estimate the elastic follow-up behavior caused by the metallurgical discontinuities. The elastic follow-up factors determined by comparing the elastic and inelastic FEA results were determined to be less than 1.5. Based on the estimated elastic follow-up factors obtained via inelastic FEA, a simplified technique using elastic FEA was proposed for evaluating the creep-fatigue life in Mod.9Cr-1Mo steel weld joints. The creep-fatigue life obtained using the plate bending test was compared to those estimated from the results of inelastic FEA and by a simplified evaluation method.

  19. The renewed HT-7 plasma control system based on real-time Linux cluster

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Q.P., E-mail: qpyuan@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei (China); Xiao, B.J.; Zhang, R.R. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei (China); Walker, M.L.; Penaflor, B.G.; Piglowski, D.A.; Johnson, R.D. [General Atomics, DIII-D National Fusion Facility, San Diego, CA (United States)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer The hardware and software structure of the new HT-7 plasma control system (HT-7 PCS) is reported. Black-Right-Pointing-Pointer All original systems were integrated in the new HT-7 PCS. And the implementation details of the control algorithms are given in the paper. Black-Right-Pointing-Pointer Different from EAST PCS, the AC operation mode is realized in HT-7 PCS. Black-Right-Pointing-Pointer The experiment results are discussed. Good control performance has been obtained. - Abstract: In order to improve the synchronization, flexibility and expansibility of the plasma control on HT-7, a new plasma control system (HT-7 PCS) was constructed. The HT-7 PCS was based on a real-time Linux cluster with a well-defined, robust and flexible software infrastructure which was adapted from DIII-D PCS. In this paper, the hardware structure and system customization details for HT-7 PCS are reported. The plasma position and current control, plasma density control and off-normal event detection, which were realized in separated systems originally, have been integrated and implemented in such HT-7 PCS. All these control algorithms have been successfully validated in the last several HT-7 experiment campaigns. Good control performance has been achieved and the experiment results are discussed in the paper.

  20. Effects of HIF-1 inhibition by chetomin on hypoxia-related transcription and radiosensitivity in HT 1080 human fibrosarcoma cells

    International Nuclear Information System (INIS)

    Staab, Adrian; Einsele, Hermann; Flentje, Michael; Vordermark, Dirk; Loeffler, Jürgen; Said, Harun M; Diehlmann, Désirée; Katzer, Astrid; Beyer, Melanie; Fleischer, Markus; Schwab, Franz; Baier, Kurt

    2007-01-01

    Hypoxia-inducible factor-1 (HIF-1) overexpression has been linked to tumor progression and poor prognosis. We investigated whether targeting of HIF-1 using chetomin, a disrupter of the interaction of HIF-1 with the transcriptional coactivator p300, influences the radiosensitivity of hypoxic HT 1080 human fibrosarcoma cells. Optimal dose of chetomin was determined by EGFP-HRE gene reporter assay in stably transfected HT 1080 cells. Cells were assayed for expression of the hypoxia-inducible genes carbonic anhydrase 9 (CA9) and vascular endothelial growth factor (VEGF) by RT-PCR and for clonogenic survival after irradiation with 2, 5 or 10 Gy, under normoxic or hypoxic (0.1% O 2 , 12 h) conditions in the presence or absence of chetomin (150 nM, 12 h, pre-treatment of 4 h). Chetomin treatment significantly reduced CA9 and VEGF mRNA expression in hypoxic cells to 44.4 ± 7.2% and 39.6 ± 16.0%, respectively, of untreated hypoxic controls. Chetomin clearly reduced the modified oxygen enhancement ratio (OER') compared to untreated cells, from 2.02 to 1.27, from 1.86 to 1.22 and from 1.49 to 1.06 at the 50%, 37% and 10% clonogenic survival levels, respectively. HIF-1 inhibition by chetomin effectively reduces hypoxia-dependent transcription and radiosensitizes hypoxic HT 1080 human fibrosarcoma cells in vitro

  1. Impaired social behavior in 5-HT3A receptor knockout mice

    Directory of Open Access Journals (Sweden)

    Laura A Smit-Rigter

    2010-11-01

    Full Text Available The 5-HT3 receptor is a ligand-gated ion channel expressed on interneurons throughout the brain. So far, analysis of the 5-HT3A knockout mouse revealed changes in nociceptive processing and a reduction in anxiety related behavior. Recently, it was shown that the 5-HT3 receptor is also expressed on Cajal-Retzius cells which play a key role in cortical development and that knockout mice lacking this receptor showed aberrant growth of the dendritic tree of cortical layer II/III pyramidal neurons. Other mouse models in which serotonergic signaling was disrupted during development showed similar morphological changes in the cortex, and in addition, also deficits in social behavior. Here, we subjected male and female 5-HT3A knockout mice and their non-transgenic littermates to several tests of social behavior. We found that 5-HT3A knockout mice display impaired social communication in the social transmission of food preference task. Interestingly, we showed that in the social interaction test only female 5-HT3A knockout mice spent less time in reciprocal social interaction starting after 5 minutes of testing. Moreover, we observed differences in preference for social novelty for male and female 5-HT3A knockout mice during the social approach test. However, no changes in olfaction, exploratory activity and anxiety were detected. These results indicate that the 5-HT3A knockout mouse displays impaired social behavior with specific changes in males and females, reminiscent to other mouse models in which serotonergic signaling is disturbed in the developing brain.

  2. Modified 9Cr-1Mo steel for advanced steam generator applications

    International Nuclear Information System (INIS)

    Brinkman, C.R.; Alexander, D.J.; Maziasz, P.J.

    1990-01-01

    Results are reported from several types of mechanical property tests conducted on a number of commercial heats of modified 9Cr-1Mo steel. Data from long term creep-rupture tests conducted on base and weldment material were compared with an analytical model which has been shown to give good agreement between measured and predicted values. Weldment material had somewhat inferior creep-rupture strength in comparison to base material due to a soft zone at the edge of the HAZ. Data are presented from elevated temperature tensile and creep-rupture tests conducted n material thermally aged for periods of up to 75,000 h (8.6 years). Some reduction in strength was shown to occur in comparison to unaged material. Models were developed for predicting the reduction in short term elevated temperature tensile and yield strength for material thermally aged in the temperature range of 482 to 704 degree C. Results from Charpy impact tests conducted on material thermally aged at 538 degree C for periods of up to 75,000 h showed an increase in the ductile-brittle transition temperature. Finally, results from transmission electron microscopy studies were presented to explain changes in mechanical properties due to thermal aging. These observations showed that Laves phase precipitation and recovery occurs on prolonged exposure of this alloy in this temperature range. 9 refs

  3. The R-enantiomer of citalopram counteracts escitalopram-induced increase in extracellular 5-HT in the frontal cortex of freely moving rats

    DEFF Research Database (Denmark)

    Mørk, A; Kreilgaard, Mads; Sánchez, C

    2003-01-01

    The selective serotonin (5-HT) reuptake inhibitor, citalopram, is a racemic mixture of an S(+)- and R(-)-enantiomer, escitalopram and R-citalopram, respectively. The present study compares the effects of escitalopram, R-citalopram and citalopram on extracellular levels of 5-HT in the frontal cortex...... of freely moving rats. In addition, co-injection of escitalopram and R-citalopram (ratios 1:2 and 1:4) were assessed. In some experiments escitalopram and R-citalopram were infused into the frontal cortex by reverse microdialysis. Finally, the extracellular level of escitalopram in the frontal cortex...... was studied after administration of escitalopram alone or in combination with R-citalopram. Escitalopram (1.0-3.9 mg/kg, s.c.) produced a greater maximal increase in extracellular 5-HT than citalopram (2.0-8.0 mg/kg, s.c.). R-citalopram (15.6 mg/kg s.c.) did not affect the 5-HT levels. When co-injected, R...

  4. Initial study on Z-phase strengthened 9-12% Cr steels by atom probe tomography

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Fang; Andren, Hans-Olof [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Applied Physics

    2010-07-01

    The microstructure of two different types of Z-phase strengthened experimental steels, CrNbN-based or CrTaN-based, was investigated. Both steels underwent aging at 650 C for relatively short period of time, 24 hours or 1005 hours. Atom probe tomography was used to study the chemical composition of the matrix and precipitates, and the size and number density of the small precipitates. Both steels contain Laves phase at prior austenite grain boundaries and martensitic lath boundaries. The CrTaN-based steel was found more promising due to its finer and more densely distributed precipitates after 1005 hour aging. (orig.)

  5. Phosphotidylinositol turnover in vascular, uterine, fundal, and tracheal smooth muscle: effect of serotonin (5HT)

    International Nuclear Information System (INIS)

    Cohen, M.L.; Wittenauer, L.A.

    1986-01-01

    In brain, platelets, and aorta, 5HT has been reported to increase phosphotidylinositol turnover, an effect linked to 5HT 2 receptors. The authors examined the effect of 5HT on 3 H-inositol-1-phosphate ( 3 H-I-P) in tissues possessing 5HT 2 receptors that mediate contraction to 5HT (rat jugular vein, aorta, uterus and guinea pig trachea) and in a tissue in which contraction to 5HT is not mediated by 5HT 2 receptors (rat stomach fundus). Tissues were incubated (37 0 C, 95% O 2 , 5% CO 2 ) with 3 H-inositol (90 min), washed, LiCl 2 (10 mM) and 5HT added for 90 min, extracted, and 3 H-I-P eluted from a Dowex-1 column. Basal 3 H-I-P was 10-fold higher in the uterus than in the other tissues. 5HT (10 -6 -10 -4 M) increased 3 H-I-P in the jugular vein, aorta, and uterus but not in the trachea or fundus. Maximum increase was greatest in the jugular vein (8-fold) with an ED 50 of 0.4 μM 5HT. The selective 5HT 2 receptor blocker, LY53857 (10 -8 M) antagonized the increase in 3 H-I-P by 5HT in the jugular vein, aorta and uterus. Pargyline (10 -5 M) added to the trachea and fundus did not unmask an effect of 5HT (10 -4 M). These data suggest that (1) the jugular vein produced the most sensitive response to 5HT-induced increases in 3 H-I-P, (2) increases in 3 H-I-P by 5HT in smooth muscle may be linked to 5HT 2 receptors and (3) activation of 5HT 2 receptors as occurred in the trachea will not always increase 3 H-I-P

  6. Low 5-HT1B receptor binding in the migraine brain

    DEFF Research Database (Denmark)

    Deen, Marie; Hansen, Hanne D; Hougaard, Anders

    2018-01-01

    Background The pathophysiology of migraine may involve dysfunction of serotonergic signaling. In particular, the 5-HT1B receptor is considered a key player due to the efficacy of 5-HT1B receptor agonists for treatment of migraine attacks. Aim To examine the cerebral 5-HT1B receptor binding....... Patients who reported migraine brain regions involved in pain modulation as regions of interest and applied a latent variable model (LVM) to assess the group effect on binding across these regions. Results Our data...... support a model wherein group status predicts the latent variable ( p = 0.038), with migraine patients having lower 5-HT1B receptor binding across regions compared to controls. Further, in a whole-brain voxel-based analysis, time since last migraine attack correlated positively with 5-HT1B receptor...

  7. Activation of glucocorticoid receptors increases 5-HT2A receptor levels

    DEFF Research Database (Denmark)

    Trajkovska, Viktorija; Kirkegaard, Lisbeth; Krey, Gesa

    2009-01-01

    an effect of GR activation on 5-HT2A levels, mature organotypic hippocampal cultures were exposed to corticosterone with or without GR antagonist mifepristone and mineralocorticoid receptor (MR) antagonist spironolactone. In GR under-expressing mice, hippocampal 5-HT2A receptor protein levels were decreased......Major depression is associated with both dysregulation of the hypothalamic pituitary adrenal axis and serotonergic deficiency, not the least of the 5-HT2A receptor. However, how these phenomena are linked to each other, and whether a low 5-HT2A receptor level is a state or a trait marker...... of depression is unknown. In mice with altered glucocorticoid receptor (GR) expression we investigated 5-HT2A receptor levels by Western blot and 3H-MDL100907 receptor binding. Serotonin fibre density was analyzed by stereological quantification of serotonin transporter immunopositive fibers. To establish...

  8. Effects of 5-HT on memory and the hippocampus: model and data.

    NARCIS (Netherlands)

    Meeter, M.; Talamini, L.M.; Schmitt, J.A.J.; Riedel, W.J.

    2006-01-01

    5-Hydroxytryptamine (5-HT) transmission has been implicated in memory and in depression. Both 5-HT depletion and specific 5-HT agonists lower memory performance, while depression is also associated with memory deficits. The precise neuropharmacology and neural mechanisms underlying these effects are

  9. MRP-1/CD9 gene transduction regulates the actin cytoskeleton through the downregulation of WAVE2.

    Science.gov (United States)

    Huang, C-L; Ueno, M; Liu, D; Masuya, D; Nakano, J; Yokomise, H; Nakagawa, T; Miyake, M

    2006-10-19

    Motility-related protein-1 (MRP-1/CD9) is involved in cell motility. We studied the change in the actin cytoskeleton, and the expression of actin-related protein (Arp) 2 and Arp3 and the Wiskott-Aldrich syndrome protein (WASP) family according to MRP-1/CD9 gene transduction into HT1080 cells. The frequency of cells with lamellipodia was significantly lower in MRP-1/CD9-transfected HT1080 cells than in control HT1080 cells (PMRP-1/CD9 gene transduction affected the subcellular localization of Arp2 and Arp3 proteins. Furthermore, MRP-1/CD9 gene transduction induced a downregulation of WAVE2 expression (PMRP-1/CD9 monoclonal antibody inhibited downregulation of WAVE2 in MRP-1/CD9-transfected HT1080 cells (PMRP-1/CD9 gene transduction. Furthermore, downregulation of WAVE2 by transfection of WAVE2-specific small interfering RNA (siRNA) mimicked the morphological effects of MRP-1/CD9 gene transduction and suppressed cell motility. However, transfection of each siRNA for Wnt1, Wnt2b1 or Wnt5a did not affect WAVE2 expression. Transfection of WAVE2-specific siRNA also did not affect expressions of these Wnts. These results indicate that MRP-1/CD9 regulates the actin cytoskeleton by downregulating of the WAVE2, through the Wnt-independent signal pathway.

  10. Detailed mapping of serotonin 5-HT1B and 5-HT1D receptor messenger RNA and ligand binding sites in guinea-pig brain and trigeminal ganglion: clues for function

    International Nuclear Information System (INIS)

    Leysen, J.E.; Schotte, A.; Jurzak, M.; Luyten, W.H.M.L.; Voorn, P.; Bonaventure, P.

    1997-01-01

    The similar pharmacology of the 5-HT 1B and 5-HT 1D receptors, and the lack of selective compounds sufficiently distinguishing between the two receptor subtypes, have hampered functional studies on these receptors. In order to provide clues for differential functional roles of the two subtypes, we performed a parallel localization study throughout the guinea-pig brain and the trigeminal ganglia by means of quantitative in situ hybridization histochemistry (using [ 35 S]-labelled riboprobes probes for receptor messenger RNA) and receptor autoradiography (using a new radioligand [ 3 H]alniditan).The anatomical patterns of 5-HT 1B and 5-HT 1D receptor messenger RNA were quite different. While 5-HT 1B receptor messenger RNA was abundant throughout the brain (with highest levels in the striatum, nucleus accumbens, olfactory tubercle, cortex, hypothalamus, hippocampal formation, amygdala, thalamus, dorsal raphe and cerebellum), 5-HT 1D receptor messenger RNA exhibited a more restricted pattern; it was found mainly in the olfactory tubercle, entorhinal cortex, dorsal raphe, cerebellum, mesencephalic trigeminal nucleus and in the trigeminal ganglion. The density of 5-HT 1B/1D binding sites (combined) obtained with [ 3 H]alniditan autoradiography was high in the substantia nigra, superior colliculus and globus pallidus, whereas lower levels were detected in the caudate-putamen, hypothalamus, hippocampal formation, amygdala, thalamus and central gray. This distribution pattern was indistinguishable from specific 5-HT 1B receptor labelling in the presence of ketanserin under conditions to occlude 5-HT 1D receptor labelling; hence the latter were below detection level. Relationships between the regional distributions of the receptor messenger RNAs and binding sites and particular neuroanatomical pathways are discussed with respect to possible functional roles of the 5-HT 1B and 5-HT 1D receptors. (Copyright (c) 1997 Elsevier Science B.V., Amsterdam. All rights reserved.)

  11. 5-HT2 and 5-HT7 receptor agonists facilitate plantar stepping in chronic spinal rats through actions on different populations of spinal neurons

    Directory of Open Access Journals (Sweden)

    Urszula eSlawinska

    2014-08-01

    Full Text Available There is considerable evidence from research in neonatal and adult rat and mouse preparations to warrant the conclusion that activation of 5-HT2 and 5-HT1A/7 receptors leads to activation of the spinal cord circuitry for locomotion. These receptors are involved in control of locomotor movements, but it is not clear how they are implicated in the responses to 5-HT agonists observed after spinal cord injury. Here we used agonists that are efficient in promoting locomotor recovery in paraplegic rats, 8-OHDPAT (acting on 5-HT1A/7 receptors and quipazine (acting on 5-HT2 receptors, to examine this issue. Analysis of intra- and interlimb coordination confirmed that the locomotor performance was significantly improved by either drug, but the data revealed marked differences in their mode of action. Interlimb coordination was significantly better after 8-OHDPAT application, and the activity of the extensor soleus muscle was significantly longer during the stance phase of locomotor movements enhanced by quipazine. Our results show that activation of both receptors facilitates locomotion, but their effects are likely exerted on different populations of spinal neurons. Activation of 5-HT2 receptors facilitates the output stage of the locomotor system, in part by directly activating motoneurons, and also through activation of interneurons of the locomotor CPG. Activation of 5-HT7/1A receptors facilitates the activity of the locomotor CPG, without direct actions on the output components of the locomotor system, including motoneurons. Although our findings show that the combined use of these two drugs results in production of well-coordinated weight supported locomotion with a reduced need for exteroceptive stimulation, they also indicate that there might be some limitations to the utility of combined treatment. Sensory feedback and some intraspinal circuitry recruited by the drugs can conflict with the locomotor activation.

  12. h5-HT(1B) receptor-mediated constitutive Galphai3-protein activation in stably transfected Chinese hamster ovary cells: an antibody capture assay reveals protean efficacy of 5-HT.

    Science.gov (United States)

    Newman-Tancredi, Adrian; Cussac, Didier; Marini, Laetitia; Touzard, Manuelle; Millan, Mark J

    2003-03-01

    1. Serotonin 5-HT(1B) receptors couple to G-proteins of the Gi/o family. However, their activation of specific G-protein subtypes is poorly characterised. Using an innovative antibody capture/guanosine-5'-0-(3-[(35)S]thio)-triphosphate ([(35)S]GTPgammaS) binding strategy, we characterised Galpha(i3) subunit activation by h5-HT(1B) receptors stably expressed in Chinese hamster ovary (CHO) cells. 2. The agonists, 5-HT, alniditan and BMS181,101, stimulated Galpha(i3), whereas methiothepin and SB224,289 behaved as inverse agonists. The selective 5-HT(1B) receptor ligand, S18127, modestly stimulated Galpha(i3) and reversed the actions of both 5-HT and methiothepin. S18127 (1 micro M) also produced parallel, dextral shifts of the 5-HT and methiothepin isotherms. 3. Isotopic dilution experiments ([(35)S]GTPgammaS versus GTPgammaS) revealed high-affinity [(35)S]GTPgammaS binding to Galpha(i3) subunits in the absence of receptor ligands indicating constitutive activity. High-affinity [(35)S]GTPgammaS binding was increased 2.8-fold by 5-HT with an increase in the affinity of GTPgammaS for Galpha(i3) subunits. In contrast, methiothepin halved the number of high-affinity binding sites and decreased their affinity. 4. h5-HT(1B) receptor-mediated Galpha(i3) subunit activation was dependent on the concentration of NaCl. At 300 mM, 5-HT stimulated [(35)S]GTPgammaS binding, basal Galpha(i3) activation was low and methiothepin was inactive. In contrast, at 10 mM NaCl, basal activity was enhanced and the inverse agonist activity of methiothepin was accentuated. Under these conditions, 5-HT decreased Galpha(i3) activation. 5. In conclusion, at h5-HT(1B) receptors expressed in CHO cells: (i) inverse agonist induced inhibition of Galpha(i3), and its reversal by S18127, reveals constitutive activation of this Galpha subunit; (ii) constitutive Galpha(i3) activation can be quantified by isotopic dilution [(35)S]GTPgammaS binding and (iii) decreasing NaCl concentrations enhances Galpha(i3

  13. Corrosion behavior of sensitized duplex stainless steel.

    Science.gov (United States)

    Torres, F J; Panyayong, W; Rogers, W; Velasquez-Plata, D; Oshida, Y; Moore, B K

    1998-01-01

    The present work investigates the corrosion behavior of 2205 duplex stainless steel in 0.9% NaCl solution after various heat-treatments, and compares it to that of 316L austenitic stainless steel. Both stainless steels were heat-treated at 500, 650, and 800 degrees C in air for 1 h, followed by furnace cooling. Each heat-treated sample was examined for their microstructures and Vickers micro-hardness, and subjected to the X-ray diffraction for the phase identification. Using potentiostatic polarization method, each heat-treated sample was corrosion-tested in 37 degrees C 0.9% NaCl solution to estimate its corrosion rate. It was found that simulated sensitization showed an adverse influence on both steels, indicating that corrosion rates increased by increasing the sensitization temperatures.

  14. Transcriptional dysregulation of 5-HT1A autoreceptors in mental illness

    Directory of Open Access Journals (Sweden)

    Albert Paul R

    2011-05-01

    Full Text Available Abstract The serotonin-1A (5-HT1A receptor is among the most abundant and widely distributed 5-HT receptors in the brain, but is also expressed on serotonin neurons as an autoreceptor where it plays a critical role in regulating the activity of the entire serotonin system. Over-expression of the 5-HT1A autoreceptor has been implicated in reducing serotonergic neurotransmission, and is associated with major depression and suicide. Extensive characterization of the transcriptional regulation of the 5-HT1A gene (HTR1A using cell culture systems has revealed a GC-rich "housekeeping" promoter that non-selectively drives its expression; this is flanked by a series of upstream repressor elements for REST, Freud-1/CC2D1A and Freud-2/CC2D1B factors that not only restrict its expression to neurons, but may also regulate the level of expression of 5-HT1A receptors in various subsets of neurons, including serotonergic neurons. A separate set of allele-specific factors, including Deaf1, Hes1 and Hes5 repress at the HTR1A C(-1019G (rs6295 polymorphism in serotonergic neurons in culture, as well as in vivo. Pet1, an obligatory enhancer for serotonergic differentiation, has been identified as a potent activator of 5-HT1A autoreceptor expression. Taken together, these results highlight an integrated regulation of 5-HT1A autoreceptors that differs in several aspects from regulation of post-synaptic 5-HT1A receptors, and could be selectively targeted to enhance serotonergic neurotransmission.

  15. Viability of Cross-Flow Fan for Vertical Take-Off and Landing Aircraft

    Science.gov (United States)

    2012-06-01

    Steel Shaft 9 3M Countersunk Screws (8) 10 1/8” Aluminum Rivets (28) 11 Stainless Steel Ball Bearing, 10 mm OD, 6 mm ID 12 Bearing Housing 13...HT: Unchecked  Combustion o Option: None 42  Thermal Radiation o Option: None  Electromagnetic Model: Unchecked Initialization...Radiation o Option: None  Electromagnetic Model: Unchecked Initialization  Domain Initialization: Checked o Coord Frame: Unchecked

  16. Alkaloids from the hook-bearing branch of Uncaria rhynchophylla and their neuroprotective effects against glutamate-induced HT22 cell death

    Science.gov (United States)

    Qi, Wen; Yue, Si-Jia; Sun, Jia-Hong; Simpkins, James W.; Zhang, Lin; Yuan, Dan

    2015-01-01

    One new alkaloid, 4-geissoschizine N-oxide methyl ether (1), was isolated from the EtOH extract of the hook-bearing branch of Uncaria rhynchophylla, together with 10 known alkaloids, 3-epi-geissoschizine methyl ether (2) isolated from U. rhynchophylla for the first time, geissoschizine methyl ether (3), 4-hirsuteine N-oxide (4), hirsuteine (5), hirsutine (6), 3α-dihydro-cadambine (7), 3β-isodihydro-cadambine (8), cadambine (9), strictosamide (10), and akuammigine (11). The structures were elucidated by spectroscopic methods including UV, ESI-QTOF MS, NMR, and circular dichroism experiments. Neuroprotective effects of 1–9 were investigated against 3 mM glutamate-induced HT22 cell death. The activity assay showed that 2, 3, 5, and 6 exhibited potent neuroprotective effects against glutamate-induced HT22 cell death. However, only weak neuroprotective activities were observed for 1, 4, 7, 8, and 9. PMID:24899363

  17. Quantitative Analysis of the Molecular Dynamics of P3HT:PCBM Bulk Heterojunction.

    Science.gov (United States)

    Guilbert, Anne A Y; Zbiri, Mohamed; Dunbar, Alan D F; Nelson, Jenny

    2017-09-28

    The optoelectronic properties of blends of conjugated polymers and small molecules are likely to be affected by the molecular dynamics of the active layer components. We study the dynamics of regioregular poly(3-hexylthiophene) (P3HT):phenyl-C61-butyric acid methyl ester (PCBM) blends using molecular dynamics (MD) simulation on time scales up to 50 ns and in a temperature range of 250-360 K. First, we compare the MD results with quasi-elastic neutron-scattering (QENS) measurements. Experiment and simulation give evidence of the vitrification of P3HT upon blending and the plasticization of PCBM by P3HT. Second, we reconstruct the QENS signal based on the independent simulations of the three phases constituting the complex microstructure of such blends. Finally, we found that P3HT chains tend to wrap around PCBM molecules in the amorphous mixture of P3HT and PCBM; this molecular interaction between P3HT and PCBM is likely to be responsible for the observed frustration of P3HT, the plasticization of PCBM, and the partial miscibility of P3HT and PCBM.

  18. Development of the 5-HT2CR-Tango System Combined with an EGFP Reporter Gene.

    Science.gov (United States)

    Watanabe, Yoshihisa; Tsujimura, Atsushi; Aoki, Miku; Taguchi, Katsutoshi; Tanaka, Masaki

    2016-02-01

    The serotonin 2C receptor (5-HT2CR) is a G-protein-coupled receptor implicated in emotion, feeding, reward, and cognition. 5-HT2CRs are pharmacological targets for mental disorders and metabolic and reward system abnormalities, as alterations in 5-HT2CR expression, RNA editing, and SNPs are involved in these disturbances. To date, 5-HT2CR activity has mainly been measured by quantifying inositol phosphate production and intracellular Ca(2+) release, but these assays are not suitable for in vivo analysis. Here, we developed a 5-HT2CR-Tango assay system, a novel analysis tool of 5-HT2CR activity based on the G-protein-coupled receptor (GPCR)-arrestin interaction. With desensitization of activated 5-HT2CR by arrestin, this system converts the 5-HT2CR-arrestin interaction into EGFP reporter gene signal via the LexA transcriptional activation system. For validation of our system, we measured activity of two 5-HT2CR RNA-editing isoforms (INI and VGV) in HEK293 cells transfected with EGFP reporter gene. The INI isoform displayed both higher basal- and 5-HT-stimulated activities than the VGV isoform. Moreover, an inhibitory effect of 5-HT2CR antagonist SB242084 was also detected by 5-HT2CR-Tango system. This novel tool is useful for in vitro high-throughput targeted 5-HT2CR drug screening and can be applied to future in vivo brain function studies associated with 5-HT2CRs in transgenic animal models.

  19. Systematic review: cardiovascular safety profile of 5-HT(4) agonists developed for gastrointestinal disorders.

    Science.gov (United States)

    Tack, J; Camilleri, M; Chang, L; Chey, W D; Galligan, J J; Lacy, B E; Müller-Lissner, S; Quigley, E M M; Schuurkes, J; De Maeyer, J H; Stanghellini, V

    2012-04-01

    The nonselective 5-HT(4) receptor agonists, cisapride and tegaserod have been associated with cardiovascular adverse events (AEs). To perform a systematic review of the safety profile, particularly cardiovascular, of 5-HT(4) agonists developed for gastrointestinal disorders, and a nonsystematic summary of their pharmacology and clinical efficacy. Articles reporting data on cisapride, clebopride, prucalopride, mosapride, renzapride, tegaserod, TD-5108 (velusetrag) and ATI-7505 (naronapride) were identified through a systematic search of the Cochrane Library, Medline, Embase and Toxfile. Abstracts from UEGW 2006-2008 and DDW 2008-2010 were searched for these drug names, and pharmaceutical companies approached to provide unpublished data. Retrieved articles on pharmacokinetics, human pharmacodynamics and clinical data with these 5-HT(4) agonists, are reviewed and summarised nonsystematically. Articles relating to cardiac safety and tolerability of these agents, including any relevant case reports, are reported systematically. Two nonselective 5-HT(4) agonists had reports of cardiovascular AEs: cisapride (QT prolongation) and tegaserod (ischaemia). Interactions with, respectively, the hERG cardiac potassium channel and 5-HT(1) receptor subtypes have been suggested to account for these effects. No cardiovascular safety concerns were reported for the newer, selective 5-HT(4) agonists prucalopride, velusetrag, naronapride, or for nonselective 5-HT(4) agonists with no hERG or 5-HT(1) affinity (renzapride, clebopride, mosapride). 5-HT(4) agonists for GI disorders differ in chemical structure and selectivity for 5-HT(4) receptors. Selectivity for 5-HT(4) over non-5-HT(4) receptors may influence the agent's safety and overall risk-benefit profile. Based on available evidence, highly selective 5-HT(4) agonists may offer improved safety to treat patients with impaired GI motility. © 2012 Blackwell Publishing Ltd.

  20. Systematic review: cardiovascular safety profile of 5-HT4 agonists developed for gastrointestinal disorders

    Science.gov (United States)

    Tack, J; Camilleri, M; Chang, L; Chey, W D; Galligan, J J; Lacy, B E; Müller-Lissner, S; Quigley, E M M; Schuurkes, J; Maeyer, J H; Stanghellini, V

    2012-01-01

    Summary Background The nonselective 5-HT4 receptor agonists, cisapride and tegaserod have been associated with cardiovascular adverse events (AEs). Aim To perform a systematic review of the safety profile, particularly cardiovascular, of 5-HT4 agonists developed for gastrointestinal disorders, and a nonsystematic summary of their pharmacology and clinical efficacy. Methods Articles reporting data on cisapride, clebopride, prucalopride, mosapride, renzapride, tegaserod, TD-5108 (velusetrag) and ATI-7505 (naronapride) were identified through a systematic search of the Cochrane Library, Medline, Embase and Toxfile. Abstracts from UEGW 2006–2008 and DDW 2008–2010 were searched for these drug names, and pharmaceutical companies approached to provide unpublished data. Results Retrieved articles on pharmacokinetics, human pharmacodynamics and clinical data with these 5-HT4 agonists, are reviewed and summarised nonsystematically. Articles relating to cardiac safety and tolerability of these agents, including any relevant case reports, are reported systematically. Two nonselective 5-HT4 agonists had reports of cardiovascular AEs: cisapride (QT prolongation) and tegaserod (ischaemia). Interactions with, respectively, the hERG cardiac potassium channel and 5-HT1 receptor subtypes have been suggested to account for these effects. No cardiovascular safety concerns were reported for the newer, selective 5-HT4 agonists prucalopride, velusetrag, naronapride, or for nonselective 5-HT4 agonists with no hERG or 5-HT1 affinity (renzapride, clebopride, mosapride). Conclusions 5-HT4 agonists for GI disorders differ in chemical structure and selectivity for 5-HT4 receptors. Selectivity for 5-HT4 over non-5-HT4 receptors may influence the agent's safety and overall risk–benefit profile. Based on available evidence, highly selective 5-HT4 agonists may offer improved safety to treat patients with impaired GI motility. PMID:22356640

  1. Linking the HOMO-LUMO gap to torsional disorder in P3HT/PCBM blends

    International Nuclear Information System (INIS)

    McLeod, John A.; Pitman, Amy L.; Moewes, Alexander; Kurmaev, Ernst Z.; Finkelstein, Larisa D.; Zhidkov, Ivan S.; Savva, Achilleas

    2015-01-01

    The electronic structure of [6,6]-phenyl C 61 butyric acid methyl ester (PCBM), poly(3-hexylthiophene) (P3HT), and P3HT/PCBM blends is studied using soft X-ray emission and absorption spectroscopy and density functional theory calculations. We find that annealing reduces the HOMO-LUMO gap of P3HT and P3HT/PCBM blends, whereas annealing has little effect on the HOMO-LUMO gap of PCBM. We propose a model connecting torsional disorder in a P3HT polymer to the HOMO-LUMO gap, which suggests that annealing helps to decrease the torsional disorder in the P3HT polymers. Our model is used to predict the characteristic length scales of the flat P3TH polymer segments in P3HT and P3HT/PCBM blends before and after annealing. Our approach may prove useful in characterizing organic photovoltaic devices in situ or even in operando

  2. Atmospheric HT and HTO: V. distribution and large-scale circulation

    International Nuclear Information System (INIS)

    Mason, A.S.; Oestlund, H.G.

    1979-01-01

    The two major chemical forms of atmospheric tritium are water vapour (HTO) and hydrogen gas (HT). These forms have quite different sources, distributions and sinks. The chemical conversion from HT to HTO in the atmosphere proceeds with a characteristic time of 6.5 years. Combined with the radioactive decay, a net lifetime of 4.8 years is estimated for atmospheric HT. HT is released predominately at the surface in mid- to high latitudes in the northern hemisphere. A negative gradient southward has been found from aircraft transects and from sampling at surface stations. After many years of a relatively constant global inventory of 1.1 kg of tritium gas, the HT mixing ratios decreased during 1977, with the sharpest drop at high latitudes. The estimated decline in annual production was 100 g. At the end of 1977, the atmospheric HT burden was 1.0 kg, and the estimated annual release was 200 g. An unknown portion is present as T 2 gas. The effect of T 2 is to decrease the net lifetime to 3.7 years. In the troposphere, the cycle of HTO has been treated exhaustively by others. The stratospheric distribution of HTO has been sampled from aircraft, and found to increase rapidly with height above the troposphere. An annual cycle has been observed, in which the lower stratosphere is depleted during the spring, and replenished by subsidence from higher levels during summer and fall. The effects of a nuclear test by the People's Republic of China in November 1976 have been clearly observed in the stratospheric HTO; however, no HT deposition was found. Presumably, the HTO at higher levels was originally deposited by the large nuclear weapons tests of the 1960s. An estimated 5 kg of tritium are now present in the stratosphere below 19 km. (author)

  3. Modifying 5-HT1A receptor gene expression as a new target for antidepressant therapy

    Directory of Open Access Journals (Sweden)

    Paul R Albert

    2010-06-01

    Full Text Available Major depression is the most common form of mental illness, and is treated with antidepressant compounds that increase serotonin (5-HT neurotransmission. Increased 5-HT1A autoreceptor levels in the raphe nuclei act as a “brake” to inhibit the 5-HT system, leading to depression and resistance to antidepressants. Several 5-HT1A receptor agonists (buspirone, flesinoxan, ipsapirone that preferentially desensitize 5-HT1A autoreceptors have been tested for augmentation of antidepressant drugs with mixed results. One explanation could be the presence of the C(-1019G 5-HT1A promoter polymorphism that prevents gene repression of the 5-HT1A autoreceptor. Furthermore, down-regulation of 5-HT1A autoreceptor expression, not simply desensitization of receptor signaling, appears to be required to enhance and accelerate antidepressant action. The current review focuses on the transcriptional regulators of 5-HT1A autoreceptor expression, their roles in permitting response to 5-HT1A-targeted treatments and their potential as targets for new antidepressant compounds for treatment-resistant depression.

  4. Novel pyridylmethylamines as highly selective 5-HT(1A) superagonists.

    Science.gov (United States)

    Bollinger, Stefan; Hübner, Harald; Heinemann, Frank W; Meyer, Karsten; Gmeiner, Peter

    2010-10-14

    To further improve the maximal serotonergic efficacy and better understand the configurational requirements for 5-HT(1A) binding and activation, we generated and biologically investigated structural variants of the lead structure befiradol. For a bioisosteric replacement of the 3-chloro-4-fluoro moiety, a focused library of 63 compounds by solution phase parallel synthesis was developed. Target binding of our compound collection was investigated, and their affinities for 5-HT(2), α(1), and α(2)-adrenergic as well as D(1)-D(4) dopamine receptors were compared. For particularly interesting test compounds, intrinsic activities at 5-HT(1A) were examined in vitro employing a GTPγS assay. The investigation guided us to highly selective 5HT(1A) superagonists. The benzothiophene-3-carboxamide 8bt revealed almost exclusive 5HT(1A) recognition with a K(i) value of 2.7 nM and a maximal efficacy of 124%. To get insights into the bioactive conformation of our compound collection, we synthesized conformationally constrained bicyclic scaffolds when SAR data indicated a chair-type geometry and an equatorially dispositioned aminomethyl substituent for the 4,4-disubstituted piperidine moiety.

  5. Is FT3 by radioligandassay (RLA) superior in the diagnosis of hyperthyroidism (HT)

    Energy Technology Data Exchange (ETDEWEB)

    Bottger, I.G.; Pabst, H.W.

    1985-05-01

    Based upon our routine experience with more than 50,000/15,000 patients having been examined by FT4/FT3 RLA the authors reported a comparable clinical value of routine parameters for free thyroid hormones. The purpose of this study was to investigate the clinical performance of FT3 by RLA in borderline HT (BHT) in more detail. Two groups of patients were studied prospectively: group I: BHT, 48 sera, HT was suspected on grounds of clinical, scintigraphical and ultrasonic findings, no therapy. Subgroup Ia: negative TRH test (TSH before and after 200 ..mu..g TRH i.v. 0.8 mU/1), T4, FT4, T4/TBG ratio and T3 in the normal range (NR), 22 sera. Subgroup Ib: T3 (NR: 1.6 - 3.6 pmol/1): 3.7 - 3.9 and/or FT4 and/or T4/TBG ratio elevated, 26 sera. Group II: thyroid ablated patients with thyroid carcinoma on TSH-suppressive 1-T4 medication (200 ..mu..g/day) with a negative TRH test, no obvious symptoms of HT, T3 normal. RLAs employed routinely: FT4/T4 and FT3/T3 (kinetic, two-tube), and TBG, Corning Medical, TSH, Henning-Berlin. Group I: T3 levels were in the middle to upper NR, 9 (19 %) of Ib being elevated, T3/TBG was predominantly at the upper limit of the NR, 20 (42%) of this group and 5 (10%) of Ia being increased. 29 (60%) of the FT3 levels in I and 8 (17%) in Ia were elevated up to 15 and 13 pmol/l, respectively. Group II: the T3/TBG ratio was increased in 13 (11%) and the FT3 concentration up to 14 pmol/l in 57 (50%) sera.

  6. Is FT3 by radioligandassay (RLA) superior in the diagnosis of hyperthyroidism (HT)

    International Nuclear Information System (INIS)

    Bottger, I.G.; Pabst, H.W.

    1985-01-01

    Based upon our routine experience with more than 50,000/15,000 patients having been examined by FT4/FT3 RLA the authors reported a comparable clinical value of routine parameters for free thyroid hormones. The purpose of this study was to investigate the clinical performance of FT3 by RLA in borderline HT (BHT) in more detail. Two groups of patients were studied prospectively: group I: BHT, 48 sera, HT was suspected on grounds of clinical, scintigraphical and ultrasonic findings, no therapy. Subgroup Ia: negative TRH test (TSH before and after 200 μg TRH i.v. 0.8 mU/1), T4, FT4, T4/TBG ratio and T3 in the normal range (NR), 22 sera. Subgroup Ib: T3 (NR: 1.6 - 3.6 pmol/1): 3.7 - 3.9 and/or FT4 and/or T4/TBG ratio elevated, 26 sera. Group II: thyroid ablated patients with thyroid carcinoma on TSH-suppressive 1-T4 medication (200 μg/day) with a negative TRH test, no obvious symptoms of HT, T3 normal. RLAs employed routinely: FT4/T4 and FT3/T3 (kinetic, two-tube), and TBG, Corning Medical, TSH, Henning-Berlin. Group I: T3 levels were in the middle to upper NR, 9 (19 %) of Ib being elevated, T3/TBG was predominantly at the upper limit of the NR, 20 (42%) of this group and 5 (10%) of Ia being increased. 29 (60%) of the FT3 levels in I and 8 (17%) in Ia were elevated up to 15 and 13 pmol/l, respectively. Group II: the T3/TBG ratio was increased in 13 (11%) and the FT3 concentration up to 14 pmol/l in 57 (50%) sera

  7. High temperature oxidation behavior of ODS steels

    Science.gov (United States)

    Kaito, T.; Narita, T.; Ukai, S.; Matsuda, Y.

    2004-08-01

    Oxide dispersion strengthened (ODS) steels are being developing for application as advanced fast reactor cladding and fusion blanket materials, in order to allow increased operation temperature. Oxidation testing of ODS steel was conducted under a controlled dry air atmosphere to evaluate the high temperature oxidation behavior. This showed that 9Cr-ODS martensitic steels and 12Cr-ODS ferritic steels have superior high temperature oxidation resistance compared to 11 mass% Cr PNC-FMS and 17 mass% Cr ferritic stainless steel. This high temperature resistance is attributed to earlier formation of the protective α-Cr 2O 3 on the outer surface of ODS steels.

  8. Modification of smoothing in 4253H[T

    Science.gov (United States)

    Azmi, Nurul Nisa'Khairol; Adam, Mohd Bakri; Shitan, Mahendran; Ali, Norhaslinda Mohd

    2017-05-01

    Some modified non-linear smoothers particularly 4253H[T] are explained in this paper. The modifications are focused on estimating the middle point of running median for even span by applying the following types of means; geometric, harmonic, quadratic and contraharmonic. The performance of the techniques is assessed by applying it to daily price index of a bank in Malaysia that issues sukuk for funding in Islamic banking and financial business. The results show that 4253H[T] with geometric mean modification is better than others in preserving variation and curve fitting.

  9. h5-HT1B receptor-mediated constitutive Gαi3-protein activation in stably transfected Chinese hamster ovary cells: an antibody capture assay reveals protean efficacy of 5-HT

    Science.gov (United States)

    Newman-Tancredi, Adrian; Cussac, Didier; Marini, Laetitia; Touzard, Manuelle; Millan, Mark J

    2003-01-01

    Serotonin 5-HT1B receptors couple to G-proteins of the Gi/o family. However, their activation of specific G-protein subtypes is poorly characterised. Using an innovative antibody capture/guanosine-5′-0-(3-[35S]thio)-triphosphate ([35S]GTPγS) binding strategy, we characterised Gαi3 subunit activation by h5-HT1B receptors stably expressed in Chinese hamster ovary (CHO) cells. The agonists, 5-HT, alniditan and BMS181,101, stimulated Gαi3, whereas methiothepin and SB224,289 behaved as inverse agonists. The selective 5-HT1B receptor ligand, S18127, modestly stimulated Gαi3 and reversed the actions of both 5-HT and methiothepin. S18127 (1 μM) also produced parallel, dextral shifts of the 5-HT and methiothepin isotherms. Isotopic dilution experiments ([35S]GTPγS versus GTPγS) revealed high-affinity [35S]GTPγS binding to Gαi3 subunits in the absence of receptor ligands indicating constitutive activity. High-affinity [35S]GTPγS binding was increased 2.8-fold by 5-HT with an increase in the affinity of GTPγS for Gαi3 subunits. In contrast, methiothepin halved the number of high-affinity binding sites and decreased their affinity. h5-HT1B receptor-mediated Gαi3 subunit activation was dependent on the concentration of NaCl. At 300 mM, 5-HT stimulated [35S]GTPγS binding, basal Gαi3 activation was low and methiothepin was inactive. In contrast, at 10 mM NaCl, basal activity was enhanced and the inverse agonist activity of methiothepin was accentuated. Under these conditions, 5-HT decreased Gαi3 activation. In conclusion, at h5-HT1B receptors expressed in CHO cells: (i) inverse agonist induced inhibition of Gαi3, and its reversal by S18127, reveals constitutive activation of this Gα subunit; (ii) constitutive Gαi3 activation can be quantified by isotopic dilution [35S]GTPγS binding and (iii) decreasing NaCl concentrations enhances Gαi3 activation and leads to protean agonist properties of 5-HT: that is a switch to inhibition of Gαi3. PMID:12684263

  10. Functional antagonistic properties of clozapine at the 5-HT3 receptor.

    Science.gov (United States)

    Hermann, B; Wetzel, C H; Pestel, E; Zieglgänsberger, W; Holsboer, F; Rupprecht, R

    1996-08-23

    The atypical neuroleptic clozapine is thought to exert its psychopharmacological actions through a variety of neurotransmitter receptors. It binds preferentially to D4 and 5-HT2 receptors; however, little is known on it's interaction with the 5-HT3 receptor. Using a cell line stably expressing the 5-HT3 receptor, whole-cell voltage-clamp analysis revealed functional antagonistic properties of clozapine at low nanomolar concentrations in view of a binding affinity in the upper nanomolar range. Because the concentration of clozapine required for an interaction with the 5-HT3 receptor can be achieved with therapeutical doses, functional antagonistic properties at this ligand-gated ion channel may contribute to its unique psychopharmacological profile.

  11. Damage development - effects of multiaxial loads on creep pore formation and fatigue damage in typical power plant steels. Final report

    International Nuclear Information System (INIS)

    Lenk, P.; Proft, D.; Kussmaul, A.; Fischer, R.

    2000-01-01

    The influence of multiaxial stress on creep pore formation in the steels 14MoV6-3 10CrMo9-10 and X10CrMoVNb9-1 was investigated on the basis of internal pressure experiments on smooth and notched hollow cylinders. In some cases, additional axial forces were applied in order to reproduce component-relevant multiaxial stresses. Local elongation during loading was investigated and analyzed using applied HT-DMS. When different strain levels had been reached, the samples were removed, analyzed, and characterized with regard to different damage parameters. It was found that no interdependence between the surface damage pattern and the deep damage pattern can be derived across the wall thickness if no information on the load state is available. Parallel to the experiments, inelastic FEA were carried out using the ABAQUS program system. The creep law of Graham and Walles was used for calculating flow and creep via a user-defined subroutine CREEP. The parameters of the creep law could be identified by adaptation to monoaxial creep tests [de

  12. Modified 9Cr-1Mo steel for advanced steam generator applications

    International Nuclear Information System (INIS)

    Brinkman, C.R.; Alexander, D.J.; Maziasa, P.J.

    1990-01-01

    Results are reported from several types of mechanical property tests conducted on a number of commercial heats of modified 9Cr-1Mo steel. Data from long term creep-rupture tests conducted on base and weldment material were compared with an analytical model which has been shown to give good agreement between measured and predicted values. Weldment material had somewhat inferior creep-rupture strength in comparison to base material due to a soft zone at the edge of the HAZ. Data are presented from elevated temperature tensile and creep-rupture tests conducted on material thermally aged for periods of up to 75,000 h (8.6 years). Some reduction in strength was shown to occur in comparison to unaged material. Models were developed for predicting the reduction in short term elevated temperature tensile and yield strength for material thermally aged in the temperature range of 482 to 704 degrees C. Results from Charpy impact tests conducted on material thermally aged at 538 degrees C for periods of up to 75,000 h show an increase in the ductile-brittle transition temperature

  13. Stability of tramadol with three 5-HT3 receptor antagonists in polyolefin bags for patient-controlled delivery systems

    Directory of Open Access Journals (Sweden)

    Chen FC

    2016-06-01

    Full Text Available Fu-chao Chen,1 Jun Zhu,1 Bin Li,1 Fang-jun Yuan,1 Lin-hai Wang2 1Department of Pharmacy, Dongfeng Hospital, 2Department of Pharmacy, Renmin Hospital, Hubei University of Medicine, Shiyan, Hubei, People’s Republic of China Background: Mixing 5-hydroxytryptamine-3 (5-HT3 receptor antagonists with patient-controlled analgesia (PCA solutions of tramadol has been shown to decrease the incidence of nausea and vomiting associated with the use of tramadol PCA for postoperative pain. However, such mixtures are not commercially available, and the stability of the drug combinations has not been duly studied. The study aimed to evaluate the stability of tramadol with three 5-HT3 receptor antagonists in 0.9% sodium chloride injection for PCA administration.Materials and methods: Test samples were prepared by adding 1,000 mg tramadol hydrochloride, 8 mg ondansetron hydrochloride, and 6 mg granisetron hydrochloride or 5 mg tropisetron hydrochloride to 100 mL of 0.9% sodium chloride injection in polyolefin bags. The samples were prepared in triplicates, stored at either 25°C or 4°C for 14 days, and assessed using the following compatibility parameters: precipitation, cloudiness, discoloration, and pH. Chemical stability was also determined using a validated high-pressure liquid chromatography method.Results: All of the mixtures were clear and colorless throughout the initial observation period. No change in the concentration of tramadol hydrochloride occurred with any of the 5-HT3 receptor antagonists during the 14 days. Similarly, little or no loss of the 5-HT3 receptor antagonists occurred over the 14-day period.Conclusion: Our results suggest that mixtures of tramadol hydrochloride, ondansetron hydrochloride, granisetron hydrochloride, or tropisetron hydrochloride in 0.9% sodium chloride injection were physically and chemically stable for 14 days when stored in polyolefin bags at both 4°C and 25°C. Keywords: tramadol, ondansetron, granisetron

  14. Thick-section weldments in 21-6-9 and 316LN stainless steel for fusion energy applications

    International Nuclear Information System (INIS)

    Alexander, D.J.; Goodwin, G.M.

    1991-01-01

    The Burning Plasma Experiment (BPX), formerly known as the Compact Ignition Tokomak, will be a major advance in the design of a fusion reactor. The successful construction of fusion reactors will require extensive welding of thick-section stainless steel plates. Severe service conditions will be experienced by the structure. Operating temperatures will range from room temperature (300 K) to liquid nitrogen temperature (77 K), and perhaps even lower. The structure will be highly stressed, and subject to sudden impact loads if plasma disruptions occur. This demands a combination of high strength and high toughness from the weldments. Significant portions of the welding will be done in the field, so preweld and postweld heat treatments will be difficult. The thick sections to be welded will require a high deposition rate process, and will result in significant residual stresses in the materials. Inspection of these thick sections in complex geometries will be very difficult. All of these constraints make it essential that the welding procedures and alloys be well understood, and the mechanical properties of the welds and their heat-affected zones must be adequately characterized. The candidate alloy for structural applications in the BPX such as the magnet cases was initially selected as 21-6-9 austenitic stainless steel, and later changed to 316LN stainless steel. This study examined several possible filler materials for thick-section (25 to 50 mm) weldments in these two materials. The tensile and Charpy V-notch properties were measured at room temperature and 77 K. The fracture toughness was measured for promising materials

  15. Correlation between the morphology and photo-physical properties of P3HT: fullerene blends

    CSIR Research Space (South Africa)

    Motaung, DE

    2010-01-01

    Full Text Available -induced charge transfer, well-known for blends of P3HT with fullerenes, was evidenced in blends of P3HT:C60 (1:1 wt ratio) by a strong partially quenching of the P3HT luminescence. The ESR measurements allowed one to quantify the charge transfer between P3HT...

  16. Effects of combined administration of 5-HT1A and/or 5-HT1B receptor antagonists and paroxetine or fluoxetine in the forced swimming test in rats.

    Science.gov (United States)

    Tatarczyńska, Ewa; Kłodzińska, Aleksandra; Chojnacka-Wójcik, Ewa

    2002-01-01

    Clinical data suggest that coadministration of pindolol, a 5-HT1A/5-HT1B/beta-adrenoceptor antagonist, and selective serotonin reuptake inhibitors (SSRIs) may shorten the time of onset of a clinical action and may increase beneficial effects of the therapy of drug-resistant depression. Effects of combined administration of SSRIs and 5-HT receptor ligands are currently evaluated in animal models for the detection of an antidepressant-like activity; however, the obtained results turned out to be inconsistent. The aim of the present study was to investigate effects of a 5-HT1A antagonist (WAY 100635), 5-HT1B antagonists (SB 216641 and GR 127935) or pindolol, given in combination with paroxetine or fluoxetine (SSRIs), in the forced swimming test in rats (Porsolt test). When given alone, paroxetine (10 and 20 mg/kg), fluoxetine (10 and 20 mg/kg), WAY 100635 (0.1 and 1 mg/kg), SB 216641 (2 mg/kg), GR 127935 (10 and 20 mg/kg) and pindolol (4 and 8 mg/kg) did not shorten the immobility time of rats in that test. Interestingly, SB 216641 administered alone at a dose of 4 mg/kg produced a significant reduction of the immobility time in that test. A combination of paroxetine (20 mg/kg) and WAY 100635 or pindolol failed to reveal a significant interaction; on the other hand, when paroxetine was given jointly with SB 216641 (2 mg/kg) or GR 127935 (10 and 20 mg/kg), that combination showed a significant antiimmobility action in the forced swimming test in rats. The active behaviors in that test did not reflect increased general activity because combined administration of both the 5-HT1B antagonists and paroxetine failed to alter the locomotor activity of rats, measured in the open field test. Coadministration of fluoxetine and all the antagonists used did not affect the behavior of rats in the forced swimming test. The obtained results seem to indicate that blockade of 5-HT1B receptors, but not 5-HT1A ones, can facilitate the antidepressant-like effect of paroxetine in the

  17. Fatigue Properties of Aged Mod. 9Cr-1Mo

    International Nuclear Information System (INIS)

    Kim, Dae Whan; Kim, Sung Ho; Lee, Chan Bock

    2007-01-01

    Ferritic/Martensitic steel has a good mechanical properties and a lower thermal expansion coefficient than austenitic stainless steel. Mechanical property of Mod. 9Cr-1Mo steel is less than austenitic stainless steel at high temperature. High temperature mechanical properties are affected by precipitation for Mod. 9Cr-1Mo. FMS steel is used for long time at high temperature and the effect of aging on mechanical properties is very important. In this study, low cycle fatigue properties with aging were investigated

  18. Water corrosion test of oxide dispersion strengthened (ODS) steel claddings

    International Nuclear Information System (INIS)

    Narita, Takeshi; Ukai, Shigeharu; Kaito, Takeji; Ohtsuka, Satoshi; Matsuda, Yasushi

    2006-07-01

    As a part of feasibility study of ODS steel cladding, its water corrosion resistance was examined under water pool condition. Although addition of Cr is effective for preventing water corrosion, excessive Cr addition leads to embrittlement due to the Cr-rich α' precipitate formation. In the ODS steel developed by the Japan Atomic Energy Agency (JAEA), the Cr content is controlled in 9Cr-ODS martensite and 12Cr-ODS ferrite. In this study, water corrosion test was conducted for these ODS steels, and their results were compared with that of conventional austenitic stainless steel and ferritic-martensitic stainless steel. Following results were obtained in this study. (1) Corrosion rate of 9Cr-ODS martensitic and 12Cr-ODS ferritic steel are significantly small and no pitting was observed. Thus, these ODS steels have superior resistance for water corrosion under the condition of 60degC and pH8-12. (2) It was showed that 9Cr-ODS martensitic steel and 12Cr-ODS ferritic steel have comparable water corrosion resistance to that of PNC316 and PNC-FMS at 60degC for 1,000h under varying pH of 8, 10. Water corrosion resistance of these alloys is slightly larger than that of PNC316 and PNC-FMS at pH12 without significant difference of appearance and uneven condition. (author)

  19. 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.)

  20. HT-7U superconducting tokamak: Physics design, engineering progress and schedule

    International Nuclear Information System (INIS)

    Wan Yuanxi

    2002-01-01

    The superconducting tokamak research program begun in China in ASIPP since 1994. The program is included in existent superconducting tokamak HT-7 and the next new superconducting tokamak HT-7U which is one of national key research projects in China. With the elongation cross-section, divertor and higher plasma parameter the main objectives of HT-7U are widely investigation both of the physics and technology for steady state advanced tokamak as well as the investigation of power and particle handle under steady-state operation condition. The physics and engineering design have been completed and significant progresses on R and D and fabrication have been achieved. HT-7U will begin assembly at 2003 and possible to get first plasma around 2004. (author)

  1. Ebselen has lithium-like effects on central 5-HT2A receptor function.

    Science.gov (United States)

    Antoniadou, I; Kouskou, M; Arsiwala, T; Singh, N; Vasudevan, S R; Fowler, T; Cadirci, E; Churchill, G C; Sharp, T

    2018-02-27

    Lithium's antidepressant action may be mediated by inhibition of inositol monophosphatase (IMPase), a key enzyme in G q protein coupled receptor signalling. Recently, the antioxidant agent ebselen was identified as an IMPase inhibitor. Here we investigated both ebselen and lithium in models of the 5-HT 2A receptor, a G q protein coupled receptor implicated in lithium's actions. 5-HT 2A receptor function was modelled in mice by measuring the behavioural (head-twitches) and cortical immediate early gene (IEG; Arc, c-fos and Erg2 mRNA) responses to 5-HT 2A receptor agonist administration. Ebselen and lithium were administered either acutely or chronically prior to assessment of 5-HT 2A receptor function. Given the SSRI augmenting action of lithium and 5-HT 2A antagonists, ebselen was also tested for this action by co-administration with the SSRI citalopram in microdialysis (extracellular 5-HT) experiments. Acute and repeated administration of ebselen inhibited behavioural and IEG responses to the 5-HT 2A receptor agonist DOI. Repeated lithium also inhibited DOI-evoked behavioural and IEG responses. In comparison, a selective IMPase inhibitor (L-690,330) attenuated the behavioural response to DOI whereas glycogen synthase kinase inhibitor (AR-A014418) did not. Finally, ebselen increased regional brain 5-HT synthesis and enhanced the increase in extracellular 5-HT induced by citalopram. The current data demonstrate lithium-mimetic effects of ebselen in different experimental models of 5-HT 2A receptor function, likely mediated by IMPase inhibition. This evidence of lithium-like neuropharmacological effects of ebselen adds further support for the clinical testing of ebselen in mood disorder, including as an antidepressant augmenting agent. This article is protected by copyright. All rights reserved.

  2. Maternal aggression in Wistar rats: effect of 5-HT2A/2C receptor agonist and antagonist microinjected into the dorsal periaqueductal gray matter and medial septum

    Directory of Open Access Journals (Sweden)

    Almeida R.M.M. de

    2005-01-01

    Full Text Available The objective of the present study was to assess the role of the 5-HT2A/2C receptor at two specific brain sites, i.e., the dorsal periaqueductal gray matter (DPAG and the medial septal (MS area, in maternal aggressive behavior after the microinjection of either a 5-HT2A/2C receptor agonist or antagonist. Female Wistar rats were microinjected on the 7th postpartum day with the selective agonist alpha-methyl-5-hydroxytryptamine maleate (5-HT2A/2C or the antagonist 5-HT2A/2C, ketanserin. The agonist was injected into the DPAG at 0.2 (N = 9, 0.5 (N = 10, and 1.0 µg/0.2 µl (N = 9, and the antagonist was injected at 1.0 µg/0.2 µl (N = 9. The agonist was injected into the medial septal area (MS at 0.2 (N = 9, 0.5 (N = 7, and 1.0 µg/0.2 µl (N = 6 and the antagonist was injected at 1.0 µg/0.2 µl (N = 5. For the control, saline was injected into the DPAG (N = 7 and the MS (N = 12. Both areas are related to aggressive behavior and contain a high density of 5-HT receptors. Non-aggressive behaviors such as horizontal locomotion (walking and social investigation and aggressive behaviors such as lateral threat (aggressive posture, attacks (frontal and lateral, and biting the intruder were analyzed when a male intruder was placed into the female resident's cage. For each brain area studied, the frequency of the behaviors was compared among the various treatments by analysis of variance. The results showed a decrease in maternal aggressive behavior (number of bites directed at the intruder after microinjection of the agonist at 0.2 and 1.0 µg/0.2 µl (1.6 ± 0.7 and 0.9 ± 0.3 into the DPAG compared to the saline group (5.5 ± 1.1. There was no dose-response relationship with the agonist. The present findings suggest that the 5-HT2A/2C receptor agonist has an inhibitory effect on maternal aggressive behavior when microinjected into the DPAG and no effect when microinjected into the MS. Ketanserin (1.0 µg/0.2 µl decreased locomotion when microinjected

  3. Influence of Hold Time and Stress Ratio on Cyclic Creep Properties Under Controlled Tension Loading Cycles of Grade 91 Steel

    International Nuclear Information System (INIS)

    Kim, Woo Gon; Park, Jae Young; Jang, Jin Sung; Ekaputra, I Made Wicaksana; Kim, Seon Jin

    2017-01-01

    Influences of hold time and stress ratio on cyclic creep properties of Grade 91 steel were systemically investigated using a wide range of cyclic creep tests, which were performed with hold times (HTs) of 1 minute, 3 minutes, 5 minutes, 10 minutes, 20 minutes, and 30 minutes and stress ratios (R) of 0.5, 0.8, 0.85, 0.90, and 0.95 under tension loading cycles at 600°C. Under the influence of HT, the rupture time increased to HT = 5 minutes at R = 0.90 and R = 0.95, but there was no influence at R = 0.50, 0.80, and 0.85. The creep rate was constant regardless of an increase in the HT, except for the case of HT = 5 minutes at R = 0.90 and R = 0.95. Under the influence of stress ratio, the rupture time increased with an increase in the stress ratio, but the creep rate decreased. The cyclic creep led to a reduction in the rupture time and an acceleration in the creep rate compared with the case of monotonic creep. Cyclic creep was found to depend dominantly on the stress ratio rather than on the HT. Fracture surfaces displayed transgranular fractures resulting from microvoid coalescence, and the amount of microvoids increased with an increase in the stress ratio. Enhanced coarsening of the precipitates in the cyclic creep test specimens was found under all conditions

  4. The influence of prior ageing on microstructure, tensile properties and hot hardness of alloy 800HT

    International Nuclear Information System (INIS)

    El-Magd, E.

    1996-01-01

    For high temperature applications especially in the construction of equipment, carbide strengthened steels are widely used because of their good mechanical properties and relatively low cost. These materials undergo microstructural changes under such service conditions which contribute greatly to the strength properties and thus play an important role in equipment design considerations. The influence of a prior thermal ageing on the tensile strength values and the hot hardness of the austenitic iron base alloy, Alloy 800HT, is examined in this work. It was therefore necessary to carry out tensile and hot hardness tests with the solution treated and overaged material at ranges between room temperature and 900 . The microstructural changes are investigated using lightmicroscopy, SEM and TEM. The changes of the material properties with thermal pretreatment conditions is studied and discussed in the context of the determined microstructural development. (orig.) [de

  5. Microstructural examination of 12% Cr martensitic stainless steel after irradiation at elevated temperatures in FFTF [Fast Flux Test Facility

    International Nuclear Information System (INIS)

    Hsu, Chen-Yih; Gelles, D.S.; Lechtenberg, T.A.

    1986-06-01

    A remelted 12% Cr martensitic stainless steel (HT-9) has been examined by transmission electron microscopy before and after irradiation in the Materials Open Test Assembly (MOTA) of the Fast Flux Test Facility (FFTF). The irradiation temperatures were 365,420, 520, and 600 degree C with the fluences as high as 7.3 x 10 22 n/cm 2 (E > 0.1 MeV) or 34 dpa. The extracted precipitates from each specimen were identified using x-ray microanalysis and selected area diffraction. The precipitates in the unirradiated condition were primarily M 23 C 6 carbides, which formed at martensite lath and prior austenite grain boundaries. During irradiation at elevated temperatures, small amounts of other phases formed, which were tentatively identified as the chromium-rich α', the nickel-silicon rich G-phase, and the intermetallic Chi phase. Irradiation-induced voids were observed only in specimens irradiated at 420 degree C to a dose of 34 dpa; no voids were found for specimens irradiated at 365, 520, and 600 degree C (∼11, ∼34, and ∼34 dpa). These results are not in agreement with previous experiments in that voids have not been reported in this alloy at relatively high fluence level (∼67 dpa) following irradiation in another fast-spectrum reactor (EBR.II). This is, however, the first observation following FFTF irradiation. The present results indicate that cavities can form in HT-9 at modest fluence levels even without significant generation of helium. Hence, the cavity formation in this class of ferritic alloys is not simply caused by helium generation but rather more complex mechanisms. 12 refs., 2 figs., 3 tabs

  6. Effect of Activated Flux on the Microstructure, Mechanical Properties, and Residual Stresses of Modified 9Cr-1Mo Steel Weld Joints

    Science.gov (United States)

    Maduraimuthu, V.; Vasudevan, M.; Muthupandi, V.; Bhaduri, A. K.; Jayakumar, T.

    2012-02-01

    A novel variant of tungsten inert gas (TIG) welding called activated-TIG (A-TIG) welding, which uses a thin layer of activated flux coating applied on the joint area prior to welding, is known to enhance the depth of penetration during autogenous TIG welding and overcomes the limitation associated with TIG welding of modified 9Cr-1Mo steels. Therefore, it is necessary to develop a specific activated flux for enhancing the depth of penetration during autogeneous TIG welding of modified 9Cr-1Mo steel. In the current work, activated flux composition is optimized to achieve 6 mm depth of penetration in single-pass TIG welding at minimum heat input possible. Then square butt weld joints are made for 6-mm-thick and 10-mm-thick plates using the optimized flux. The effect of flux on the microstructure, mechanical properties, and residual stresses of the A-TIG weld joint is studied by comparing it with that of the weld joints made by conventional multipass TIG welding process using matching filler wire. Welded microstructure in the A-TIG weld joint is coarser because of the higher peak temperature in A-TIG welding process compared with that of multipass TIG weld joint made by a conventional TIG welding process. Transverse strength properties of the modified 9Cr-1Mo steel weld produced by A-TIG welding exceeded the minimum specified strength values of the base materials. The average toughness values of A-TIG weld joints are lower compared with that of the base metal and multipass weld joints due to the presence of δ-ferrite and inclusions in the weld metal caused by the flux. Compressive residual stresses are observed in the fusion zone of A-TIG weld joint, whereas tensile residual stresses are observed in the multipass TIG weld joint.

  7. Application of a TiAIN coating for the increase wear resistance of a passage floodgate manufactured in steel T9

    International Nuclear Information System (INIS)

    Montes de Oca, J.; Gonzalez, H. J.; Solis, E.; Moreno, J.; Munoz S, J.

    2009-01-01

    The present work reports a study to increase wear resistance of a ball passage floodgate (steel type T9) trough the application of a thick film (coating). This study have included a material and process selection, synthesis of the coating on steel plates as substrates and spherical device, assembling of the coated floodgate on the ball valves, and finally an evaluation of the valves in the process of a thermoelectric power station. Taking into account the different requirements, a TiAIN coating prepared by cathodic arc evaporation was finally retained. The crystal structure, morphology and chemical composition of the coating were evaluated by x-ray diffraction (XRD) and scanning electron microscopy equipped with an energy dispersive spectrometer (SEM-EDS). Finally, mechanical properties such as hardness and Young modulus were determined by nano indentation. (Author)

  8. Serotonergic 5-HT6 Receptor Antagonists: Heterocyclic Chemistry and Potential Therapeutic Significance.

    Science.gov (United States)

    Bali, Alka; Singh, Shalu

    2015-01-01

    The serotonin 5-HT(6) receptor (5- HT(6)R) is amongst the recently discovered serotonergic receptors with almost exclusive localization in the brain. Hence, this receptor is fast emerging as a promising target for cognition enhancement in central nervous system (CNS) diseases such as Alzheimer's disease (cognitive function), obesity, schizophrenia and anxiety. The last decade has seen a surge of literature reports on the functional role of this receptor in learning and memory processes and investigations related to the chemistry and pharmacology of 5-HT(6) receptor ligands, especially 5- HT(6) receptor antagonists. Studies show the involvement of multiple neurotransmitter systems in cognitive enhancement by 5-HT(6)R antagonists including cholinergic, glutamatergic, and GABAergic systems. Several of the 5-HT(6)R ligands are indole based agents bearing structural similarity to the endogenous neurotransmitter serotonin. Based on the pharmacophoric models proposed for these agents, drug designing has been carried out incorporating various heterocyclic replacements for the indole nucleus. In this review, we have broadly summarized the medicinal chemistry and current status of this fairly recent class of drugs along with their potential therapeutic applications.

  9. G-LiHT: Goddard's LiDAR, Hyperspectral and Thermal Airborne Imager

    Science.gov (United States)

    Cook, Bruce; Corp, Lawrence; Nelson, Ross; Morton, Douglas; Ranson, Kenneth J.; Masek, Jeffrey; Middleton, Elizabeth

    2012-01-01

    Scientists at NASA's Goddard Space Flight Center have developed an ultra-portable, low-cost, multi-sensor remote sensing system for studying the form and function of terrestrial ecosystems. G-LiHT integrates two LIDARs, a 905 nanometer single beam profiler and 1550 nm scanner, with a narrowband (1.5 nanometers) VNIR imaging spectrometer and a broadband (8-14 micrometers) thermal imager. The small footprint (approximately 12 centimeters) LIDAR data and approximately 1 meter ground resolution imagery are advantageous for high resolution applications such as the delineation of canopy crowns, characterization of canopy gaps, and the identification of sparse, low-stature vegetation, which is difficult to detect from space-based instruments and large-footprint LiDAR. The hyperspectral and thermal imagery can be used to characterize species composition, variations in biophysical variables (e.g., photosynthetic pigments), surface temperature, and responses to environmental stressors (e.g., heat, moisture loss). Additionally, the combination of LIDAR optical, and thermal data from G-LiHT is being used to assess forest health by sensing differences in foliage density, photosynthetic pigments, and transpiration. Low operating costs (approximately $1 ha) have allowed us to evaluate seasonal differences in LiDAR, passive optical and thermal data, which provides insight into year-round observations from space. Canopy characteristics and tree allometry (e.g., crown height:width, canopy:ground reflectance) derived from G-LiHT data are being used to generate realistic scenes for radiative transfer models, which in turn are being used to improve instrument design and ensure continuity between LiDAR instruments. G-LiHT has been installed and tested in aircraft with fuselage viewports and in a custom wing-mounted pod that allows G-LiHT to be flown on any Cessna 206, a common aircraft in use throughout the world. G-LiHT is currently being used for forest biomass and growth estimation

  10. High density operation on the HT-7 superconducting tokamak

    International Nuclear Information System (INIS)

    Xiang Gao

    2000-01-01

    The structure of the operation region has been studied in the HT-7 superconducting tokamak, and progress on the extension of the HT-7 ohmic discharge operation region is reported. A density corresponding to 1.2 times the Greenwald limit was achieved by RF boronization. The density limit appears to be connected to the impurity content and the edge parameters, so the best results are obtained with very clean plasmas and peaked electron density profiles. The peaking factors of electron density profiles for different current and line averaged densities were observed. The density behaviour and the fuelling efficiency for gas puffing (20-30%), pellet injection (70-80%) and molecular beam injection (40-50%) were studied. The core crash sawteeth and MHD behaviour, which were induced by an injected pellet, were observed and the events correlated with the change of current profile and reversed magnetic shear. The MARFE phenomena on HT-7 are summarized. The best correlation has been found between the total input ohmic power and the product of the edge line averaged density and Z eff . HT-7 could be easily operated in the high density region MARFE-free using RF boronization. (author)

  11. 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.

  12. Corrosion of ferrous alloys in eutectic lead-lithium environments

    International Nuclear Information System (INIS)

    Chopra, O.K.; Smith, D.L.

    1983-09-01

    Corrosion data have been obtained on austenitic prime candidate alloy (PCA) and Type 316 stainless steel and ferritic HT-9 and Fe-9Cr-1Mo steels in a flowing Pb-17 at. % Li environment at 727 and 700 K (454 and 427 0 C). The results indicate that the dissolution rates for both austenitic and ferritic steels in Pb-17Li are an order of magnitude greater than in flowing lithium. The influence of time, temperature, and alloy composition on the corrosion behavior in Pb-17Li is similar to that in lithium. The weight losses for the austenitic steels are an order of magnitude greater than for the ferritic steels. The rate of weight loss for the ferritic steels is constant, whereas the dissolution rates for the austenitic steels decrease with time. After exposure to Pb-17Li, the austenitic steels develop a very weak and porous ferrite layer which easily spalls from the specimen surface

  13. Paroxetine-induced reduction of sexual incentive motivation in female rats is not modified by 5-HT1B or 5-HT2C antagonists.

    Science.gov (United States)

    Kaspersen, Helge; Agmo, Anders

    2012-03-01

    Clinical data show that paroxetine causes sexual dysfunction in a substantial proportion of women taking this compound. This work was conducted to determine whether chronic paroxetine reduces sexual incentive motivation in female rats and whether this compound can modify any aspect of paced mating. The role of the 5-HT(1B) and 5-HT(2C) receptors in any potential effects was also evaluated. Ovariectomized female rats were implanted with osmotic minipumps releasing 10 mg/kg per day of paroxetine or vehicle for 28 days. Tests for sexual incentive motivation and paced mating were performed just before implantation and at regular intervals thereafter. The females were primed with estradiol benzoate (25 μg/rat) and progesterone (1 mg/rat) before each of these tests. On days 25-27 of treatment, the females were injected with the 5-HT(1B) antagonist GR125,743 (5 mg/kg), the 5-HT(2C) antagonist SB206,553 (5 mg/kg) and vehicle in counterbalanced order. Preinjection time was 30 min. Paroxetine reduced sexual incentive motivation on day 20 of treatment without affecting any aspect of paced mating. None of the antagonists modified the inhibitory effect of paroxetine on sexual incentive motivation. In the group chronically treated with vehicle, SB206,553 reduced proceptive behaviors in the paced mating test. No other effect was obtained. The effects of paroxetine seen in female rats are similar to those observed in women, suggesting that disturbances of sexual incentive motivation in rats are predictive of sexual dysfunction in women. The 5-HT(1B) and 5-HT(2C) receptors do not seem to be of any importance for paroxetine's inhibitory effect.

  14. Operant learning and differential-reinforcement-of-low-rate 36-s responding in 5-HT1A and 5-HT1B receptor knockout mice.

    NARCIS (Netherlands)

    Pattij, T.; Broersen, L.M.; Linde, J. van der; Groenink, L.; Gugten, J. van der; Maes, R.A.A.; Olivier, B.

    2003-01-01

    Previous studies with mice lacking 5-HT(1A) (1AKO) and 5-HT(1B) (1BKO) receptors in hippocampus-dependent learning and memory paradigms, suggest that these receptors play an important role in learning and memory, although their precise role is unclear. In the present study, 1AKO and 1BKO mice were

  15. Mechanism of creep in stainless steel

    International Nuclear Information System (INIS)

    Monteiro, S.N.; Silveira, T.L.

    In the present work the creep criterions to identify the deformation mechanisms through the exponent of the strain rate versus stress relationship are presented. When applied to several stainless steels these criterions show an apparent contradiction for the proper mechanism acting at Σ/D above 10 9 /cm 2 . Microstructural aspects interfering in different manners with the fracture of these steels could be a reason for rationalizing the contradictory behavior. This is discussed in suggested deformation maps for the steels investigated [pt

  16. A comparison of the iraddiated tensile properties of a high-manganese austenitic steel and type 316 stainless steel

    International Nuclear Information System (INIS)

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

    1984-01-01

    The USSR steel EP-838 is a high-manganese, low-nickel steel that also has lower chromium and molybdenum than type 316 stainless steel. Tensile specimens of 20%-cold-worked EP-838 and type 316 stainless steel were irradiated in the High Flux Isotope Reactor (HFIR) at the coolant temperature (approx.=50 0 C). A displacement damage level of 5.2 dpa was reached for the EP-838 and up to 9.5 dpa for the type 316 stainless steel. Tensile tests at room temperature and 300 0 C on the two steels indicated that the irradiation led to increased strength and decreased ductility compared to the unirradiated steels. Although the 0.2% yield stress of the type 316 stainless steel in the unirradiated condition was greater than that for the EP-838, after irradiation there was essentially no difference between the strength or ductility of the two steels. The results indicate that the replacement of the majority of the nickel by manganese and a reduction of chromium and molybdenum in an austenitic stainless steel of composition near that for type 316 stainless steel has little effect on the irradiated and unirradiated tensile properties at low temperatures. (orig.)

  17. Additional materials for welding of the EP99 heat resisting alloy with the EI868 alloy and 12Kh18N9T steel

    International Nuclear Information System (INIS)

    Sorokin, L.I.; Filippova, S.P.; Petrova, L.A.

    1978-01-01

    Presented are the results of the studies aimed at selecting an additive material for argon-arc welding process involving heat-resistant nickel EP99 alloy to be welded to the EI868 alloy and 12Kh18N9T steel. As the additive material use was made of wire made of nickel-chromium alloys and covered electrodes made of the EP367 alloy with additions of tungsten. It has been established that in order to improve the resistance of metal to hot-crack formation during argon arc welding of the EP99 alloy with the EI868 alloy, it is advisable to use an additive material of the EP533 alloy, and while welding the same alloy with the 12Kh18N9T steel, filler wire of the EP367 alloy is recommended

  18. Enhancement of tribological properties of 9Cr18 stainless steel by dual Mo and S Co implantation

    International Nuclear Information System (INIS)

    Zhang Tao; Song Jiaohua; Li Guoqing; Chu, Paul K.; Brown, Ian G.

    2001-01-01

    Mo and S ions were simultaneously implanted into 9Cr18 stainless steel samples. The frictional properties of the implanted samples were assessed using a pin-on-disk tester and the elemental depth profiles were measured by Auger electron spectroscopy. The hardness of the samples was also measured. We find that this dual-element implantation process reduces the coefficient of friction by a factor of 2 and increases the low-friction lifetime by a factor of 4 compared to the 9Cr18 surface with Mo or S implantation alone. This enhancement is related to the synergistic coexistence of the implanted elements at the same place. We have also investigated the process using computer simulation. The simulation results help disclose the characteristics of the modified layer and explain the effects of dual-element ion implantation

  19. Vacuum physics analysis of HT-7 superconducting tokamak pump limiter

    International Nuclear Information System (INIS)

    Hu Jiansheng; Li Chengfu; He Yexi

    1998-10-01

    The pump limiter is analysed with HT-7 superconducting tokamak parameter and the pump limiter construction. The particle exhaust of the pump limiter can be to achieve about 7.7%. So the pump limiter can be applied in the HT-7 device and will make good affection in plasma discharge

  20. Liaison of 3H 5-HT and adenyl cyclasic activation induced by the 5-HT in preparations of brain glial membranes

    International Nuclear Information System (INIS)

    Fillion, Gilles; Beaudoin, Dominique; Rousselle, J.-C.; Jacob, Joseph

    1980-01-01

    Purified glial membrane preparations have been isolated from horse brain striatum. Tritiated 5-HT bound to these membranes with a high affinity (K(D)=10 nM); the corresponding bindings is reversible and appears specific of the serotoninergic structure. In parallel, 5-HT activates an adenylate cyclase with a low affinity (K(D)=1 μM). The sites involved in this binding and in this adenylate cyclase activation appear different from the serotoninergic sites reported in the neuronal membrane preparations [fr

  1. Detailed mapping of serotonin 5-HT{sub 1B} and 5-HT{sub 1D} receptor messenger RNA and ligand binding sites in guinea-pig brain and trigeminal ganglion: clues for function

    Energy Technology Data Exchange (ETDEWEB)

    Leysen, J.E. [Graduate School Neurosciences, Amsterdam (Netherlands); Schotte, A.; Jurzak, M.; Luyten, W.H.M.L. [Department of Biochemical Pharmacology, Janssen Research Foundation, Beerse (Belgium); Voorn, P.; Bonaventure, P. [Graduate School Neurosciences, Amsterdam (Netherlands)

    1997-10-17

    The similar pharmacology of the 5-HT{sub 1B} and 5-HT{sub 1D} receptors, and the lack of selective compounds sufficiently distinguishing between the two receptor subtypes, have hampered functional studies on these receptors. In order to provide clues for differential functional roles of the two subtypes, we performed a parallel localization study throughout the guinea-pig brain and the trigeminal ganglia by means of quantitative in situ hybridization histochemistry (using [{sup 35}S]-labelled riboprobes probes for receptor messenger RNA) and receptor autoradiography (using a new radioligand [{sup 3}H]alniditan).The anatomical patterns of 5-HT{sub 1B} and 5-HT{sub 1D} receptor messenger RNA were quite different. While 5-HT{sub 1B} receptor messenger RNA was abundant throughout the brain (with highest levels in the striatum, nucleus accumbens, olfactory tubercle, cortex, hypothalamus, hippocampal formation, amygdala, thalamus, dorsal raphe and cerebellum), 5-HT{sub 1D} receptor messenger RNA exhibited a more restricted pattern; it was found mainly in the olfactory tubercle, entorhinal cortex, dorsal raphe, cerebellum, mesencephalic trigeminal nucleus and in the trigeminal ganglion. The density of 5-HT{sub 1B/1D} binding sites (combined) obtained with [{sup 3}H]alniditan autoradiography was high in the substantia nigra, superior colliculus and globus pallidus, whereas lower levels were detected in the caudate-putamen, hypothalamus, hippocampal formation, amygdala, thalamus and central gray. This distribution pattern was indistinguishable from specific 5-HT{sub 1B} receptor labelling in the presence of ketanserin under conditions to occlude 5-HT{sub 1D} receptor labelling; hence the latter were below detection level. Relationships between the regional distributions of the receptor messenger RNAs and binding sites and particular neuroanatomical pathways are discussed with respect to possible functional roles of the 5-HT{sub 1B} and 5-HT{sub 1D} receptors. (Copyright (c

  2. Creep Rupture Analysis and Life Estimation of 1.25Cr-0.5Mo, 2.25Cr-1Mo and Modified 9Cr-1Mo Steel: A Comparative Study

    Science.gov (United States)

    Roy, Prabir Kumar

    2018-04-01

    This paper highlights a comparative assessment of creep life of 1.25Cr-0.5Mo, 2.25Cr-1Mo and modified 9Cr-1Mo steels based on accelerated creep rupture tests. Creep rupture test data have been analysed and creep life of the above mentioned materials have been assessed using Larson Miller parameter at the stress levels of 60 and 42 MPa for different temperatures. Limiting steam temperatures for minimum design life of 105 h at 42 and 60 MPa for the above mentioned steels have also been calculated. Microstructural studies for the three above mentioned steels are also done.

  3. Impact of 5-HT(3) RA selection within triple antiemetic regimens on uncontrolled highly emetogenic chemotherapy-induced nausea/vomiting.

    Science.gov (United States)

    Schwartzberg, Lee; Jackson, James; Jain, Gagan; Balu, Sanjeev; Buchner, Deborah

    2011-08-01

    It is recommended that patients initiate triple antiemetic therapy with one of the 5-hydroxytryptamine receptor antagonists (5-HT(3) RAs), aprepitant (or its intravenous prodrug fosaprepitant) and dexamethasone prior to the start of highly emetogenic chemotherapy (HEC). However, the impact of 5-HT(3) RA selection within triple antiemetic regimens on the risk of uncontrolled chemotherapy-induced nausea and vomiting (CINV) with HEC has not been well studied. To assess the likelihood of an uncontrolled CINV event following antiemetic prophylaxis with the 5-HT(3) RA palonosetron + aprepitant/fosaprepitant + dexamethasone (palonosetron cohort) versus any of the other 5-HT(3) RAs + aprepitant/fosaprepitant + dexamethasone (other 5-HT(3) RA cohort) among single-day HEC cycles. Single-day HEC cycles (a gap of at least 5 days between two administrations) among patients with a cancer diagnosis and receiving antiemetic prophylaxis with the aforementioned regimens between 1/1/2006 and 6/30/2010 were identified from the IMS LifeLink claims database. Uncontrolled CINV events were identified through ICD-9-CM codes (nausea and vomiting), Current Procedural Terminology codes (hydration), rescue medications and/or use of antiemetic therapy from days 2-5 following HEC administration. Risks for an uncontrolled CINV event among all patients, and within breast cancer and multiple cancer subpopulations, were analyzed at cycle level using logistic multivariate regression models. A total of 8018 cycles for the palonosetron cohort and 1926 cycles for the other 5-HT(3) RA cohort (3574 and 978 patients, respectively) were analyzed. Single-day HEC cycles received by the palonosetron cohort had a significantly lower unadjusted risk of an uncontrolled CINV event (17.5 vs 20.7% for the other 5-HT(3) RA cohort; p = 0.0010), with a 17% lower adjusted risk for palonosetron-administered cycles (odds ratio: 0.83; 95% CI: 0.73-0.94; p = 0.0042). Results in the breast cancer and multiple cancer

  4. 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

  5. Effect of HIP temperature and cooling rate on microstructure and hardness of joints for ODS-RAFM steels and JLF-1 steel

    International Nuclear Information System (INIS)

    Fu, Haiying; Nagasaka, Takuya; Muroga, Takeo; Kimura, Akihiko; Ukai, Shigeharu

    2016-01-01

    Dissimilar-metal joints between ODS-RAFM (oxide-dispersion-strengthened reduced activation ferritic/martensitic) steels and JLF-1 steel were fabricated by hot isostatic pressing (HIP) at 1000 - 1100degC with a cooling rate of 5degC/min. After the HIP, it was always quenched martensite for JLF-1 steel. However, coarse precipitates were found in 9Cr-ODS. Additional annealing experiments to simulate HIP conditions were conducted for 9Cr-ODS with cooling rate ranged from 0.5 to 36degC/min at 800 - 1100degC. The results showed that, to form quenched martensite for 9Cr-ODS, the HIP temperature should be above 1000degC with cooling rate no less than 25dgeC/min. When the cooling rate is increased to 36degC/min, the microstructure of 9Cr-ODS is quenched martensite with precipitate size similar as that before HIP. If the limitation of precipitate size in 9Cr-ODS is 0.2 µm, HIP temperature above 1050degC with cooling rate no less than 30degC/min is needed. In this case, post-weld heat treatment (PWHT) with only tempering is necessary to recover the microstructure of 9Cr-ODS to tempered martensite. For 12Cr-ODS, the HIP temperature and cooling rate has no effect on hardness and precipitate size. PWHT is not necessary for the single-metal joint of 12Cr-ODS from the view point of precipitation control. However, for the dissimilar-metal joints between ODS-RAFM steels and JLF-1 steel, the PWHT condition should be comprehensively determined by considering microstructural evolution of each part in the joints after HIP. (author)

  6. Field studies of HT oxidation and dispersion in the environment. I

    International Nuclear Information System (INIS)

    Brown, R.M.

    1987-01-01

    The environmental dispersion and oxidation of a controlled atmospheric release of tritiated hydrogen (HT) was studied in a pilot-scale field experiment. This study was designed to test procedures and obtain preliminary results for planning a more intensive experiment to determine the environmental behaviour of HT with emphasis on the processes leading to the appearance of HTO in the atmosphere, ie., conversion, deposition and resuspension. Field observations led to the following conclusions: 1) no evidence was found for the rapid conversion of HT to HTO in the atmosphere, 2) observations support the hypothesis that the dominant process giving rise to the observed HTO in air was HT oxidation in the soil by microbial action followed by resuspension of HTO, 3) HT deposition velocities to soil ranged between 0.041 cm/s and 0.13 cm/s, consistent with previous chamber measurements, 4) the rate of HTO loss from soil, averaged over 21 days, was less than 1% per hour, and 5) vegetation HTO concentrations initially increased with time then by 48 hours decreased exponentially at a rate similar to soils. These results will be validated and extended by the intensive experiment scheduled for June, 1987

  7. Preparation and characterization of Sr-Ti-hardystonite (Sr-Ti-HT nanocomposite for bone repair application

    Directory of Open Access Journals (Sweden)

    Hossein Mohammadi

    2015-07-01

    Full Text Available Objective(s: Hardystonite (HT is Zn-modified silicate bioceramics with promising results for bone tissue regeneration. However, HT possesses no obvious apatite formation. Thus, in this study we incorporated Sr and Ti into HT to prepare Sr-Ti-hardystonite (Sr-Ti-HT nanocomposite and evaluated its in vitro bioactivity with the purpose of developing a more bioactive bone substitute material. Materials and methods:The HT and Sr-Ti-HT were prepared by mechanical milling and subsequent heat treatment. Calcium oxide (CaO, zinc oxide (ZnO and silicon dioxide (SiO2 (all from Merck were mixed with molar ratio of 2:1:2. The mixture of powders mixture was then milled in a planetary ball mill for 20 h. In the milling run, the ball-to-powder weight ratio was 10:1 and the rotational speed was 200 rpm. After synthesis of HT, 3% nanotitanium dioxide (TiO2, Degussa and 3% strontium carbonate (SrCO3, Merck were added to HT and then the mixture was ball milled and calcined at 1150°C for 6 h. Simultaneous thermal analysis (STA, X-ray diffraction (XRD, Transmission electron microscopy (TEM and Fourier transform infra-red spectroscopy (FT-IR performed to characterize the powders. Results:XRD and FT-IR confirmed the crystal phase and silicate structure of HT and TEM images demonstrated the nanostructure of powders. Further, Sr-Ti-HT induced apatite formation and showed a higher human mesenchymal stem cell (hMSCs adhesion and proliferation compared to HT. Conclusion:Our study revealed that Sr-Ti-HT with a nanostructured crystal structure of 50 nm, can be prepared by mechanical activation to use as biomaterials for orthopedic applications.

  8. Pet imaging of human pituitary 5-HT2 receptors with F-18 setoperone

    Energy Technology Data Exchange (ETDEWEB)

    Fischman, A.J.; Bonab, A.A.; Babich, J.W. [Massachusetts General Hospital, Boston, MA (United States)] [and others

    1995-05-01

    Serotonin (5-HT) receptors play an important role in the regulation of pituitary function. In particular, 5HT agonists stimulate ACTH, {beta}-endorphin, prolactin and growth hormone secretion but inhibit TSH release. 5-HT binding sites have been identified by autoradiographic studies of rat and human pituitary. In the present investigation, we used PET with F-18 setoperone to image 5-HT2 receptors in normal humans. Setoperone, a piperidine derivative with potent 5-HT2 receptor blocking properties was labelled with F-18 by nucleophilic substitution on the nitro derivative. After HPLC purification, specific activity was between 10,000 and 15,000 mCi/{mu} mole and radiochemical purity was >98%. Six healthy male volunteers were injected with 5-7 mCi of F-18. Setoperone and serial PET images and arterial blood samples were collected over 2 hrs. Specific binding to 5-HT2 receptors in the frontal cortex (FC), striatum (ST) and pituitary (P) was quantitated using the cerebellum (C) as reference. The tracer showed clear retention in FC, ST and P (known to contain a high density of 5-HT2 receptors) relative to C (known to be devoid of 5-HT2 receptors). In all subjects, FC/C, ST/C and P/C ratios increased during the first hr. and remained stable thereafter. For FC and ST, the ratios reached similar values; 3.92{plus_minus}0.73 and 3.53{plus_minus}0.32. For pituitary, a significantly higher ratio, was measured at all times; 6.53{plus_minus}1.82 (p<0.01). These results indicate that F-18 setoperone is an effective PET radiopharmaceutical for imaging 5-HT2 receptors in the human pituitary. Future applications of this agent could provide important new insights into neuroendocrine function.

  9. Design of small diameter HT/HP sour service reeled rigid pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Carneiro, Daniel; Gouveia, Joao; Tardelli, Luciano [Tecnitas, Rio de Janeiro, RJ (Brazil)], e-mail: daniel.carneiro@br.bureauveritas.com; Parrilha, Rafael [Bureau Veritas Group, London (United Kingdom); Oazen, Eduardo; Cardoso, Carlos [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)

    2009-12-19

    The paper presents an overview of the challenges overcome in the engineering design of two 219 mm diameter, 6 km length oil production pipelines, to be installed by reeling at Espirito Santo Basin, offshore Brazilian coast in 1500 m water depth. The high temperature and high pressure (HT/HP) operating conditions and sour content associated with the small diameter required to single well oil production would usually lead to flexible flow line solution in Brazilian fields. The decision of employing small diameter thick-walled rigid C-Mn steel pipelines with thick thermal insulation made necessary extensive engineering work to achieve a safe and robust thermal expansion control arrangement, including the design of walking mitigation and buckle initiation apparatus; a feasible weld acceptance criterion covering both high cycle fatigue due to pipe lay and vortex induced vibration (VIV) at free spans, and high strain low cycle fatigue and fracture growth induced by reeling installation and in-service lateral buckling. Several studies were performed using highly non-linear three-dimensional finite element models considering: pipe-soil interaction with full 3D seabed bathymetry; load history maintained from pipe lay to operational cycles, including temperature transient effects; high plastic strains (including steel properties de-rating due to high temperature) and section ovalization; mechanical contact between pipe and appurtenances during both installation and operational phases. Pipe-soil interaction comprised embedment considering dynamic effects of pipe lay and full non-linear lateral and axial response curves including break-out and residual resistance. Strain concentration factors due to field joints were evaluated using detailed solid models considering non-linear response of both steel and insulation materials. Susceptibility to VIV at free spans was assessed considering post loaded deformed span natural frequencies, including multi-span interaction effects and

  10. Optical and electrical properties of P3HT:graphene composite based devices

    Science.gov (United States)

    Yadav, Anjali; Verma, Ajay Singh; Gupta, Saral Kumar; Negi, Chandra Mohan Singh

    2018-04-01

    The polymer-carbon derivate composites are well known for their uses and performances in the photovoltaic and optoelectronic industries. In this paper, we synthesis P3HT:graphene composites and discuss their optical and electrical properties. The composites have been prepared by using spin-coating technique onto the glass substrates. It has been found that the incorporation of graphene reduces absorption intensity. However, absorption peak remain unchanged with addition of graphene. The surface morphology studies display homogeneous distribution of graphene with P3HT. Raman studies suggest that chemical structure was not affected by graphene doping. Devices having the structure of glass/ITO/P3HT/ Al and glass ITO/P3HT:graphene/Al were then fabricated. I-V behavior of the fabricated devices was found to be similar to the Schottky diode. ITO/P3HT:graphene/Al structure shows tremendous increase in current values as compared to the ITO/P3HT/Al. Furthermore, charge transport mechanism were studied by analyzing the double logarithmic J-V characteristics curve, which indicates that the current at low voltage follows Ohmic behavior, trap-charge limited conduction (TCLC) mechanism at an intermediate voltage and space charge limited conduction (SCLC) mechanism at sufficiently high voltages.

  11. Hot spot manifestation in eclipsing dwarf nova HT Cassiopeiae

    OpenAIRE

    Bakowska, K.; Olech, A.

    2014-01-01

    We report the detection of the hot spot in light curves of the eclipsing dwarf nova HT Cassiopeiae during its superoutburst in 2010 November. Analysis of eight reconstructed light curves of the hot spot eclipses showed directly that the brightness of the hot spot was changing significantly during the superoutburst. Thereby, detected hot spot manifestation in HT Cas is the newest observational evidence for the EMT model for dwarf novae.

  12. Thermomechanical Model and Bursting Tests to Evaluate the Risk of Swelling and Bursting of Modified 9Cr-1Mo Steel Steam Generator Tubes during a Sodium-Water Reaction Accident

    Directory of Open Access Journals (Sweden)

    C. Bertrand

    2014-01-01

    Full Text Available The MECTUB code was developed to evaluate the risk of swelling and bursting of Steam Generator (SG tubes. This code deals with the physic of intermediate steam-water leaks into sodium which induce a Sodium-Water Reaction (SWR. It is based on a one-dimensional calculation to describe the thermomechanical behavior of tubes under a high internal pressure and a fast external overheating. The mechanical model of MECTUB is strongly correlated with the kind of the material of the SG tubes. It has been developed and validated by using experiments performed on the alloy 800. A change to tubes made of Modified 9Cr-1Mo steel requires more knowledge of Modified 9Cr-1Mo steel behavior which influences the bursting time at high temperatures (up to 1200°C. Studies have been initiated to adapt the mechanical model and to qualify it for this material. The first part of this paper focuses on the mechanical law modelling (elasticity, plasticity, and creep for Modified 9Cr-1Mo steel and on overheating thermal data. In a second part, the results of bursting tests performed on Modified 9Cr-1Mo tubes in the SQUAT facility of CEA are used to validate the mechanical model of MECTUB for the Modified 9Cr-1Mo material.

  13. Function and distribution of 5-HT2 receptors in the honeybee (Apis mellifera.

    Directory of Open Access Journals (Sweden)

    Markus Thamm

    Full Text Available BACKGROUND: Serotonin plays a pivotal role in regulating and modulating physiological and behavioral processes in both vertebrates and invertebrates. In the honeybee (Apis mellifera, serotonin has been implicated in division of labor, visual processing, and learning processes. Here, we present the cloning, heterologous expression, and detailed functional and pharmacological characterization of two honeybee 5-HT2 receptors. METHODS: Honeybee 5-HT2 receptor cDNAs were amplified from brain cDNA. Recombinant cell lines were established constitutively expressing receptor variants. Pharmacological properties of the receptors were investigated by Ca(2+ imaging experiments. Quantitative PCR was applied to explore the expression patterns of receptor mRNAs. RESULTS: The honeybee 5-HT2 receptor class consists of two subtypes, Am5-HT2α and Am5-HT2β. Each receptor gene also gives rise to alternatively spliced mRNAs that possibly code for truncated receptors. Only activation of the full-length receptors with serotonin caused an increase in the intracellular Ca(2+ concentration. The effect was mimicked by the agonists 5-methoxytryptamine and 8-OH-DPAT at low micromolar concentrations. Receptor activities were blocked by established 5-HT receptor antagonists such as clozapine, methiothepin, or mianserin. High transcript numbers were detected in exocrine glands suggesting that 5-HT2 receptors participate in secretory processes in the honeybee. CONCLUSIONS: This study marks the first molecular and pharmacological characterization of two 5-HT2 receptor subtypes in the same insect species. The results presented should facilitate further attempts to unravel central and peripheral effects of serotonin mediated by these receptors.

  14. Function and distribution of 5-HT2 receptors in the honeybee (Apis mellifera).

    Science.gov (United States)

    Thamm, Markus; Rolke, Daniel; Jordan, Nadine; Balfanz, Sabine; Schiffer, Christian; Baumann, Arnd; Blenau, Wolfgang

    2013-01-01

    Serotonin plays a pivotal role in regulating and modulating physiological and behavioral processes in both vertebrates and invertebrates. In the honeybee (Apis mellifera), serotonin has been implicated in division of labor, visual processing, and learning processes. Here, we present the cloning, heterologous expression, and detailed functional and pharmacological characterization of two honeybee 5-HT2 receptors. Honeybee 5-HT2 receptor cDNAs were amplified from brain cDNA. Recombinant cell lines were established constitutively expressing receptor variants. Pharmacological properties of the receptors were investigated by Ca(2+) imaging experiments. Quantitative PCR was applied to explore the expression patterns of receptor mRNAs. The honeybee 5-HT2 receptor class consists of two subtypes, Am5-HT2α and Am5-HT2β. Each receptor gene also gives rise to alternatively spliced mRNAs that possibly code for truncated receptors. Only activation of the full-length receptors with serotonin caused an increase in the intracellular Ca(2+) concentration. The effect was mimicked by the agonists 5-methoxytryptamine and 8-OH-DPAT at low micromolar concentrations. Receptor activities were blocked by established 5-HT receptor antagonists such as clozapine, methiothepin, or mianserin. High transcript numbers were detected in exocrine glands suggesting that 5-HT2 receptors participate in secretory processes in the honeybee. This study marks the first molecular and pharmacological characterization of two 5-HT2 receptor subtypes in the same insect species. The results presented should facilitate further attempts to unravel central and peripheral effects of serotonin mediated by these receptors.

  15. 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)

  16. Heat treatment effects on impact toughness of 9Cr-1MoVNb and 12Cr-1MoVW steels irradiated to 100 dpa

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-08-01

    Plates of 9Cr-1MoVNb and 12Cr-1MoVW steels were given four different heat treatments: two normalizing treatments were used and for each normalizing treatment two tempers were used. Miniature Charpy specimens from each heat treatment were irradiated to {approx}19.5 dpa at 365{degrees}C and to {approx}100 dpa at 420{degrees}C in the Fast Flux Test Facility (FFTF). In previous work, the same materials were irradiated to 4-5 dpa at 365{degrees}C and 35-36 dpa at 420{degrees}C in FFTF. The tests indicated that prior austenite grain size, which was varied by the different normalizing treatments, had a significant effect on impact behavior of the 9Cr-1MoVNb but not on the 12Cr-1MoVW. Tempering treatment had relatively little effect on the shift in DBTT for both steels. Conclusions are presented on how heat treatment can be used to optimize impact properties.

  17. Heat treatment effects on impact toughness of 9Cr-1MoVNb and 12Cr-1MoVW steels irradiated to 100 dpa

    International Nuclear Information System (INIS)

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

    1997-01-01

    Plates of 9Cr-1MoVNb and 12Cr-1MoVW steels were given four different heat treatments: two normalizing treatments were used and for each normalizing treatment two tempers were used. Miniature Charpy specimens from each heat treatment were irradiated to ∼19.5 dpa at 365 degrees C and to ∼100 dpa at 420 degrees C in the Fast Flux Test Facility (FFTF). In previous work, the same materials were irradiated to 4-5 dpa at 365 degrees C and 35-36 dpa at 420 degrees C in FFTF. The tests indicated that prior austenite grain size, which was varied by the different normalizing treatments, had a significant effect on impact behavior of the 9Cr-1MoVNb but not on the 12Cr-1MoVW. Tempering treatment had relatively little effect on the shift in DBTT for both steels. Conclusions are presented on how heat treatment can be used to optimize impact properties

  18. Serotonin inputs to the dorsal BNST modulate anxiety in a 5-HT1A receptor dependent manner

    Science.gov (United States)

    Garcia-Garcia, Alvaro L.; Canetta, Sarah; Stujenske, Joseph M.; Burghardt, Nesha S.; Ansorge, Mark S.; Dranovsky, Alex; Leonardo, E. David

    2017-01-01

    Serotonin (5-HT) neurons project from the raphe nuclei throughout the brain where they act to maintain homeostasis. Here, we study 5-HT inputs into the bed nucleus of the stria terminalis (BNST), a major subdivision of the extended amygdala that has been proposed to regulate responses to anxiogenic environments in humans and rodents. While the dorsal part of the BNST (dBNST) receives dense 5-HT innervation, whether and how 5-HT in the dBNST normally modulates anxiety remains unclear. Using optogenetics, we demonstrate that activation of 5-HT terminals in the dBNST reduces anxiety in a highly anxiogenic environment. Further analysis revealed that optogenetic inhibition of 5-HT inputs into the dBNST increases anxiety in a less anxiogenic environment. We found that 5-HT predominantly hyperpolarizes dBNST neurons, reducing their activity in a manner that can be blocked by a 5-HT1A antagonist. Finally, we demonstrate that activation of 5-HT1A receptors in the dBNST is necessary for the anxiolytic effect observed following optogenetic stimulation of 5-HT inputs into the dBNST. These data reveal that 5-HT release in the dBNST modulates anxiety-like behavior via 5-HT1A receptors under naturalistic conditions. PMID:28761080

  19. Antidepressant activity: contribution of brain microdialysis in knock-out mice to the understanding of BDNF/5-HT transporter/5-HT autoreceptor interactions

    Directory of Open Access Journals (Sweden)

    Alain M Gardier

    2013-08-01

    Full Text Available Why antidepressants vary in terms of efficacy is currently unclear. Despite the leadership of Selective serotonin reuptake inhibitors (SSRIs in the treatment of depression, the precise neurobiological mechanisms involved in their therapeutic action are poorly understood. A better knowledge of molecular interactions between monoaminergic system, pre- and post-synaptic partners, brain neuronal circuits and regions involved may help to overcome limitations of current treatments and to identify new therapeutic targets. Intracerebral in vivo microdialysis (ICM already provided important information about the brain mechanism of action of antidepressants first in anesthetized rats in the early 90s, and since then in conscious wild-type or knockout mice. The principle of ICM is based on the balance between release of neurotransmitters (e.g., monoamines, and re-uptake by selective transporters (e.g., SERT for serotonin 5-HT. Complementary to electrophysiology, this technique reflects presynaptic monoamines release and intrasynaptic events corresponding to ≈ 80% of whole brain tissue content. The inhibitory role of serotonergic autoreceptors infers that they limit somatodendritic and nerve terminal 5-HT release. It has been proposed that activation of 5-HT1A and 5-HT1B receptor sub-types limit the antidepressant-like activity of Selective Serotonin Reuptake Inhibitors (SSRI. This hypothesis is based partially on results obtained in ICM experiments performed in naïve, non-stressed Rodents. The present review will first remind the principle and methodology of ICM performed in mice. The crucial need of developing animal models that display anxiety and depression-like behaviors, neurochemical and brain morphological phenotypes reminiscent of these mood disorders in Human, will be underlined. Recently developed genetic mouse models have been generated to independently manipulate 5-HT1A auto and hetero-receptors and ICM helped to clarify the role of the

  20. Glucose-dependent trafficking of 5-HT3 receptors in rat gastrointestinal vagal afferent neurons

    Science.gov (United States)

    Babic, Tanja; Troy, Amanda E; Fortna, Samuel R; Browning, Kirsteen N

    2012-01-01

    Background Intestinal glucose induces gastric relaxation via vagally mediated sensory-motor reflexes. Glucose can alter the activity of gastrointestinal (GI) vagal afferent (sensory) neurons directly, via closure of ATP-sensitive potassium channels, as well as indirectly, via the release of 5-hydroxytryptamine (5-HT) from mucosal enteroendocrine cells. We hypothesized that glucose may also be able to modulate the ability of GI vagal afferent neurons to respond to the released 5-HT, via regulation of neuronal 5-HT3 receptors. Methods Whole cell patch clamp recordings were made from acutely dissociated GI-projecting vagal afferent neurons exposed to equiosmolar Krebs’ solution containing different concentrations of D-glucose (1.25–20mM) and the response to picospritz application of 5-HT assessed. The distribution of 5-HT3 receptors in neurons exposed to different glucose concentrations was also assessed immunohistochemically. Key Results Increasing or decreasing extracellular D-glucose concentration increased or decreased, respectively, the 5-HT-induced inward current as well as the proportion of 5-HT3 receptors associated with the neuronal membrane. These responses were blocked by the Golgi-disrupting agent Brefeldin-A (5µM) suggesting involvement of a protein trafficking pathway. Furthermore, L-glucose did not mimic the response of D-glucose implying that metabolic events downstream of neuronal glucose uptake are required in order to observe the modulation of 5-HT3 receptor mediated responses. Conclusions & Inferences These results suggest that, in addition to inducing the release of 5-HT from enterochromaffin cells, glucose may also increase the ability of GI vagal sensory neurons to respond to the released 5-HT, providing a means by which the vagal afferent signal can be amplified or prolonged. PMID:22845622

  1. Asiakaslähtöisen hoidon toteutuminen nuorisopsykiatriassa

    OpenAIRE

    Ruotsalo, Heli

    2015-01-01

    Tämän kehittämistyön tarkoituksena oli kartoittaa eräässä nuorisopsykiatrisessa yksikössä asiakaslähtöisyyden toteutumista valmiin HUS-asiakastyytyväisyyskyselyn avulla ja kuvata fokusryhmähaastattelun avulla nuorisopsykiatrisen hoitohenkilökunnan näkemyksiä, toiveita ja tarpeita asiakaslähtöisyyden toteutumiselle. Kehittämistyön tavoitteena oli tuottaa tietoa tietojohtamisen avuksi psykiatrisen hoidon muutostilanteessa kohti avohoidon lisäämistä ja kehittämistä. Tavoitteena oli myös aktivoid...

  2. Neuroticism and serotonin 5-HT1A receptors in healthy subjects

    DEFF Research Database (Denmark)

    Hirvonen, Jussi; Tuominen, Lauri; Någren, Kjell

    2015-01-01

    subjects is unclear. We measured brain serotonin 5-HT1A receptor in 34 healthy subjects in vivo using positron emission tomography (PET) and [carbonyl-(11)C]WAY-100635. Binding potential (BPP) was determined using the golden standard of kinetic compartmental modeling using arterial blood samples...... and radiometabolite determination. Personality traits were assessed using the Karolinska Scales of Personality. We found a strong negative association between serotonin 5-HT1A receptor BPP and neuroticism. That is, individuals with high neuroticism tended to have lower 5-HT1A receptor binding than individuals...... with low neuroticism. This finding was confirmed with an independent voxel-based whole-brain analysis. Other personality traits did not correlate with 5-HT1A receptor BPP. Previous observations have reported lower serotonin 5-HT1A receptor density in major depression. This neurobiological finding may...

  3. Pharmacology of the hypothermic response to 5-HT1A receptor activation in humans.

    Science.gov (United States)

    Lesch, K P; Poten, B; Söhnle, K; Schulte, H M

    1990-01-01

    The selective 5-HT1A receptor ligand ipsapirone (IPS) caused dose-related hypothermia in humans. The response was attenuated by the nonselective 5-HT1/2 receptor antagonist metergoline and was completely antagonized by the nonselective beta-adrenoceptor antagonist pindolol, which interacts stereoselectively with the 5-HT1A receptor. The selective beta 1-adrenergic antagonist betaxolol had no effect. The findings indicate that IPS-induced hypothermia specifically involves activation of (presynaptic) 5-HT1A receptors. Therefore, the hypothermic response to IPS may provide a convenient in vivo paradigma to assess the function of the presynaptic 5-HT receptor in affective disorders and its involvement in the effects of psychotropic drugs.

  4. Peripheral and spinal 5-HT receptors participate in the pronociceptive and antinociceptive effects of fluoxetine in rats.

    Science.gov (United States)

    Cervantes-Durán, C; Rocha-González, H I; Granados-Soto, V

    2013-11-12

    The role of 5-HT receptors in fluoxetine-induced nociception and antinociception in rats was assessed. Formalin produced a typical pattern of flinching and licking/lifting behaviors. Local peripheral ipsilateral, but not contralateral, pre-treatment with fluoxetine (0.3-3 nmol/paw) increased in a dose-dependent fashion 0.5% formalin-induced nociception. In contrast, intrathecal pretreatment with fluoxetine (0.3-3 nmol/rat) prevented nociception induced by formalin. The peripheral pronociceptive effect of fluoxetine was prevented by the 5-HT2A (ketanserin, 3-10 pmol/paw), 5-HT2B (3-(2-[4-(4-fluorobenzoyl)-1-piperidinyl]ethyl)-2,4(1H,3H)-quinazolinedione(+) tartrate, RS-127445, 3-10 pmol/paw), 5-HT2C (8-[5-(2,4-dimethoxy-5-(4-trifluoromethylphenylsulphonamido) phenyl-5-oxopentyl]1,3,8-triazaspiro[4.5] decane-2,4-dione hydrochloride, RS-102221, 3-10 pmol/paw), 5-HT3 (ondansetron, 3-10 nmol/paw), 5-HT4 ([1-[2-methylsulphonylamino ethyl]-4-piperidinyl]methyl 1-methyl-1H-indole-3-carboxylate, GR-113808, 3-100 fmol/paw), 5-HT6 (4-iodo-N-[4-methoxy-3-(4-methyl-1-piperazinyl)phenyl]benzene-sulfonamide hydrochloride, SB-258585, 3-10 pmol/paw) and 5-HT7 ((R)-3-(2-(2-(4-methylpiperidin-1-yl) ethyl) pyrrolidine-1-sulfonyl) phenol hydrochloride, SB-269970, 0.3-1 nmol/paw), but not by the 5-HT1A (N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-2-pyridinylcyclohexanecarboxamide maleate, WAY-100635, 0.3-1 nmol/paw), 5-HT1B/1D (N-[4-methoxy-3-(4-methyl-1-piperazinyl)phenyl]-2'-methyl-4'-(5-methyl-1,2,4-oxadiazol-3-yl)-1,1'-biphenyl-4-carboxamide hydrochloride hydrate, GR-127935, 0.3-1 nmol/paw), 5-HT1B (1'-methyl-5-[[2'-methyl-4'-(5-methyl-1,2,4-oxadiazol-3-yl)biphenyl-4-yl]carbonyl]-2,3,6,7-tetrahydrospiro[furo[2,3-f]indole-3,4'-piperidine hydrochloride, SB-224289, 0.3-1 nmol/paw), 5-HT1D (4-(3-chlorophenyl)-α-(diphenylmethyl)-1-piperazineethanol hydrochloride, BRL-15572, 0.3-1nmol/paw) nor 5-HT5A ((N-[2-(dimethylamino)ethyl]-N-[[4'-[[(2-phenylethyl)amino]methyl][1,1'-biphenyl]-4

  5. Radioiodinated SB 207710 as a radioligand in vivo: imaging of brain 5-HT{sub 4} receptors with SPET

    Energy Technology Data Exchange (ETDEWEB)

    Pike, Victor W. [MRC Cyclotron Unit, Imperial College School of Medicine, Hammersmith Hospital, Ducane Road, W12 0NN, London (United Kingdom); PET Radiopharmaceutical Sciences Section, Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346A, 10 Center Drive, MD 20892-1003, Bethesda (United States); Halldin, Christer; Nobuhara, Kenji; Swahn, Carl-Gunnar; Karlsson, Per; Olsson, Hans; Larsson, Stig; Schnell, Per-Olof; Farde, Lars [Department of Clinical Neuroscience, Psychiatry Section, Karolinska Institutet, Karolinska Hospital, 17176, Stockholm (Sweden); Hiltunen, Julka [MAP Medical Technologies, Oy, Tikkakoski (Finland); Mulligan, Rachel S. [MRC Cyclotron Unit, Imperial College School of Medicine, Hammersmith Hospital, Ducane Road, W12 0NN, London (United Kingdom); Institute of Psychiatry, SE 8AF, De Crespigny Park, Denmark Hill, London (United Kingdom); Centre for PET, Austin and Repatriation Medical Centre, Studley Road, Melbourne VIC 3084 (Australia); Hume, Susan P.; Hirani, Ella [MRC Cyclotron Unit, Imperial College School of Medicine, Hammersmith Hospital, Ducane Road, W12 0NN, London (United Kingdom); Imaging Research Solutions Ltd., Cyclotron Building, Hammersmith Hospital, Ducane Road, W12 0NN, London (United Kingdom); Whalley, Jaqueline [MRC Cyclotron Unit, Imperial College School of Medicine, Hammersmith Hospital, Ducane Road, W12 0NN, London (United Kingdom); Pilowsky, Lyn S. [Institute of Psychiatry, SE 8AF, De Crespigny Park, Denmark Hill, London (United Kingdom); Institute of Nuclear Medicine, Royal Free and University College, Medical School, Mortimer Street, W1N 8AA, London (United Kingdom); Ell, Peter J. [Institute of Nuclear Medicine, Royal Free and University College, Medical School, Mortimer Street, W1N 8AA, London (United Kingdom)

    2003-11-01

    Single-photon emission tomography (SPET) and positron emission tomography (PET), when coupled to suitable radioligands, are uniquely powerful for investigating the status of neurotransmitter receptors in vivo. The serotonin subtype-4 (5-HT{sub 4}) receptor has discrete and very similar distributions in rodent and primate brain. This receptor population may play a role in normal cognition and memory and is perhaps perturbed in some neuropsychiatric disorders. SB 207710 [(1-butyl-4-piperidinylmethyl)-8-amino-7-iodo-1,4-benzodioxan-5-carboxylate] is a selective high-affinity antagonist at 5-HT{sub 4} receptors. We explored radioiodinated SB 207710 as a possible radioligand for imaging 5-HT{sub 4} receptors in vivo. Rats were injected intravenously with iodine-125 labelled SB 207710, euthanised at known times and dissected to establish radioactivity content in brain tissues. Radioactivity entered brain but cleared rapidly and to a high extent from blood and plasma. Between 45 and 75 min after injection, the ratios of radioactivity concentration in each of 12 selected brain tissues to that in receptor-poor cerebellum correlated with previous measures of 5-HT{sub 4} receptor density distribution in vitro. The highest ratio was about 3.4 in striatum. SB 207710 was labelled with iodine-123 by an iododestannylation procedure. A cynomolgus monkey was injected intravenously with [{sup 123}I]SB 207710 and examined by SPET. Maximal whole brain uptake of radioactivity was 2.3% of the injected dose at 18 min after radioligand injection. Brain images acquired between 9 and 90 min showed high radioactivity uptake in 5-HT{sub 4} receptor-rich regions, such as striatum, and low uptake in receptor-poor cerebellum. At 169 min the ratio of radioactivity concentration in striatum to that in cerebellum was 4.0. In a second SPET experiment, the cynomolgus monkey was pretreated with a selective 5-HT{sub 4} receptor antagonist, SB 204070, at 20 min before [{sup 123}I]SB 207710 injection

  6. Microstructure and annealing behavior of a modified 9Cr-1Mo steel after dynamic plastic deformation to different strains

    DEFF Research Database (Denmark)

    Zhang, Zhenbo; Mishin, Oleg; Tao, N.R.

    2015-01-01

    The microstructure, hardness and tensile properties of a modified 9Cr-1Mo steel processed by dynamic plastic deformation (DPD) to different strains (0.5 and 2.3) have been investigated in the as-deformed and annealed conditions. It is found that significant structural refinement and a high level...... in a loss of strength with only a small gain in ductility, coarsening combined with pronounced partial recrystallization enables a combination of appreciably increased ductility and comparatively high strength....

  7. Performance and analysis of the TVTS diagnostic system on HT-7 tokamak

    International Nuclear Information System (INIS)

    Han Xiaofeng; Shao Chunqiang; Xi Xiaoqi; Zhao Junyu; Qing Zang; Yang Jianhua; Dai Xingxing

    2013-01-01

    A high spatial resolution imaging Thomson scattering diagnostic system was developed in ASIPP. After about one month trial running on the superconducting HT-7 tokamak, the system was proved to be capable of measuring plasma electron temperature. The system setup and data calibration are described in this paper and then the instrument function is studied in detail, as well as the measurement capability, an electron temperature of 50 eV to 2 keV and density beyond 1x10"1"9 m"-"3. Finally, the data processing method and experimental results are presented. (author)

  8. Behavior of LASL-made graphite, ZrC, and ZrC-containing coated particles in irradiation tests HT-28 and HT-29

    International Nuclear Information System (INIS)

    Reiswig, R.D.; Wagner, P.; Hollabaugh, C.M.; White, R.W.; O'Rourke, J.A.; Davidson, K.V.; Schell, D.H.

    1976-01-01

    Three types of materials, extruded graphite, hot-pressed ZrC, and particles with ZrC coatings, were irradiated in ORNL High Fluence Isotope Reactor Irradiation tests HT-28 and HT-29. The ZrC seemed unaffected. The graphite changed in dimensions, x-ray diffraction parameters, and thermal conductivity. The four types of coated particles tested all resisted the irradiation well, except one set of particles with double-graded C-ZrC-C coats. Overall, the results were considered encouraging for use of ZrC and extruded graphite fuel matrices. 16 fig

  9. Inverse agonist and neutral antagonist actions of synthetic compounds at an insect 5-HT1 receptor.

    Science.gov (United States)

    Troppmann, B; Balfanz, S; Baumann, A; Blenau, W

    2010-04-01

    5-Hydroxytryptamine (5-HT) has been shown to control and modulate many physiological and behavioural functions in insects. In this study, we report the cloning and pharmacological properties of a 5-HT(1) receptor of an insect model for neurobiology, physiology and pharmacology. A cDNA encoding for the Periplaneta americana 5-HT(1) receptor was amplified from brain cDNA. The receptor was stably expressed in HEK 293 cells, and the functional and pharmacological properties were determined in cAMP assays. Receptor distribution was investigated by RT-PCR and by immunocytochemistry using an affinity-purified polyclonal antiserum. The P. americana 5-HT(1) receptor (Pea5-HT(1)) shares pronounced sequence and functional similarity with mammalian 5-HT(1) receptors. Activation with 5-HT reduced adenylyl cyclase activity in a dose-dependent manner. Pea5-HT(1) was expressed as a constitutively active receptor with methiothepin acting as a neutral antagonist, and WAY 100635 as an inverse agonist. Receptor mRNA was present in various tissues including brain, salivary glands and midgut. Receptor-specific antibodies showed that the native protein was expressed in a glycosylated form in membrane samples of brain and salivary glands. This study marks the first pharmacological identification of an inverse agonist and a neutral antagonist at an insect 5-HT(1) receptor. The results presented here should facilitate further analyses of 5-HT(1) receptors in mediating central and peripheral effects of 5-HT in insects.

  10. Degree of phase separation effects on the charge transfer properties of P3HT:Graphene nanocomposites

    International Nuclear Information System (INIS)

    Bkakri, R.; Kusmartseva, O.E.; Kusmartsev, F.V.; Song, M.; Bouazizi, A.

    2015-01-01

    Graphene layers were introduced into the matrix of regioregular poly (3-hexylthiophene-2, 5-diyl) (RR-P3HT) via solution processing in the perspective of the development of organic nanocomposites with high P3HT/Graphene interfaces areas for efficient charge transfer process. P3HT and graphene act as electrons donor and electrons acceptor materials, respectively. Spatial Fourier Transforms (FFT) and power spectral density (PSD) analysis of the AFM images show that the phase separation decreases with increasing the graphene weight ratio in the P3HT matrix. The Raman spectra of the P3HT:Graphene nanocomposites shows that the G-band of graphene shifts to low frequencies with progressive addition of graphene which proves that there is an interaction between the nanowires of P3HT and the graphene layers. We suggest that the shift of the G-band is due to electrons transfer from P3HT to graphene. The quenching of the photoluminescence (PL) intensity of P3HT with addition of graphene proves also that an electrons transfer process occurred at the P3HT/Graphene interfaces. - Highlights: • Graphene layers are elaborated from expandable graphite oxide. • The effects of the graphene doping level on the charge transfer process were studied. • The phase separation process decreases with increasing the graphene content in the P3HT matrix. • Quenching of the PL intensity is due to electrons transfer from P3HT to graphene

  11. Thick-section weldments in 21-6-9 and 316LN stainless steel for fusion energy applications

    International Nuclear Information System (INIS)

    Alexander, D.J.; Goodwin, G.M.

    1991-01-01

    The mechanical properties of several weldments in 21-6-9 and 316LN stainless steel metals have been measured at 77 K and room temperature. Filler metals for the 211-6-9 included Nitronic 35W and 40W, 21-6-9, Inconel 82, 182, 625, and 625 PLUS. For the 316LN base metal, 316L, 316L-T3, 316L-4K-O, and Inconel 82 filler metals were used. At room temperature all of the filler metals had yield strengths that exceeded those of the base metals. At 77K only the Nitronics and the 21-6-9 filler metals exceeded those of the base metals, and the Inconel filler metals were significantly weaker. The impact properties of the weld metals were very good at room temperature, with the exception of Inconel 625. At 77 K the impact toughness was greatly reduced for all of the filler metals, with the dramatic exception of Inconel 82. The 316L-4K-O filler metal showed higher impact energies than the other ferrite-containing filler metals, although the levels were still much lower than for the Inconel filler metals. The Inconel 82 filler had excellent fracture toughness at both temperatures

  12. Water corrosion resistance of ODS ferritic-martensitic steel tubes

    International Nuclear Information System (INIS)

    Narita, Takeshi; Ukai, Shigeharu; Kaito, Takeji; Ohtsuka, Satoshi; Matsuda, Yasuji

    2008-01-01

    Oxide dispersion strengthened (ODS) ferritic-martensitic steels have superior radiation resistance; it is possible to achieve a service temperature of up to around 973 K because of their superior creep strength. These advantages of ODS steels facilities their application to long-life cladding tubes in advanced fast reactor fuel elements. In addition to neutron radiation resistance, sufficient general corrosion resistance to maintain the strength of the cladding, and the stress corrosion cracking (SCC) resistance for spent-fuel-pool cooling systems and high-temperature oxidation for the fuel-clad chemical interaction (FCCI) of ODS ferritic steel are required. Although the addition of Cr to ODS is effective in preventing water corrosion and high-temperature oxidation, an excessively high amount of Cr leads to embrittlement due to the formation of a Cr-rich α' precipitate. The Cr content in 9Cr-ODS martensite and 12Cr-ODS ferrite, the ODS steels developed by the Japan Atomic Energy Agency (JAEA), is controlled. In a previous paper, it has been demonstrated that the resistances of 9Cr- and 12Cr-ODS ferritic-martensitic steels for high-temperature oxidation are superior to those of conventional 12Cr ferritic steel. However, the water corrosion data of ODS ferritic-martensitic steels are very limited. In this study, a water corrosion test was conducted on ODS steels in consideration of the spent-fuel-pool cooling condition, and the results were compared with those of conventional austenitic stainless steel and ferritic-martensitic stainless steel. (author)

  13. Targeting to 5-HT1F Receptor Subtype for Migraine Treatment

    DEFF Research Database (Denmark)

    Mitsikostas, Dimos D; Tfelt-Hansen, Peer

    2012-01-01

    attacks with efficacy in the same range as oral sumatriptan 100mg, the gold standard for triptans. The LY334370 project withdrew because of toxicity in animals, while lasmiditan is still testing. In this review we present all the available preclinical and clinical data on the 5-HT1F agonists...... inhibited markers associated with electrical stimulation of the TG. Thus 5-HT1F receptor represents an ideal target for anti-migraine drugs. So far two selective 5-HT1F agonists have been tested in human trials for migraine: LY334370 and lasmiditan. Both molecules were efficient in attenuating migraine...

  14. Serotonin inputs to the dorsal BNST modulate anxiety in a 5-HT1A receptor-dependent manner.

    Science.gov (United States)

    Garcia-Garcia, A L; Canetta, S; Stujenske, J M; Burghardt, N S; Ansorge, M S; Dranovsky, A; Leonardo, E D

    2017-08-01

    Serotonin (5-HT) neurons project from the raphe nuclei throughout the brain where they act to maintain homeostasis. Here, we study 5-HT inputs into the bed nucleus of the stria terminalis (BNST), a major subdivision of the extended amygdala that has been proposed to regulate responses to anxiogenic environments in humans and rodents. While the dorsal part of the BNST (dBNST) receives dense 5-HT innervation, whether and how 5-HT in the dBNST normally modulates anxiety remains unclear. Using optogenetics, we demonstrate that activation of 5-HT terminals in the dBNST reduces anxiety in a highly anxiogenic environment. Further analysis revealed that optogenetic inhibition of 5-HT inputs into the dBNST increases anxiety in a less anxiogenic environment. We found that 5-HT predominantly hyperpolarizes dBNST neurons, reducing their activity in a manner that can be blocked by a 5-HT 1A antagonist. Finally, we demonstrate that activation of 5-HT 1A receptors in the dBNST is necessary for the anxiolytic effect observed following optogenetic stimulation of 5-HT inputs into the dBNST. These data reveal that 5-HT release in the dBNST modulates anxiety-like behavior via 5-HT 1A receptors under naturalistic conditions.Molecular Psychiatry advance online publication, 1 August 2017; doi:10.1038/mp.2017.165.

  15. Tuning of the Morphology and Optoelectronic Properties of ZnO/P3HT/P3HT- b-PEO Hybrid Films via Spray Deposition Method.

    Science.gov (United States)

    Wang, Kun; Bießmann, Lorenz; Schwartzkopf, Matthias; Roth, Stephan V; Müller-Buschbaum, Peter

    2018-06-20

    The self-assembly of amphiphilic diblock copolymers yields the possibility of using them as a template for tailoring the film morphologies of sol-gel chemistry-derived inorganic electron transport materials, such as mesoporous ZnO and TiO 2 . However, additional steps including etching and backfilling are required for the common bulk heterojunction fabrication process when using insulating diblock copolymers. Here, we use the conducting diblock copolymer poly(3-hexylthiophene)- block-poly(ethylene oxide) (P3HT- b-PEO) in which P3HT acts as charge carrier transport material and light absorber, whereas PEO serves as a template for ZnO synthesis. The initial solution is subsequently spray-coated to obtain the hybrid film. Scanning electron microscopy and grazing-incidence small-angle X-ray scattering measurements reveal a significant change in the morphology of the hybrid films during deposition. Optoelectronic properties illustrate the improved charge separation and charge transfer process. Both the amount of the diblock copolymer and the annealing temperature play an important role in tuning the morphology and the optoelectronic properties. Hybrid films being sprayed from a solution with the ratio of ω ZnO , ω P3HT , and ω P3HT- b-PEO of 2:1:1 and subsequent annealing at 80 °C show the most promising morphology combined with an optimal photoluminescence quenching. Thus, the presented simple, reagent- and energy-saving fabrication method provides a promising approach for a large-scale preparation of bulk heterojunction P3HT/ZnO films on flexible substrates.

  16. Stress-induced alterations in 5-HT1A receptor transcriptional modulators NUDR and Freud-1.

    Science.gov (United States)

    Szewczyk, Bernadeta; Kotarska, Katarzyna; Daigle, Mireille; Misztak, Paulina; Sowa-Kucma, Magdalena; Rafalo, Anna; Curzytek, Katarzyna; Kubera, Marta; Basta-Kaim, Agnieszka; Nowak, Gabriel; Albert, Paul R

    2014-11-01

    The effect of stress on the mRNA and protein level of the 5-HT1A receptor and two of its key transcriptional modulators, NUDR and Freud-1, was examined in the prefrontal cortex (PFC) and hippocampus (Hp) using rodent models: olfactory bulbectomy (OB) and prenatal stress (PS) in male and female rats; chronic mild stress in male rats (CMS) and pregnancy stress. In PFC, CMS induced the most widespread changes, with significant reduction in both mRNA and protein levels of NUDR, 5-HT1A receptor and in Freud-1 mRNA; while in Hp 5-HT1A receptor and Freud-1 protein levels were also decreased. In male, but not female OB rats PFC Freud-1 and 5-HT1A receptor protein levels were reduced, while in Hp 5-HT1A receptor, Freud-1 and NUDR mRNA's but not protein were reduced. In PS rats PFC 5-HT1A receptor protein was reduced more in females than males; while in Hp Freud-1 protein was increased in females. In pregnancy stress, PFC NUDR, Freud-1 and 5-HT1A protein receptor levels were reduced, and in HP 5-HT1A receptor protein levels were also reduced; in HP only NUDR and Freud-1 mRNA levels were reduced. Overall, CMS and stress during pregnancy produced the most salient changes in 5-HT1A receptor and transcription factor expression, suggesting a primary role for altered transcription factor expression in chronic regulation of 5-HT1A receptor expression. By contrast, OB (in males) and PS (in females) produced gender-specific reductions in PFC 5-HT1A receptor protein levels, suggesting a role for post-transcriptional regulation. These and previous data suggest that chronic stress might be a key regulator of NUDR/Freud-1 gene expression.

  17. A Simple and Specific Noncompetitive ELISA Method for HT-2 Toxin Detection

    Directory of Open Access Journals (Sweden)

    Henri O. Arola

    2017-04-01

    Full Text Available We developed an HT-2 toxin-specific simple ELISA format with a positive read-out. The assay is based on an anti-immune complex (IC scFv antibody fragment, which is genetically fused with alkaline phosphatase (AP. The anti-IC antibody specifically recognizes the IC between a primary anti-HT-2 toxin Fab fragment and an HT-2 toxin molecule. In the IC ELISA format, the sample is added together with the scFv-AP antibody to the ELISA plate coated with the primary antibody. After 15 min of incubation and a washing step, the ELISA response is read. A competitive ELISA including only the primary antibody recognizes both HT-2 and T-2 toxins. The anti-IC antibody makes the assay specific for HT-2 toxin, and the IC ELISA is over 10 times more sensitive compared to the competitive assay. Three different naturally contaminated matrices: wheat, barley and oats, were used to evaluate the assay performance with real samples. The corresponding limits of detection were 0.3 ng/mL (13 µg/kg, 0.1 ng/mL (4 µg/kg and 0.3 ng/mL (16 µg/kg, respectively. The IC ELISA can be used for screening HT-2 toxin specifically and in relevant concentration ranges from all three tested grain matrices.

  18. 5HT-1A receptors and anxiety-like behaviours: studies in rats with constitutionally upregulated/downregulated serotonin transporter.

    Science.gov (United States)

    Bordukalo-Niksic, Tatjana; Mokrovic, Gordana; Stefulj, Jasminka; Zivin, Marko; Jernej, Branimir; Cicin-Sain, Lipa

    2010-12-01

    Altered activity of brain serotonergic (5HT) system has been implicated in a wide range of behaviours and behavioural disorders, including anxiety. Functioning of 5HT-1A receptor has been suggested as a modulator of emotional balance in both, normal and pathological forms of anxiety. Here, we studied serotonergic modulation of anxiety-like behaviour using a genetic rat model with constitutional differences in 5HT homeostasis, named Wistar-Zagreb 5HT (WZ-5HT) rats. The model, consisting of high-5HT and low-5HT sublines, was developed by selective breeding of animals for extreme activities of peripheral (platelet) 5HT transporter, but selection process had affected also central 5HT homeostasis, as evidenced from neurochemical and behavioural studies. Anxiety-like behaviour in WZ-5HT rats was evaluated by two commonly used paradigms: open field and elevated-plus maze. The involvement of 5HT-1A receptors in behavioural response was assessed by measuring mRNA expression in cell bodies (raphe nuclei) and projection regions (frontal cortex, hippocampus) by use of RT-PCR and in situ hybridization, and by measuring functionality of cortical 5HT-1A receptors by use of [(3)H]8-OH-DPAT radioligand binding. Animals from the high-5HT subline exhibit increased anxiety-like behaviour and decreased exploratory activity when exposed to novel environment. No measurable differences in constitutional (baseline) functionality or expression of 5HT-1A receptors between sublines were found. The results support contribution of increased serotonergic functioning to the anxiety-like behaviour. They also validate the high-5HT subline of WZ-5HT rats as a potential model to study mechanisms of anxiety, especially of its nonpathological form, while the low-5HT subline may be useful to model sensation seeking phenotype. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  19. Inelastic constitutive models for the simulation of a cyclic softening behavior of modified 9Cr-lMo steel at elevated temperatures

    International Nuclear Information System (INIS)

    Koo, Gyeong Hoi; Lee, Jae Han

    2007-01-01

    In this paper, the inelastic constitutive models for the simulations of the cyclic softening behavior of the modified 9Cr-1Mo steel, which has a significant cyclic softening characteristic especially in elevated temperature regions, are investigated in detail. To do this, the plastic modulus, which primarily governs the calculation scheme of the plasticity, is formulated for the inelastic constitutive models such as the Armstrong-Frederick model, Chaboche model, and Ohno-Wang model. By implementing the extracted plastic modulus and the consistency conditions into the computer program, the inelastic constitutive parameters are identified to present the best fit of the uniaxial cyclic test data by strain-controlled simulations. From the computer simulations by using the obtained constitutive parameters, it is found that the Armstrong-Frederick model is simple to use but it causes significant overestimated strain results when compared with the Chaboche and the Ohno-Wang models. And from the ratcheting simulation results, it is found that the cyclic softening behavior of the modified 9Cr-1Mo steel can invoke a ratcheting instability when the applied cyclic loads exceed a certain level of the ratchet loading condition

  20. Central 5-HT4 receptor binding as biomarker of serotonergic tonus in humans

    DEFF Research Database (Denmark)

    Haahr, M E; Fisher, P M; Jensen, Christian Gaden

    2014-01-01

    levels, is associated with a decline in brain 5-HT4R binding. A total of 35 healthy men were studied in a placebo-controlled, randomized, double-blind study. Participants were assigned to receive 3 weeks of oral dosing with placebo or fluoxetine, 40 mg per day. Brain 5-HT4R binding was quantified...... at baseline and at follow-up with [(11)C]SB207145 positron emission tomography (PET). Three weeks of intervention with fluoxetine was associated with a 5.2% reduction in brain 5-HT4R binding (P=0.017), whereas placebo intervention did not change 5-HT4R binding (P=0.52). Our findings are consistent...