WorldWideScience

Sample records for dpa

  1. DOE contractor vulnerability analysis: DPA or MAIT

    International Nuclear Information System (INIS)

    Six, D.E.; Nichols, D.H.

    1980-01-01

    Two vulnerability analysis techniques, Diversion Path Analysis (DPA) and Matrix Analysis of the Insider Threat (MAIT), were applied by EG and G Idaho, Inc. Safeguards and Security to the same item accountable SNM storage area at INEL. Technical and cost data for each methodology were collected and compared. A recommendation that MAIT be utilized for future vulnerability analyses of item accountable SNM storage and use areas operated by EG and G Idaho for DOE-ID resulted. Unclassified results of the two techniques and MAIT/DPA technical and cost comparisons will be presented which show that MAIT can be used for vulnerability analyses to comply with Department of Energy (DOE) requirements

  2. Differential dpa calculations with SPECTRA-PKA

    Science.gov (United States)

    Gilbert, M. R.; Sublet, J.-Ch.

    2018-06-01

    The processing code SPECTRA-PKA produces energy spectra of primary atomic recoil events (or primary knock-on atoms, PKAs) for any material composition exposed to an irradiation spectrum. Such evaluations are vital inputs for simulations aimed at understanding the evolution of damage in irradiated material, which is generated in cascade displacement events initiated by PKAs. These PKA spectra present the full complexity of the input (to SPECTRA-PKA) nuclear data-library evaluations of recoil events. However, the commonly used displacements per atom (dpa) measure, which is an integral measure over all possible recoil events of the displacement damage dose, is still widely used and has many useful applications - as both a comparative and correlative quantity. This paper describes the methodology employed that allows the SPECTRA-PKA code to evaluate dpa rates using the energy-dependent recoil (PKA) cross section data used for the PKA distributions. This avoids the need for integral displacement kerma cross sections and also provides new insight into the relative importance of different reaction channels (and associated different daughter residual and emitted particles) to the total integrated dpa damage dose. Results are presented for Fe, Ni, W, and SS316. Fusion dpa rates are compared to those in fission, highlighting the increased contribution to damage creation in the former from high-energy threshold reactions.

  3. Characterization of 18F-dipicolylamine (DPA) derivatives in cells infected with influenza virus

    International Nuclear Information System (INIS)

    Li, Junling; Gerlach, Rachael L.; Jonsson, Colleen B.; Gray, Brian D.; Pak, Koon Y.; Ng, Chin K.

    2015-01-01

    Objective: Bis(Zn-dipicolylamine (Zn-DPA)) coordination complexes represent a new class of synthetic small molecules that can target anionic phosphatidylserine (PS) in the apoptotic cells with high affinity and specificity. In this study, we labeled Zn-DPA and Cy7-Zn-DPA with different 18 F-prosthetic groups and characterized their uptake in A549 cells infected with influenza A virus from the 2009 pandemic (H1N1pdm). Methods: DPA was labeled with N-succinimidyl 4- 18 F-fluorobenzoate ( 18 F-SFB), 4-nitrophenyl 2- 18 F-fluoropropionate ( 18 F-NFP), 2- 18 F-Fluoroethyl toslyate ( 18 F-FET), and 18 F-aluminum (Al 18 F), respectively. Cy7-DPA was labeled with 18 F-SFB and 18 F-NFP only. The tracers were reconstituted with zinc nitrate before use. Apoptosis in A549 cells was induced by infection with the H1N1pdm virus for 48 h. Three μCi of each tracer was added to each well and incubated at 37 °C. The effect of different prosthetic groups, different MOI, and incubation time on percent cellular uptake was studied. Cell internalization and efflux was evaluated within 2 h of incubation. The competitive binding assay was performed with increasing concentration (10 −12 -10 −5 M) of Zn-DPA or Cy7-Zn-DPA prior to the addition of either 18 F-FB-Zn-DPA or 18 F-FB-Cy7-Zn-DPA into each well. IC 50 values for the two Zn-DPA analogues were estimated by GraphPad Prism 6.0. Results: Among all the four prosthetic groups, the 18 F-SFB method provided the highest conjugation yield for DPA and the highest uptake ratio between the infection cells and the control when both Zn-DPA and Cy7-Zn-DPA were present in the complex. The uptake ratio was similar for 18 F-FB-Zn-DPA and 18 F-FB-Cy7-Zn-DPA. Uptake of 18 F-FB-Zn-DPA and 18 F-FB-Cy7-Zn-DPA was proportional to the degree of apoptosis with a plateau at MOI 3. Uptake of 18 F-FB-Cy7-Zn-DPA also increased over incubation time and reached a plateau at 1 h, whereas uptake of 18 F-FB-Zn-DPA did not show any significant change over time

  4. Analysis and recommendations for DPA calculations in SiC

    International Nuclear Information System (INIS)

    Heinisch, H.L.

    1998-01-01

    Recent modeling results, coupled with the implications of available experimental results, provide sufficient information to achieve consensus on the values of threshold displacement energies to use in displacements per atom (DPA) calculations. The values recommended here, 20 eV for C and 35 eV for Si, will be presented for adoption by the international fusion materials community at the next IEA SiC/SiC workshop

  5. Correlating Fast Fluence to dpa in Atypical Locations

    Directory of Open Access Journals (Sweden)

    Drury Thomas H.

    2016-01-01

    Full Text Available Damage to a nuclear reactor's materials by high-energy neutrons causes changes in the ductility and fracture toughness of the materials. The reactor vessel and its associated piping's ability to withstand stress without brittle fracture are paramount to safety. Theoretically, the material damage is directly related to the displacements per atom (dpa via the residual defects from induced displacements. However in practice, the material damage is based on a correlation to the high-energy (E > 1.0 MeV neutron fluence. While the correlated approach is applicable when the material in question has experienced the same neutron spectrum as test specimens which were the basis of the correlation, this approach is not generically acceptable. Using Monte Carlo and discrete ordinates transport codes, the energy dependent neutron flux is determined throughout the reactor structures and the reactor vessel. Results from the models provide the dpa response in addition to the high-energy neutron flux. Ratios of dpa to fast fluence are calculated throughout the models. The comparisons show a constant ratio in the areas of historical concern and thus the validity of the correlated approach to these areas. In regions above and below the fuel however, the flux spectrum has changed significantly. The correlated relationship of material damage to fluence is not valid in these regions without adjustment. An adjustment mechanism is proposed.

  6. Correlating Fast Fluence to dpa in Atypical Locations

    Science.gov (United States)

    Drury, Thomas H.

    2016-02-01

    Damage to a nuclear reactor's materials by high-energy neutrons causes changes in the ductility and fracture toughness of the materials. The reactor vessel and its associated piping's ability to withstand stress without brittle fracture are paramount to safety. Theoretically, the material damage is directly related to the displacements per atom (dpa) via the residual defects from induced displacements. However in practice, the material damage is based on a correlation to the high-energy (E > 1.0 MeV) neutron fluence. While the correlated approach is applicable when the material in question has experienced the same neutron spectrum as test specimens which were the basis of the correlation, this approach is not generically acceptable. Using Monte Carlo and discrete ordinates transport codes, the energy dependent neutron flux is determined throughout the reactor structures and the reactor vessel. Results from the models provide the dpa response in addition to the high-energy neutron flux. Ratios of dpa to fast fluence are calculated throughout the models. The comparisons show a constant ratio in the areas of historical concern and thus the validity of the correlated approach to these areas. In regions above and below the fuel however, the flux spectrum has changed significantly. The correlated relationship of material damage to fluence is not valid in these regions without adjustment. An adjustment mechanism is proposed.

  7. Microstructural examination of commercial ferritic alloys at 299 DPA

    International Nuclear Information System (INIS)

    Gelles, D.S.

    1995-11-01

    Microstructures and density change measurements are reported for Martensitic commercial steels HT-9 and Modified 9Cr-lMo (T9) and oxide dispersion strengthened ferritic alloys MA956 and NU957 following irradiation in the FFTF/MOTA at 420 degrees C to 200 DPA. Swelling as determined by density change remains below 2% for all conditions. Microstructures are found to be stable except in recrystallized grains of MA957, which are fabrication artifacts, with only minor swelling in the Martensitic steels and α' precipitation in alloys with 12% or more chromium. These results further demonstrate the high swelling resistance and microstructural stability of the ferritic alloy class

  8. Design of power balance SRAM for DPA-resistance

    Science.gov (United States)

    Keji, Zhou; Pengjun, Wang; Liang, Wen

    2016-04-01

    A power balance static random-access memory (SRAM) for resistance to differential power analysis (DPA) is proposed. In the proposed design, the switch power consumption and short-circuit power consumption are balanced by discharging and pre-charging the key nodes of the output circuit and adding an additional short-circuit current path. Thus, the power consumption is constant in every read cycle. As a result, the DPA-resistant ability of the SRAM is improved. In 65 nm CMOS technology, the power balance SRAM is fully custom designed with a layout area of 5863.6 μm2. The post-simulation results show that the normalized energy deviation (NED) and normalized standard deviation (NSD) are 0.099% and 0.04%, respectively. Compared to existing power balance circuits, the power balance ability of the proposed SRAM has improved 53%. Project supported by the Zhejiang Provincial Natural Science Foundation of China (No. LQ14F040001), the National Natural Science Foundation of China (Nos. 61274132, 61234002), and the K. C. Wong Magna Fund in Ningbo University, China.

  9. Radiation response of alloy T91 at damage levels up to 1000 peak dpa

    Energy Technology Data Exchange (ETDEWEB)

    Gigax, J.G., E-mail: gigaxj@tamu.edu [Department of Nuclear Engineering, Texas A& M University, College Station, TX 77840 (United States); Chen, T.; Kim, Hyosim [Department of Nuclear Engineering, Texas A& M University, College Station, TX 77840 (United States); Wang, J. [Department of Nuclear Engineering, Texas A& M University, College Station, TX 77840 (United States); Pacific Northwest National Lab, Richland, WA 99354 (United States); Price, L.M. [Department of Nuclear Engineering, Texas A& M University, College Station, TX 77840 (United States); Aydogan, E. [Department of Nuclear Engineering, Texas A& M University, College Station, TX 77840 (United States); Los Alamos National Lab, Los Alamos, NM 87545 (United States); Maloy, S.A. [Los Alamos National Lab, Los Alamos, NM 87545 (United States); Schreiber, D.K.; Toloczko, M.B. [Pacific Northwest National Lab, Richland, WA 99354 (United States); Garner, F.A. [Department of Nuclear Engineering, Texas A& M University, College Station, TX 77840 (United States); Radiation Effects Consulting, Richland, WA 99354 (United States); Shao, Lin [Department of Nuclear Engineering, Texas A& M University, College Station, TX 77840 (United States)

    2016-12-15

    Ferritic/martensitic alloys are required for advanced reactor components to survive 500–600 neutron-induced dpa. Ion-induced void swelling of ferritic/martensitic alloy T91 in the quenched and tempered condition has been studied using a defocused, non-rastered 3.5 MeV Fe-ion beam at 475 °C to produce damage levels up to 1000 peak displacements per atom (dpa). The high peak damage level of 1000 dpa is required to reach 500–600 dpa level due to injected interstitial suppression of void nucleation in the peak dpa region, requiring data extraction closer to the surface at lower dpa levels. At a relatively low peak damage level of 250 dpa, voids began to develop, appearing first in the near-surface region. With increasing ion fluence, swelling was observed deeper in the specimen, but remained completely suppressed in the back half of the ion range, even at 1000 peak dpa. The local differences in dpa rate in the front half of the ion range induce an “internal temperature shift” that strongly influences the onset of swelling, with shorter transient regimes resulting from lower dpa rates, in agreement not only with observations in neutron irradiation studies but also in various ion irradiations. Swelling was accompanied by radiation-induced precipitation of Cu-rich and Si, Ni, Mn-rich phases were observed by atom probe tomography, indicating concurrent microchemical evolution was in progress. In comparison to other ferritic/martensitic alloys during ion irradiation, T91 exhibits good swelling resistance with a swelling incubation period of about 400 local dpa.

  10. Radiation response of alloy T91 at damage levels up to 1000 peak dpa

    Energy Technology Data Exchange (ETDEWEB)

    Gigax, J. G.; Chen, T.; Kim, Hyosim; Wang, J.; Price, L. M.; Aydogan, E.; Maloy, S. A.; Schreiber, D. K.; Toloczko, M. B.; Garner, F. A.; Shao, Lin

    2016-12-01

    Ferritic/martensitic alloys are required for advanced reactor components to survive 500e600 neutroninduced dpa. Ion-induced void swelling of ferritic/martensitic alloy T91 in the quenched and tempered condition has been studied using a defocused, non-rastered 3.5 MeV Fe-ion beam at 475 C to produce damage levels up to 1000 peak displacements per atom (dpa). The high peak damage level of 1000 dpa is required to reach 500e600 dpa level due to injected interstitial suppression of void nucleation in the peak dpa region, requiring data extraction closer to the surface at lower dpa levels. At a relatively low peak damage level of 250 dpa, voids began to develop, appearing first in the near-surface region. With increasing ion fluence, swelling was observed deeper in the specimen, but remained completely suppressed in the back half of the ion range, even at 1000 peak dpa. The local differences in dpa rate in the front half of the ion range induce an “internal temperature shift” that strongly influences the onset of swelling, with shorter transient regimes resulting from lower dpa rates, in agreement not only with observations in neutron irradiation studies but also in various ion irradiations. Swelling was accompanied by radiation-induced precipitation of Cu-rich and Si, Ni, Mn-rich phases were observed by atom probe tomography, indicating concurrent microchemical evolution was in progress. In comparison to other ferritic/martensitic alloys during ion irradiation, T91 exhibits good swelling resistance with a swelling incubation period of about 400 local dpa.

  11. A study to compute integrated dpa for neutron and ion irradiation environments using SRIM-2013

    Science.gov (United States)

    Saha, Uttiyoarnab; Devan, K.; Ganesan, S.

    2018-05-01

    Displacements per atom (dpa), estimated based on the standard Norgett-Robinson-Torrens (NRT) model, is used for assessing radiation damage effects in fast reactor materials. A computer code CRaD has been indigenously developed towards establishing the infrastructure to perform improved radiation damage studies in Indian fast reactors. We propose a method for computing multigroup neutron NRT dpa cross sections based on SRIM-2013 simulations. In this method, for each neutron group, the recoil or primary knock-on atom (PKA) spectrum and its average energy are first estimated with CRaD code from ENDF/B-VII.1. This average PKA energy forms the input for SRIM simulation, wherein the recoil atom is taken as the incoming ion on the target. The NRT-dpa cross section of iron computed with "Quick" Kinchin-Pease (K-P) option of SRIM-2013 is found to agree within 10% with the standard NRT-dpa values, if damage energy from SRIM simulation is used. SRIM-2013 NRT-dpa cross sections applied to estimate the integrated dpa for Fe, Cr and Ni are in good agreement with established computer codes and data. A similar study carried out for polyatomic material, SiC, shows encouraging results. In this case, it is observed that the NRT approach with average lattice displacement energy of 25 eV coupled with the damage energies from the K-P option of SRIM-2013 gives reliable displacement cross sections and integrated dpa for various reactor spectra. The source term of neutron damage can be equivalently determined in the units of dpa by simulating self-ion bombardment. This shows that the information of primary recoils obtained from CRaD can be reliably applied to estimate the integrated dpa and damage assessment studies in accelerator-based self-ion irradiation experiments of structural materials. This study would help to advance the investigation of possible correlations between the damages induced by ions and reactor neutrons.

  12. Ion-induced swelling of ODS ferritic alloy MA957 tubing to 500 dpa

    Energy Technology Data Exchange (ETDEWEB)

    Toloczko, M.B., E-mail: mychailo.toloczko@pnnl.gov [Pacific Northwest National Laboratory, Richland, WA 99354 (United States); Garner, F.A. [Radiation Effects Consulting, Richland, WA 99354 (United States); Voyevodin, V.N.; Bryk, V.V.; Borodin, O.V.; Mel’nychenko, V.V.; Kalchenko, A.S. [Kharkov Institute of Physics and Technology, Kharkov (Ukraine)

    2014-10-15

    In order to study the potential swelling behavior of the ODS ferritic alloy MA957 at very high dpa levels, specimens were prepared from pressurized tubes that were unirradiated archives of tubes previously irradiated in FFTF to doses as high as 110 dpa. These unirradiated specimens were irradiated with 1.8 MeV Cr{sup +} ions to doses ranging from 100 to 500 dpa and examined by transmission electron microscopy. No co-injection of helium or hydrogen was employed. It was shown that compared to several tempered ferritic/martensitic steels irradiated in the same facility, these tubes were rather resistant to void swelling, reaching a maximum value of only 4.5% at 500 dpa and 450 °C. In this fine-grained material, the distribution of swelling was strongly influenced by the presence of void denuded zones along the grain boundaries.

  13. Tunable paramagnetic relaxation enhancements by [Gd(DPA)3]3- for protein structure analysis

    International Nuclear Information System (INIS)

    Yagi, Hiromasa; Loscha, Karin V.; Su, Xun-Cheng; Stanton-Cook, Mitchell; Huber, Thomas; Otting, Gottfried

    2010-01-01

    Paramagnetic relaxation enhancements (PRE) present a powerful source of structural information in nuclear magnetic resonance (NMR) studies of proteins and protein-ligand complexes. In contrast to conventional PRE reagents that are covalently attached to the protein, the complex between gadolinium and three dipicolinic acid (DPA) molecules, [Gd(DPA) 3 ] 3- , can bind to proteins in a non-covalent yet site-specific manner. This offers straightforward access to PREs that can be scaled by using different ratios of [Gd(DPA) 3 ] 3- to protein, allowing quantitative distance measurements for nuclear spins within about 15 A of the Gd 3+ ion. Such data accurately define the metal position relative to the protein, greatly enhancing the interpretation of pseudocontact shifts induced by [Ln(DPA) 3 ] 3- complexes of paramagnetic lanthanide (Ln 3+ ) ions other than gadolinium. As an example we studied the quaternary structure of the homodimeric GCN4 leucine zipper.

  14. Microstructure of RERTR DU-alloys irradiated with krypton ions up to 100 dpa

    Energy Technology Data Exchange (ETDEWEB)

    Gan, J. [Nuclear Fuels and Materials Division, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-6188 (United States); Keiser, D.D., E-mail: Dennis.Keiser@inl.gov [Nuclear Fuels and Materials Division, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-6188 (United States); Miller, B.D.; Wachs, D.M. [Nuclear Fuels and Materials Division, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-6188 (United States); Allen, T.R. [Department of Engineering Physics, University of Wisconsin, 1500 Engineering Drive, Madison, WI 53706 (United States); Kirk, M.; Rest, J. [Materials Science Division, Argonne National Laboratory, 9700 S. Cass Ave, Argonne, IL 60439 (United States)

    2011-04-15

    The radiation stability of the interaction product formed at the fuel-matrix interface of research reactor dispersion fuels, under fission-product bombardment, has a strong impact on fuel performance. Three depleted uranium alloys were cast that consisted of the following five phases to be investigated: U(Si, Al){sub 3}, (U, Mo)(Si, Al){sub 3}, UMo{sub 2}Al{sub 20}, U{sub 6}Mo{sub 4}Al{sub 43}, and UAl{sub 4}. Irradiation of transmission electron microscopy (TEM) disc samples with 500-keV Kr ions at 200 deg. C to doses up to {approx}100 displacements per atom (dpa) were conducted using a 300-keV electron microscope equipped with an ion accelerator. TEM results show that the U(Si, Al){sub 3} and UAl{sub 4} phases remain crystalline at 100 dpa without forming voids. The (U, Mo)(Si, Al){sub 3} and UMo{sub 2}Al{sub 20} phases become amorphous at 1 and {approx}2 dpa, respectively, and show no evidence of voids at 100 dpa. The U{sub 6}Mo{sub 4}Al{sub 43} phase goes to amorphous at less than 1 dpa and reveals high density voids at 100 dpa.

  15. Microstructure of RERTR DU-alloys irradiated with krypton ions up to 100 dpa

    Science.gov (United States)

    Gan, J.; Keiser, D. D., Jr.; Miller, B. D.; Wachs, D. M.; Allen, T. R.; Kirk, M.; Rest, J.

    2011-04-01

    The radiation stability of the interaction product formed at the fuel-matrix interface of research reactor dispersion fuels, under fission-product bombardment, has a strong impact on fuel performance. Three depleted uranium alloys were cast that consisted of the following five phases to be investigated: U(Si, Al) 3, (U, Mo)(Si, Al) 3, UMo 2Al 20, U 6Mo 4Al 43, and UAl 4. Irradiation of transmission electron microscopy (TEM) disc samples with 500-keV Kr ions at 200 °C to doses up to ˜100 displacements per atom (dpa) were conducted using a 300-keV electron microscope equipped with an ion accelerator. TEM results show that the U(Si, Al) 3 and UAl 4 phases remain crystalline at 100 dpa without forming voids. The (U, Mo)(Si, Al) 3 and UMo 2Al 20 phases become amorphous at 1 and ˜2 dpa, respectively, and show no evidence of voids at 100 dpa. The U 6Mo 4Al 43 phase goes to amorphous at less than 1 dpa and reveals high density voids at 100 dpa.

  16. Regulation of the Docosapentaenoic Acid/Docosahexaenoic Acid Ratio (DPA/DHA Ratio) in Schizochytrium limacinum B4D1.

    Science.gov (United States)

    Zhang, Ke; Li, Huidong; Chen, Wuxi; Zhao, Minli; Cui, Haiyang; Min, Qingsong; Wang, Haijun; Chen, Shulin; Li, Demao

    2017-05-01

    Docosapentaenoic acid/docosahexaenoic acid ratio (DPA/DHA ratio) in Schizochytrium was relatively stable. But ideally the ratio of DPA/DHA will vary according to the desired end use. This study reports several ways of modulating the DPA/DHA ratio. Incubation times changed the DPA/DHA ratio, and changes in this ratio were associated with the variations in the saturated fatty acid (SFAs) content. Propionic acid sharply increased the SFAs content in lipids, dramatically decreased the even-chain SFAs content, and reduced the DPA/DHA ratio. Pentanoic acid (C5:0) and heptanoic acid (C7:0) had similar effects as propionic acid, whereas butyric acid (C4:0), hexanoic acid (C6:0), and octanoic acid (C8:0) did not change the fatty acid profile and the DPA/DHA ratio. Transcription analyses show that β-oxidation might be responsible for this phenomenon. Iodoacetamide upregulated polyunsaturated fatty acid (PUFA) synthase genes, reduced the DHA content, and improved the DPA content, causing the DPA/DHA ratio to increase. These results present new insights into the regulation of the DPA/DHA ratio.

  17. New remarks on KERMA factors and DPA cross section data in ACE files

    International Nuclear Information System (INIS)

    Konno, Chikara; Sato, Satoshi; Ohta, Masayuki; Kwon, Saerom; Ochiai, Kentaro

    2016-01-01

    KERMA factors and DPA cross section data are essential for nuclear heating and material damage estimation in fusion reactor designs. Recently we compared KERMA factors and DPA cross section data in the latest official ACE files of JENDL-4.0, ENDF/B-VII.1, JEFF-3.2 and FENDL-3.0 and it was found out that the KERMA factors and DPA cross section data of a lot of nuclei did not always agree among the nuclear data libraries. We investigated the nuclear data libraries and the nuclear data processing code NJOY and specified new reasons for the discrepancies; (1) incorrect nuclear data and NJOY bugs, (2) huge helium production cross section data, (3) gamma production data format in the nuclear data, (4) no detailed secondary particle data (energy–angular distribution data). These problems should be resolved based on this study.

  18. New remarks on KERMA factors and DPA cross section data in ACE files

    Energy Technology Data Exchange (ETDEWEB)

    Konno, Chikara, E-mail: konno.chikara@jaea.go.jp; Sato, Satoshi; Ohta, Masayuki; Kwon, Saerom; Ochiai, Kentaro

    2016-11-01

    KERMA factors and DPA cross section data are essential for nuclear heating and material damage estimation in fusion reactor designs. Recently we compared KERMA factors and DPA cross section data in the latest official ACE files of JENDL-4.0, ENDF/B-VII.1, JEFF-3.2 and FENDL-3.0 and it was found out that the KERMA factors and DPA cross section data of a lot of nuclei did not always agree among the nuclear data libraries. We investigated the nuclear data libraries and the nuclear data processing code NJOY and specified new reasons for the discrepancies; (1) incorrect nuclear data and NJOY bugs, (2) huge helium production cross section data, (3) gamma production data format in the nuclear data, (4) no detailed secondary particle data (energy–angular distribution data). These problems should be resolved based on this study.

  19. Monte Carlo study of electron irradiation effect on YBCO dpa profiles

    International Nuclear Information System (INIS)

    Pinnera, I.; Cruz, C.; Abreu, Y.; Leyva, A.; Van Espen, P.

    2011-01-01

    The Monte Carlo assisted Classical Method (MCCM) consists on a calculation procedure for determining the displacements per atom (dpa) distribution in solid materials. This algorithm allows studying the gamma and electron irradiation damage in different materials. It is based on the electrons elastic scattering classic theories and the use of Monte Carlo simulation for the physical processes involved. The present study deals with the Monte Carlo simulation of electron irradiation effects on YBa 2 Cu 3 O 7-x (YBCO) slabs using the MCNPX code system. Displacements per atom distributions are obtained through the MCCM for electron irradiation up to 10 MeV. In-depth dpa profiles for electrons and positrons are obtained and analyzed. Also, for each atomic species in the material, the dpa distributions are calculated. All the results are discussed in the present contribution. (Author)

  20. Spore inactivation and DPA release in Alicyclobacillus acidoterrestris under different stress conditions.

    Science.gov (United States)

    Bevilacqua, Antonio; Ciuffreda, Emanuela; Sinigaglia, Milena; Corbo, Maria Rosaria

    2015-04-01

    This paper reports on the inactivation of spores of 5 strains of Alicyclobacillus acidoterrestris under different stress conditions (acidic and alkaline pH, high temperature, addition of lysozyme, hydrogen peroxide and p-coumaric acid). The research was divided into two different steps; first, each stress was studied alone, thus pointing out a partial uncoupling between spore inactivation and DPA release, as H2O2 reduced spore level below the detection but it did not cause the release of DPA. A partial correlation was found only for acidic and alkaline pH. 2nd step was focused on the combination of pH, temperature and H2O2 through a factorial design; experiments were performed on both fresh and 4 month-old spores and pinpointed a different trend for DPA release as a function of spore age. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Effects of irradiation on low-activation ferritic alloys to 45 dpa

    International Nuclear Information System (INIS)

    Gelles, D.S.; Hamilton, M.L.

    1986-06-01

    Nine low activation ferritic alloys covering the range 2 to 12Cr with alloying additions of tungsten and/or vanadium have been irradiated to intermediate fluences of 30 to 45 dpa and tensile tested or examined by transmission electron microscopy in order to determine the effect of increasing neutron dose on properties and microstructure. Changes in properties and microstructure are for the most part completed within 10 dpa but swelling and dislocation evolution continue with increasing dose at 420/degree/C and subgrain coarsening occurs at 600/degree/C. 9 refs., 7 figs., 2 tabs

  2. A functional method for estimating DPA tallies in Monte Carlo calculations of Light Water Reactors

    International Nuclear Information System (INIS)

    Read, Edward A.; Oliveira, Cassiano R.E. de

    2011-01-01

    There has been a growing need in recent years for the development of methodology to calculate radiation damage factors, namely displacements per atom (dpa), of structural components for Light Water Reactors (LWRs). The aim of this paper is to discuss the development and implementation of a dpa method using Monte Carlo method for transport calculations. The capabilities of the Monte Carlo code Serpent such as Woodcock tracking and fuel depletion are assessed for radiation damage calculations and its capability demonstrated and compared to those of the Monte Carlo code MCNP for radiation damage calculations of a typical LWR configuration. (author)

  3. Relationship between swelling and irradiation creep in cold worked PCA stainless steel to 178 DPA at∼400 degrees C

    International Nuclear Information System (INIS)

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

    1993-01-01

    At 178 dpa and ∼400 degrees C, the irradiation creep behavior of 20% cold-worked PCA has become dominated by the creep disappearance phenomenon. The total diametral deformation rate has reached the limiting value of 0.33%/dpa at the three highest stress levels. The stress-enhancement of swelling tends to camouflage the onset of creep disappearance, however

  4. An AES chip with DPA resistance using hardware-based random order execution

    International Nuclear Information System (INIS)

    Yu Bo; Li Xiangyu; Chen Cong; Sun Yihe; Wu Liji; Zhang Xiangmin

    2012-01-01

    This paper presents an AES (advanced encryption standard) chip that combats differential power analysis (DPA) side-channel attack through hardware-based random order execution. Both decryption and encryption procedures of an AES are implemented on the chip. A fine-grained dataflow architecture is proposed, which dynamically exploits intrinsic byte-level independence in the algorithm. A novel circuit called an HMF (Hold-Match-Fetch) unit is proposed for random control, which randomly sets execution orders for concurrent operations. The AES chip was manufactured in SMIC 0.18 μm technology. The average energy for encrypting one group of plain texts (128 bits secrete keys) is 19 nJ. The core area is 0.43 mm 2 . A sophisticated experimental setup was built to test the DPA resistance. Measurement-based experimental results show that one byte of a secret key cannot be disclosed from our chip under random mode after 64000 power traces were used in the DPA attack. Compared with the corresponding fixed order execution, the hardware based random order execution is improved by at least 21 times the DPA resistance. (semiconductor integrated circuits)

  5. An AES chip with DPA resistance using hardware-based random order execution

    Science.gov (United States)

    Bo, Yu; Xiangyu, Li; Cong, Chen; Yihe, Sun; Liji, Wu; Xiangmin, Zhang

    2012-06-01

    This paper presents an AES (advanced encryption standard) chip that combats differential power analysis (DPA) side-channel attack through hardware-based random order execution. Both decryption and encryption procedures of an AES are implemented on the chip. A fine-grained dataflow architecture is proposed, which dynamically exploits intrinsic byte-level independence in the algorithm. A novel circuit called an HMF (Hold-Match-Fetch) unit is proposed for random control, which randomly sets execution orders for concurrent operations. The AES chip was manufactured in SMIC 0.18 μm technology. The average energy for encrypting one group of plain texts (128 bits secrete keys) is 19 nJ. The core area is 0.43 mm2. A sophisticated experimental setup was built to test the DPA resistance. Measurement-based experimental results show that one byte of a secret key cannot be disclosed from our chip under random mode after 64000 power traces were used in the DPA attack. Compared with the corresponding fixed order execution, the hardware based random order execution is improved by at least 21 times the DPA resistance.

  6. Method for the Calculation of DPA in the Reactor Pressure Vessel of Atucha II

    Directory of Open Access Journals (Sweden)

    J. A. Mascitti

    2011-01-01

    It was determined that the maximum DPA rate in the RPV wall with fresh fuel element (FE is 3.76(3 × 10-12 s-1, it takes place in front of FEs BA42 and BL43, and it is symmetrical about the central channel, LG04, and LH03.

  7. Effects of neutron irradiation to 63 dpa on the properties of various commercial copper alloys

    International Nuclear Information System (INIS)

    Brager, H.R.

    1985-04-01

    High purity copper and six commercial copper alloys were neutron irradiated to 47 and 63 dpa at about 450 0 C in the FFTF. Immersion density measurements showed a wide range of swelling behavior after irradiation to 63 dpa. At one extreme was CuBe in the aged and tempered (AT) condition which had densified slightly. At the other extreme was 20% CW Cu-0.1% Ag which swelled over 45%. Electrical resistivity measurements followed trends similar to previously published results for the same alloys irradiated to 16 dpa: a continued change in conductivity with fluence which appears to relate to void formation, transmutation products and coarsening of second phase precipitates. These results were compared with electrical conductivity of unirradiated alloys examined after aging for 10,000 hours. The most irradiation resistant high-conductivity copper alloys examined after 63 dpa are A125 and MZC. Cu-2.0Be, only a moderate-conductivity alloy, exhibits very consistent irradiation resistant properties

  8. Further Charpy impact test results of low activation ferritic alloys, irradiated at 430{degrees}C to 67 dpa

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-04-01

    Miniature CVN specimens of four ferritic alloys, GA3X, F82H, GA4X and HT9, have been impact tested following irradiation at 430{degrees}C to 67 dpa. Comparison of the results with those of the previously tested lower dose irradiation condition indicates that the GA3X and F82H alloys, two primary candidate low activation alloys, exhibit virtually identical behavior following irradiation at 430{degrees}C to {approximately}67 dpa and at 370{degrees}C to {approximately}15 dpa. Very little shift is observed in either DBTT or USE relative to the unirradiated condition. The shifts in DBTT and USE observed in both GA4X and HT9 were smaller after irradiation at 430{degrees}C to {approximately}67 dpa than after irradiation at 370{degrees}C to {approximately}15 dpa.

  9. Further Charpy impact test results of low activation ferritic alloys, irradiated at 430 degrees C to 67 dpa

    International Nuclear Information System (INIS)

    Schubert, L.E.; Hamilton, M.L.; Gelles, D.S.

    1997-01-01

    Miniature CVN specimens of four ferritic alloys, GA3X, F82H, GA4X and HT9, have been impact tested following irradiation at 430 degrees C to 67 dpa. Comparison of the results with those of the previously tested lower dose irradiation condition indicates that the GA3X and F82H alloys, two primary candidate low activation alloys, exhibit virtually identical behavior following irradiation at 430 degrees C to ∼67 dpa and at 370 degrees C to ∼15 dpa. Very little shift is observed in either DBTT or USE relative to the unirradiated condition. The shifts in DBTT and USE observed in both GA4X and HT9 were smaller after irradiation at 430 degrees C to ∼67 dpa than after irradiation at 370 degrees C to ∼15 dpa

  10. Metabolism and quantification of [18F]DPA-714, a new TSPO positron emission tomography radioligand

    International Nuclear Information System (INIS)

    Peyronneau, Marie-Anne; Saba, Wadad; Goutal, Sebastien; Damont, Annelaure; Dolle, Frederic; Bottlaender, Michel; Valette, Heric; Kassiou, Michael

    2013-01-01

    [ 18 F]DPA-714 [N,N-diethyl-2-(2-(4-(2[ 18 F]-fluoroethoxy)phenyl) 5,7-dimethyl-pyrazolo[1,5a]pyrimidin-3-yl)acetamide] is a new radioligand currently used for imaging the 18-kDa translocator protein in animal models of neuro-inflammation and recently in humans. The biodistribution by positron emission tomography (PET) in baboons and the in vitro and in vivo metabolism of [ 18 F]DPA-714 were investigated in rats, baboons, and humans. Whole-body PET experiments showed a high uptake of radioactivity in the kidneys, heart, liver, and gallbladder. The liver was a major route of elimination of [ 18 F]DPA-714, and urine was a route of excretion for radio-metabolites. In rat and baboon plasma, high-performance liquid chromatography (HPLC) metabolic profiles showed three major radio-metabolites accounting for 85% and 89% of total radioactivity at 120 minutes after injection, respectively. Rat microsomal incubations and analyses by liquid chromatography-mass spectrometry (LC-MS) identified seven metabolites, characterized as O-de-ethyl, hydroxyl, and N-de-ethyl derivatives of nonradioactive DPA-714, two of them having the same retention times than those detected in rat and baboon plasma. The third plasma radio-metabolite was suggested to be a carboxylic acid compound that accounted for 15% of the rat brain radioactivity. O-de-ethylation led to a nonradioactive compound and [ 18 F] fluoroacetic acid. Human CYP3A4 and CYP2D6 were shown to be involved in the oxidation of the radioligand. Finally an easy, rapid, and accurate method-indispensable for PET quantitative clinical studies - for quantifying [ 18 F]DPA-714 by solid-phase extraction was developed. In vivo, an extensive metabolism of [ 18 F]DPA-714 was observed in rats and baboons, identified as [ 18 F]de-ethyl, [ 18 F]hydroxyl, and [ 18 F]carboxylic acid derivatives of [ 18 F]DPA-714. The main route of excretion of the unchanged radioligand in baboons was hepatobiliary while that of radio-metabolites was the urinary

  11. Rate maximum calculation of Dpa in CNA-II pressure vessel

    International Nuclear Information System (INIS)

    Mascitti, J. A

    2012-01-01

    The maximum dpa rate was calculated for the reactor in the following state: fresh fuel, no Xenon, a Boron concentration of 15.3 ppm, critical state, its control rods in the criticality position, hot, at full power (2160 MW). It was determined that the maximum dpa rate under such conditions is 3.54(2)x10 12 s -1 and it is located in the positions corresponding to θ=210 o in the azimuthal direction, and z=20 cm and -60 cm respectively in the axial direction, considering the calculation mesh centered at half height of the fuel element (FE) active length. The dpa rate spectrum was determined as well as the contribution to it for 4 energy groups: a thermal group, two epithermal groups and a fast one. The maximum dpa rate considering the photo-neutrons production from (γ, n) reaction in the heavy water of coolant and moderator was 3.93(4)x10 12 s -1 that is 11% greater than the obtained without photo-neutrons. This verified significant difference between both cases, suggest that photo-neutrons in large heavy water reactors such as CNA-II should not be ignored. The maximum DPA rate in the first mm of the reactor pressure vessel was calculated too and it was obtained a value of 4.22(6)x10 12 s -1 . It should be added that the calculation was carried out with the reactor complete accurate model, with no approximations in spatial or energy variables. Each value has, between parentheses, a percentage relative error representing the statistical uncertainty due to the probabilistic Monte Carlo method used to estimate it. More representative values may be obtained with this method if equilibrium burn-up distribution is used (author)

  12. Interactive Influence on Void Swelling in 300 Series Stainless Steels of Coupled Gradients in Temperature and DPA Rate

    International Nuclear Information System (INIS)

    Garner, F.

    2007-01-01

    Full text of publication follows: Recently, experimental evidence has accumulated that demonstrates that the dependence of swelling in austenitic steels on dpa rate has been strongly underestimated. In development of swelling correlations for both fusion and fission reactor applications the dpa rate is frequently but inadvertently incorporated into the temperature dependence. This inability to separate the separate dependencies of dpa rate and temperature is closely associated with the coupling of gradients in neutron flux-spectra and irradiation temperature along the axial length of components, especially for relatively small cores. In order to demonstrate the separate action of dpa rate and temperature, previously unpublished swelling data are presented from hexagonal ducts, fuel pins and pressurized tubes irradiated in EBR-II, all possessing both axial and radial gradients in dpa rate. Annealed AISI 304 components were chosen to avoid complications of precipitation found in other alloys such as AISI 316 or PCA. Since this steel never develops multiple-peak swelling behavior and experiences very little precipitation at high dpa rates, it use in this effort is ideal for separation of environmental variables. It is demonstrated that the transient regime of void selling is increased by increasing dpa rate and by decreasing temperature. It is also shown that the combined effect of dpa rate and temperature distribution along the length of any given structural component produces a well defined, scatter-free 'swelling loop' vs. dpa that uniquely allows estimation and separation of the separate dependencies of swelling on temperature and dpa rate. One consequence of the derived flux dependence is that components subject to a dpa rate gradient in general suffer much less distortion than predicted by equations that do not explicitly incorporate a dependence on dpa rate. It is also shown that over a wide range of irradiation conditions the terminal steady-state swelling

  13. The translocator protein ligand [{sup 18}F]DPA-714 images glioma and activated microglia in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Winkeler, Alexandra; Boisgard, Raphael; Awde, Ali R.; Dubois, Albertine; Theze, Benoit; Zheng, Jinzi [Universite Paris Sud, Inserm, U1023, Laboratoire d' Imagerie Moleculaire Experimentale, Orsay (France); CEA, I2BM, SHFJ, Orsay (France); Ciobanu, Luisa [CEA, DSV, I2BM, NeuroSpin, LRMN, Gif sur Yvette (France); Dolle, Frederic [CEA, I2BM, SHFJ, Orsay (France); Viel, Thomas; Jacobs, Andreas H. [Westfaelische Wilhelm-Universitaet Muenster (WWU), European Institute for Molecular Imaging (EIMI), Muenster (Germany); Tavitian, Bertrand [Universite Paris Sud, Inserm, U1023, Laboratoire d' Imagerie Moleculaire Experimentale, Orsay (France)

    2012-05-15

    In recent years there has been an increase in the development of radioligands targeting the 18-kDa translocator protein (TSPO). TSPO expression is well documented in activated microglia and serves as a biomarker for imaging neuroinflammation. In addition, TSPO has also been reported to be overexpressed in a number of cancer cell lines and human tumours including glioma. Here we investigated the use of [{sup 18}F]DPA-714, a new TSPO positron emission tomography (PET) radioligand to image glioma in vivo. We studied the uptake of [{sup 18}F]DPA-714 in three different rat strains implanted with 9L rat glioma cells: Fischer (F), Wistar (W) and Sprague Dawley (SD) rats. Dynamic [{sup 18}F]DPA-714 PET imaging, kinetic modelling of PET data and in vivo displacement studies using unlabelled DPA-714 and PK11195 were performed. Validation of TSPO expression in 9L glioma cell lines and intracranial 9L gliomas were investigated using Western blotting and immunohistochemistry of brain tissue sections. All rats showed significant [{sup 18}F]DPA-714 PET accumulation at the site of 9L tumour implantation compared to the contralateral brain hemisphere with a difference in uptake among the three strains (F > W > SD). The radiotracer showed high specificity for TSPO as demonstrated by the significant reduction of [{sup 18}F]DPA-714 binding in the tumour after administration of unlabelled DPA-714 or PK11195. TSPO expression was confirmed by Western blotting in 9L cells in vitro and by immunohistochemistry ex vivo. The TSPO radioligand [{sup 18}F]DPA-714 can be used for PET imaging of intracranial 9L glioma in different rat strains. This preclinical study demonstrates the feasibility of employing [{sup 18}F]DPA-714 as an alternative radiotracer to image human glioma. (orig.)

  14. Primary Damage in Ceramics: Complexity and Inapplicability of the NRT Dpa

    International Nuclear Information System (INIS)

    Crocombette, Jean-Paul

    2012-01-01

    It is shown that the studies on ceramics bring even more complexity is an already difficult situation about the NRT dpa. First in ceramics amorphized by direct impact, the very concept of surviving FPs which is what the NRT dpa is supposed to measure is meaningless. One then has to return to the bare number of displaced atoms to quantify the damage. Second in more complex situations where the damage is mixed between amorphization and creation of point defects, it is almost impossible to define a quantity to measure atomic disorder induced by cascades. Finally it was shown that the amount and nature of damage depends not only on the energy of the PKA but also on its nature. Finally one should keep in mind that even in the regular cases, the number of surviving Frenkel pairs may vary with temperature as their recombinations can be thermally activated

  15. Irradiation performance of oxide dispersion strengthened copper alloys to 150 dpa at 415 degree C

    International Nuclear Information System (INIS)

    Edwards, D.J.; Kumar, A.S.; Anderson, K.R.; Stubbins, J.F.; Garner, F.A.; Hamilton, M.L.

    1991-11-01

    Results have been obtained on the post-irradiation properties of various oxide dispersion strengthened copper alloys irradiated from 34 to 150 dpa at 415 degrees C in the Fast Flux Test Facility. The GlidCop alloys strengthened by Al 2 O 3 continue to outperform other alloys with respect to swelling resistance, and retention of both electrical conductivity and yield strength. Several castable ODS alloys and a Cr 2 O 3 -strengthened alloy show increasingly poor resistance to radiation, especially in their swelling behavior. A HfO 2 -strengthened alloy retains most of its strength and its electrical conductivity reaches a constant level after 50 dpa, but it exhibits a higher residual radioactivity

  16. [18F]DPA 714 PET Imaging Reveals Global Neuroinflammation in Zika Virus Infected Mice

    Science.gov (United States)

    2017-09-12

    with neurotropic viruses and the evaluation of therapeutics being developed for treatment of infectious diseases. Keywords: Zika virus , Animal...18F]DPA-714 PET Imaging Reveals Global Neuroinflammation in Zika Virus - Infected Mice Kyle Kuszpit1†, Bradley S. Hollidge2†, Xiankun Zeng3, Robert...Running Head: PET Imaging of Zika Virus -Induced Neuroinflammation Manuscript Category: Article Affiliations: 1Molecular and Translational

  17. On the ductile-to-brittle transition behavior of martensitic alloys neutron irradiated to 26 dpa

    International Nuclear Information System (INIS)

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

    1987-01-01

    Charpy impact tests were conducted on specimens made of HT-9 and 9Cr-1Mo in various heat treatment conditions which were irradiated in EBR-II to 26 dpa at 390 to 500 0 C. The results are compared with previous results on specimens irradiated to 13 dpa. HT-9 base metal irradiated at low temperatures showed a small additional increase in ductile brittle transition temperature and a decrease in upper shelf energy from 13 to 26 dpa. No fluence effect was observed in 9Cr-1Mo base metal. The 9Cr-1Mo weldment showed degraded DBTT but improved USE response compared to base metal, contrary to previous findings on HT-9. Significant differences were observed in HT-9 base metal between mill annealed material and normalized and tempered material. The highest DBTT for HT-9 alloys was 50 0 C higher than for the worst case in 9Cr-1Mo alloys. Fractography and hardness measurements were also obtained. Significant differences in fracture appearance were observed in different product forms, although no dependence on fluence was observed. Failure was controlled by the preirradiation microstructure

  18. Neutron and Gamma Fluxes and dpa Rates for HFIR Vessel Beltline Region (Present and Upgrade Designs)

    Energy Technology Data Exchange (ETDEWEB)

    Blakeman, E.D.

    2001-01-11

    The Oak Ridge National Laboratory (ORNL) High Flux Isotope Reactor (HFIR) is currently undergoing an upgrading program, a part of which is to increase the diameters of two of the four radiation beam tubes (HB-2 and HB-4). This change will cause increased neutron and gamma radiation dose rates at and near locations where the tubes penetrate the vessel wall. Consequently, the rate of radiation damage to the reactor vessel wall at those locations will also increase. This report summarizes calculations of the neutron and gamma flux (particles/cm{sup 2}/s) and the dpa rate (displacements/atom/s) in iron at critical locations in the vessel wall. The calculated dpa rate values have been recently incorporated into statistical damage evaluation codes used in the assessment of radiation induced embrittlement. Calculations were performed using models based on the discrete ordinates methodology and utilizing ORNL two-dimensional and three-dimensional discrete ordinates codes. Models for present and proposed beam tube designs are shown and their results are compared. Results show that for HB-2, the dpa rate in the vessel wall where the tube penetrates the vessel will be increased by {approximately}10 by the proposed enlargement. For HB-4, a smaller increase of {approximately}2.6 is calculated.

  19. Non-edible Oil Cakes as a Novel Substrate for DPA Production and Augmenting Biocontrol Activity of Paecilomyces variotii.

    Science.gov (United States)

    Arora, Kalpana; Sharma, Satyawati; Krishna, Suresh B N; Adam, Jamila K; Kumar, Ashwani

    2017-01-01

    The present study investigated the use of waste non-edible oil cakes (Jatropha, Karanja, Neem, and Mahua) as a substrate for the growth of Paecilomyces variotii and dipicolinic acid (DPA) production. Previous researches proved the efficacy of DPA in suppressing certain pathogens that are deleterious to the plants in the rhizosphere. DPA production was statistical optimized by amending non-edible oil cakes in growing media as nitrogen and sugars (Dextrose, Glucose, and Lactose) as carbon source. Plackett-Burman design (PBD), indicated that Jatropha cake, Karanja cake, and Dextrose were the most significant components ( p edible oil cakes as a substrate offer an efficient and viable approach for DPA production by P. variotii .

  20. Comparative Evaluation of the Translocator Protein Radioligands 11C-DPA-713, 18F-DPA- 714, and 11C-PK11195 in a Rat Model of Acute Neuro-inflammation

    International Nuclear Information System (INIS)

    Chauveau, F.; Van Camp, N.; Dolle, F.; Kuhnast, B.; Hinnen, F.; Damont, A.; Boutin, H.; Tavitian, B.; Chauveau, F.; Van Camp, N.; Boutin, H; Tavitian, B.; Chauveau, F.; Boutin, H.; James, M.; Kassiou, M.; Kassiou, M.

    2009-01-01

    Overexpression of the translocator protein, TSPO (18 kDa), formerly known as the peripheral benzodiazepine receptor, is a hallmark of activation of cells of monocytic lineage (micro-glia and macrophages) during neuro-inflammation. Radiolabeling of TSPO ligands enables the detection of neuro-inflammatory lesions by PET. Two new radioligands, 11 C-labeled N, N-diethyl-2-[2-(4- methoxy-phenyl)-5, 7-dimethylpyrazolo[1, 5-a]pyrimidin-3-yl] acetamide (DPA-713) and 18 F-labeled N, N-diethyl-2-(2-(4-(2- fluoroethoxy)phenyl)-5, 7-dimethylpyrazolo[1, 5-a]pyrimidin-3-yl) acetamide (DPA-714), both belonging to the pyrazolopyrimidine class, were compared in vivo and in vitro using a rodent model of neuro-inflammation. Methods: 11 C-DPA-713 and 18 F-DPA-714, as well as the classic radioligand 11 C-labeled (R)-N-methyl- N-(1-methylpropyl)-1-(2-chlorophenyl)isoquinoline-3-carboxamide (PK11195), were used in the same rat model, in which intra-striatal injection of (R, S)-a-amino-3-hydroxy-5-methyl-4-isoxazolopropionique gave rise to a strong neuro-inflammatory response. Comparative endpoints included in vitro autoradiography and in vivo imaging on a dedicated small-animal PET scanner under identical conditions. Results: 11 C-DPA-713 and 18 F-DPA-714 could specifically localize the neuro-inflammatory site with a similar signal-to-noise ratio in vitro. In vivo, 18 F-DPA-714 performed better than 11 C-DPA-713 and 11 C-PK11195, with the highest ratio of ipsilateral to contralateral uptake and the highest binding potential. Conclusion: 18 F-DPA-714 appears to be an attractive alternative to 11 C-PK11195 because of its increased bioavailability in brain tissue and its reduced nonspecific binding. Moreover, its labeling with 18 F, the preferred PET isotope for radiopharmaceutical chemistry, favors its dissemination and wide clinical use. 18 F-DPA-714 will be further evaluated in longitudinal studies of neuro-inflammatory conditions such as are encountered in stroke or neuro

  1. Quantitative Trait Locus and Brain Expression of HLA-DPA1 Offers Evidence of Shared Immune Alterations in Psychiatric Disorders

    Directory of Open Access Journals (Sweden)

    Ling Z. Morgan

    2016-03-01

    Full Text Available Genome-wide association studies of schizophrenia encompassing the major histocompatibility locus (MHC were highly significant following genome-wide correction. This broad region implicates many genes including the MHC complex class II. Within this interval we examined the expression of two MHC II genes (HLA-DPA1 and HLA-DRB1 in brain from individual subjects with schizophrenia (SZ, bipolar disorder (BD, major depressive disorder (MDD, and controls by differential gene expression methods. A third MHC II mRNA, CD74, was studied outside of the MHC II locus, as it interacts within the same immune complex. Exon microarrays were performed in anterior cingulate cortex (ACC in BD compared to controls, and both HLA-DPA1 and CD74 were decreased in expression in BD. The expression of HLA-DPA1 and CD74 were both reduced in hippocampus, amygdala, and dorsolateral prefrontal cortex regions in SZ and BD compared to controls by specific qPCR assay. We found several novel HLA-DPA1 mRNA variants spanning HLA-DPA1 exons 2-3-4 as suggested by exon microarrays. The intronic rs9277341 SNP was a significant cis expression quantitative trait locus (eQTL that was associated with the total expression of HLA-DPA1 in five brain regions. A biomarker study of MHC II mRNAs was conducted in SZ, BD, MDD, and control lymphoblastic cell lines (LCL by qPCR assay of 87 subjects. There was significantly decreased expression of HLA-DPA1 and CD74 in BD, and trends for reductions in SZ in LCLs. The discovery of multiple splicing variants in brain for HLA-DPA1 is important as the HLA-DPA1 gene is highly conserved, there are no reported splicing variants, and the functions in brain are unknown. Future work on the function and localization of MHC Class II proteins in brain will help to understand the role of alterations in neuropsychiatric disorders. The HLA-DPA1 eQTL is located within a large linkage disequilibrium block that has an irrefutable association with schizophrenia. Future

  2. The Daily Physical Activity (DPA) policy in Ontario: is it working? an examination using accelerometry-measured physical activity data.

    Science.gov (United States)

    Stone, Michelle R; Faulkner, Guy E J; Zeglen-Hunt, Laura; Bonne, Jennifer Cowie

    2012-01-01

    In 2005, the Ontario Ministry of Education announced a policy requiring that all elementary students be provided with opportunities to participate in a minimum of 20 minutes of sustained moderate-to-vigorous physical activity (MVPA) each school day during instructional time. To the authors' knowledge, this policy has never been formally evaluated. In a form of natural experiment with Project BEAT, we explored within 16 Toronto District School Board schools the proportion of children who participate in DPA, and the proportion who achieve sustained MVPA within these sessions; these are the objectives of this article. Consent was given by 1027 parents/guardians for their children to participate (boys, n=478; girls, n=549). Physical activity (PA) was measured using accelerometry and classroom schedules collected to identify sessions of DPA. The frequency of DPA and number and duration of sustained bouts of MVPA (> or =5 min) were computed and explored relative to PA levels and health outcomes. Fewer than half of the participating children were provided with DPA every day and not a single child engaged in sustained MVPA for > or =20 minutes. On the more positive side, children who engaged in DPA every day were significantly more active than their peers. Those accumulating at least 1 bout of MVPA were more active and likely to meet PA guidelines, and fewer of these children were overweight. The majority of schools are not meeting the DPA policy. However, as the frequency and intensity of DPA increases, so do positive health outcomes. This paper provides supporting evidence that when this policy is implemented, the intended health benefits are achievable.

  3. Preliminary study on DPA cross-section of 184W in JEFF-3.2

    International Nuclear Information System (INIS)

    Konno, C.

    2016-01-01

    I investigated reasons why the DPA cross-section data of JEFF-3.2 184 W was too large above 30 MeV. As a result, I found out that the production yield of 182Ta in mf6 mt5 in JEFF-3.2 184W was too large and demonstrated that the problem was solved if the production yield of 182 Ta was modified. I picked out that the same issue also occurred in 182W, 183W and 186W. The production yield data of all the tungsten isotopes in JEFF-3.2 should be reconfirmed and revised if they have mistakes. (author)

  4. User interface tool based on the MCCM for the calculation of dpa distributions

    International Nuclear Information System (INIS)

    Pinnera, I.; Cruz, C.; Abreu, Y.; Leyva, A.

    2009-01-01

    The Monte Carlo assisted Classical Method (MCCM) was introduced by the authors to calculate the displacements per atom (dpa) distributions in solid materials, making use of the standard outputs of simulation code system MCNP and the classical theories of electron elastic scattering. Based on this method a new DLL with several user interface functions was implemented. Then, an application running on Windows systems was development in order to allow the easy handle of different useful functionalities included on it. In the present work this application is presented and some examples of it successful use in different interesting materials are exposed. (Author)

  5. The influence of He/dpa ratio and displacement rate on microstructural evolution: a comparison of theory and experiment

    International Nuclear Information System (INIS)

    Katoh, Yutai; Stoller, Roger E.; Kohno, Yutaka; Kohyama, Akira

    1994-01-01

    A kinetic model was developed to investigate the influence of the displacement rate and helium generation rate on microstructural evolution in austenitic stainless steels. The model integrates the rate equations describing the evolution of point defects, small point defect clusters, helium-vacancy clusters, and the larger cavity size distribution that is responsible for observable swelling. Cavity (bubble) nucleation is accounted for by the helium-vacancy cluster evolution, while void formation occurs when bubbles grow beyond a critical size in the larger cavity distribution. A series of ion irradiation experiments were used to both calibrate the model and to provide a comparison between model predictions and experimental observations. The experiments involved single and dual-beam irradiations of solution annealed AISI-316 stainless steel at 873 K. The displacement rates were in the range of 2x10 -3 to 1x10 -2 dpa/s and the helium-to-dpa ratios were in the range of 0 to 50 appm He/dpa. The maximum displacement dose was 25 dpa. The experiments revealed a significant effect of helium on both the dislocation structure and the cavity distribution. The model predictions of helium effects over a broad range of He/dpa ratios and displacement rates were consistent with experimental observations. ((orig.))

  6. Mechanical property and conductivity changes in several copper alloys after 13.5 dpa neutron irradiation

    International Nuclear Information System (INIS)

    Ames, M.; Kohse, G.; Lee, T.S.; Grant, N.J.; Harling, O.K.

    1986-01-01

    A scoping experiment in which 25 different copper materials of 17 alloy compositions were irradiated to approx.13.5 dpa approx.400 0 C in a fast reactor is described. The materials include rapidly solidified (RS) alloys, with and without oxide dispersion strengthening, as well as conventionally processed alloys. Immersion density (swelling), electrical conductivity (which can be related to thermal conductivity), and yield stress and ductility by miniature disk bend testing have been measured before and after irradiation. It was found, in general, that the Rs alloys are stable under irradiation to 13.5 dpa, showing small conductivity changes and little or no swelling. Reduction of strength and ductility, in post-irradiation tests at the irradiation temperature, are not generally observed. Some conventionally processed alloys also performed well, although irradiation softening and swelling of several percent were observed in some cases, and pure copper swelled in excess of 5%. It is concluded that a number of copper alloys should receive further study, and that higher dose irradiations will be required to establish the limits of swelling suppression in these alloys

  7. Synthesis of [Dy(DPA)(HDPA)] and its potential as gunshot residue marker

    Energy Technology Data Exchange (ETDEWEB)

    Melo Lucena, Marcella A. [PGMTR - CCEN, Federal University of Pernambuco - UFPE, Avenida Professor Luiz Freire, S/N, Cidade Universitária, 50740-540 Recife (Brazil); Rodrigues, Marcelo Oliveira; Gatto, Claudia C. [LIMA, Chemistry Institute, University of Brasília-UNB, P.O. Box 04478, 70904-970 Brasília (Brazil); Talhavini, Marcio; Maldaner, Adriano O. [National Institute of Criminalistics, Brazilian Federal Police, SAIS Quadra 07, Lote 23, 70610-200 Brasília, DF (Brazil); Alves, Severino [Fundamental Chemistry Department-DQF, Federal University of Pernambuco - UFPE, Avenida Professor Luiz Freire, S/N, Cidade Universitária, 50740-540 Recife (Brazil); Weber, Ingrid T., E-mail: ingrid@ufpe.br [PGMTR - CCEN, Federal University of Pernambuco - UFPE, Avenida Professor Luiz Freire, S/N, Cidade Universitária, 50740-540 Recife (Brazil); LIMA, Chemistry Institute, University of Brasília-UNB, P.O. Box 04478, 70904-970 Brasília (Brazil)

    2016-02-15

    The 2D metal-organic framework (MOF) [Dy(DPA)(HDPA)] (where H{sub 2}DPA=dipicolinic acid) was synthesized under hydrothermal conditions and exhibited a whitish yellow color (CIE coordinates: 0.362, 0.416) when excited at 365 nm. This color arises from the simultaneous blue ({sup 4}F{sub 9/2}–{sup 6}H{sub 15/2}), yellow ({sup 4}F{sub 9/2}–{sup 6}H{sub 13/2}) and red ({sup 4}F{sub 9/2}–{sup 6}H{sub 11/2}) transitions of Dy{sup 3+}. This MOF exhibited a high potential for use as a luminescent marker for gunshot residue (GSR) and in the ammunition encoding process because it was possible to observe visually the luminescent gunshot residue (LGSR) on the shooter’s hands, both on the firearm and at the firing range, using an UV lamp. These particles were easily collected and characterized by photoluminescence spectroscopy and SEM–EDS. The particles exhibited a typical morphology and a composition, making them easy to differentiate from particles of occupational or environmental origin. - Highlights: • First example of a luminescent GSR marker based on Dy{sup 3+} luminescence. • New luminescent marker which can be used for ammunition encoding process. • Thermal and chemically stable MOF which can be used to visually identify GSR.

  8. The independence of irradiation creep in austenitic alloys of displacement rate and helium to dpa ratio

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-04-01

    The majority of high fluence data on the void swelling and irradiation creep of austenitic steels were generated at relatively high displacement rates and relatively low helium/dpa levels that are not characteristic of the conditions anticipated in ITER and other anticipated fusion environments. After reanalyzing the available data, this paper shows that irradiation creep is not directly sensitive to either the helium/dpa ratio or the displacement rate, other than through their possible influence on void swelling, since one component of the irradiation creep rate varies with no correlation to the instantaneous swelling rate. Until recently, however, the non-swelling-related creep component was also thought to exhibit its own strong dependence on displacement rate, increasing at lower fluxes. This perception originally arose from the work of Lewthwaite and Mosedale at temperatures in the 270-350{degrees}C range. More recently this perception was thought to extend to higher irradiation temperatures. It now appears, however, that this interpretation is incorrect, and in fact the steady-state value of the non-swelling component of irradiation creep is actually insensitive to displacement rate. The perceived flux dependence appears to arise from a failure to properly interpret the impact of the transient regime of irradiation creep.

  9. Swelling and microstructural development in path A PCA and type 316 stainless steel irradiated in HFIR to about 22 dpa

    International Nuclear Information System (INIS)

    Maziasz, P.J.; Braski, D.N.

    1983-01-01

    Irradiation of several microstructural variants of PCA and 20%-cold-worked N-lot type 316 stainess steel (CW 316) in HFIR to about 10 dpa produced no visible cavities at 300 0 C, bubbles at 400 0 C, and varying distributions of bubbles and voids at 500 and 600 0 C. The PCA-B1 swells the most and CW 316 (N-lot) the least at 600 0 C. Irradiations have been extended to about 22 dpa. The PCA-Al swells 0.06%/dpa at 600 0 C but at a much lower rate at 500 0 C. The PCA-A3 shows the lowest swelling at 600 0 C, about the half the swelling rate of type 316 stainless steel

  10. Molecular imaging of inflammation in the ApoE -/- mouse model of atherosclerosis with IodoDPA

    Energy Technology Data Exchange (ETDEWEB)

    Foss, Catherine A., E-mail: cfoss1@jhmi.edu [Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD 21287 (United States); Bedja, Djahida [Department of Medicine, Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, MD 21287 (United States); Faculty of Medicine and Health Sciences, Macquarie University, Sydney (Australia); Mease, Ronnie C.; Wang, Haofan [Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD 21287 (United States); Kass, David A. [Department of Medicine, Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, MD 21287 (United States); Chatterjee, Subroto [Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21287 (United States); Pomper, Martin G. [Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD 21287 (United States)

    2015-05-22

    Background: Atherosclerosis is a common and serious vascular disease predisposing individuals to myocardial infarction and stroke. Intravascular plaques, the pathologic lesions of atherosclerosis, are largely composed of cholesterol-laden luminal macrophage-rich infiltrates within a fibrous cap. The ability to detect those macrophages non-invasively within the aorta, carotid artery and other vessels would allow physicians to determine plaque burden, aiding management of patients with atherosclerosis. Methods and results: We previously developed a low-molecular-weight imaging agent, [{sup 125}I]iodo-DPA-713 (iodoDPA), which selectively targets macrophages. Here we use it to detect both intravascular macrophages and macrophage infiltrates within the myocardium in the ApoE -/- mouse model of atherosclerosis using single photon emission computed tomography (SPECT). SPECT data were confirmed by echocardiography, near-infrared fluorescence imaging and histology. SPECT images showed focal uptake of radiotracer at the aortic root in all ApoE -/- mice, while the age-matched controls were nearly devoid of radiotracer uptake. Focal radiotracer uptake along the descending aorta and within the myocardium was also observed in affected animals. Conclusions: IodoDPA is a promising new imaging agent for atherosclerosis, with specificity for the macrophage component of the lesions involved. - Highlights: • [{sup 125}I]iodoDPA SPECT detects atherosclerotic plaques in ApoE -/- mice with high contrast. • Plaques are detected in ApoE -/- mice regardless of diet with iodoDPA. • iodoDPA has very low uptake in healthy tissue including healthy TSPO + tissues at 24 h.

  11. Effect of DPA and 1-MCP on chemical compounds related to superficial scald of Granny Smith apples

    Energy Technology Data Exchange (ETDEWEB)

    Moggia, C.; Moya-Leon, M. A.; Pereira, M.; Yuri, J. A.; Lobos, G. A.

    2010-07-01

    Research was carried out to study the mode of action of diphenylamine (DPA) and 1-methylcyclopropene (1-MCP), on control of superficial scald of Granny Smith apples (Malus domestica Borkh.), and its relation with chemical compounds. Fruit was harvested from a commercial orchard in Chile, 182 and 189 days after full bloom and received the following treatments: DPA (2,000 ppm); 1-MCP (1.2 ppm) and control (no treatment). All fruit was stored for 4 or 6 months at 0 degree centigrade. A completely randomized factorial design was used (2 harvest dates by 3 post harvest treatments). Monthly measurements were made on maturity indices, ethylene production rate (EPR), scald related compounds [a-farnesene (AF), conjugated trienes (CT), total anti-oxidants (AO)], and cell membrane stability. Following 4 and 6 months of storage, plus 7 days at 20 degree centigrade, scald was evaluated. After 6 months, DPA-treated fruit, from both harvests, showed similar firmness, EPR and AO, compared to the control. However, AF and CT were lower, and cell membrane stability higher. Conversely, 1-MCP-treated fruit showed a noticeable EPR suppression and AF inhibition, along with higher firmness, lower CT and AO, compared to the control and DPA. Furthermore, cell membrane stability was superior to that of the control and similar to that of the DPA. Treated fruit (DPA and 1-MCP) showed an important reduction in scald compared to the control. The effect of 1-MCP on the investigated compounds and the reduction in scald, confirms that ethylene plays a major role on its development. (Author) 50 refs.

  12. Molecular imaging of inflammation in the ApoE -/- mouse model of atherosclerosis with IodoDPA

    International Nuclear Information System (INIS)

    Foss, Catherine A.; Bedja, Djahida; Mease, Ronnie C.; Wang, Haofan; Kass, David A.; Chatterjee, Subroto; Pomper, Martin G.

    2015-01-01

    Background: Atherosclerosis is a common and serious vascular disease predisposing individuals to myocardial infarction and stroke. Intravascular plaques, the pathologic lesions of atherosclerosis, are largely composed of cholesterol-laden luminal macrophage-rich infiltrates within a fibrous cap. The ability to detect those macrophages non-invasively within the aorta, carotid artery and other vessels would allow physicians to determine plaque burden, aiding management of patients with atherosclerosis. Methods and results: We previously developed a low-molecular-weight imaging agent, [ 125 I]iodo-DPA-713 (iodoDPA), which selectively targets macrophages. Here we use it to detect both intravascular macrophages and macrophage infiltrates within the myocardium in the ApoE -/- mouse model of atherosclerosis using single photon emission computed tomography (SPECT). SPECT data were confirmed by echocardiography, near-infrared fluorescence imaging and histology. SPECT images showed focal uptake of radiotracer at the aortic root in all ApoE -/- mice, while the age-matched controls were nearly devoid of radiotracer uptake. Focal radiotracer uptake along the descending aorta and within the myocardium was also observed in affected animals. Conclusions: IodoDPA is a promising new imaging agent for atherosclerosis, with specificity for the macrophage component of the lesions involved. - Highlights: • [ 125 I]iodoDPA SPECT detects atherosclerotic plaques in ApoE -/- mice with high contrast. • Plaques are detected in ApoE -/- mice regardless of diet with iodoDPA. • iodoDPA has very low uptake in healthy tissue including healthy TSPO + tissues at 24 h

  13. Non-edible Oil Cakes as a Novel Substrate for DPA Production and Augmenting Biocontrol Activity of Paecilomyces variotii

    Directory of Open Access Journals (Sweden)

    Ashwani Kumar

    2017-05-01

    Full Text Available The present study investigated the use of waste non-edible oil cakes (Jatropha, Karanja, Neem, and Mahua as a substrate for the growth of Paecilomyces variotii and dipicolinic acid (DPA production. Previous researches proved the efficacy of DPA in suppressing certain pathogens that are deleterious to the plants in the rhizosphere. DPA production was statistical optimized by amending non-edible oil cakes in growing media as nitrogen and sugars (Dextrose, Glucose, and Lactose as carbon source. Plackett-Burman design (PBD, indicated that Jatropha cake, Karanja cake, and Dextrose were the most significant components (p < 0.05 of the media and were further optimized using response surface methodology (RSM. Jatropha cake, Karanja cake, and Dextrose at the concentration of 12.5, 4.5, and 10 g/l, respectively, yielded 250 mg/l of DPA, which was 2.5 fold more than that obtained from basal medium. HPLC analysis of the optimized medium (peak at retention time of 30 min confirmed the enhanced DPA production by P. variotii. The scanning electron microscopy (SEM images showed that optimized medium impose a stress like condition (due to less C:N ratio for the fungus and generated more spores as compared to the basal medium in which carbon source is easily available for the mycelial growth. The antimicrobial activity of the fungal extract was tested and found to be effective even at 10−2 dilution after 72 h against two plant pathogens, Fusarium oxysporum and Verticillium dahlia. Statistical experimental design of this study and the use of non-edible oil cakes as a substrate offer an efficient and viable approach for DPA production by P. variotii.

  14. TENDL-TMC for Δdpa and Δpka

    International Nuclear Information System (INIS)

    Rochman, D.; Ferroukhi, H.; Koning, A.J.; Sjostrand, H.; Helgesson, P.; Gilbert, M.; Sublet, J.C.

    2016-01-01

    Full text: The TENDL library (Talys Evaluated Nuclear Data Library) contains the necessary information (e.g. recoil spectra, double differential data) to calculate quantities of interest for the material damage. Additionally, it is one of the most complete libraries in terms of number of isotopes and format-wise: 2800 isotopes (ground states and isomers) and all ENDF-6 sections from MF1 to MF40. It can then be naturally used for the estimation of “DPA” and “PKA”, given the correct NJOY processing. Details of the library, its production, formatting and processing are given during the technical meeting. Comparison with other libraries indicated the importance of including all the “MT” sections for the correct processing with NJOY, but also it showed the difference obtained depending of the format chosen to store the decay data. Regarding the uncertainties on DPA and PKA, the TMC method seems to be one of the most convenient methods. As presented during the meeting, the uncertainty propagation using random ENDF-6 files produced from variations of model parameters leads to non-Gaussian distributions for the damage quantities. As a function of the incident neutron energy, the skewness of such distributions can strongly vary and be far from 0. This indicates that the standard deviation alone cannot represent, well enough, the dispersion of the calculated data. A viable alternative is the production of so-called random ENDF-6 files based on given covariance information. This method is limited by the available information given in the covariance files, but can help to capture part of the uncertainties for the DPA and PKA quantities. For TENDL-2016, the covariance format MF32 will be less used and efforts will be devoted to produce MF33, which will facilitate the production of random ENDF-6 files with SCK codes such as SANDY. A PSI internal project to link the nuclear data with the atomistic simulation of damage formation and microstructure evolution was also

  15. Synthesis of [125I]iodoDPA-713: A new probe for imaging inflammation

    International Nuclear Information System (INIS)

    Wang, Haofan; Pullambhatla, Mrudula; Guilarte, Tomas R.; Mease, Ronnie C.; Pomper, Martin G.

    2009-01-01

    [ 125 I]IodoDPA-713 [ 125 I]1, which targets the translocator protein (TSPO, 18 kDa), was synthesized in seven steps from methyl-4-methoxybenzoate as a tool for quantification of inflammation in preclinical models. Preliminary in vitro autoradiography and in vivo small animal imaging were performed using [ 125 I]1 in a neurotoxicant-treated rat and in a murine model of lung inflammation, respectively. The radiochemical yield of [ 125 I]1 was 44 ± 6% with a specific radioactivity of 51.8 GBq/μmol (1400 mCi/μmol) and >99% radiochemical purity. Preliminary studies showed that [ 125 I]1 demonstrated increased specific binding to TSPO in a neurotoxicant-treated rat and increased radiopharmaceutical uptake in the lungs of an experimental inflammation model of lung inflammation. Compound [ 125 I]1 is a new, convenient probe for preclinical studies of TSPO activity.

  16. Mechanical properties and TEM examination of RAFM steels irradiated up to 70 dpa in BOR-60

    Energy Technology Data Exchange (ETDEWEB)

    Gaganidze, E., E-mail: Ermile.Gaganidze@kit.edu [Karlsruher Institut fuer Technologie, Institut fuer Angewandte Materialien, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Petersen, C.; Materna-Morris, E.; Dethloff, C.; Weiss, O.J.; Aktaa, J. [Karlsruher Institut fuer Technologie, Institut fuer Angewandte Materialien, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Povstyanko, A.; Fedoseev, A.; Makarov, O.; Prokhorov, V. [Joint Stock Company ' State Scientific Centre Research Institute of Atomic Reactors' , 433510 Dimitrovgrad-10, Ulyanovsk Region (Russian Federation)

    2011-10-01

    Mechanical properties of Reduced Activation Ferritic/Martensitic (RAFM) steels were studied after irradiation in BOR-60 reactor to a neutron displacement damage of 70 dpa at 330-340 deg. C. Yield stress and Ductile-to-Brittle-Transition-Temperature of EUROFER97 indicate saturation of hardening and embrittlement. The phenomenological models for description of microstructure evolution and resulting irradiation hardening and embrittlement are discussed. The evolution of yield stress with dose is qualitatively understood within a Whapham and Makin model. Dislocation loops examined in TEM are considered a main source for low-temperature irradiation hardening. The analysis of the fatigue data in terms of the inelastic strain reveals comparable fatigue behaviour both for unirradiated and irradiated conditions, which can be described by a common Manson-Coffin relation. The study of helium effects in B-doped model steels indicated progressive material embrittlement with helium content. Post-irradiation annealing of RAFM steels yielded substantial recovery of mechanical properties.

  17. Quantitation of bone mineral by dual photon absorptiometry (DPA): Evaluation of instrument performance

    International Nuclear Information System (INIS)

    Dunn, W.L.; O'Duffy, A.; Wahner, H.W.

    1984-01-01

    Quantitation of bone mineral is used with increasing frequency for clinical studies. This paper details the principle of DPA and present an evaluation of the technique. DPA measurements were performed with a scanning dual photon system constructed at this institution and modeled after the device developed at the University of Wisconsin. The components are a rectilinear scanner frame, 1.5 Ci Gd-153 source, NaI(TL) detector and a PDP 11/03 computer. Dual discriminator windows are set on the 44 and 100 keV photon energies of Gd-153. Instrument linearity, accuracy and reproducibility were evaluated with ashed bone standards and simulated tissue covering. In these experiments computed and actual bone mineral have a correlation coefficient of 1.0 and a SEE of approximately 1.0% (Linear regression analysis). Precision and accuracy of a standard were studied over a period of two years. Mean error between actual and measured bone mineral was 0.28%. In vivo precision in six subjects averaged 2.3% (CV) for lumbar spine measurements. The effect of soft tissue compositional change was studied with ashed bone standards and human cadaver spine specimens. Intraosseous fat changes of 50% produced an average bone mineral measurement error of 1.4%. A 20% change in fat thickness produced a 2.5% error. In situ and in vitro scans of 9 cadaver spines were performed to study the effect of extraosseous fat. The mean percent difference between the two measurements was 0.7% (SEE=3.2%)

  18. Continuous gradient temperature Raman spectroscopy of n-6 DPA and DHA from -100 C to 20°C

    Science.gov (United States)

    One of the great unanswered questions with respect to biological science in general is the absolute necessity of DHA in fast signal processing tissues. N-6 DPA, with just one less diene, group, is fairly abundant in terrestrial food chains yet cannot substitute for DHA. Gradient Temperature Raman sp...

  19. Experimental Charge Density Study of Trichromium Linear Metal String Complex – Cr3(dpa)4Cl2

    DEFF Research Database (Denmark)

    Wu, Lai-Chin; Cheng, Ming-Chuan; Thomsen, Maja Krüger

    An experimental and theoretical charge density study, based on Bader’s Quantum Theory: Atoms in Molecule (QTAIM), on a trichromium metal string complex, Cr3(dpa)4Cl2(C2H5OC2H5)x(CH2Cl2)1-x (1, dpa- = bis(2-pyridyl)amido)) is performed. The structure and multipole model of 1 are performed by using...... experimental X-ray diffraction data which are collected at both 100 K using conventional X-ray source (DS1) and 15 K using synchrotron source (DS2). The three chromium metal string is bridged by four dpa- ligands. These tri-chromium metal ions are bonded to each other and terminated by two Cl- ions on the both...... ends, forming a [Cl(1)Cr(1)Cr(2)Cr(3)Cl(2)] linear string. Each Cr atoms are coordinated by four N atoms of each dpa- ligand. This metal string is slightly unsymmetrical at both data sets. The bond distance, from DS1 (DS2), of Cr(1)Cr(2), 2.3480(2) (2.3669(1)) Å, is 0.03 (0.003) Å shorter than Cr...

  20. Analysis of dpa Rates in the HFIR Reactor Vessel using a Hybrid Monte Carlo/Deterministic Method*

    Directory of Open Access Journals (Sweden)

    Risner J.M.

    2016-01-01

    Full Text Available The Oak Ridge High Flux Isotope Reactor (HFIR, which began full-power operation in 1966, provides one of the highest steady-state neutron flux levels of any research reactor in the world. An ongoing vessel integrity analysis program to assess radiation-induced embrittlement of the HFIR reactor vessel requires the calculation of neutron and gamma displacements per atom (dpa, particularly at locations near the beam tube nozzles, where radiation streaming effects are most pronounced. In this study we apply the Forward-Weighted Consistent Adjoint Driven Importance Sampling (FW-CADIS technique in the ADVANTG code to develop variance reduction parameters for use in the MCNP radiation transport code. We initially evaluated dpa rates for dosimetry capsule locations, regions in the vicinity of the HB-2 beamline, and the vessel beltline region. We then extended the study to provide dpa rate maps using three-dimensional cylindrical mesh tallies that extend from approximately 12 in. below to approximately 12 in. above the height of the core. The mesh tally structures contain over 15,000 mesh cells, providing a detailed spatial map of neutron and photon dpa rates at all locations of interest. Relative errors in the mesh tally cells are typically less than 1%.

  1. HLA DRB1*, DQB1*, DPA1* y DPB1* y su asociación con la patogénesis de las leucemias en población venezolana

    Directory of Open Access Journals (Sweden)

    Sergio E. Rivera-Pirela

    2016-08-01

    Full Text Available Background: The HLA complex is involved in the pathogenesis of leukemia. Objectives: The presence of class II HLA alleles DRB1 *, DQB1 *, DPA1 *, and DPB1 * was evaluated in 47 patients with acute lymphoblastic leukemia (ALL and 48 with chronic myeloid leukemia (CML for comparison with 48 healthy volunteers in Zulia, Venezuela, and to evaluate potential associations of HLA with leukemia. Methods: Low- and high-resolution PCR-SSP was used for class II HLA regions DRB1 *, DQB1 *, DPA1 *, and DPB1 * following the instructions of KIT Olerup SSP Genovision. Results: Alleles HLA-DRB1*14, especially DRB1*14:21, -DPA1*1:06, -DPA1*01:03,-DPA1*02:01, and the haplotypes HLA-DPA1*01:03-DPB1*04:01, DPA1*01:03-DPB1*02:01, DPA1*01:03-DPB1*99:01, -DRB1*14-DPA1*01:03, -DRB1*15-DPA1*01:03 were associated with CML (RR > 3; alleles HLA-DRB1*13, -DQB1*02, -DPA1*01:05, -DPA1*01:09 and the haplotypes HLA-DPA1*01:09-DPB1*02:01, DPA1*01:09-DPB1*04:01 were protective (RR < 1. Alleles HLA-DQB1*04, -DQB1*05, -DPA1*1:06, -DPA1*01:07, -DPA1*1:08 had a positive association with ALL. Alleles HLA-DPA1*01:09, -DPA1*02:01, -DPB1*02:01, -DPB1*03:01 and the haplotypes HLA-DPA1*01:03-DPB1*04:02, -DPA1*01:09-DPB1*02:01, -DPA1*01:09-DPB1*04:01, -DPA1*02:01-DPB1*04:02 were negatively associated. Conclusions: The absence of associations with HLA-DRB1 * region in ALL and other association patterns identified suggest marked differences in the pathogenesis of leukemia, which suggests possible deficiencies in antigen presentation for ALL or potential effects of molecular mimicry in CML.

  2. PET imaging of neuroinflammation in a rat traumatic brain injury model with radiolabeled TSPO ligand DPA-714

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yu [Medical School of Southeast University, Jiangsu Key Laboratory of Molecular Imaging and Functional Imaging, Department of Radiology, Zhongda Hospital, Nanjing (China); National Institutes of Health - NIH, Laboratory of Molecular Imaging and Nanomedicine - LOMIN, National Institute of Biomedical Imaging and Bioengineering - NIBIB, Bethesda, MD (United States); Yue, Xuyi; Kiesewetter, Dale O.; Niu, Gang; Chen, Xiaoyuan [National Institutes of Health - NIH, Laboratory of Molecular Imaging and Nanomedicine - LOMIN, National Institute of Biomedical Imaging and Bioengineering - NIBIB, Bethesda, MD (United States); Teng, Gaojun [Medical School of Southeast University, Jiangsu Key Laboratory of Molecular Imaging and Functional Imaging, Department of Radiology, Zhongda Hospital, Nanjing (China)

    2014-07-15

    The inflammatory response in injured brain parenchyma after traumatic brain injury (TBI) is crucial in the pathological process. In order to follow microglia activation and neuroinflammation after TBI, we performed PET imaging in a rat model of TBI using {sup 18}F-labeled DPA-714, a ligand of the 18-kDa translocator protein (TSPO). TBI was induced in male SD rats by a controlled cortical impact. The success of the TBI model was confirmed by MRI. [{sup 18}F]DPA-714 was synthesized using a slightly modified TRACERLab FX-FN module and an automated procedure. In vivo PET imaging was performed at different time points after surgery using an Inveon small-animal PET scanner. The specificity of [{sup 18}F]DPA-714 was confirmed by a displacement study with an unlabeled competitive TSPO ligand, PK11195. Ex vivo autoradiography as well as immunofluorescence staining was carried out to confirm the in vivo PET results. Both in vivo T{sub 2}-weighted MR images and ex vivo TTC staining results revealed successful establishment of the TBI model. Compared with the sham-treated group, [{sup 18}F]DPA-714 uptake was significantly higher in the injured brain area on PET images. Increased lesion-to-normal ratios of [{sup 18}F]DPA-714 were observed in the brain of TBI rats on day 2 after surgery. Ratios peaked around day 6 (2.65 ± 0.36) and then decreased gradually to nearly normal levels on day 28. The displacement study using PK11195 confirmed the specific binding of [{sup 18}F]DPA-714 to TSPO. The results of ex vivo autoradiography were consistent with in vivo PET results. Immunofluorescence staining showed the time course of TSPO expression after TBI and the temporal and the spatial distribution of microglia in the damaged brain area. TSPO-targeted PET using [{sup 18}F]DPA-714 as the imaging probe can be used to dynamically monitor the inflammatory response after TBI in a noninvasive manner. This method will not only facilitate a better understanding of the inflammatory process

  3. Calculation of DPA in the Reactor Internal Structural Materials of Nuclear Power Plant

    International Nuclear Information System (INIS)

    Kim, Yong Deong; Lee, Hwan Soo

    2014-01-01

    The embrittlement is mainly caused by atomic displacement damage due to irradiations with neutrons, especially fast neutrons. The integrity of the reactor internal structural materials has to be ensured over the reactor life time, threatened by the irradiation induced displacement damage. Accurate modeling and prediction of the displacement damage is a first step to evaluate the integrity of the reactor internal structural materials. Traditional approaches for analyzing the displacement damage of the materials have relied on tradition model, developed initially for simple metals, Kinchin and Pease (K-P), and the standard formulation of it by Norgett et al. , often referred to as the 'NRT' model. An alternative and complementary strategy for calculating the displacement damage is to use MCNP code. MCNP uses detailed physics and continuous-energy cross-section data in its simulations. In this paper, we have performed the evaluation of the displacement damage of the reactor internal structural materials in Kori NPP unit 1 using detailed Monte Carlo modeling and compared with predictions results of displacement damage using the classical NRT model. The evaluation of the displacement damage of the reactor internal structural materials in Kori NPP unit 1 using detailed Monte Carlo modeling has been performed. The maximum value of the DPA rate was occurred at the baffle side of the reactor internal where the node has the maximum neutron flux

  4. Effects of neutron irradiation at 4500C and 16 dpa on the properties of various commercial copper alloys

    International Nuclear Information System (INIS)

    Brager, H.R.; Heinisch, H.L.; Garner, F.A.

    1985-01-01

    High-purity copper and eight copper alloys were irradiated to approx.16 dpa at approx.450 0 C in the MOTA experiment in FFTF. These alloys were also examined after aging at 400 0 C for 1000 hours. The radiation-induced changes in the electrical conductivity, tensile properties, and density were measured and compared to those of the aged materials. The changes in conductivity can be either positive or negative depending on the alloy. Changes in tensile properties of most, but not all, of the alloys seem to be primarily dependent on thermal effects rather than the effect of atomic displacements. Radiation at 450 0 C induced changes in density varying from 0.66% densification to 16.6% swelling. The latter occurred in Cu-O.1% Ag and implies a swelling rate of at least 1%/dpa. 6 references, 3 figures, 2 tables

  5. Tensile mechanical properties of a stainless steel irradiated up to 19 dpa in the Swiss spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Shigeru, E-mail: saito.shigeru@jaea.go.jp [JAEA, J-PARC Center, Tokai-mura, Ibaraki-ken 319-1195 (Japan); Kikuchi, Kenji [Ibaraki Univ., iFRC, Tokai-mura, Ibaraki-ken 319-1106 (Japan); Hamaguchi, Dai [JAEA, J-PARC Center, Tokai-mura, Ibaraki-ken 319-1195 (Japan); Usami, Kouji; Endo, Shinya; Ono, Katsuto; Matsui, Hiroki [JAEA, Dept. of Hot Laboratories, Tokai-mura, Ibaraki-ken 319-1195 (Japan); Kawai, Masayoshi [KEK, Tsukuba-shi, Ibaraki-ken 305-0801 (Japan); Dai, Yong [PSI, Spallation Source Division, Villigen PSI (Switzerland)

    2012-12-15

    To evaluate the lifetime of the beam window of an accelerator-driven transmutation system (ADS), post irradiation examination (PIE) of the STIP (SINQ target irradiation program, SINQ; Swiss spallation neutron source) specimens was carried out. The specimens tested in this study were made from the austenitic steel Japan primary candidate alloy (JPCA). The specimens were irradiated at SINQ Target 4 (STIP-II) with high-energy protons and spallation neutrons. The irradiation conditions were as follows: the proton energy was 580 MeV, irradiation temperatures ranged from 100 to 430 Degree-Sign C, and displacement damage levels ranged from 7.1 to 19.5 dpa. Tensile tests were performed in air at room temperature (RT), 250 Degree-Sign C and 350 Degree-Sign C. Fracture surface observation after the tests was done by Scanning electron microscope (SEM). Results of the tensile tests performed at R.T. showed the extra hardening of JPCA at higher dose compared to the fission neutron irradiated data. At the higher temperatures, 250 Degree-Sign C and 350 Degree-Sign C, the extra hardening was not observed. Degradation of ductility bottomed around 10 dpa, and specimens kept their ductility until 19.5 dpa. All specimens fractured in ductile manner.

  6. Continuous gradient temperature Raman spectroscopy and differential scanning calorimetry of N-3DPA and DHA from -100 to 10°C.

    Science.gov (United States)

    Broadhurst, C Leigh; Schmidt, Walter F; Nguyen, Julie K; Qin, Jianwei; Chao, Kuanglin; Aubuchon, Steven R; Kim, Moon S

    2017-04-01

    Docosahexaenoic acid (DHA, 22:6n-3) is exclusively utilized in fast signal processing tissues such as retinal, neural and cardiac. N-3 docosapentaenoic acid (n-3DPA, 22:5n-3), with just one less double bond, is also found in the marine food chain yet cannot substitute for DHA. Gradient temperature Raman spectroscopy (GTRS) applies the temperature gradients utilized in differential scanning calorimetry (DSC) to Raman spectroscopy, providing a straightforward technique to identify molecular rearrangements that occur near and at phase transitions. Herein we apply GTRS and both conventional and modulated DSC to n-3DPA and DHA from -100 to 20°C. Three-dimensional data arrays with 0.2°C increments and first derivatives allowed complete assignment of solid, liquid and transition state vibrational modes. Melting temperatures n-3DPA (-45°C) and DHA (-46°C) are similar and show evidence for solid-state phase transitions not seen in n-6DPA (-27°C melt). The C6H2 site is an elastic marker for temperature perturbation of all three lipids, each of which has a distinct three dimensional structure. N-3 DPA shows the spectroscopic signature of saturated fatty acids from C1 to C6. DHA does not have three aliphatic carbons in sequence; n-6DPA does but they occur at the methyl end, and do not yield the characteristic signal. DHA appears to have uniform twisting from C6H2 to C12H2 to C18H2 whereas n-6DPA bends from C12 to C18, centered at C15H2. For n-3DPA, twisting is centered at C6H2 adjacent to the C2-C3-C4-C5 aliphatic moiety. These molecular sites are the most elastic in the solid phase and during premelting. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. [18F]DPA-714: direct comparison with [11C]PK11195 in a model of cerebral ischemia in rats.

    Directory of Open Access Journals (Sweden)

    Hervé Boutin

    Full Text Available PURPOSE: Neuroinflammation is involved in several brain disorders and can be monitored through expression of the translocator protein 18 kDa (TSPO on activated microglia. In recent years, several new PET radioligands for TSPO have been evaluated in disease models. [(18F]DPA-714 is a TSPO radiotracer with great promise; however results vary between different experimental models of neuroinflammation. To further examine the potential of [(18F]DPA-714, it was compared directly to [(11C]PK11195 in experimental cerebral ischaemia in rats. METHODS: Under anaesthesia, the middle cerebral artery of adult rats was occluded for 60 min using the filament model. Rats were allowed recovery for 5 to 7 days before one hour dynamic PET scans with [(11C]PK11195 and/or [(18F]DPA-714 under anaesthesia. RESULTS: Uptake of [(11C]PK11195 vs [(18F]DPA-714 in the ischemic lesion was similar (core/contralateral ratio: 2.84±0.67 vs 2.28±0.34 respectively, but severity of the brain ischemia and hence ligand uptake in the lesion appeared to vary greatly between animals scanned with [(11C]PK11195 or with [(18F]DPA-714. To solve this issue of inter-individual variability, we performed a direct comparison of [(11C]PK11195 and [(18F]DPA-714 by scanning the same animals sequentially with both tracers within 24 h. In this direct comparison, the core/contralateral ratio (3.35±1.21 vs 4.66±2.50 for [(11C]PK11195 vs [(18F]DPA-714 respectively showed a significantly better signal-to-noise ratio (1.6 (1.3-1.9, 95%CI fold by linear regression for [(18F]DPA-714. CONCLUSIONS: In a clinically relevant model of neuroinflammation, uptake for both radiotracers appeared to be similar at first, but a high variability was observed in our model. Therefore, to truly compare tracers in such models, we performed scans with both tracers in the same animals. By doing so, our result demonstrated that [(18F]DPA-714 displayed a higher signal-to-noise ratio than [(11C]PK11195. Our results suggest

  8. [18F]DPA-714: Direct comparison with [11C]PK11195 in a model of cerebral ischemia in rats

    International Nuclear Information System (INIS)

    Boutin, Herve; Prenant, Christian; Smigova, Alison; Cawthorne, Christopher; Brown, Gavin; Herholz, Karl; Maroy, Renaud; Galea, James; Greenhalgh, Andrew D.; Rothwell, Nancy J.; Julyan, Peter; Wilkinson, Shane M.; Banister, Samuel D.; Kassiou, Michael

    2013-01-01

    Neuro-inflammation is involved in several brain disorders and can be monitored through expression of the translocator protein 18 kDa (TSPO) on activated micro-glia. In recent years, several new PET radioligands for TSPO have been evaluated in disease models. [ 18 F]DPA-714 is a TSPO radiotracer with great promise; however results vary between different experimental models of neuro-inflammation. To further examine the potential of [ 18 F]DPA-714, it was compared directly to [ 11 C]PK11195 in experimental cerebral ischaemia in rats. Under anaesthesia, the middle cerebral artery of adult rats was occluded for 60 min using the filament model. Rats were allowed recovery for 5 to 7 days before one hour dynamic PET scans with [ 11 C]PK11195 and/or [ 18 F]DPA-714 under anaesthesia. Uptake of [ 11 C]PK11195 vs [ 18 F]DPA-714 in the ischemic lesion was similar (core/contralateral ratio: 2.8460.67 vs 2.2860.34 respectively), but severity of the brain ischemia and hence ligand uptake in the lesion appeared to vary greatly between animals scanned with [ 11 C]PK11195 or with [ 18 F]DPA-714. To solve this issue of inter-individual variability, we performed a direct comparison of [ 11 C]PK11195 and [ 18 F]DPA-714 by scanning the same animals sequentially with both tracers within 24 h. In this direct comparison, the core/contralateral ratio (3.3561.21 vs 4.6662.50 for [ 11 C]PK11195 vs [ 18 F]DPA-714 respectively) showed a significantly better signal-to-noise ratio (1.6 (1.3-1.9, 95%CI) fold by linear regression) for [ 18 F]DPA-714. In a clinically relevant model of neuro-inflammation, uptake for both radiotracers appeared to be similar at first, but a high variability was observed in our model. Therefore, to truly compare tracers in such models, we performed scans with both tracers in the same animals. By doing so, our result demonstrated that [ 18 F]DPA-714 displayed a higher signal-to-noise ratio than [ 11 C]PK11195. Our results suggest that, with the longer half-life of [ 18 F

  9. [{sup 18}F]DPA-714 PET imaging of translocator protein TSPO (18 kDa) in the normal and excitotoxically-lesioned nonhuman primate brain

    Energy Technology Data Exchange (ETDEWEB)

    Lavisse, S.; Inoue, K.; Jan, C.; Petit, F.; Dauguet, J.; Guillermier, M.; Rbah-Vidal, L.; Van Camp, N.; Aron-Badin, R.; Hantraye, P. [CEA, I2BM, MIRCen, Fontenay-aux-Roses (France); CEA, CNRS, URA2210, Fontenay-aux-Roses (France); Peyronneau, M.A.; Goutal, S.; Dolle, F. [CEA, I2BM, Service Hospitalier Frederic Joliot, Orsay (France); Remy, P. [CEA, I2BM, MIRCen, Fontenay-aux-Roses (France); CEA, CNRS, URA2210, Fontenay-aux-Roses (France); Service de Neurologie, CHU Henri Mondor, Creteil (France)

    2014-12-09

    We aimed to characterize pharmacologically the TSPO- radioligand [{sup 18}F]DPA-714 in the brain of healthy cynomolgus monkeys and evaluate the cellular origin of its binding in a model of neurodegeneration induced by intrastriatal injection of quinolinic acid (QA). [{sup 18}F]DPA-714 PET images were acquired before and at 2, 7, 14, 21, 49, 70, 91 days after putaminal lesioning. Blocking and displacement studies were carried out (PK11195). Different modelling approaches estimated rate constants and V{sub T} (total distribution volume) which was used to measure longitudinal changes in the lesioned putamen. Sections for immunohistochemical labelling were prepared at the same time-points to evaluate correlations between in vivo [{sup 18}F]DPA-714 binding and microglial/astrocytic activation. [{sup 18}F]DPA-714 showed a widespread distribution with a higher signal in the thalamus and occipital cortex and lower binding in the cerebellum. TSPO was expressed throughout the whole brain and about 73 % of [{sup 18}F]DPA-714 binding was specific for TSPO in vivo. The one-tissue compartment model (1-TCM) provided good and reproducible estimates of V{sub T} and rate constants, and V{sub T} values from the 1-TCM and the Logan approach were highly correlated (r {sup 2} = 0.85). QA lesioning induced an increase in V{sub T}, which was +17 %, +54 %, +157 % and +39 % higher than baseline on days 7, 14, 21 and 91 after QA injection, respectively. Immunohistochemistry revealed an early microglial and a delayed astrocytic activation after QA injection. [{sup 18}F]DPA-714 binding matched TSPO immunopositive areas and showed a stronger colocalization with CD68 microglia than with GFAP-activated astrocytes. [{sup 18}F]DPA-714 binds to TSPO with high specificity in the primate brain under normal conditions and in the QA model. This tracer provides a sensitive tool for assessing neuroinflammation in the human brain. (orig.)

  10. Extreme embrittlement of austenitic stainless steel irradiated to 75-81 dpa at 335-360{degrees}C

    Energy Technology Data Exchange (ETDEWEB)

    Porollo, S.I.; Vorobjev, A.N.; Konobeev, Yu.V. [Institute of Physics and Power Engineering, Obninsk (Russian Federation)] [and others

    1997-04-01

    It is generally accepted that void swelling of austenitic steels ceases below some temperature in the range 340-360{degrees}C, and exhibits relatively low swelling rates up to {approximately}400{degrees}C. This perception may not be correct at all irradiation conditions, however, since it was largely developed from data obtained at relatively high displacement rates in fast reactors whose inlet temperatures were in the range 360-370{degrees}C. There is an expectation, however, that the swelling regime can shift to lower temperatures at low displacement rates via the well-known {open_quotes}temperature shift{close_quotes} phenomenon. It is also known that the swelling rates at the lower end of the swelling regime increase continuously at a sluggish rate, never approaching the terminal 1%/dpa level within the duration of previous experiments. This paper presents the results of an experiment conducted in the BN-350 fast reactor in Kazakhstan that involved the irradiation of argon-pressurized thin-walled tubes (0-200 MPa hoop stress) constructed from Fe-16Cr-15Ni-3Mo-Nb stabilized steel in contact with the sodium coolant, which enters the reactor at {approx}270{degrees}C. Tubes in the annealed condition reached 75 dpa at 335{degrees}C, and another set in the 20% cold-worked condition reached 81 dpa at 360{degrees}C. Upon disassembly all tubes, except those in the stress-free condition, were found to have failed in an extremely brittle fashion. The stress-free tubes exhibited diameter changes that imply swelling levels ranging from 9 to 16%. It is expected that stress-enhancement of swelling induced even larger swelling levels in the stressed tubes.

  11. Wavelength-Modulated Differential Photoacoustic (WM-DPA) imaging: a high dynamic range modality towards noninvasive diagnosis of cancer

    Science.gov (United States)

    Dovlo, Edem; Lashkari, Bahman; Choi, Sung soo Sean; Mandelis, Andreas

    2016-03-01

    This study explores wavelength-modulated differential photo-acoustic (WM-DPA) imaging for non-invasive early cancer detection via sensitive characterization of functional information such as hemoglobin oxygenation (sO2) levels. Well-known benchmarks of tumor formation such as angiogenesis and hypoxia can be addressed this way. While most conventional photo-acoustic imaging has almost entirely employed high-power pulsed lasers, frequency-domain photo-acoustic radar (FD-PAR) has seen significant development as an alternative technique. It employs a continuous wave laser source intensity-modulated and driven by frequency-swept waveforms. WM-DPA imaging utilizes chirp modulated laser beams at two distinct wavelengths for which absorption differences between oxy- and deoxygenated hemoglobin are minimum (isosbestic point, 805 nm) and maximum (680 nm) to simultaneously generate two signals detected using a standard commercial array transducer as well as a single-element transducer that scans the sample. Signal processing is performed using Lab View and Matlab software developed in-house. Minute changes in total hemoglobin concentration (tHb) and oxygenation levels are detectable using this method since background absorption is suppressed due to the out-of-phase modulation of the laser sources while the difference between the two signals is amplified, thus allowing pre-malignant tumors to become identifiable. By regulating the signal amplitude ratio and phase shift the system can be tuned to applications like cancer screening, sO2 quantification and hypoxia monitoring in stroke patients. Experimental results presented demonstrate WM-DPA imaging of sheep blood phantoms in comparison to single-wavelength FD-PAR imaging. Future work includes the functional PA imaging of small animals in vivo.

  12. Extreme embrittlement of austenitic stainless steel irradiated to 75-81 dpa at 335-360 degrees C

    International Nuclear Information System (INIS)

    Porollo, S.I.; Vorobjev, A.N.; Konobeev, Yu.V.

    1997-01-01

    It is generally accepted that void swelling of austenitic steels ceases below some temperature in the range 340-360 degrees C, and exhibits relatively low swelling rates up to ∼400 degrees C. This perception may not be correct at all irradiation conditions, however, since it was largely developed from data obtained at relatively high displacement rates in fast reactors whose inlet temperatures were in the range 360-370 degrees C. There is an expectation, however, that the swelling regime can shift to lower temperatures at low displacement rates via the well-known open-quotes temperature shiftclose quotes phenomenon. It is also known that the swelling rates at the lower end of the swelling regime increase continuously at a sluggish rate, never approaching the terminal 1%/dpa level within the duration of previous experiments. This paper presents the results of an experiment conducted in the BN-350 fast reactor in Kazakhstan that involved the irradiation of argon-pressurized thin-walled tubes (0-200 MPa hoop stress) constructed from Fe-16Cr-15Ni-3Mo-Nb stabilized steel in contact with the sodium coolant, which enters the reactor at ∼270 degrees C. Tubes in the annealed condition reached 75 dpa at 335 degrees C, and another set in the 20% cold-worked condition reached 81 dpa at 360 degrees C. Upon disassembly all tubes, except those in the stress-free condition, were found to have failed in an extremely brittle fashion. The stress-free tubes exhibited diameter changes that imply swelling levels ranging from 9 to 16%. It is expected that stress-enhancement of swelling induced even larger swelling levels in the stressed tubes

  13. Charpy impact test results of four low activation ferritic alloys irradiated at 370{degrees}C to 15 DPA

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-10-01

    Miniature CVN specimens of four low activation ferritic alloys have been impact tested following irradiation at 370{degrees}C to 15 dpa. Comparison of the results with those of control specimens indicates that degradation in the impact behavior occurs in each of these four alloys. The 9Cr-2W alloy referred to as GA3X and the similar alloy F82H with 7.8Cr-2W appear most promising for further consideration as candidate structural materials in fusion energy system applications. These two alloys exhibit a small DBTT shift to higher temperatures but show increased absorbed energy on the upper shelf.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-10-01

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

  15. Neutron radiation damage studies in the structural materials of a 500 MWe fast breeder reactor using DPA cross-sections from ENDF / B-VII.1

    Science.gov (United States)

    Saha, Uttiyoarnab; Devan, K.; Bachchan, Abhitab; Pandikumar, G.; Ganesan, S.

    2018-04-01

    The radiation damage in the structural materials of a 500 MWe Indian prototype fast breeder reactor (PFBR) is re-assessed by computing the neutron displacement per atom (dpa) cross-sections from the recent nuclear data library evaluated by the USA, ENDF / B-VII.1, wherein revisions were taken place in the new evaluations of basic nuclear data because of using the state-of-the-art neutron cross-section experiments, nuclear model-based predictions and modern data evaluation techniques. An indigenous computer code, computation of radiation damage (CRaD), is developed at our centre to compute primary-knock-on atom (PKA) spectra and displacement cross-sections of materials both in point-wise and any chosen group structure from the evaluated nuclear data libraries. The new radiation damage model, athermal recombination-corrected displacement per atom (arc-dpa), developed based on molecular dynamics simulations is also incorporated in our study. This work is the result of our earlier initiatives to overcome some of the limitations experienced while using codes like RECOIL, SPECTER and NJOY 2016, to estimate radiation damage. Agreement of CRaD results with other codes and ASTM standard for Fe dpa cross-section is found good. The present estimate of total dpa in D-9 steel of PFBR necessitates renormalisation of experimental correlations of dpa and radiation damage to ensure consistency of damage prediction with ENDF / B-VII.1 library.

  16. Irradiation creep and swelling of AISI 316 to exposures of 130 dpa at 385?400$deg;C

    Science.gov (United States)

    Garner, F. A.; Porter, D. L.

    1988-07-01

    The creep and swelling of AISI 316 stainless steel have been studied at 385 to 400°C in EBR-II to doses of 130 dpa. Most creep capsules were operated at constant stress and temperature but mid-life changes in these variables were also made. This paper concentrates on the behavior of the 20% cold-worked condition but five other conditions were also studied. Swelling at ⩽ 400° C was found to lose the sensitivity to stress exhibited at higher temperatures while the creep rate was found to retain linear dependencies on both stress and swelling rate. The creep coefficients extracted at 400°C agree with those found in other experiments conducted at higher temperatures. In the temperature range of ⩽ 400° C, swelling is in the recombinationdominated regime and the swelling rate falls strongly away from the ~1%/dpa rate observed at higher temperatures. These lower rates of creep and swelling, coupled with the attainment of high damage levels without failure, encourage the use of AISI 316 in the construction of water-cooled fusion first walls operating at temperatures below 400°C.

  17. Analysis of Proton Induced Material Damage Using the DPA Cross-sections Based on NRT and BCA-MD Models

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyung-O; Roh, Gyuhong; Lee, Byungchul [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    The level of radiation induced material damage is mainly quantified by using the unit of Displacements Per Atom (DPA), and particularly, the displacement cross-section is used for characterizing/analyzing the radiation damage from incident neutrons and charged particles. Not long ago, the standard Norgett-Robinson-Torrens (NRT) model had been applied to produce the nuclear data due to its simplicity and implementation in commonly used codes, such as NJOY and MCNP codes. However, the evaluations based on NRT model represent the severe disagreement with experimental data and more accurate calculations. Hence, the evaluations with existing and new nuclear data are performed/compared in this study. It is assumed that a high energy proton beam is directly moved to the target, and a series of calculations are performed by using MCNPX code. The proton induced material damage is evaluated by using the displacement cross-sections, and the effect of nuclear data on the evaluation is specifically analyzed with MCNPX code. First, there is significant difference between the nuclear data from existing and new models, and the new evaluated data is generally lower than the existing one. Second, the position of maximum DPA is slightly differed with the position of maximum energy deposition, and the evaluation using new evaluated data is lower about 2 times than the other.

  18. Microchemical and microstructural evolution of AISI 304 stainless steel irradiated in EBR-II at PWR-relevant dpa rates

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Y. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Sencer, B.H. [Idaho National Laboratory, Idaho Falls, ID 83402 (United States); Garner, F.A. [Radiation Effects Consulting, Richland, WA 99354 (United States); Marquis, E.A., E-mail: emarq@umich.edu [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109 (United States)

    2015-12-15

    AISI 304 stainless steel was irradiated at 416 °C and 450 °C at a 4.4 × 10{sup −9} and 3.05 × 10{sup −7} dpa/s to ∼0.4 and ∼28 dpa, respectively, in the reflector of the EBR-II fast reactor. Both unirradiated and irradiated conditions were examined using standard and scanning transmission electron microscopy, energy dispersive spectroscopy, and atom probe tomography on very small specimens produced by focused ion beam milling. These results are compared with previous electron microscopy examination of 3 mm disks from essentially the same material. By comparing a very low dose specimen with a much higher dose specimen, both derived from a single reactor assembly, it has been demonstrated that the coupled microstructural and microchemical evolution of dislocation loops and other sinks begins very early, with elemental segregation producing at these sinks what appears to be measurable precursors to fully formed precipitates found at higher doses. The nature of these sinks and their possible precursors are examined in detail.

  19. Microchemical and microstructural evolution of AISI 304 stainless steel irradiated in EBR-II at PWR-relevant dpa rates

    Science.gov (United States)

    Dong, Y.; Sencer, B. H.; Garner, F. A.; Marquis, E. A.

    2015-12-01

    AISI 304 stainless steel was irradiated at 416 °C and 450 °C at a 4.4 × 10-9 and 3.05 × 10-7 dpa/s to ∼0.4 and ∼28 dpa, respectively, in the reflector of the EBR-II fast reactor. Both unirradiated and irradiated conditions were examined using standard and scanning transmission electron microscopy, energy dispersive spectroscopy, and atom probe tomography on very small specimens produced by focused ion beam milling. These results are compared with previous electron microscopy examination of 3 mm disks from essentially the same material. By comparing a very low dose specimen with a much higher dose specimen, both derived from a single reactor assembly, it has been demonstrated that the coupled microstructural and microchemical evolution of dislocation loops and other sinks begins very early, with elemental segregation producing at these sinks what appears to be measurable precursors to fully formed precipitates found at higher doses. The nature of these sinks and their possible precursors are examined in detail.

  20. Long-chain omega-3 fatty acids and the brain: a review of the independent and shared effects of EPA, DPA and DHA.

    Science.gov (United States)

    Dyall, Simon C

    2015-01-01

    Omega-3 polyunsaturated fatty acids (PUFAs) exhibit neuroprotective properties and represent a potential treatment for a variety of neurodegenerative and neurological disorders. However, traditionally there has been a lack of discrimination between the different omega-3 PUFAs and effects have been broadly accredited to the series as a whole. Evidence for unique effects of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and more recently docosapentaenoic acid (DPA) is growing. For example, beneficial effects in mood disorders have more consistently been reported in clinical trials using EPA; whereas, with neurodegenerative conditions such as Alzheimer's disease, the focus has been on DHA. DHA is quantitatively the most important omega-3 PUFA in the brain, and consequently the most studied, whereas the availability of high purity DPA preparations has been extremely limited until recently, limiting research into its effects. However, there is now a growing body of evidence indicating both independent and shared effects of EPA, DPA and DHA. The purpose of this review is to highlight how a detailed understanding of these effects is essential to improving understanding of their therapeutic potential. The review begins with an overview of omega-3 PUFA biochemistry and metabolism, with particular focus on the central nervous system (CNS), where DHA has unique and indispensable roles in neuronal membranes with levels preserved by multiple mechanisms. This is followed by a review of the different enzyme-derived anti-inflammatory mediators produced from EPA, DPA and DHA. Lastly, the relative protective effects of EPA, DPA and DHA in normal brain aging and the most common neurodegenerative disorders are discussed. With a greater understanding of the individual roles of EPA, DPA and DHA in brain health and repair it is hoped that appropriate dietary recommendations can be established and therapeutic interventions can be more targeted and refined.

  1. Reduced PBR/TSPO Expression After Minocycline Treatment in a Rat Model of Focal Cerebral Ischemia: A PET Study Using [18F]DPA-714

    International Nuclear Information System (INIS)

    Martin, A.; Boisgard, R.; Tavitian, B.; Kassiou, M.; Dolle, F.

    2011-01-01

    Background: Many new candidate pharmaceuticals designed to improve recovery after stroke have been proposed recently, but there are still too few molecular imaging methods capable to assess their efficacy. A hallmark of the inflammatory reaction that follows focal cerebral ischemia is overexpression of the mitochondrial peripheral benzodiazepine receptor/18 kDa translocator protein (PBR/TSPO) in the monocytic lineage and astrocytes. This overexpression can be imaged with positron emission tomography (PET) using PBR/TSPO-selective radioligands such as [ 18 F]DPA-714. Purpose: Here, we tested whether PET with [ 18 F]DPA-714 would evidence the effect of minocycline, a broad spectrum antibiotic presently tested as neuro-protective agent after stroke, on the inflammatory reaction induced in an experimental model of stroke. Procedures: Ten rats were subjected to a 2-h transient middle cerebral artery occlusion with reperfusion. Minocycline or saline was intravenously administrated 1 h after reperfusion and daily during the following 6 days. PET studies were performed using [ 18 F]DPA-714 at 7 days after cerebral ischemia. Results: In vivo PET imaging showed a significant decrease in [ 18 F]DPA-714 uptake at 7 days after cerebral ischemia in rats treated with minocycline with respect to saline-treated animals. Minocycline treatment had no effect on the size of the infarcted area. Conclusion: Minocycline administered daily during 7 days after ischemia decreases [ 18 F]DPA- 714 binding, suggesting that the drug exerts an anti-inflammatory activity. [ 18 F]DPA-714 PET is a useful bio-marker to study novel anti-inflammatory strategies in experimental cerebral ischemia. (authors)

  2. Helium influence on the microstructure and swelling of 9%Cr ferritic steel after neutron irradiation to 16.3 dpa

    International Nuclear Information System (INIS)

    Klimenkov, M.; Möslang, A.; Materna-Morris, E.

    2014-01-01

    Specially fabricated samples of the European reference 9Cr-WTaV steel EUROFER 97 alloyed with 0.081 mass% natural B and 0.081 and 0.114 mass% pure isotope 10 B were neutron-irradiated with about 16.3 dpa at temperatures in the range from 523 K to 723 K to study the influence of helium produced by 10 B(n,α) 7 Li transmutation reaction on microstructure, swelling and hardness. The spatial and size distributions of helium bubbles or cavities after irradiation at different temperatures were investigated by transmission electron microscopy. Vickers microhardness HV0.1 tests were performed on the as received specimens and specimens after irradiation. The influence of irradiation temperature and helium concentration on the size and density of the bubbles or cavities was analyzed and correlations with the hardness, tensile properties, and the fracture surface were discussed

  3. 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.)

  4. Mechanical behavior of AISI 304SS determined by miniature test methods after neutron irradiation to 28 dpa

    Energy Technology Data Exchange (ETDEWEB)

    Rabenberg, Ellen M.; Jaques, Brian J. [Department of Materials Science and Engineering, Boise State University, 1910 University Dr., Boise, ID 83725 (United States); Center for Advanced Energy Studies, 995 University Blvd., Idaho Falls, ID 83401 (United States); Sencer, Bulent H. [Center for Advanced Energy Studies, 995 University Blvd., Idaho Falls, ID 83401 (United States); Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Garner, Frank A. [Radiation Effects Consulting, 2003 Howell Ave., Richland, WA 99354 (United States); Freyer, Paula D. [Westinghouse Electric Company LLC, Pittsburgh, PA 15235 (United States); Okita, Taira [Research Into Artifacts Dept., Center for Engineering, University of Tokyo, Tokyo (Japan); Butt, Darryl P., E-mail: DarrylButt@BoiseState.edu [Department of Materials Science and Engineering, Boise State University, 1910 University Dr., Boise, ID 83725 (United States); Center for Advanced Energy Studies, 995 University Blvd., Idaho Falls, ID 83401 (United States)

    2014-05-01

    The mechanical properties of AISI 304 stainless steel irradiated for over a decade in the Experimental Breeder Reactor (EBR-II) were measured using miniature mechanical testing methods. The shear punch method was used to evaluate the shear strengths of the neutron-irradiated steel and a correlation factor was empirically determined to predict its tensile strength. The strength of the stainless steel slightly decreased with increasing irradiation temperature, and significantly increased with increasing dose until it saturated above approximately 5 dpa. An effective tensile strain hardening exponent was also obtained from the data which shows a relative decrease in ductility of steel with increased irradiation damage. Ferromagnetic measurements were used to observe and deduce the effects of the stress-induced austenite to martensite transformation as a result of shear punch testing.

  5. 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

  6. PIE of nuclear grade SiC/SiC flexural coupons irradiated to 10 dpa at LWR temperature

    Energy Technology Data Exchange (ETDEWEB)

    Koyanagi, Takaaki [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Katoh, Yutai [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-03-01

    Silicon carbide fiber-reinforced SiC matrix (SiC/SiC) composites are being actively investigated for accident-tolerant core structures of light water reactors (LWRs). Owing to the limited number of irradiation studies previously conducted at LWR-coolant temperature, this study examined SiC/SiC composites following neutron irradiation at 230–340°C to 2.0 and 11.8 dpa in the High Flux Isotope Reactor. The investigated materials are chemical vapor infiltrated (CVI) SiC/SiC composites with three different reinforcement fibers. The fiber materials were monolayer pyrolytic carbon (PyC)-coated Hi-NicalonTM Type-S (HNS), TyrannoTM SA3 (SA3), and SCS-UltraTM (SCS) SiC fibers. The irradiation resistance of these composites was investigated based on flexural behavior, dynamic Young’s modulus, swelling, and microstructures. There was no notable mechanical properties degradation of the irradiated HNS and SA3 SiC/SiC composites except for reduction of the Young’s moduli by up to 18%. The microstructural stability of these composites supported the absence of degradation. In addition, no progressive swelling from 2.0 to 11.8 dpa was confirmed for these composites. On the other hand, the SCS composite showed significant mechanical degradation associated with cracking within the fiber. This study determined that SiC/SiC composites with HNS or SA3 SiC/SiC fibers, a PyC interphase, and a CVI SiC matrix retain their properties beyond the lifetime dose for LWR fuel cladding at the relevant temperature.

  7. Extreme embrittlement of austenitic stainless steel irradiated to 75--81 dpa at 335--360 C

    International Nuclear Information System (INIS)

    Porollo, S.I.; Vorobjev, A.N.; Konobeev, Yu.V.; Garner, F.A.

    1998-01-01

    This paper presents the results of an experiment conducted in the BN-350 fast reactor in Kazakhstan that involved the irradiation of argon-pressurized thin-walled tubes (0--2000 MPa hoop stress) constructed from Fe-16Cr-15Ni-3Mo-Nb stabilized steel in contact with the sodium coolant, which enters the reactor at ∼270 C. Tubes in the annealed condition reached 75 dpa at 335 C, and another set in the 20% cold-worked condition reached 81 dpa at 360 C. Upon disassembly all tubes, except those in the stress-free condition, were found to have failed in an extremely brittle fashion. The stress-free tubes exhibited diameter changes that imply swelling levels ranging from 9 to 16%. It is expected that stress-enhancement of swelling induced even larger swelling levels in the stressed tubes. The embrittlement is explained in terms of the sensitivity of the swelling regime to displacement rate and the large, unprecedented levels of swelling reached at 335--360 C at these high neutron fluences. The failure mechanism appears to be identical to that observed at similar swelling levels in other austenitic steels irradiated in US fast reactors at 400--425 C, whereby stress-concentration between voids and nickel segregation at void surfaces predisposes the steel to an epsilon martensite transformation followed by formation of alpha martensite at crack tips. The very slow strain rate inherent in such creep tests and the relatively high helium levels may also contribute to the failure

  8. 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

  9. Continuous gradient temperature Raman spectroscopy and differential scanning calorimetry of N-3DPA and DHA from -100 to 10°C

    Science.gov (United States)

    Docosahexaenoic acid (DHA, 22:6n-3) is exclusively utilized in fast signal processing tissues such as retinal, neural and cardiac. N-3 docosapentaenoic acid (n-3DPA, 22:5n-3), with just one less double bond, is also found in the marine food chain yet cannot substitute for DHA. Gradient Temperature R...

  10. 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.

  11. Quantification of TSPO overexpression in a rat model of local neuroinflammation induced by intracerebral injection of LPS by the use of [18F]DPA-714 PET

    International Nuclear Information System (INIS)

    Ory, Dieter; Celen, Sofie; Verbruggen, Alfons; Bormans, Guy; Postnov, Andrey; Koole, Michel; Laat, Bart de; Laere, Koen van; Casteels, Cindy

    2016-01-01

    [ 18 F]DPA-714 is a radiotracer with high affinity for TSPO. We have characterized the kinetics of [ 18 F]DPA-714 in rat brain and evaluated its ability to quantify TSPO expression with PET using a neuroinflammation model induced by unilateral intracerebral injection of lipopolysaccharide (LPS). Dynamic small-animal PET scans with [ 18 F]DPA-714 were performed in Wistar rats on a FOCUS-220 system for up to 3 h. Both plasma and perfused brain homogenates were analysed using HPLC to quantify radiometabolites. Full kinetic modelling of [ 18 F]DPA-714 brain uptake was performed using a metabolite-corrected arterial plasma input function. Binding potential (BP ND ) calculated as the distribution volume ratio minus one (DVR-1) between affected and healthy brain tissue was used as the outcome measure and evaluated against reference tissue models. The percentage of intact [ 18 F]DPA-714 in arterial plasma samples was 92 ± 4 % at 10 min, 75 ± 8 % at 40 min and 52 ± 6 % at 180 min. The radiometabolite fraction in brain was negligible (<3 % at 30 min). Among the models investigated, the reversible two-tissue (2T) compartment model best described [ 18 F]DPA-714 brain kinetics. BP ND values obtained with a simplified and a multilinear reference tissue model (SRTM, MRTM) using the contralateral striatum as the reference region correlated well (Spearman's r = 0.96, p ≤ 0.003) with 2T BP ND values calculated as DVR-1, and showed comparable bias (bias range 17.94 %, 20.32 %). Analysis of stability over time suggested that the acquisition time should be at least 90 min for SRTM and MRTM. Quantification of [ 18 F]DPA-714 binding to TSPO with full kinetic modelling is feasible using a 2T model. SRTM and MRTM can be suggested as reasonable substitutes with the contralateral striatum as the reference region and a scan duration of at least 90 min. However, selection of the reference region depends on the disease model used. (orig.)

  12. Quantification of TSPO overexpression in a rat model of local neuroinflammation induced by intracerebral injection of LPS by the use of [{sup 18}F]DPA-714 PET

    Energy Technology Data Exchange (ETDEWEB)

    Ory, Dieter; Celen, Sofie; Verbruggen, Alfons; Bormans, Guy [KU Leuven, Laboratory for Radiopharmacy, Department of Pharmaceutical and Pharmacological Sciences, Leuven (Belgium); Postnov, Andrey; Koole, Michel; Laat, Bart de; Laere, Koen van; Casteels, Cindy [University Hospital and KU Leuven, Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, Leuven (Belgium)

    2016-01-15

    [{sup 18}F]DPA-714 is a radiotracer with high affinity for TSPO. We have characterized the kinetics of [{sup 18}F]DPA-714 in rat brain and evaluated its ability to quantify TSPO expression with PET using a neuroinflammation model induced by unilateral intracerebral injection of lipopolysaccharide (LPS). Dynamic small-animal PET scans with [{sup 18}F]DPA-714 were performed in Wistar rats on a FOCUS-220 system for up to 3 h. Both plasma and perfused brain homogenates were analysed using HPLC to quantify radiometabolites. Full kinetic modelling of [{sup 18}F]DPA-714 brain uptake was performed using a metabolite-corrected arterial plasma input function. Binding potential (BP{sub ND}) calculated as the distribution volume ratio minus one (DVR-1) between affected and healthy brain tissue was used as the outcome measure and evaluated against reference tissue models. The percentage of intact [{sup 18}F]DPA-714 in arterial plasma samples was 92 ± 4 % at 10 min, 75 ± 8 % at 40 min and 52 ± 6 % at 180 min. The radiometabolite fraction in brain was negligible (<3 % at 30 min). Among the models investigated, the reversible two-tissue (2T) compartment model best described [{sup 18}F]DPA-714 brain kinetics. BP{sub ND} values obtained with a simplified and a multilinear reference tissue model (SRTM, MRTM) using the contralateral striatum as the reference region correlated well (Spearman's r = 0.96, p ≤ 0.003) with 2T BP{sub ND} values calculated as DVR-1, and showed comparable bias (bias range 17.94 %, 20.32 %). Analysis of stability over time suggested that the acquisition time should be at least 90 min for SRTM and MRTM. Quantification of [{sup 18}F]DPA-714 binding to TSPO with full kinetic modelling is feasible using a 2T model. SRTM and MRTM can be suggested as reasonable substitutes with the contralateral striatum as the reference region and a scan duration of at least 90 min. However, selection of the reference region depends on the disease model used. (orig.)

  13. The translocator protein radioligand 18F-DPA-714 monitors antitumor effect of erufosine in a rat 9L intracranial glioma model

    International Nuclear Information System (INIS)

    Awde, Ali R.; Boisgard, Raphael; Theze, Benoit; Dubois, Albertine; Zheng, Jinzi; Winkeler, Alexandra; Dolle, Frederic; Jacobs, Andreas H.; Tavitian, Bertrand

    2013-01-01

    On the one hand, the translocator protein (TSPO) radioligand N,N-diethyl-2-(2-(4-(2- 18 F-fluoroethoxy)phenyl)-5,7-dimethylpyrazolo[1,5-a] pyrimidin-3-yl)acetamide ( 18 F-DPA-714) has been suggested to serve as an alternative radiotracer to image human glioma, and on the other hand the alkyl-phosphocholine erufosine (ErPC3) has been reported to induce apoptosis in otherwise highly apoptosis resistant glioma cell lines. The induction of apoptosis by ErPC3 requires TSPO, a mitochondrial membrane protein highly expressed in malignant gliomas. In this preclinical study, we monitored the effect of ErPC3 treatment in vivo using 18 F-DPA-714 PET. Methods: In vitro studies investigated the antitumor effect of ErPC3 in 9L rat gliosarcoma cells. In vivo, glioma-bearing rats were imaged with 18 F-DPA-714 for the time of treatment. Results: A significant decrease in 9L cell proliferation and viability and a significant increase in apoptosis and caspase-3 activation were demonstrated on ErPC3 treatment in cell culture. In the rat model, ErPC3 administration resulted in significant changes in 18 F-DPA-714 tumor uptake over the course of the treatment. Immunohistochemistry revealed reduced tumor volume and increased cell death in ErPC3-treated animals accompanied by infiltration of the tumor core by CD11b-positive micro-glia/macrophages and glial fibrillary acidic protein-positive astrocytes. Conclusion: Our findings demonstrate a potent antitumor effect of ErPC3 in vitro, in vivo, and ex vivo. PET imaging of TSPO expression using 18 F-DPA-714 allows effective monitoring and quantification of disease progression and response to ErPC3 therapy in intracranial 9L gliomas. (authors)

  14. Effect of helium and DPA's on tensile properties of V-5Ti and V-3Ti-1Si

    International Nuclear Information System (INIS)

    Witzenburg, W. van; Vries, E. de.

    1991-02-01

    Specimens of the alloys V-5Ti and V-3Ti-1Si were irradiated in a mixed-spectrum fission reactor in reactor grade liquid sodium to a fast neutron fluence of 3.8 x 10 25 m -2 (E>0.1 MeV), which corresponds to 6.2 dpa. Irradiation temperatures were 500, 600 and 700 deg C. Some of the specimens were pre-injected with helium to 100 appm at approx 50 deg C by means of a cyclotron. In addition, part of the specimens were doped with boron-10 to concentrations of 100 and 600 appm. Tensile testing, at temperatures equal to the irradiation temperatures and at a strain rate of 10 -4 s -1 , showed an increase in strength and reduced elongation at 500 deg C and to a lesser extent at 600 deg C. These changes are caused by displacement damage. Helium, pre-injected as well as produced by transmutation of boron-10, did not have a significant influence on the tensile properties. Cavities seen in the irradiated materials at low concentrations, were not preferentially located on grain boundaries. There was no apparent deleterious effect of lithium, which is also a transmutation product of boron-10. (author). 12 refs.; 8 figs.; 3 tabs

  15. Microstructural response of titanium-modified austenitic stainless steels to neutron exposure of 70 dpa in FFTF/MOTA

    International Nuclear Information System (INIS)

    Katoh, Yutai; Kohno, Yutaka; Kohyama, Akira

    1994-01-01

    JPCA, a titanium-modified austenitic stainless steel, in solution-annealed or cold-worked condition and a compositionally modified JPCA in solution-annealed condition were examined by transmission electron microscopy following irradiation in FFTF/MOTA to an exposure level of up to about 70 dpa at 390 to 600 C. At lower temperatures, all the materials developed qualitatively similar cavity-, dislocation- and precipitate-microstructures. The lower-temperature swelling peak, which appeared at near 410 C, was more efficiently suppressed by phosphorus addition than cold-working. Irradiation at or above 520 C produced substantially large swelling in solution-annealed JPCA. The cavities contributed to this higher-temperature swelling developed in association with M 6 C-type precipitates. Neither cavities other than very small helium bubbles nor massive particles of M 6 C-type precipitates were observed in cold-worked and phosphorus-modified materials, in which MC-type precipitates developed at very high concentration. The effect of pre-irradiation microstructure and compositional modification on the behavior of these precipitates is discussed. ((orig.))

  16. Energy Deposition and DPA in the Superconducting Links for the HILUMI LHC Project at the LHC Interaction Points

    CERN Document Server

    AUTHOR|(CDS)2092158; Broggi, Francesco; Santini, C; Ballarino, Amalia; Cerutti, Francesco; Esposito, Luigi Salvatore

    2015-01-01

    In the framework of the upgrade of the LHC machine, the powering of the LHC magnets foresees the removal of the power converters and distribution feedboxes from the tunnel and its location at the surface[1]. The Magnesium Diboride (MgB2) connecting lines in the tunnel will be exposed to the debris from 7+7 TeV p-p interaction. The Superconducting (SC) Links will arrive from the surface to the tunnel near the separation dipole, at about 80 m from the Interaction Point at IP1 and IP5. The Connection Box (where the cables of the SC Links are connected to the NbTi bus bar) will be close to the beam pipe. The debris and its effect on the MgB2 SC links in the connection box (energy deposition and displacement per atom) are presented. The effect of thermal neutrons on the Boron consumption and the contribution of the lithium nucleus and the alpha particle on the DPA are evaluated. The results are normalized to an integrated luminosity of 3000 fb-1, value that represents the LHC High Luminosity lifetime. The dose de...

  17. Electrochemical characterization of azo dye (E)-1-(4-((4-(phenylamino)phenyl)diazenyl)phenyl)ethanone (DPA)

    International Nuclear Information System (INIS)

    Surucu, Ozge; Abaci, Serdar; Seferoğlu, Zeynel

    2016-01-01

    Highlights: • Electrochemical characterization of azo dye DPA was performed. • Pencil graphite electrode was used as working electrode. • Cyclic voltammetry was used to determine the effect of scan rate and pH. • Chronoamperometry was used to determine diffusion constant. • Square wave voltammetry verified the results of cyclic voltammetry. - Abstract: An enormous range of possible dyes are available, especially as the starting molecules are readily available and cheap. As other dye classes become less viable from either an environmental or economic reasons, azo dyes come to the forefront. Therefore, electrochemical characterization of a novel synthesized azo dye (E)-1-(4-((4-(phenylamino) phenyl)diazenyl)phenyl)ethanone was achieved for the first time. Cyclic voltammetry, chronoamperometry and square wave voltammetry techniques were used to investigate the electrochemical behavior and electrocatalytic effect of azo dye (E)-1-(4-((4-(phenylamino) phenyl)diazenyl)phenyl)ethanone at pencil graphite electrode. Cyclic voltammograms were utilized to determine the effect of scan rate and pH on the peak current and peak potential. Chronoamperometry technique was used to determine diffusion constant, D and the type of adsorption isotherms. The kinetics parameters which were the apparent electron transfer rate constant, k s and charge transfer coefficient, α were calculated. Square wave voltammetry was used to verify responses of cyclic voltammetry technique.

  18. Differences among KERMA or DPA data calculated from JENDL-4.0, ENDF/B-VII.1, JEFF-3.2 and FENDL-3.1b with NJOY

    International Nuclear Information System (INIS)

    Konno, C.

    2016-01-01

    KERMA factors and DPA cross-section data below 20 MeV in the official ACE files of JENDL-4.0, ENDF/B-VII.1, JEFF-3.2 and FENDL-3.1b were compared in detail. As a result, it was found out that the KERMA and DPA data of a lot of nuclei were different among the nuclear data libraries. Reasons of most of the differences were successfully categorized to the nuclear data and NJOY issues. The KERMA factors and DPA cross-section data in the ACE files with the problems should be revised. (author)

  19. Relationship between swelling and irradiation creep in cold-worked PCA stainless steel irradiated to ∼178 dpa at ∼400 degrees C

    International Nuclear Information System (INIS)

    Toloczko, M.B.

    1993-09-01

    The eighth and final irradiation segment for pressurized tubes constructed from the fusion Prime Candidate Alloy (PCA) has been completed in FFTF. At 178 dpa and ∼400 degrees C, the irradiation creep of 20% cold-worked PCA has become dominated by the open-quotes creep disappearanceclose quotes phenomenon. The total diametral deformation rate has reached the limiting value of 0.33%/dpa at the three highest stress levels employed in this test. The stress-enhancement of swelling tends to camouflage the onset of creep disappearance, however, requiring the use of several non-traditional techniques to extract the creep coefficients. No failures occurred in these tubes, even though the swelling ranged from ∼20 to ∼40%

  20. The effect of irradiation on the stability and properties of monolithic silicon carbide and SiCf/SiC composites up to 25 dpa

    International Nuclear Information System (INIS)

    Hollenberg, G.W.; Henager, C.H. Jr.; Youngblood, G.E.; Trimble, D.J.; Simonson, S.A.; Newsome, G.A.; Lewis, E.

    1994-04-01

    Stability and properties of monolithic and SiC f /SiC composites were measured before and after irradiation in a fast neutron spectrum up to 25 dpa between 500 and 1500C. Dimensional changes were relatively consistent with previous investigations. Strength and modulus of SiC f /SiC composites decreased after irradiation as a result of fiber/matrix decoupling. For some composites, uniform elongation was not significantly degraded by irradiation. Thermal conductivity also decreased after irradiation at low temperatures because of the introduction of lattice defects as phonon scattering sites. Retention of properties under the severe conditions of 25 dpa and 800C suggests that a composite tailored for neutron damage resistance can be developed

  1. Relationship between swelling and irradiation creep in cold-worked PCA stainless steel irradiated to similar 178 dpa at similar 400 C

    International Nuclear Information System (INIS)

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

    1994-01-01

    The eighth and final irradiation segment for pressurized tubes constructed from the fusion Prime Candidate Alloy (PCA) has been completed in FFTF. At 178 dpa and similar 400 C, the irradiation creep of 20% cold-worked PCA has become dominated by the ''creep disappearance'' phenomenon. The total diametral deformation rate has reached the limiting value of 0.33%/dpa at the three highest stress levels employed in this test. The stress-enhancement of swelling tends to camouflage the onset of creep disappearance, however, requiring the use of several non-traditional techniques to extract the creep coefficients. No failures occurred in these tubes, even though the swelling ranged from similar 20 to 40%. ((orig.))

  2. Relationship between swelling and irradiation creep in cold-worked PCA stainless steel irradiated to similar 178 dpa at similar 400 C

    Energy Technology Data Exchange (ETDEWEB)

    Toloczko, M.B. (Department of Chemical and Nuclear Engineering, University of California, Santa Barbara, CA 93106 (United States)); Garner, F.A. (Pacific Northwest Laboratory, Richland, WA 99352 (United States))

    1994-09-01

    The eighth and final irradiation segment for pressurized tubes constructed from the fusion Prime Candidate Alloy (PCA) has been completed in FFTF. At 178 dpa and similar 400 C, the irradiation creep of 20% cold-worked PCA has become dominated by the creep disappearance'' phenomenon. The total diametral deformation rate has reached the limiting value of 0.33%/dpa at the three highest stress levels employed in this test. The stress-enhancement of swelling tends to camouflage the onset of creep disappearance, however, requiring the use of several non-traditional techniques to extract the creep coefficients. No failures occurred in these tubes, even though the swelling ranged from similar 20 to 40%. ((orig.))

  3. Brain energy metabolism and neuroinflammation in ageing APP/PS1-21 mice using longitudinal 18F-FDG and 18F-DPA-714 PET imaging.

    Science.gov (United States)

    Takkinen, Jatta S; López-Picón, Francisco R; Al Majidi, Rana; Eskola, Olli; Krzyczmonik, Anna; Keller, Thomas; Löyttyniemi, Eliisa; Solin, Olof; Rinne, Juha O; Haaparanta-Solin, Merja

    2017-08-01

    Preclinical animal model studies of brain energy metabolism and neuroinflammation in Alzheimer's disease have produced conflicting results, hampering both the elucidation of the underlying disease mechanism and the development of effective Alzheimer's disease therapies. Here, we aimed to quantify the relationship between brain energy metabolism and neuroinflammation in the APP/PS1-21 transgenic mouse model of Alzheimer's disease using longitudinal in vivo 18 F-FDG and 18 F-DPA-714) PET imaging and ex vivo brain autoradiography. APP/PS1-21 (TG, n = 9) and wild type control mice (WT, n = 9) were studied longitudinally every third month from age 6 to 15 months with 18 F-FDG and 18 F-DPA-714 with a one-week interval between the scans. Additional TG (n = 52) and WT (n = 29) mice were used for ex vivo studies. In vivo, the 18 F-FDG SUVs were lower and the 18 F-DPA-714 binding ratios relative to the cerebellum were higher in the TG mouse cortex and hippocampus than in WT mice at age 12 to 15 months ( p < 0.05). The ex vivo cerebellum binding ratios supported the results of the in vivo 18 F-DPA-714 studies but not the 18 F-FDG studies. This longitudinal PET study demonstrated decreased energy metabolism and increased inflammation in the brains of APP/PS1-21 mice compared to WT mice.

  4. Imaging of brain TSPO expression in a mouse model of amyotrophic lateral sclerosis with 18F-DPA-714 and micro-PET/CT

    International Nuclear Information System (INIS)

    Gargiulo, S.; Gramanzini, M.; Anzilotti, S.; Salvatore, M.; Coda, A.R.D.; Panico, M.; Zannetti, A.; Vicidomini, C.; Quarantelli, M.; Pappata, S.; Greco, A.; Brunetti, A.; Vinciguerra, A.; Pignataro, G.; Dolle, F.; Annunziato, L.

    2016-01-01

    To evaluate the feasibility and sensitivity of 18 F-DPA-714 for the study of microglial activation in the brain and spinal cord of transgenic SOD1 G93A mice using high-resolution PET/CT and to evaluate the Iba1 and TSPO expression with immunohistochemistry. Nine symptomatic SOD1 G93A mice (aged 117 ± 12.7 days, clinical score range 1 - 4) and five WT SOD1 control mice (aged 108 ± 28.5 days) underwent 18 F-DPA-714 PET/CT. SUV ratios were calculated by normalizing the cerebellar (rCRB), brainstem (rBS), motor cortex (rMCX) and cervical spinal cord (rCSC) activities to that of the frontal association cortex. Two WT SOD1 and six symptomatic SOD1 G93A mice were studied by immunohistochemistry. In the symptomatic SOD1 G93A mice, rCRB, rBS and rCSC were increased as compared to the values in WT SOD1 mice, with a statistically significantly difference in rBS (2.340 ± 0.784 vs 1.576 ± 0.287, p = 0.014). Immunofluorescence studies showed that TSPO expression was increased in the trigeminal, facial, ambiguus and hypoglossal nuclei, as well as in the spinal cord, of symptomatic SOD1 G93A mice and was colocalized with increased Iba1 staining. Increased 18 F-DPA-714 uptake can be detected with high-resolution PET/CT in the brainstem of transgenic SOD1 G93A mice, a region known to be a site of degeneration and increased microglial activation in amyotrophic lateral sclerosis, in agreement with increased TSPO expression in the brainstem nuclei shown by immunostaining. Therefore, 18 F-DPA-714 PET/CT might be a suitable tool to evaluate microglial activation in the SOD1 G93A mouse model. (orig.)

  5. Tensile behavior of RAFM alloys after neutron irradiation of up to 16.3 dpa between 250 and 450 °C

    Energy Technology Data Exchange (ETDEWEB)

    Materna-Morris, E., E-mail: edeltraud.materna-morris@kit.edu; Schneider, H.-C., E-mail: hans-christian.schneider@kit.edu; Möslang, A., E-mail: anton.moeslang@kit.edu

    2014-12-15

    Tensile specimen of steel EUROFER97 and other alloys on the basis of RAFM steels such, as OPTIFER and F82H alloys, and Ga3X were irradiated and post-examined during a neutron irradiation program of up to 16.3 dpa between 250 and 450 °C in the HFR (High Flux Reactor) in the Netherlands. These tensile results were compared with former irradiation programs, with lower neutron doses of up to 0.8 and 2.4 dpa to quantify the difference in tensile strengthening. The average increase of tensile strength was in a range of 300 MPa between 0.8 and 16.3 dpa at temperatures of 250–300 °C. This behavior can be correlated with irradiation-induced changes in the microstructure. Most of the hardening can be attributed to dislocation loops, point defects or small precipitates as observed in boron-free alloys as F82H mod. and EUROFER97. Whereas the hardening in boron-containing alloys OPTIFER alloys and Ga3X can be correlated in addition with the combination of helium bubbles. At the highest irradiation and test temperature at 450 °C, all tensile data of all investigated materials were in the range of those of non-irradiated and irradiated material due to thermal aging effects.

  6. Tensile behavior of RAFM alloys after neutron irradiation of up to 16.3 dpa between 250 and 450 °C

    International Nuclear Information System (INIS)

    Materna-Morris, E.; Schneider, H.-C.; Möslang, A.

    2014-01-01

    Tensile specimen of steel EUROFER97 and other alloys on the basis of RAFM steels such, as OPTIFER and F82H alloys, and Ga3X were irradiated and post-examined during a neutron irradiation program of up to 16.3 dpa between 250 and 450 °C in the HFR (High Flux Reactor) in the Netherlands. These tensile results were compared with former irradiation programs, with lower neutron doses of up to 0.8 and 2.4 dpa to quantify the difference in tensile strengthening. The average increase of tensile strength was in a range of 300 MPa between 0.8 and 16.3 dpa at temperatures of 250–300 °C. This behavior can be correlated with irradiation-induced changes in the microstructure. Most of the hardening can be attributed to dislocation loops, point defects or small precipitates as observed in boron-free alloys as F82H mod. and EUROFER97. Whereas the hardening in boron-containing alloys OPTIFER alloys and Ga3X can be correlated in addition with the combination of helium bubbles. At the highest irradiation and test temperature at 450 °C, all tensile data of all investigated materials were in the range of those of non-irradiated and irradiated material due to thermal aging effects

  7. Engineering [Ln(DPA){sub 3}]{sup 3-} binding sites in proteins: a widely applicable method for tagging proteins with lanthanide ions

    Energy Technology Data Exchange (ETDEWEB)

    Jia Xinying; Yagi, Hiromasa; Su Xuncheng; Stanton-Cook, Mitchell; Huber, Thomas; Otting, Gottfried, E-mail: gottfried.otting@anu.edu.au [Australian National University, Research School of Chemistry (Australia)

    2011-08-15

    Paramagnetic relaxation enhancements from unpaired electrons observed in nuclear magnetic resonance (NMR) spectra present powerful long-range distance restraints. The most frequently used paramagnetic tags, however, are tethered to the protein via disulfide bonds, requiring proteins with single cysteine residues for covalent attachment. Here we present a straightforward strategy to tag proteins site-specifically with paramagnetic lanthanides without a tether and independent of cysteine residues. It relies on preferential binding of the complex between three dipicolinic acid molecules (DPA) and a lanthanide ion (Ln{sup 3+}), [Ln(DPA){sub 3}]{sup 3-}, to a pair of positively charged amino acids whose charges are not compensated by negatively charged residues nearby. This situation rarely occurs in wild-type proteins, allowing the creation of specific binding sites simply by introduction of positively charged residues that are positioned far from glutamate or aspartate residues. The concept is demonstrated with the hnRNPLL RRM1 domain. In addition, we show that histidine- and arginine-tags present binding sites for [Ln(DPA){sub 3}]{sup 3-}.

  8. Preliminary Assessment of the Impact on Reactor Vessel dpa Rates Due to Installation of a Proposed Low Enriched Uranium (LEU) Core in the High Flux Isotope Reactor (HFIR)

    Energy Technology Data Exchange (ETDEWEB)

    Daily, Charles R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-10-01

    An assessment of the impact on the High Flux Isotope Reactor (HFIR) reactor vessel (RV) displacements-per-atom (dpa) rates due to operations with the proposed low enriched uranium (LEU) core described by Ilas and Primm has been performed and is presented herein. The analyses documented herein support the conclusion that conversion of HFIR to low-enriched uranium (LEU) core operations using the LEU core design of Ilas and Primm will have no negative impact on HFIR RV dpa rates. Since its inception, HFIR has been operated with highly enriched uranium (HEU) cores. As part of an effort sponsored by the National Nuclear Security Administration (NNSA), conversion to LEU cores is being considered for future HFIR operations. The HFIR LEU configurations analyzed are consistent with the LEU core models used by Ilas and Primm and the HEU balance-of-plant models used by Risner and Blakeman in the latest analyses performed to support the HFIR materials surveillance program. The Risner and Blakeman analyses, as well as the studies documented herein, are the first to apply the hybrid transport methods available in the Automated Variance reduction Generator (ADVANTG) code to HFIR RV dpa rate calculations. These calculations have been performed on the Oak Ridge National Laboratory (ORNL) Institutional Cluster (OIC) with version 1.60 of the Monte Carlo N-Particle 5 (MCNP5) computer code.

  9. TEM examination of the effect of post-irradiation annealing on 7.7 dpa AISI 304 stainless steel

    International Nuclear Information System (INIS)

    Karlsen, W.; Ivanchenko, M.; Pakarinen, J.; Karlsen, T.

    2015-01-01

    Stainless steels exposed to neutron irradiation during service in light water reactors (LWR) can become susceptible to intergranular cracking, referred to as irradiation assisted stress corrosion cracking (IASCC). Analytical transmission electron microscopy (ATEM) was used to examine the effect of post-irradiation annealing (PIA) on radiation-induced segregation (RIS) at the grain boundaries of 7.7 dpa AISI 304 stainless steel. The grain boundary profiles and the irradiation damage were analysed in the as-irradiated state and after PIA of 6 hours at 500 C. degrees and after 25 hours at 500 C. degrees and 550 C. degrees by using transmission electron microscopy (TEM). As a main conclusion from the TEM examinations, the effects of PIA were found to be relatively small after only 6 hours, while after 25 hours of PIA at both 500 and 550 C. degrees, RIS was almost recovered and only marginal deviation in chemical composition could be found near the GB. The as-irradiated state showed extreme RIS values of Si 4.9 wt%, Cr 14.7 wt%, Ni 23.4 wt%, and P 1.4 wt%., while upon PIA for 6 hours the extreme values for RIS were Si 3.9 wt%, Cr 16.0 wt%, Ni 21 wt%, and P 0.9 wt%. After 6 hours annealing at 500 C. dislocation loops start to grow, while dislocation density remains of the same order of magnitude. After annealing for 25 hours at 500 C. degrees the average size of dislocation loops remains nearly the same, while dislocation density was reduced almost by one fold. In the areas where dislocation density was found to be the lowest some features, which can most likely be attributed to stacking fault tetrahedral (SFT) were found. Annealing at even higher temperature (550 C.) affected the average size of the dislocation loops, making them almost twice as large as well as resulting in a very broad distribution of dislocation sizes. Density of dislocations is also reduced by one fold in comparison to the as irradiated condition and leads to formation of SFTs, which could be

  10. Imaging of brain TSPO expression in a mouse model of amyotrophic lateral sclerosis with {sup 18}F-DPA-714 and micro-PET/CT

    Energy Technology Data Exchange (ETDEWEB)

    Gargiulo, S.; Gramanzini, M. [National Research Council, Institute of Biostructure and Bioimaging, Naples (Italy); Ceinge Biotecnologie Avanzate s.c. a r.l., Naples (Italy); Anzilotti, S.; Salvatore, M. [IRCCS SDN, Naples (Italy); Coda, A.R.D.; Panico, M.; Zannetti, A.; Vicidomini, C.; Quarantelli, M.; Pappata, S. [National Research Council, Institute of Biostructure and Bioimaging, Naples (Italy); Greco, A.; Brunetti, A. [University ' ' Federico II' ' , Department of Advanced Biomedical Sciences, Naples (Italy); Ceinge Biotecnologie Avanzate s.c. a r.l., Naples (Italy); Vinciguerra, A.; Pignataro, G. [University ' ' Federico II' ' , Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Naples (Italy); Dolle, F. [CEA, Institute for Biomedical Imaging, Orsay (France); Annunziato, L. [University ' ' Federico II' ' , Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Naples (Italy); IRCCS SDN, Naples (Italy)

    2016-07-15

    To evaluate the feasibility and sensitivity of {sup 18}F-DPA-714 for the study of microglial activation in the brain and spinal cord of transgenic SOD1{sup G93A} mice using high-resolution PET/CT and to evaluate the Iba1 and TSPO expression with immunohistochemistry. Nine symptomatic SOD1{sup G93A} mice (aged 117 ± 12.7 days, clinical score range 1 - 4) and five WT SOD1 control mice (aged 108 ± 28.5 days) underwent {sup 18}F-DPA-714 PET/CT. SUV ratios were calculated by normalizing the cerebellar (rCRB), brainstem (rBS), motor cortex (rMCX) and cervical spinal cord (rCSC) activities to that of the frontal association cortex. Two WT SOD1 and six symptomatic SOD1{sup G93A} mice were studied by immunohistochemistry. In the symptomatic SOD1{sup G93A} mice, rCRB, rBS and rCSC were increased as compared to the values in WT SOD1 mice, with a statistically significantly difference in rBS (2.340 ± 0.784 vs 1.576 ± 0.287, p = 0.014). Immunofluorescence studies showed that TSPO expression was increased in the trigeminal, facial, ambiguus and hypoglossal nuclei, as well as in the spinal cord, of symptomatic SOD1{sup G93A} mice and was colocalized with increased Iba1 staining. Increased {sup 18}F-DPA-714 uptake can be detected with high-resolution PET/CT in the brainstem of transgenic SOD1{sup G93A} mice, a region known to be a site of degeneration and increased microglial activation in amyotrophic lateral sclerosis, in agreement with increased TSPO expression in the brainstem nuclei shown by immunostaining. Therefore, {sup 18}F-DPA-714 PET/CT might be a suitable tool to evaluate microglial activation in the SOD1{sup G93A} mouse model. (orig.)

  11. Standard Practice for Characterizing Neutron Exposures in Iron and Low Alloy Steels in Terms of Displacements Per Atom (DPA), E 706(ID)

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2001-01-01

    1.1 This practice describes a standard procedure for characterizing neutron irradiations of iron (and low alloy steels) in terms of the exposure index displacements per atom (dpa) for iron. 1.2 Although the general procedures of this practice apply to any material for which a displacement cross section d(E) is known (see Practice E 521), this practice is written specifically for iron. 1.3 It is assumed that the displacement cross section for iron is an adequate approximation for calculating displacements in steels that are mostly iron (95 to 100 %) in radiation fields for which secondary damage processes are not important. 1.4 Procedures analogous to this one can be formulated for calculating dpa in charged particle irradiations. (See Practice E 521.) 1.5 The application of this practice requires knowledge of the total neutron fluence and flux spectrum. Refer to Practice E 521 for determining these quantities. 1.6 The correlation of radiation effects data is beyond the scope of this practice. This stand...

  12. Microstructural evolution of austenitic stainless steels irradiated to 17 dpa in spectrally tailored experiment of the ORR and HFIR at 400{degrees}C

    Energy Technology Data Exchange (ETDEWEB)

    Wakai, E.; Hashimoto, N.; Gibson, L.T. [Oak Ridge National Lab., TN (United States)] [and others

    1997-08-01

    The microstructural evolution of austenitic JPCA aged and solution annealed JPCA, 316R, C, K, and HP steels irradiated at 400{degrees}C in spectrally tailored experiments of the ORR and HFIR has been investigated. The helium generation rates were about 12-16 appm He/dpa on the average up to 17.3 dpa. The number densities and average diameters of dislocation loops in the steels have ranges of 3.3 x 10{sup 21} m{sup -3} and 15.2-26.3 nm, respectively, except for HP steel for which they are 1.1 x 10{sup 23} m{sup -3} and 8.0 nm. Precipitates are formed in all steels except for HP steel, and the number densities and average diameters have ranges of 5.2 x 10{sup 20} - 7.7 x 10{sup 21} m{sup -3} and 3.4- 19.3 nm, respectively. In the 216R, C, and K steels, the precipitates are also formed at grain boundaries, and the mean sizes of these are about 110, 50, and 50 nm, respectively. The number densities of cavities are about 1 x 10{sup 22} m{sup -3} in all the steels. The swelling is low in the steels which form the precipitates.

  13. 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

  14. A Calculation Method of PKA, KERMA and DPA from Evaluated Nuclear Data with an Effective Single-particle Emission Approximation (ESPEA) and Introduction of Event Generator Mode in PHITS Code

    International Nuclear Information System (INIS)

    Fukahori, Tokio; Iwamoto, Yosuke

    2012-01-01

    The displacement calculation method from evaluated nuclear data file has been developed by using effective single-particle emission approximation (ESPEA). The ESPEA can be used effectively below about 50 MeV, because of since multiplicity of emitted particles. These are also reported in the Ref. 24. The displacement calculation method in PHITS has been developed. In the high energy region (≥ 20 MeV) for proton and neutron beams, DPA created by secondary particles increase due to nuclear reactions. For heavy-ion beams, DPA created by the primaries are dominant to total DPA due to the large Coulomb scattering cross sections. PHITS results agree with FLUKA ones within a factor of 1.7. In the high-energy region above 10 MeV/nucleon, comparisons among codes and measurements of displacement damage cross section are necessary. (author)

  15. Red Blood Cell Docosapentaenoic Acid (DPA n-3) is Inversely Associated with Triglycerides and C-reactive Protein (CRP) in Healthy Adults and Dose-Dependently Increases Following n-3 Fatty Acid Supplementation

    Science.gov (United States)

    Skulas-Ray, Ann C.; Flock, Michael R.; Richter, Chesney K.; Harris, William S.; West, Sheila G.; Kris-Etherton, Penny M.

    2015-01-01

    The role of the long-chain omega-3 (n-3) fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in lipid metabolism and inflammation has been extensively studied; however, little is known about the relationship between docosapentaenoic acid (DPA, 22:5 n-3) and inflammation and triglycerides (TG). We evaluated whether n-3 DPA content of red blood cells (RBC) was associated with markers of inflammation (interleukin-6 (IL-6), tumor necrosis factor α (TNF-α), and C-reactive protein (CRP) and fasting TG prior to n-3 supplementation in two studies (Study 1: n = 115, aged 20–44 years, body mass index (BMI) 20–30 kg/m2, TG = 34–176 mg/dL; Study 2: n = 28, aged 22–65 years, BMI 24–37 kg/m2, TG = 141–339 mg/dL). We also characterized the dose-response effects of n-3 fatty acid supplementation on RBC n-3 DPA after five months of supplementation with fish oil (Study 1: 0, 300, 600, 900, and 1800 mg/day EPA + DHA) and eight weeks of prescription n-3 ethyl esters (Study 2: 0, 850, and 3400 mg/day EPA + DHA). In Study 1, RBC n-3 DPA was inversely correlated with CRP (R2 = 36%, p < 0.001) and with fasting TG (r = −0.30, p = 0.001). The latter finding was replicated in Study 2 (r = −0.33, p = 0.04). In both studies, n-3 supplementation significantly increased RBC n-3 DPA dose-dependently. Relative increases were greater for Study 1, with increases of 29%–61% vs. 14%–26% for Study 2. The associations between RBC n-3 DPA, CRP, and fasting TG may have important implications for the prevention of atherosclerosis and chronic inflammatory diseases and warrant further study. PMID:26247967

  16. Influence of damage rate on physical and mechanical properties and swelling of 18Cr-9Ni austenitic steel in the range of 3.10-9 to 4.10-8 dpa/sec

    International Nuclear Information System (INIS)

    Shcherbakov, E.N.; Kozlov, A.V.; Yagovitin, R.I.; Evseev, M.V.; Kinev, E.A.; Isobe, Y.; Sagisaka, M.; Okita, T.; Sekimura, N.; Garner, F.

    2007-01-01

    Full text of publication follows: Whereas most data on radiation-induced changes in mechanical properties or dimensional stability needed for fusion - relevant dpa levels and dpa rates are generated at relatively high neutron flux in fast reactors, many fusion and fission components will operate at much lower dpa rates. Much less data are available from long-lived structural components operating at very low flux levels. In addition most published data were generated from relatively thin specimens (∼1-2 mm or less), while some actual fusion structural components can be on the order of 1-2 cm thick. In this study we have examined a 9 cm diameter pipe constructed from Fe-18Cr-9Ni steel analogous to AISI 304 that stayed outside the core of BN-600 for 22 years. The walls of the pipe were 2 cm thick and experienced temperatures in the range 370-375 deg. C. The walls were sectioned into 5 slices at a number of positions to yield doses in the range 1.5 to 22 dpa at 3 x 10 -9 to 4 x 10 -8 dpa/s. Changes in elastic moduli were studied using an ultrasonic technique and changes in electrical resistivity and mechanical properties of the 18Cr9Ni austenitic steel was examined. Swelling was measured both by immersion density and electron microscopy, reaching a maximum of ∼3 %. Swelling appears to be accelerated somewhat at these lower dpa rates as observed in other recent studies. Tensile properties were also measured. Radiation-induced changes of electrical resistivity, Young's and shear moduli were observed but did not agree fully with predictions based on voids alone. Strong contributions from second phase precipitates were found to be contributing to changes in both physical and mechanical properties. (authors)

  17. Red Blood Cell Docosapentaenoic Acid (DPA n-3) is Inversely Associated with Triglycerides and C-reactive Protein (CRP) in Healthy Adults and Dose-Dependently Increases Following n-3 Fatty Acid Supplementation

    OpenAIRE

    Skulas-Ray, Ann C.; Flock, Michael R.; Richter, Chesney K.; Harris, William S.; West, Sheila G.; Kris-Etherton, Penny M.

    2015-01-01

    The role of the long-chain omega-3 (n-3) fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in lipid metabolism and inflammation has been extensively studied; however, little is known about the relationship between docosapentaenoic acid (DPA, 22:5 n-3) and inflammation and triglycerides (TG). We evaluated whether n-3 DPA content of red blood cells (RBC) was associated with markers of inflammation (interleukin-6 (IL-6), tumor necrosis factor α (TNF-α), and C-reactive protei...

  18. Evolution of microstructure after irradiation creep in several austenitic steels irradiated up to 120 dpa at 320 °C

    Energy Technology Data Exchange (ETDEWEB)

    Renault-Laborne, A., E-mail: alexandra.renault@cea.fr [DEN-Service de Recherches Métallurgiques Appliquées, CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette (France); Garnier, J.; Malaplate, J. [DEN-Service de Recherches Métallurgiques Appliquées, CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette (France); Gavoille, P. [DEN-Service d' Etudes des Matériaux Irradiés, CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette (France); Sefta, F. [EDF R& D, MMC, Site des Renardières, F-77818, Morêt-sur-Loing Cedex (France); Tanguy, B. [DEN-Service d' Etudes des Matériaux Irradiés, CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette (France)

    2016-07-15

    Irradiation creep was investigated in different austenitic steels. Pressurized tubes with stresses of 127–220 MPa were irradiated in BOR-60 at 320 °C to 120 dpa. Creep behavior was dependent on both chemical composition and metallurgical state of steels. Different steels irradiated with and without stress were examined by TEM. Without stress, the irradiation produced high densities of dislocation lines and Frank loops and, depending on the type of steels, precipitates. Stress induced an increase of the precipitate mean size and density and, for some grades, an increase of the mean loop size and a decrease of their density. An anisotropy of Frank loop density or size induced by stress was not observed systematically. Dislocation line microstructure seems not to be different between the stressed and unstressed specimens. No cavities were detectable in these specimens. By comparing with the data from this work, the main irradiation creep models are discussed.

  19. Evolution of secondary-phase precipitates during annealing of the 12Kh18N9T steel irradiated with neutrons to a dose of 5 DPA

    Science.gov (United States)

    Tsai, K. V.; Maksimkin, O. P.; Turubarova, L. G.

    2007-03-01

    The formation and evolution of thermally-induced secondary precipitates in an austenitic stainless steel 12Kh18N9T irradiated in the core of a laboratory reactor VVR-K to a dose of 5 dpa and subjected to post-radiation isochronous annealings for 1 h in a temperature range from 450 to 1050°C have been studied using transmission electron microscopy (TEM) and microhardness measurements. It has been shown that the formation of stitch (secondary) titanium carbides and M 23C6 carbides at grain and twin boundaries after annealing at 1050°C is preceded by a complex evolution of fineparticles of secondary phases (titanium carbides and nitrides) precipitated at dislocation loops and dislocations during annealing at temperatures above 750°C.

  20. Strain-induced phase transformation at the surface of an AISI-304 stainless steel irradiated to 4.4 dpa and deformed to 0.8% strain

    Energy Technology Data Exchange (ETDEWEB)

    Gussev, M.N., E-mail: gussevmn@ornl.gov; Field, K.G.; Busby, J.T.

    2014-03-15

    Surface relief due to localized deformation in a 4.4-dpa neutron-irradiated AISI 304 stainless steel was investigated using scanning electron microscopy coupled with electron backscattering diffraction and scanning transmission electron microscopy. It was found a body-centered-cubic (BCC) phase (deformation-induced martensite) had formed at the surface of the deformed specimen along the steps generated from dislocation channels. Martensitic hill-like formations with widths of ∼1 μm and depths of several microns were observed at channels with heights greater than ∼150 nm above the original surface. Martensite at dislocation channels was observed in grains along the [0 0 1]–[1 1 1] orientation but not in those along the [1 0 1] orientation.

  1. Strain-induced phase transformation at the surface of an AISI-304 stainless steel irradiated to 4.4 dpa and deformed to 0.8% strain

    International Nuclear Information System (INIS)

    Gussev, M.N.; Field, K.G.; Busby, J.T.

    2014-01-01

    Surface relief due to localized deformation in a 4.4-dpa neutron-irradiated AISI 304 stainless steel was investigated using scanning electron microscopy coupled with electron backscattering diffraction and scanning transmission electron microscopy. It was found a body-centered-cubic (BCC) phase (deformation-induced martensite) had formed at the surface of the deformed specimen along the steps generated from dislocation channels. Martensitic hill-like formations with widths of ∼1 μm and depths of several microns were observed at channels with heights greater than ∼150 nm above the original surface. Martensite at dislocation channels was observed in grains along the [0 0 1]–[1 1 1] orientation but not in those along the [1 0 1] orientation

  2. The comparison of microstructure and nanocluster evolution in proton and neutron irradiated Fe–9%Cr ODS steel to 3 dpa at 500 °C

    Energy Technology Data Exchange (ETDEWEB)

    Swenson, M.J., E-mail: matthewswenson1@u.boisestate.edu; Wharry, J.P.

    2015-12-15

    A model Fe–9%Cr oxide dispersion strengthened (ODS) steel was irradiated with protons or neutrons to a dose of 3 displacements per atom (dpa) at a temperature of 500 °C, enabling a direct comparison of ion to neutron irradiation effects at otherwise fixed irradiation conditions. The irradiated microstructures were characterized using transmission electron microscopy and atom probe tomography including cluster analysis. Both proton and neutron irradiations produced a comparable void and dislocation loop microstructure. However, the irradiation response of the Ti–Y–O oxide nanoclusters varied. Oxides remained stable under proton irradiation, but exhibited dissolution and an increase in Y:Ti composition ratio under neutron irradiation. Both proton and neutron irradiation also induced varying extents of Si, Ni, and Mn clustering at existing oxide nanoclusters. Protons are able to reproduce the void and loop microstructure of neutron irradiation carried out to the same dose and temperature. However, since nanocluster evolution is controlled by both diffusion and ballistic impacts, protons are rendered unable to reproduce the nanocluster evolution of neutron irradiation at the same dose and temperature. - Highlights: • Fe–9% Cr ODS was irradiated with protons and neutrons to 3 dpa at 500 °C. • Dislocation loop size and density were similar upon proton and neutron irradiation. • Oxide nanocluster size and density decreased more with neutron irradiation. • Oxide Y:Ti ratio increased from 0.54 to 0.97 upon neutron irradiation. • Irradiation induced enrichment of Si, Mn, and Ni at oxide locations.

  3. Tensile behavior of EUROFER ODS steel after neutron irradiation up to 16.3 dpa between 250 and 450 °C

    International Nuclear Information System (INIS)

    Materna-Morris, Edeltraud; Lindau, Rainer; Schneider, Hans-Christian; Möslang, Anton

    2015-01-01

    Highlights: • The first 9%CrWVTa steel (0.5% Y_2O_3), EUROFER ODS HIP, have been neutron irradiated up to 16.3 dpa, between 250 and 450 °C, in the High Flux Reactor (HFR). • After post-irradiation tensile tests, there was not any increase of the upper yield strength or strain localization after irradiation which is typical of RAFM steels. • Initially higher yield strength, R_p_0_._2, and distinctive tensile strength, R_m, of EUROFER ODS HIP compared to EUROFER97 steel. • These values increased due to the neutron irradiation at lower irradiation temperatures. - Abstract: During the development of structural material for future fusion reactors, a 50 kg heat of reduced-activation ferritic-martensitic 9%CrWVTa steel with nanoscaled Y_2O_3-particles, EUROFER97 ODS HIP, was produced using powder metallurgy fabrication technology. This first batch of EUROFER97 ODS HIP and, for comparison, the steel EUROFER97 were prepared for a post-irradiation tensile test program. During neutron irradiation in the HFR (High Flux Reactor, The Netherlands), an accumulated dose of up to 16.3 dpa was reached for 771 days at full power, with the irradiation temperature ranging between 250 and 450 °C. During the post-examinations, all specimens showed the highest tensile strength at lower irradiation temperatures between 250 and 350 °C. However, ODS-alloy and steel were found to clearly differ in the mechanical behavior, which could be documented by fully instrumented tensile tests. In the un-irradiated state, tensile strength of the ODS-alloy already was increased considerably by about 60% compared to the steel. Strengthening was further increased by another 20% after neutron irradiation, but with a much better ductility than observed in the steel. The typical irradiation-induced strain localization of EUROFER97 or RAFM steels could not be observed in the EUROFER97 ODS HIP alloy.

  4. A new and unusual deformation behavior observed in 12Cr18Ni10Ti stainless steel irradiated at 307 deg. C to 55 dpa in BN-350

    International Nuclear Information System (INIS)

    Gusev, M.; Maksimkin, O.; Osipov, I.S.; Garner, F.

    2007-01-01

    Full text of publication follows: It is currently accepted that neutron irradiation of stainless steels in general leads to increased strength, reduction of ductility and inevitably to embrittlement. The microstructural origins of such changes in mechanical behavior are well understood. Occasionally, however, a new phenomenon is observed at higher fluences. Void-induced embrittlement is an example whereby the ductility loss is strongly accelerated when new microstructural conditions develop from voids that cause stress concentration, removal of nickel from the matrix and thereby induce a martensitic transformation. This process occurs at moderately high temperatures where high void swelling can occur. It now appears that there is another, previously unobserved phenomenon that develops in austenitic steel irradiated to relatively high dose and relatively low temperature. In this case, however, the loss of plasticity commonly developed at lower dose is reversed and is replaced by an unusually high deformation. The plastic deformation was studied of miniature flat tensile specimens of 12Cr18Ni10Ti austenitic steel cut from a fuel assembly wrapper irradiated in the BN-350 reactor to 55 dpa at 580 K (307 deg. C). A new optical extensometry technique was employed that uses a video camera and multiple tiny markers painted on the specimen, allowing visualization and recording of the strain distribution as it develops along the specimen. The total deformation derived from the engineering diagrams for these specimens was 35-40%, while 3-7% was expected from previous studies conducted at lower dpa levels. The video record showed that the material resists necking and involves a moving deformation wave that initiates near one of the tensile grippers and spreads along ∼3/4 of the gauge length before failure occurs. Such behavior, often called a 'moving neck' has been observed previously in pure iron and Al-Mg alloys but has not been observed in irradiated stainless steels

  5. In vitro response to EPA, DPA, and DHA: Comparison of effects on ruminal fermentation and biohydrogenation of 18-carbon fatty acids in cows and ewes.

    Science.gov (United States)

    Toral, P G; Hervás, G; Carreño, D; Leskinen, H; Belenguer, A; Shingfield, K J; Frutos, P

    2017-08-01

    The modulation of milk fat nutritional quality through fish oil supplementation seems to be largely explained by the action of n-3 very long chain polyunsaturated fatty acids (PUFA) on ruminal biohydrogenation (BH) of C18 fatty acids (FA). However, relationships among this action, disappearance of those PUFA in the rumen, and potential detrimental consequences on ruminal fermentation remain uncertain. This study compared the effect of 20:5n-3 (eicosapentaenoic acid; EPA), 22:5n-3 (docosapentaenoic acid; DPA), and 22:6n-3 (docosahexaenoic acid; DHA) on rumen fermentation and BH of C18 FA and was conducted simultaneously in cows and sheep to provide novel insights into interspecies differences. The trial was performed in vitro using batch cultures of rumen microorganisms with inocula collected from cannulated cows and ewes. The PUFA were added at a dose of 2% incubated dry matter, and treatment effects on ruminal C18 FA concentrations, PUFA disappearances, and fermentation parameters (gas production, ammonia and volatile FA concentrations, and dry matter and neutral detergent fiber disappearances) were examined after 24 h of incubation. A principal component analysis suggested that responses to PUFA treatments explained most of the variability; those of ruminant species were of lower relevance. Overall, EPA and DHA were equally effective for inhibiting the saturation of trans-11 18:1 to 18:0 and had a similar influence on ruminal fermentation in cows and sheep (e.g., reductions in gas production and acetate:propionate ratio). Nevertheless, DHA further promoted alternative BH pathways that lead to trans-10 18:1 accumulation, and EPA seemed to have specific effects on 18:3n-3 metabolism. Only minor variations attributable to DPA were observed in the studied parameters, suggesting a low contribution of this FA to the action of marine lipids. Although most changes due to the added PUFA were comparable in bovine and ovine, there were also relevant specificities, such as a

  6. Tensile and low cycle fatigue properties of EUROFER97-steel after 16.3 dpa neutron irradiation at 523, 623 and 723 K

    Energy Technology Data Exchange (ETDEWEB)

    Materna-Morris, E., E-mail: edeltraud.materna-morris@kit.edu; Möslang, A., E-mail: anton.moeslang@kit.edu; Schneider, H.-C., E-mail: hans-christian.schneider@kit.edu

    2013-11-15

    Neutron-irradiated specimens of the reduced-activation tempered martensitic steel EUROFER97 were tested by tensile and low cycle conditions to detect the impact of irradiation on strength and lifetime. The irradiation temperature ranged from 523 to 723 K with an accumulated dose of up to 16.3 dpa. Tensile tests revealed a significant irradiation-induced hardening below 673 K with a peak of ∼430 MPa at 573 K but none was seen at 723 K, as expected. Despite the significant irradiation-induced reduction of uniform elongation, the total elongation is only reduced by about 50% below 673 K. Post-irradiation strain-controlled fatigue tests have been carried out at T{sub irrad} = T{sub test} = 523, 623 and 723 K. Pronounced cyclic softening was observed in all specimens. At 623 and 723 K, neutron irradiation had no effect on fatigue life within the data scatter. A significant lifetime increase has been observed at T{sub irrad} = T{sub test} = 523 K that advances with decreasing stress amplitude Δε (1% → 0.5%) up to a factor of ten. Scanning electron microscopy (SEM) analysis revealed ductile fracture and fatigue striations on the fracture surfaces. After push–pull fatigue testing, transmission electron microscopy (TEM) investigations showed the typical sub-cell formation, even at T{sub irrad} = T{sub test} = 523 K.

  7. Synthesis, Characterization, and Initial Biological Evaluation of [99m Tc]Tc-Tricarbonyl-labeled DPA-α-MSH Peptide Derivatives for Potential Melanoma Imaging.

    Science.gov (United States)

    Gao, Feng; Sihver, Wiebke; Bergmann, Ralf; Belter, Birgit; Bolzati, Cristina; Salvarese, Nicola; Steinbach, Jörg; Pietzsch, Jens; Pietzsch, Hans-Jürgen

    2018-06-06

    α-Melanocyte stimulating hormone (α-MSH) derivatives target the melanocortin-1 receptor (MC1R) specifically and selectively. In this study, the α-MSH-derived peptide NAP-NS1 (Nle-Asp-His-d-Phe-Arg-Trp-Gly-NH 2 ) with and without linkers was conjugated with 5-(bis(pyridin-2-ylmethyl)amino)pentanoic acid (DPA-COOH) and labeled with [ 99m Tc]Tc-tricarbonyl by two methods. With the one-pot method the labeling was faster than with the two-pot method, while obtaining similarly high yields. Negligible trans-chelation and high stability in physiological solutions was determined for the [ 99m Tc]Tc-tricarbonyl-peptide conjugates. Coupling an ethylene glycol (EG)-based linker increased the hydrophilicity. The peptide derivatives displayed high binding affinity in murine B16F10 melanoma cells as well as in human MeWo and TXM13 melanoma cell homogenates. Preliminary in vivo studies with one of the [ 99m Tc]Tc-tricarbonyl-peptide conjugates showed good stability in blood and both renal and hepatobiliary excretion. Biodistribution was performed on healthy rats to gain initial insight into the potential relevance of the 99m Tc-labeled peptides for in vivo imaging. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Chemical functionalization of crystalline silicon surface with complexes of type (M3 (Dpa) 4X2) for the development of electronic devices

    International Nuclear Information System (INIS)

    Sanchez Zamora, Maria Alejandra

    2012-01-01

    New surfaces on crystalline silicon (100) diamines have been developed. The diamines 4-aminopyridine, 4-aminomethylpyridine and 1,12-dodecildiame, and self-assembled surfaces Si-diamine-metallic complexes, with cooper (II) acetate and trimetal Cu 3 (dpa) 4 CI 2 were studied. These surfaces are characterized with X-ray photoelectron spectroscopy (XPS), chemical force microscopy (CFM), by contact angle and cyclic voltammetry (CV). The XPS has suggested the formation of diamines monolayers with covalent binding to crystalline silicon, and modification of these surfaces, with metal complexes by coordination chemistry. The CFM has confirmed that surfaces are modified with diamines and cooper (II) acetate, and that were determined different chemical forces according to the change. The contact angle has been suggested that the functionalized surface with 4-aminomethylpyridine has had similar basicity to 1,12-dodecildiame, and more than 4-aminopyridine. This implies that the coordination with metallics complexes is benefited with 4-aminopyridine, which in turn is reflected with electrochemical data. Cyclic voltammetry analysis have showed that silicon surfaces with 4-aminomethylpyridine and 4-aminopyridine with cooper (II) acetate and trimetal have been electrochemically active. Thus, the surfaces could to have interesting applications in molecular electronics. (author) [es

  9. Recent results on the neutron irradiation of ITER candidate copper alloys irradiated in DR-3 at 250{degrees}C to 0.3 dpa

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, D.J. [Pacific Northwest National Lab., Richland, WA (United States); Singh, B.N.; Toft, P.; Eldrup, M.

    1997-04-01

    Tensile specimens of CuCrZr and CuNiBe alloys were given various heat treatments corresponding to solution anneal, prime-ageing and bonding thermal treatment with additional specimens re-aged and given a reactor bakeout treatment at 350{degrees}C for 100 h. CuAl-25 was also heat treated to simulate the effects of a bonding thermal cycle on the material. A number of heat treated specimens were neutron irradiated at 250{degrees}C to a dose level of {approximately}0.3 dpa in the DR-3 reactor as Riso. The main effect of the bonding thermal cycle heat treatment was a slight decrease in strength of CuCrZr and CuNiBe alloys. The strength of CuAl-25, on the other hand, remained almost unaltered. The post irradiation tests at 250{degrees}C showed a severe loss of ductility in the case of the CuNiBe alloy. The irradiated CuAl-25 and CuCrZr specimens exhibited a reasonable amount of uniform elongation, with CuCrZr possessing a lower strength.

  10. Effect on fast neutron irradiation to 4 dpa at 400{degrees}C on the properties of V-(4-5)Cr-(4-5)Ti alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zinkle, S.J.; Alexander, D.J.; Robertson, J.P. [Oak Ridge National Lab., TN (United States)] [and others

    1997-04-01

    Tensile, Charpy impact and electrical resistivity measurements have been performed at ORNL on V-4Cr-4Ti and V-5Cr-5Ti specimens that were prepared at ANL and irradiated in the lithium-bonded X530 experiment in the EBR-II fast reactor. All of the specimens were irradiated to a damage level of about 4 dpa at a temperature of {approximately}400{degrees}C. A significant amount of radiation hardening was evident in both the tensile and Charpy impact tests. The irradiated V-4Cr-4Ti yield strength measured at {approximately}390{degrees}C was >800 MPa, which is more than three times as high as the unirradiated value. The uniform elongations of the irradiated tensile specimens were typically {approximately}1%, with corresponding total elongations of 4-6%. The ductile to brittle transition temperature of the irradiated specimens was less than the unirradiated resistivity, which suggests that hardening associated with interstitial solute pickup was minimal.

  11. Calculation of the displacement cross sections and the DPA distribution in hydrogenated amorphous silicon semiconductors detectors in medical digital imaging applications

    International Nuclear Information System (INIS)

    Leyva Fabelo, Antonio; Piñera Hernández, Ibrahin; Shtejer Díaz, Katerin; Abreu Alfonso, Yamiel; Cruz Inclán, Carlos Manuel

    2007-01-01

    In present paper the dependence of the displacement cross sections of the different species of atoms in the a-Si:H structure, with the energy of the secondary electrons generated by the X-rays of the typical energies using in medical imaging applications, was calculated using the Mott-McKinley- Feshbach approach. It was verified that for electron energies higher than 1.52 keV it is possible the occurrence of hydrogen atoms displacements, while for the silicon atoms the threshold energy is 126 keV. These results were compared with those obtained for similar detectors but developed with crystalline silicon. With the use of the mathematical simulation of the radiation transport in the matter, the energy spectrum of the secondary electrons was calculated in order to estimate the number of atomic displacements, which take place in the semiconducting amorphous device in working regime. The spatial distribution of the dpa in the detectors volume, as well as its behavior with the depth in the work region are presented and discussed in the text. (author)

  12. Irradiation testing of stainless steel plate material and weldments. Report on ITER Task T14, Part B. Tensile properties after 0.5 and 5 dpa at 350 and 500 K

    International Nuclear Information System (INIS)

    Rensman, J.W.; Boskeljon, J.; Horsten, M.G.; De Vries, M.I.

    1997-10-01

    The tensile properties of unirradiated and neutron irradiated type 316L(N)-SPH stainless steel plate, EB weldments, 16-8 TIG-weldments, and full 16-8 TIG-deposits have been measured. Miniature 4 mm diameter test specimens of the European Reference Heat 1 and 2 (ERH), and 4 mm and some 8 mm diameter specimens of the weldments mentioned above, were irradiated in the High Flux Reactor (HFR) in Petten, The Netherlands, simulating the first wall conditions by a combination of high displacement damage with high amounts of helium. The irradiation conditions were 0.5 and 5 displacements per atom (dpa) at 350K and 0.5 and 5 dpa at 500K. Testing temperatures ranged from 300K to 850K. This work was performed as part of the European Fusion Technology Programme for ITER as 'Irradiation testing of stainless steel' The report contains the experimental conditions and summarises the results. The tensile properties of the unirradiated ERH's 1 and 2 plate materials were found to differ slightly but significantly: ERH2 has a lower UTS, but higher yield strength and ductility than ERH1. The plate materials have lower yield strength in the unirradiated condition than all of the weldments (EB, TIG-weld and TIG-deposit), accompanied by a higher ductility of the plate materials. When irradiated at 350K the differences in strength between the plate and weld materials decrease, but the ductility of the plate remains higher than that of the weldments. A saturation of irradiation damage has taken place already at about 0.5 dpa. When irradiated at 500K the plate material continuously hardens up to 5 dpa, where it has lost all uniform plastic ductility. The weldments show similar but less dramatic hardening and loss of ductility as the plate material for both irradiation conditions. 54 figs., 17 tabs., 21 refs

  13. Continuous gradient temperature Raman spectroscopy of the long chain polyunsaturated fatty acids docosapentaenoic (DPA, 22:5n-6) and docosahexaenoic (DHA; 22:6n-3) from -100 to 20° C

    Science.gov (United States)

    Broadhurst, C. Leigh; Schmidt, Walter F.; Kim, Moon S.; Nguyen, Julie K.; Qin, Jianwei; Chao, Kuanglin; Bauchan, Gary L.; Shelton, Daniel R.

    2016-05-01

    The structural, cognitive and visual development of the human brain and retina strictly require long-chain polyunsaturated fatty acids (LC-PUFA). Excluding water, the mammalian brain is about 60% lipid. One of the great unanswered questions with respect to biological science in general is the absolute necessity of the LC-PUFA docosahexaenoic acid (DHA; 22:6n-3) in these fast signal processing tissues. A lipid of the same chain length with just one less diene group, docosapentaenoic acid (DPA; 22:5n-6) is fairly abundant in terrestrial food chains yet cannot substitute for DHA. Gradient Temperature Raman spectroscopy (GTRS) applies the temperature gradients utilized in differential scanning calorimetry to Raman spectroscopy, providing a straightforward technique to identify molecular rearrangements that occur near and at phase transitions. Herein we apply GTRS to DPA, and DHA from -100 to 20°C. 20 Mb three-dimensional data arrays with 1°C increments and first/second derivatives allows complete assignment of solid, liquid and transition state vibrational modes, including low intensity/frequency vibrations that cannot be readily analyzed with conventional Raman. DPA and DHA show significant spectral changes with premelting (-33 and -60°C, respectively) and melting (-27 and -44°C, respectively). The CH2-(HC=CH)-CH2 moieties are not identical in the second half of the DHA and DPA structures. The DHA molecule contains major CH2 twisting (1265 cm-1) with no noticeable CH2 bending, consistent with a flat helical structure with small pitch. Further modeling of neuronal membrane phospholipids must take into account this structure for DHA, which would be configured parallel to the hydrophilic head group line.

  14. Important comments on KERMA factors and DPA cross-section data in ACE files of JENDL-4.0, JEFF-3.2 and ENDF/B-VII.1

    Science.gov (United States)

    Konno, Chikara; Tada, Kenichi; Kwon, Saerom; Ohta, Masayuki; Sato, Satoshi

    2017-09-01

    We have studied reasons of differences of KERMA factors and DPA cross-section data among nuclear data libraries. Here the KERMA factors and DPA cross-section data included in the official ACE files of JENDL-4.0, ENDF/B-VII.1 and JEFF-3.2 are examined in more detail. As a result, it is newly found out that the KERMA factors and DPA cross-section data of a lot of nuclei are different among JENDL-4.0, ENDF/B-VII.1 and JEFF-3.2 and reasons of the differences are the followings: 1) large secondary particle production yield, 2) no secondary gamma data, 3) secondary gamma data in files12-15 mt = 3, 4) mt = 103-107 data without mt = 600 s-800 s data in file6. The issue 1) is considered to be due to nuclear data, while the issues 2)-4) seem to be due to NJOY. The ACE files of JENDL-4.0, ENDF/B-VII.1 and JEFF-3.2 with these problems should be revised after correcting wrong nuclear data and NJOY problems.

  15. Imaging micro-glial/macrophage activation in spinal cords of experimental autoimmune encephalomyelitis rats by Positron Emission Tomography using the mitochondrial 18 kDa translocator protein radioligand [18F]DPA-714

    International Nuclear Information System (INIS)

    Abourbeh, Galith; Theze, Benoit; Dubois, Albertine; Tavitian, Bertrand; Boisgard, Raphael; Maroy, Renaud; Brulon, Vincent; Fontyn, Yoann; Dolle, Frederic

    2012-01-01

    Multiple sclerosis (MS) is an inflammatory demyelinating disease of the CNS. Activated micro-glia/macrophages play a key role in the immuno-pathogenesis of MS and its corresponding animal models, experimental autoimmune encephalomyelitis (EAE). Micro-glia activation begins at early stages of the disease and is associated with elevated expression of the 18 kDa mitochondrial translocator protein (TSPO). Thus, positron emission tomography (PET) imaging of micro-glial activation using TSPO-specific radioligands could be valuable for monitoring disease-associated neuro-inflammatory processes. EAE was induced in rats using a fragment of myelin basic protein, yielding acute clinical disease that reflects extensive spinal cord inflammation. Enhanced TSPO expression in spinal cords of EAE rats versus those of controls was confirmed by Western blot and immunohistochemistry. Biodistribution studies in control and EAE rats were performed using the TSPO radioligand [ 18 F]DPA-714 [N,N-diethyl-2-(2-(4-(2-fluoroethoxy)phenyl)-5,7-dimethylpyrazolo[1,5- a]pyrimidin-3-yl)acetamide]. At 1 h after injection, almost fivefold higher levels of [ 18 F]DPA-714 were measured in spinal cords of EAE rats versus controls. The specific binding of [ 18 F]DPA-714 to TSPO in spinal cords was confirmed in competition studies, using unlabeled (R,S)-PK11195 [(R,S)-N-methyl-N-(1-methylpropyl)-1-(2-chlorophenyl) - isoquinoline-3-carboxamide)] or DPA-714 in excess. MicroPET studies affirm that this differential radioactivity uptake in spinal cords of EAE versus control rats could be detected and quantified. Using [ 18 F]DPA-714, neuro-inflammation in spinal cords of EAE-induced rats could be visualized by PET, offering a sensitive technique for monitoring neuro-inflammatory lesions in the CNS and particularly in the spinal cord. In addition to current MRI protocols, this approach could provide molecular images of neuro-inflammation for detection, monitoring, and research in MS. (authors)

  16. Raman spectral titration method: an informative technique for studying the complexation of uranyl with uranyl(vi)-DPA/oxalate systems as examples.

    Science.gov (United States)

    Liu, Qian; Zhang, Qianci; Yang, Suliang; Zhu, Haiqiao; Liu, Quanwei; Tian, Guoxin

    2017-10-10

    The Raman band at about 870 cm -1 originating from the symmetric stretch vibration (ν 1 ) of uranyl, UO 2 2+ , has proven to be very informative for investigating the complexation of uranyl using perchlorate or nitrate of known concentration as internal standards. The concentration of uranyl can be conveniently calculated by using the ratio of the directly read band intensities of uranyl and the added reference, ClO 4 - , with a factor of 1.72. While with NO 3 - of concentration lower than 1.8 M as the reference, a factor of 0.85 should be used. Furthermore, with added internal standards, the linear relationship between the Raman intensity and the concentration of the corresponding species is illustrated by the spectral titration of U(vi) with a very strong ligand, dipicolinic acid (DPA); and the application of a spectral titration method with Raman spectroscopy in studying the complexation of uranyl is demonstrated by the titration of U(vi) with oxalate. The stepwise changes in the Raman shift of 18, 17, and 6 cm -1 , corresponding to the three oxalate anions successively bonding to UO 2 2+ , imply that the coordination modes are different. In the 1 : 1 and 1 : 2 ratios of metal to ligand complexes, the oxalate anions bond to the uranyl ion in side-on bidentate mode, but in the 1 : 3 complex the third oxalate bonds in head-on mode, which is much weaker than the first two.

  17. Experimental investigation of high He/dpa microstructural effects in neutron irradiated B-alloyed Eurofer97 steel by means of small angle neutron scattering (SANS and electron microscopy

    Directory of Open Access Journals (Sweden)

    R. Coppola

    2016-12-01

    Full Text Available High He/dpa microstructural effects have been investigated, by means of small-angle neutron scattering (SANS and transmission electron microscopy (TEM, in B-alloyed ferritic/martensitic steel Eurofer97-1 (0.12 C, 9 Cr, 0.2V, 1.08W wt%, B contents variable between 10 and 1000ppm, neutron irradiated at the High Flux Reactor of the JRC-Petten at temperatures between 250 °C and 450 °C, up do a dose level of 16 dpa. Under these irradiation parameters, B activation is expected to produce corresponding helium contents variable between 80 and 5600appm, with helium bubble distributions relevant for the technological applications. The SANS measurements were carried out under magnetic field to separate nuclear and magnetic SANS components; a reference, un-irradiated sample was also measured to evaluate as accurately as possible the genuine effect of the irradiation on the microstructure. Increasing the estimated helium content from 400 to 5600appm, the analysis of the SANS cross-sections yields an increase in the volume fraction, attributed to helium bubbles, of almost one order of magnitude (from 0.007 to 0.038; furthermore, the difference between nuclear and magnetic SANS components is strongly reduced. These results are discussed in correlation with TEM observations of the same samples and are tentatively attributed to the effect of drastic microstructural changes in Eurofer97-1 for high He/dpa ratio values, possibly relating to the dissolution of large B-carbides due to transmutation reactions.

  18. Post irradiation examination of RAF/M steels after fast reactor irradiation up to 33 dpa and < 340 C (ARBOR1). RAFM steels. Metallurgical and mechanical characterisation. Final report for TW2-TTMS-001b, D9

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, C. [Forschungszentrum Karlsruhe GmbH Technik und Umwelt (Germany). EURATOM, Inst. fuer Materialforschung, Programm Kernfusion

    2010-07-01

    In an energy generating fusion reactor structural materials will be exposed to very high dpa-levels of about 100 dpa. Due to this fact and because fast reactor irradiation facilities in Europe are not available anymore, a reactor irradiation at the State Scientific Center of the Russian Federation with its Research Institute of Atomic Reactors (SSC RIAR), Dimitrovgrad, had been performed in the fast reactor BOR 60 with an instrumented test rig. This test rig contained tensile, impact and Low Cycle Fatigue type specimens used at FZK since many years. Samples of actual Reduced Activation Ferritic/Martensitic (RAF/M) -steels (e.g. EUROFER 97) had been irradiated in this reactor at a lower temperature (< 340 C) up to a damage of 33 dpa. This irradiation campaign was called ARBOR 1. Starting in 2003 one half of these irradiated samples were post irradiation examined (PIE) by tensile testing, low cycle fatigue testing and impact testing under the ISTC Partner Contract 2781p in the hot cells of SSC RIAR. In the post irradiation instrumented impact tests a significant increase in the Ductile to Brittle Transition Temperature as an effect of irradiation has been detected. During tensile testing the strength values are increasing and the strain values reduced due to substantial irradiation hardening. The hardening rate is decreasing with increasing damage level, but it does not show saturation. The low cycle fatigue behaviour of all examined RAF/M - steels show at total strain amplitudes below 1 % an increase of number of cycles to failure, due to irradiation hardening. From these post irradiation experiments, like tensile, low cycle fatigue and impact tests, radiation induced design data, e.g. for verification of design codes, can be generated.

  19. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion related to the Tolerable Upper Intake Level of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and docosapentaenoic acid (DPA)

    DEFF Research Database (Denmark)

    Tetens, Inge

    Following a request from the European Commission, the Panel on Dietetic Products, Nutrition and Allergies was asked to deliver a scientific opinion on the Tolerable Upper Intake Level (UL) of the n-3 LCPUFAs eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and docosapentaenoic acid (DPA......). Available data are insufficient to establish a UL for n-3 LCPUFA (individually or combined) for any population group. At observed intake levels, consumption of n-3 LCPUFA has not been associated with adverse effects in healthy children or adults. Long-term supplemental intakes of EPA and DHA combined up...... to about 5 g/day do not appear to increase the risk of spontaneous bleeding episodes or bleeding complications, or affect glucose homeostasis immune function or lipid peroxidation, provided the oxidative stability of the n-3 LCPUFAs is guaranteed. Supplemental intakes of EPA and DHA combined at doses of 2...

  20. Exploring the association between whole blood Omega-3 Index, DHA, EPA, DHA, AA and n-6 DPA, and depression and self-esteem in adolescents of lower general secondary education.

    Science.gov (United States)

    van der Wurff, I S M; von Schacky, C; Bergeland, T; Leontjevas, R; Zeegers, M P; Kirschner, P A; de Groot, R H M

    2018-03-16

    Depression is common in adolescents and long-chain polyunsaturated fatty acids (LCPUFA) are suggested to be associated with depression. However, research in adolescents is limited. Furthermore, self-esteem has never been studied in relation to LCPUFA. The objective here was to determine associations of depression and self-esteem with eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), Omega-3 Index (O3I), n-6 docosapentaenoic acid (n-6 DPA, also called Osbond acid, ObA), n-3 docosapentaenoic acid (DPA), and arachidonic acid (AA) concentrations in blood of adolescents attending lower general secondary education (LGSE). Baseline cross-sectional data from a krill oil supplementation trial in adolescents attending LGSE with an O3I ≤ 5% were analysed using regression models built with the BayesFactor package in R. Fatty acids and O3I were determined in blood. Participants filled out the Centre for Epidemiologic Studies Depression (CES-D) scale and the Rosenberg Self-Esteem scale (RSE). Scores indicative of depression (CES-D ≥ 16) were found in 29.4% of the respondents. Of all fatty acids, we found extreme evidence [Bayes factor (BF) > 100] for a weak negative association between ObA and depression score [- 0.16; 95% credible interval (CI) - 0.28 to - 0.04; BF 10  = 245], and substantial evidence for a weak positive association between ObA and self-esteem score (0.09; 95% CI, - 0.03 to 0.20; BF 10  = 4). When all fatty acids were put in one model as predictors of CES-D or RSE, all of the 95% CI contained 0, i.e., no significant association. No evidence was found for associations of DHA, EPA and O3I with depression or self-esteem scores in LGSE adolescents with O3I ≤ 5%. The associations of higher ObA status with lower depression and higher self-esteem scores warrant more research.

  1. [{sup 18}F]DPA-714, [{sup 18}F]PBR111 and [{sup 18}F]FEDAA1106-Selective radioligands for imaging TSPO 18 kDa with PET: Automated radiosynthesis on a TRACERLAb FX-FN synthesizer and quality controls

    Energy Technology Data Exchange (ETDEWEB)

    Kuhnast, Bertrand, E-mail: bertrand.kuhnast@cea.fr [CEA, I2BM, Service Hospitalier Frederic Joliot, 4 Place du General Leclerc, F-91401, Orsay Cedex (France); Damont, Annelaure; Hinnen, Francoise; Catarina, Tony; Demphel, Stephane; Le Helleix, Stephane; Coulon, Christine; Goutal, Sebastien; Gervais, Philippe; Dolle, Frederic [CEA, I2BM, Service Hospitalier Frederic Joliot, 4 Place du General Leclerc, F-91401, Orsay Cedex (France)

    2012-03-15

    Imaging of TSPO 18 kDa with PET is more and more considered as a relevant biomarker of inflammation in numerous diseases. Development of new radiotracers for TSPO 18 kDa has seen acceleration in the last years and the challenge today is to make available large amounts of such a radiotracer in compliance with GMP standards for application in humans. We present in this technical note automated productions of [{sup 18}F]DPA-714, [{sup 18}F]PBR111 and [{sup 18}F]FEDAA1106, three promising radiotracers for TSPO 18 kDa imaging, using a TRACERlab FX-FN synthesizer. This note also includes the quality control data of the validation batches for the manufacturing qualification of clinical production of [{sup 18}F]DPA-714. - Highlights: Black-Right-Pointing-Pointer Protein TSPO 18 kDa is recognized as a biomarker of inflammation involved in many diseases. Black-Right-Pointing-Pointer Radiotracers targeting TSPO prepared in compliance with GMPs are mandatory as new imaging tools. Black-Right-Pointing-Pointer An automated radiosynthesis of promising radiotracers and full QC have been implemented.

  2. Airborne Precision Spacing (APS) Dependent Parallel Arrivals (DPA)

    Science.gov (United States)

    Smith, Colin L.

    2012-01-01

    The Airborne Precision Spacing (APS) team at the NASA Langley Research Center (LaRC) has been developing a concept of operations to extend the current APS concept to support dependent approaches to parallel or converging runways along with the required pilot and controller procedures and pilot interfaces. A staggered operations capability for the Airborne Spacing for Terminal Arrival Routes (ASTAR) tool was developed and designated as ASTAR10. ASTAR10 has reached a sufficient level of maturity to be validated and tested through a fast-time simulation. The purpose of the experiment was to identify and resolve any remaining issues in the ASTAR10 algorithm, as well as put the concept of operations through a practical test.

  3. Urea/thiourea derivatives and Zn(II)-DPA complex as receptors for ...

    Indian Academy of Sciences (India)

    of industries related to agricultural fertilizers, food additives and water. Along with these, recent emphasis on environmental concern — both industrially and ...... Tocci G M, Kruger P E and Pfeffer F M 2006 Coord. Chem. Rev. 250 3094; (p) Filby M H and Steed J W 2006. Coord. Chem. Rev. 250 3200; (q) O'Neil E J and ...

  4. Review of the research and application of KERMA factor and DPA cross section

    International Nuclear Information System (INIS)

    1991-03-01

    The data for recoil atom spectra, KERMA factor and displacement cross sections from neutron-induced reactions are calling increasing interest for applications to the study of radiation damage, calculation of heat generation in reactor, neutron therapy and biological research. PKA spectra sub-working group was recently established in Japanese Nuclear Data Committee as a part of developing JENDL Special Purpose Data Files. Current status of the data and various features of application of the KERMA-related problems were reviewed and discussed at the first meeting of the sub-working group. Present report is a compilation of the items presented at the meeting, covering a brief review of the existing research and the data, method of calculation, the KERMA factor data in neutron therapy, the deduction of KERMA factor of C-12 from neutron reaction measurement and analysis, the data base for radiation damage, the damage simulation calculation, and the method of storaging the evaluated data in ENDF/B-VI format. (author)

  5. Neutron Fluence And DPA Rate Analysis In Pebble-Bed HTR Reactor Vessel Using MCNP

    Science.gov (United States)

    Hamzah, Amir; Suwoto; Rohanda, Anis; Adrial, Hery; Bakhri, Syaiful; Sunaryo, Geni Rina

    2018-02-01

    In the Pebble-bed HTR reactor, the distance between the core and the reactor vessel is very close and the media inside are carbon and He gas. Neutron moderation capability of graphite material is theoretically lower than that of water-moderated reactors. Thus, it is estimated much more the fast neutrons will reach the reactor vessel. The fast neutron collisions with the atoms in the reactor vessel will result in radiation damage and could be reducing the vessel life. The purpose of this study was to obtain the magnitude of neutron fluence in the Pebble-bed HTR reactor vessel. Neutron fluence calculations in the pebble-bed HTR reactor vessel were performed using the MCNP computer program. By determining the tally position, it can be calculated flux, spectrum and neutron fluence in the position of Pebble-bed HTR reactor vessel. The calculations results of total neutron flux and fast neutron flux in the reactor vessel of 1.82x108 n/cm2/s and 1.79x108 n/cm2/s respectively. The fast neutron fluence in the reactor vessel is 3.4x1017 n/cm2 for 60 years reactor operation. Radiation damage in stainless steel material caused by high-energy neutrons (> 1.0 MeV) will occur when it has reached the neutron flux level of 1.0x1024 n/cm2. The neutron fluence results show that there is no radiation damage in the Pebble-bed HTR reactor vessel, so it is predicted that it will be safe to operate at least for 60 years.

  6. Improved posttraumatic acquisition of a place learning task after repeated administration of a serotonergic agonist 8-OH-DPA

    DEFF Research Database (Denmark)

    Mala, Hana; Mogensen, Jesper

    2008-01-01

    specifically to 5-HT1A receptor subtypes. The effects were evaluated in terms of functional performance on an allocentric place learning task.    Participants/Materials/Methods: 68 animals served as experimental subjects. Initially, the rats were divided into 6 experimental groups, three of which were...... was given a single dose (5mg/kg/b.w.) of 8-OH-DPAT immediately after surgery (SINGLE TREATM), and one group was treated with daily administration of 8-OH-DPAT (5mg/kg/b.w.) for the six subsequent days (the first administration taking place immediately after surgery) (REPEATED TREATM). The acquisition...... of the water maze based place learning task started on the 8th day after surgery and continued daily for the next 25 days.   Results: The results show that within the lesioned groups, the group that was subjected to repeated administration of 8-OH-DPAT (REPEAT TREATM) showed a significantly improved...

  7. Lifetime prediction of EC, DPA, akardite II and MNA stabilized triple base propellants, comparison of heat generation rate and stabilizer consumption

    NARCIS (Netherlands)

    Boers, M.N.; Klerk, W.P.C. de

    2005-01-01

    A lifetime prediction study is carried out on four triple base propellant compositions by artificial ageing. The ageing effects are studied with High Performance Liquid Chromatography (HPLC) and Heat Flow Calorimetry (HFC) in order to find the most effective stabilizer and to evaluate the advantages

  8. Lifetime prediction of EC, DPA, Akardite II and MNA stabilized triple base propellants, comparison of heat generation rate and stabilizer consumption

    Energy Technology Data Exchange (ETDEWEB)

    Boers, Marco N.; Klerk, Willem (Wim) P.C. de [TNO Defence, Security and Safety, P. O. Box 45, 2280 AA Rijswijk ZH (Netherlands)

    2005-10-01

    A lifetime prediction study is carried out on four triple base propellant compositions by artificial ageing. The ageing effects are studied with High Performance Liquid Chromatography (HPLC) and Heat Flow Calorimetry (HFC) in order to find the most effective stabilizer and to evaluate the advantages and disadvantages of both methods. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

  9. Influence of cold work to increase swelling of pure iron irradiated in the BR-10 reactor to ∼6 and ∼25 dpa at ∼400 deg. C

    International Nuclear Information System (INIS)

    Dvoriashin, A.M.; Porollo, S.I.; Konobeev, Yu.V.; Garner, F.A.

    2000-01-01

    Irradiation of pure iron in several starting conditions at 400 deg. C has been conducted in the BR-10 fast reactor. Contrary to expectations, cold working appears to significantly accelerate the onset of void swelling. When compared to a similar experiment conducted in this reactor at the same time, it appears that iron experiences a rather long transient duration before the onset of steady-state swelling. The transient appears to be shortened by both cold-working and lower atomic displacement rates

  10. Daily Physical Activity Survey Report

    Science.gov (United States)

    Alberta Education, 2008

    2008-01-01

    The intent of the Daily Physical Activity (DPA) Survey was to gather school-level information from teachers and principals regarding their perceptions of DPA, thus providing a greater understanding of DPA implementation in grades 1 to 9. This study aimed to help identify the many variables that influence the attainment of the DPA outcomes and…

  11. Continuous gradient temperature Raman spectroscopy of the long chain polyunsaturated fatty acids Docosapentaenoic (DPA, 22:5n-6) and Docosahexaenoic (DHA; 22:6n-3) from -100 to 20° C

    Science.gov (United States)

    The structural, cognitive and visual development of the human brain and retina strictly require long-chain polyunsaturated fatty acids (LC-PUFA). Excluding water, the mammalian brain is about 60% lipid. One of the great unanswered questions with respect to biological science in general is the absolu...

  12. Increased dipicolinic acid production with an enhanced spoVF operon in Bacillus subtilis and medium optimization.

    Science.gov (United States)

    Takahashi, Fumikazu; Sumitomo, Nobuyuki; Hagihara, Hiroshi; Ozaki, Katsuya

    2015-01-01

    Dipicolinic acid (DPA) is a multi-functional agent for cosmetics, antimicrobial products, detergents, and functional polymers. The aim of this study was to design a new method for producing DPA from renewable material. The Bacillus subtilis spoVF operon encodes enzymes for DPA synthase and the part of lysine biosynthetic pathway. However, DPA is only synthesized in the sporulation phase, so the productivity of DPA is low level. Here, we report that DPA synthase was expressed in vegetative cells, and DPA was produced in the culture medium by replacement of the spoVFA promoter with other highly expressed promoter in B. subtilis vegetative cells, such as spoVG promoter. DPA levels were increased in the culture medium of genetically modified strains. DPA productivity was significantly improved up to 29.14 g/L in 72 h culture by improving the medium composition using a two-step optimization technique with the Taguchi methodology.

  13. Microstructural examination of irradiated vanadium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gelles, D.S. [Pacific Northwest National Lab., Richland, WA (United States); Chung, H.M. [Argonne National Lab., IL (United States)

    1997-04-01

    Microstructural examination results are reported for a V-5Cr-5Ti unirradiated control specimens of heat BL-63 following annealing at 1050{degrees}C, and V-4Cr-4Ti heat BL-47 irradiated in three conditions from the DHCE experiment: at 425{degrees}C to 31 dpa and 0.39 appm He/dpa, at 600{degrees}C to 18 dpa and 0.54 appm He/dpa and at 600{degrees}C to 18 dpa and 4.17 appm He/dpa.

  14. SHORT COMMUNICATION KINETICS AND MECHANISM OF ...

    African Journals Online (AJOL)

    Preferred Customer

    DPA) has been studied spectrophotometrically in alkaline media in the temperature range 288.2-303.2 K. The reaction is first order with respect to [DPA] and fractional order with respect to [AB]. The observed rate constant (kobs) decreased.

  15. [On the influence of D-penicillamine on collage metabolism - investigations of the rupture of strength in tailfibre in rats of several ages (author's transl)].

    Science.gov (United States)

    Trzenschik, K; Lindenhayn, K; Mühlbach, R; Napieralski, P; Noack, K

    1980-01-01

    The tensile strength of rat tail tendons of animals wtih a different age is more influenced by D-Penicillamine (DPA) in younger rats than in elderly rats. DPA has the best effect in the regions with the highest collagen turnover. After the use of DPA the collagen of tails of the elderly rats resembles the collagen of the younger animals. The reason of this alteration is probably a lower degree of cross-links of the collagen after the use of DPA.

  16. Isolation of a diphenylamine-degrading bacterium and characterization of its metabolic capacities, bioremediation and bioaugmentation potential.

    Science.gov (United States)

    Perruchon, Chiara; Batianis, Christos; Zouborlis, Stelios; Papadopoulou, Evangelia S; Ntougias, Spyridon; Vasileiadis, Sotirios; Karpouzas, Dimitrios G

    2015-12-01

    The antioxidant diphenylamine (DPA) is used in fruit-packaging plants for the control of the physiological disorder apple scald. Its use results in the production of DPA-contaminated wastewater which should be treated before finally discharged. Biological treatment systems using tailored-made microbial inocula with specific catabolic activities comprise an appealing and sustainable solution. This study aimed to isolate DPA-degrading bacteria, identify the metabolic pathway of DPA and evaluate their potential for future implementation in bioremediation and biodepuration applications. A Pseudomonas putida strain named DPA1 able to rapidly degrade and utilize DPA as the sole C and N source was enriched from a DPA-contaminated soil. The isolated strain degraded spillage-level concentrations of DPA in liquid culture (2000 mg L(-1)) and in contaminated soil (1000 mg kg(-1)) and metabolized DPA via the transient formation of aniline and catechol. Further evidence for the bioremediation and biodepuration potential of the P. putida strain DPA1 was provided by its capacity to degrade the post-harvest fungicide ortho-phenylphenol (OPP), concurrently used by the fruit-packaging plants, although at slower rates and DPA in a wide range of pH (4.5-9) and temperatures (15-37 °C). These findings revealed the high potential of the P. putida strain DPA1 for use in future soil bioremediation strategies and/or as start-up inocula in wastewater biodepuration systems.

  17. Biosynthethesis of dipicolinic acid in Clostridium roseum

    International Nuclear Information System (INIS)

    Prakasan, K.M.; Sharma, D.; Gollakota, K.G.; Lakechaura, B.D.

    1975-01-01

    Dipicolinic acid (DPA) is a major constituent of bacterial endospores and the thermal resistance of spores is closely correlated with their calcium dipicolinate content. The biosynthesis of DPA in anaerobes was studied in Cl. roseum using the technique of endotrophic sporulation. The cells from the complex medium were harvested at a stage when they were refractile and stainable, resuspended in nongrowth promoting mineral water supplemented with radioactive presumptive precursors of DPA and incubated. The incorporation in DPA of exogenously supplied individual metabolites was followed by radioactictivity (C 14 ) measurements. Glutamic acid, aspartic acid, alanine, serine, and acetate were found efficient precursors of DPA. (author)

  18. Perturbing Tandem Energy Transfer in Luminescent Heterobinuclear Lanthanide Coordination Polymer Nanoparticles Enables Real-Time Monitoring of Release of the Anthrax Biomarker from Bacterial Spores.

    Science.gov (United States)

    Gao, Nan; Zhang, Yunfang; Huang, Pengcheng; Xiang, Zhehao; Wu, Fang-Ying; Mao, Lanqun

    2018-06-05

    Lanthanide-based luminescent sensors have been widely used for the detection of the anthrax biomarker dipicolinic acid (DPA). However, mainly based on DPA sensitization to the lanthanide core, most of them failed to realize robust detection of DPA in bacterial spores. We proposed a new strategy for reliable detection of DPA by perturbing a tandem energy transfer in heterobinuclear lanthanide coordination polymer nanoparticles simply constructed by two kinds of lanthanide ions, Tb 3+ and Eu 3+ , and guanosine 5'-monophosphate. This smart luminescent probe was demonstrated to exhibit highly sensitive and selective visual luminescence color change upon exposure to DPA, enabling accurate detection of DPA in complex biosystems such as bacterial spores. DPA release from bacterial spores on physiological germination was also successfully monitored in real time by confocal imaging. This probe is thus expected to be a powerful tool for efficient detection of bacterial spores in responding to anthrax threats.

  19. A Novel UV-Shielding and Transparent Polymer Film: When Bioinspired Dopamine-Melanin Hollow Nanoparticles Join Polymers.

    Science.gov (United States)

    Wang, Yang; Su, Jing; Li, Ting; Ma, Piming; Bai, Huiyu; Xie, Yi; Chen, Mingqing; Dong, Weifu

    2017-10-18

    Ultraviolet (UV) light is known to be harmful to human health and cause organic materials to undergo photodegradation. In this Research Article, bioinspired dopamine-melanin solid nanoparticles (Dpa-s NPs) and hollow nanoparticles (Dpa-h NPs) as UV-absorbers were introduced to enhance the UV-shielding performance of polymer. First, Dpa-s NPs were synthesized through autoxidation of dopamine in alkaline aqueous solution. Dpa-h NPs were prepared by the spontaneous oxidative polymerization of dopamine solution onto polystyrene (PS) nanospheres template, followed by removal of the template. Poly(vinyl alcohol) (PVA)/Dpa nanocomposite films were subsequently fabricated by a simple casting solvent. UV irradiation protocols were set up, allowing selective study of the extra-shielding effects of Dpa-s versus Dpa-h NPs. In contrast to PVA/Dpa-s films, PVA/Dpa-h films exhibit stronger UV-shielding capabilities and can almost block the complete UV region (200-400 nm). The excellent UV-shielding performance of the PVA/Dpa-h films mainly arises from multiple absorption because of the hollow structure and large specific area of Dpa-h NPs. Moreover, the wall thickness of Dpa-h NPs can be simply controlled from 28 to 8 nm, depending on the ratio between PS and dopamine. The resulting films with Dpa-h NPs (wall thickness = ∼8 nm) maintained relatively high transparency to visible light because of the thinner wall thickness. The results indicate that the prepared Dpa-h NPs can be used as a novel UV absorber for next-generation transparent UV-shielding materials.

  20. The development of summary components for the Disablement in the Physically Active scale in collegiate athletes.

    Science.gov (United States)

    Houston, Megan N; Hoch, Johanna M; Van Lunen, Bonnie L; Hoch, Matthew C

    2015-11-01

    The Disablement in the Physically Active scale (DPA) is a generic patient-reported outcome designed to evaluate constructs of disability in physically active populations. The purpose of this study was to analyze the DPA scale structure for summary components. Four hundred and fifty-six collegiate athletes completed a demographic form and the DPA. A principal component analysis (PCA) was conducted with oblique rotation. Factors with eigenvalues >1 that explained >5 % of the variance were retained. The PCA revealed a two-factor structure consistent with paradigms used to develop the original DPA. Items 1-12 loaded on Factors 1 and Items 13-16 loaded on Factor 2. Items 1-12 pertain to impairment, activity limitations, and participation restrictions. Items 13-16 address psychosocial and emotional well-being. Consideration of item content suggested Factor 1 concerned physical function, while Factor 2 concerned mental well-being. Thus, items clustered around Factor 1 and 2 were identified as physical (DPA-PSC) and mental (DPA-MSC) summary components, respectively. Together, the factors accounted for 65.1 % of the variance. The PCA revealed a two-factor structure for the DPA that resulted in DPA-PSC and DPA-MSC. Analyzing the DPA as separate constructs may provide distinct information that could help to prescribe treatment and rehabilitation strategies.

  1. The LH2 complexes are assembled in the cells of purple sulfur bacterium Ectothiorhodospira haloalkaliphila with inhibition of carotenoid biosynthesis.

    Science.gov (United States)

    Ashikhmin, Aleksandr; Makhneva, Zoya; Moskalenko, Andrey

    2014-03-01

    The effect of the inhibitor of carotenoid (Car) biosynthesis, diphenylamine (DPA), on the cells of the purple sulfur bacterium Ectothiorhodospira (Ect.) haloalkaliphila has been studied. There occurs an inhibition of the biosynthesis of colored Cars (≥99 %) at 71 μM DPA. Considering "empty" Car pockets (Moskalenko and Makhneva 2012) the content of Cars in the DPA-treated samples is first calculated more correctly. The total content of the colored Cars in the sample at 71 μM DPA does not exceed 1 % of the wild type. In the DPA-treated cells (membranes) a complete set of pigment-protein complexes is retained. The LH2 complex at 71 μM DPA is isolated, which is identical to the LH2 complex of the wild type in near IR absorption spectra. This suggests that the principles for assembling this LH2 complex in vivo in the absence of colored Cars remain the same. These results are in full agreement with the data obtained earlier for Allochromatium (Alc.) minutissimum (Moskalenko and Makhneva 2012). They are as follows: (1) DPA almost entirely inhibits the biosynthesis of the colored Cars in Ect. haloalkaliphila cells. (2) In the DPA-treated samples non-colored Cars are detected at 53.25 μM DPA (as traces) and at 71 μM DPA. (3) DPA may affect both phytoene synthase (at ≤71 μM DPA) and phytoene desaturase (at ≥53.25 μM DPA). (4) The assembly of LH2 complex does occur without any colored Cars.

  2. Health-Related Quality of Life in University Dance Students.

    Science.gov (United States)

    White, Hayley M; Hoch, Johanna M; Hoch, Matthew C

    2018-03-01

    Injuries are common among dancers and may negatively affect health-related quality of life (HRQL). The modified Disablement in the Physically Active Scale (mDPA) is a generic patient-reported outcome instrument that could be used when providing care to patients participating in performing arts. The objective of this pilot study was to examine the internal consistency of the mDPA and assess overall HRQL using the mDPA in university dance students. Thirty-one female university dance students completed the mDPA during one data collection session. Higher scores on the Physical Summary Component (mDPA-PSC), the Mental Summary Component (mDPAMSC), and mDPA-Total indicated increased disablement. The internal consistency was determined using Cronbachs alpha. The mDPA-Total, mDPA-PSC, and mDPAMSC scores were examined descriptively using mean and standard deviations. Individual item responses were also examined. The proportion of university dance students with clinically relevant levels of disablement on the mDPA-Total was examined using a previously established minimally clinically important difference value. The internal consistency for the mDPA-MSC (a=0.91) and mDPATotal (a=0.90) was excellent and good for the mDPA-PSC (a=0.88). A large proportion (71%) of university dance students demonstrated clinically relevant levels of disablement despite fully participating in dance-related activities. Pain, impaired motion, and stress were the greatest contributors to increased disablement in these individuals. The mDPA scores observed in this pilot study indicate that many dance students experience levels of disablement and decreased HRQL which may warrant physical and mental intervention. Clinicians providing healthcare services to performing artists should consider using the mDPA to provide patient-centered care.

  3. Fast dynamics perturbation analysis for prediction of protein functional sites

    Directory of Open Access Journals (Sweden)

    Cohn Judith D

    2008-01-01

    Full Text Available Abstract Background We present a fast version of the dynamics perturbation analysis (DPA algorithm to predict functional sites in protein structures. The original DPA algorithm finds regions in proteins where interactions cause a large change in the protein conformational distribution, as measured using the relative entropy Dx. Such regions are associated with functional sites. Results The Fast DPA algorithm, which accelerates DPA calculations, is motivated by an empirical observation that Dx in a normal-modes model is highly correlated with an entropic term that only depends on the eigenvalues of the normal modes. The eigenvalues are accurately estimated using first-order perturbation theory, resulting in a N-fold reduction in the overall computational requirements of the algorithm, where N is the number of residues in the protein. The performance of the original and Fast DPA algorithms was compared using protein structures from a standard small-molecule docking test set. For nominal implementations of each algorithm, top-ranked Fast DPA predictions overlapped the true binding site 94% of the time, compared to 87% of the time for original DPA. In addition, per-protein recall statistics (fraction of binding-site residues that are among predicted residues were slightly better for Fast DPA. On the other hand, per-protein precision statistics (fraction of predicted residues that are among binding-site residues were slightly better using original DPA. Overall, the performance of Fast DPA in predicting ligand-binding-site residues was comparable to that of the original DPA algorithm. Conclusion Compared to the original DPA algorithm, the decreased run time with comparable performance makes Fast DPA well-suited for implementation on a web server and for high-throughput analysis.

  4. Biosynthesis of dipicolinic acid in Clostridium roseum

    Energy Technology Data Exchange (ETDEWEB)

    Prakasan, K. (Paraiba Univ., Joao Pessoa (Brazil)); Sharma, D. (Gobind Ballabh Pant Univ. of Agriculture and Technology, Nainital (India))

    1981-02-01

    Dipicolinic acid (DPA) synthesis was studied in Clostridium roseum by permitting the organism to complete vegetative growth in trypticase medium and trasfering the cells to a non-growth-promoting-medium, supplemented with the appropriate /sup 14/C-labelled precursors to complete sporulation and assaying the incorporation of label into DPA. Glu, asp, ala, ser and acetate were found to be efficient precursors of DPA and each one influenced the incorporation of other into DPA. The data suggest that a C/sub 5/ precursor is being trasformed into a C/sub 4/ intermediate, and a C/sub 2/ precursor into a C/sub 4/ intermediate, before their entry into DPA carbon structure. A C/sub 4/ plus C/sub 3/ condensation is favoured over C/sub 5/ plus C/sub 2/ or other condensation in the DPA biosynthesis.

  5. Biosynthesis of dipicolinic acid in Clostridium roseum

    International Nuclear Information System (INIS)

    Prakasan, K.; Sharma, D.

    1981-01-01

    Dipicolinic acid (DPA) synthesis was studied in Clostridium roseum by permitting the organism to complete vegetative growth in trypticase medium and trasfering the cells to a non-growth-promoting-medium, supplemented with the appropriate 14 C-labelled precursors to complete sporulation and assaying the incorporation of label into DPA. Glu, asp, ala, ser and acetate were found to be efficient precursors of DPA and each one influenced the incorporation of other into DPA. The data suggest that a C 5 precursor is being trasformed into a C 4 intermediate, and a C 2 precursor into a C 4 intermediate, before their entry into DPA carbon structure. A C 4 plus C 3 condensation is favoured over C 5 plus C 2 or other condensation in the DPA biosynthesis. (Author) [pt

  6. Diversion Path Analysis Handbook. Volume 1. Methodology

    International Nuclear Information System (INIS)

    Goodwin, K.E.; Schleter, J.C.; Maltese, M.D.K.

    1978-11-01

    Diversion Path Analysis (DPA) is a safeguards evaluation tool which is used to determine the vulnerability of the Material Control and Material Accounting (MC and MA) Subsystems to the threat of theft of Special Nuclear Material (SNM) by a knowledgeable Insider. The DPA team should consist of two individuals who have technical backgrounds. The implementation of DPA is divided into five basic steps: Information and Data Gathering, Process Characterization, Analysis of Diversion Paths, Results and Findings, and Documentation

  7. Anionic subsites of the acetylcholinesterase from Torpedo californica: affinity labelling with the cationic reagent N,N-dimethyl-2-phenyl-aziridinium.

    OpenAIRE

    Weise, C; Kreienkamp, H J; Raba, R; Pedak, A; Aaviksaar, A; Hucho, F

    1990-01-01

    Several peptides of acetylcholinesterase of Torpedo californica labelled with the alkylating reagent [3H]N,N-dimethyl-2-phenyl-aziridinium (DPA) were localized within the primary structure. One peptide had the sequence KPQELIDVE (positions 270-278); the incorporation of DPA into this peptide could be specifically suppressed by propidium, which suggests that it is part of the peripheral anionic site. The incorporation of DPA into two other peptides was insensitive to propidium but could be pre...

  8. Diversion Path Analysis handbook. Volume 4 (of 4 volumes). Computer Program 2

    International Nuclear Information System (INIS)

    Schleter, J.C.

    1978-11-01

    The FORTRAN IV computer program, DPA Computer Program 2 (DPACP-2) is used to produce tables and statistics on modifications identified when performing a Diversion Path Analysis (DPA) in accord with the methodology given in Volume 1. The program requires 259088 bytes exclusive of the operating system. The data assembled and tabulated by DPACP-2 assist the DPA team in analyzing and evaluating modifications to the plant's safeguards system that would eliminate, or reduce the severity of, vulnerabilities identified by means of the DPA. These vulnerabilities relate to the capability of the plant's material control and material accounting subsystems to indicate diversion of special nuclear material (SNM) by a knowledgeable insider

  9. Monte Carlo simulation study of the positron contribution to displacements per atom production in YBCO superconductors

    International Nuclear Information System (INIS)

    Pinera, I.; Cruz, C.M.; Abreu, Y.; Leyva, A.

    2008-01-01

    The contribution from positrons to the displacements per atom (dpa) distribution induced by the gamma irradiation on YBCO superconducting slabs is presented. The procedure implemented previously by the authors was adapted to take into account the contribution from positrons to dpa induced by the gamma radiation. The results show that, when positrons are considered in the atom displacement process, the total dpa almost doubles at 10 MeV of incident gamma radiation. At that energy positrons contribute 7% more to the total dpa than electrons, although electrons maintain having the highest contribution up to about 8 MeV.

  10. Imaging anatomy of dorsal pancreatic artery in patients with diabetes: a comparative study between CTA and DSA

    International Nuclear Information System (INIS)

    Lin Yuning; Li Hui; Yang Xizhang; Chen Ziqian; Tan Jianming; Zhong Qun; Yang Li; Wu Zhixian; Li Huimin; Huang Yisheng

    2011-01-01

    Objective: To investigate the clinical value of 64-section CT angiography (CTA) in detecting the origin of dorsal pancreatic artery (DPA). Methods: Ninety-seven consecutive patients with diabetes received transcatheter infusion of autologous bone marrow-derived stem cell transplantation into DPA. Abdominal CTA was performed in 42 patients before angiography. Celiac trunk, splenic, common hepatic and superior mesenteric arteries were reconstructed in order to locate the origin and traveling course of DPA. A routine angiography of both celiac and superior mesenteric arteries was performed for the demonstration of DPA. Further angiography of splenic and gastroduodenal arteries was carried out if necessary. Taking DSA images as the reference standard, the sensitivity, specificity and accuracy of CTA for DPA detection were calculated. Results: DPA was the main supply artery of pancreas in 85.7% patients (36/42). CTA demonstrated the origin of DPA in 35 cases, although one of which was confirmed to be misjudged (false positive). In seven cases CTA could not demonstrate DPA, and DSA proved that 2 of them was misjudged (false negative). The sensitivity,specificity and accuracy of CTA for DPA detection were 94.4%, 83.3% and 92.9%, respectively. Conclusion: 64-section CTA can accurately detect the origin of main supply artery of pancreas, which is of great value in guiding the interventional procedure for pancreatic diseases. (authors)

  11. Open source platform Digital Personal Assistant

    OpenAIRE

    Usachev, Denis; Khusnutdinov, Azat; Mazzara, Manuel; Khan, Adil; Panchenko, Ivan

    2018-01-01

    Nowadays Digital Personal Assistants (DPA) become more and more popular. DPAs help to increase quality of life especially for elderly or disabled people. In this paper we develop an open source DPA and smart home system as a 3-rd party extension to show the functionality of the assistant. The system is designed to use the DPA as a learning platform for engineers to provide them with the opportunity to create and test their own hypothesis. The DPA is able to recognize users' commands in natura...

  12. 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

  13. Clay/Polyaniline Hybrid through Diazonium Chemistry: Conductive Nanofiller with Unusual Effects on Interfacial Properties of Epoxy Nanocomposites.

    Science.gov (United States)

    Jlassi, Khouloud; Chandran, Sarath; Poothanari, Mohammed A; Benna-Zayani, Mémia; Thomas, Sabu; Chehimi, Mohamed M

    2016-04-12

    The concept of conductive network structure in thermoset matrix without sacrificing the inherent mechanical properties of thermoset polymer (e.g., epoxy) is investigated here using "hairy" bentonite fillers. The latter were prepared through the in situ polymerization of aniline in the presence of 4-diphenylamine diazonium (DPA)-modified bentonite (B-DPA) resulting in a highly exfoliated bentonite-DPA/polyaniline (B-DPA/PANI). The nanocomposite filler was mixed with diglycidyl ether of bisphenol A (DGEBA), and the curing agent (4,4'-diaminodiphenylsulfone) (DDS) at high temperature in order to obtain nanocomposites through the conventional melt mixing technique. The role of B-DPA in the modification of the interface between epoxy and B-DPA/polyaniline (B-DPA/PANI) is investigated and compared with the filler B/PANI prepared without any diazonium modification of the bentonite. Synergistic improvement in dielectric properties and mechanical properties points to the fact that the DPA aryl groups from the diazonium precursor significantly modify the interface by acting as an efficient stress transfer medium. In DPA-containing nanocomposites, unique fibril formation was observed on the fracture surface. Moreover, dramatic improvement (210-220%) in fracture toughness of epoxy composite was obtained with B-DPA/PANI filler as compared to the weak improvement of 20-30% noted in the case of the B/PANI filler. This work shows that the DPA diazonium salt has an important effect on the improvement of the interfacial properties and adhesion of DGEBA and clay/PANI nanofillers.

  14. Synthesis and characterization of dipicolinate sensitized LaF3:Tb3+ nanoparticles and their interaction with bovine serum albumin

    International Nuclear Information System (INIS)

    Jing, Kui; Guo, Xingjia; Diao, Xin; Wu, Qiong; Jiang, Yuchun; Sun, Ye; Pan, Xintong; Zhou, Nannan; Zhu, Yanjun

    2015-01-01

    Dipicolinate sensitized LaF 3 :Tb 3+ luminescent nanoparticles (DPA-NPs) have been successfully synthesized and characterized for their morphology, structural and optical properties. It was found that the prepared DPA-NPs were spherical with an average diameter of 10 nm and their surfaces were capped by citric acid radicals and DPA. And then the interaction between DPA-NPs and bovine serum albumin (BSA) was investigated by fluorescence quenching, UV–visible absorption, circular dichroism (CD) and Fourier transform infrared (FT-IR) spectroscopy under the simulative physiological conditions. The results showed that DPA-NPs had a strong ability to quench the intrinsic fluorescence of BSA by forming 1:1 ground-state complexes with a binding constant of about 10 4 L mol −1 . Moreover, the values of the calculated thermodynamic parameters suggested that hydrophobic forces and hydrogen bonds played major roles in stabilizing the complex. The displacement experiments indicated that the binding of DPA-NPs primarily occurred in sub-domain II A (site I) of BSA. The binding distance r was calculated to be 1.9 nm based on the theory of Förster's non-radiation energy transfer. Finally, the analysis of synchronous fluorescence, FT-IR, CD, and three-dimensional fluorescence spectra revealed that the microenvironment of amino acid residues and the conformation of BSA were changed after the addition of DPA-NPs. - Highlights: • Dipicolinate sensitized LaF 3 :Tb 3+ luminescent nanoparticles (DPA-NPs) were synthesized by the hydrothermal method. • DPA-NPs have a strong ability to quench the intrinsic fluorescence of BSA by forming a 1:1 ground state complex. • Hydrophobic force and hydrogen bond played major roles in the binding of DPA-NPs to BSA. • The microenvironment of amino acid residues and the conformation of BSA were changed upon addition of DPA-NPs

  15. The value of time-to-onset in statistical signal detection of adverse drug reactions : a comparison with disproportionality analysis in spontaneous reports from the Netherlands

    NARCIS (Netherlands)

    Scholl, Joep H G; van Puijenbroek, Eugène P

    2016-01-01

    PURPOSE: In pharmacovigilance, the commonly used disproportionality analysis (DPA) in statistical signal detection is known to have its limitations. The aim of this study was to investigate the value of the time to onset (TTO) of ADRs in addition to DPA. METHODS: We performed a pilot study using

  16. Theoretical Investigations of CO 2 and H 2 Sorption in an Interpenetrated Square-Pillared Metal–Organic Material

    KAUST Repository

    Pham, Tony; Forrest, Katherine A.; McLaughlin, Keith; Tudor, Brant; Nugent, Patrick; Hogan, Adam; Mullen, Ashley; Cioce, Christian R.; Zaworotko, Michael J.; Space, Brian

    2013-01-01

    Simulations of CO2 and H2 sorption and separation were performed in [Cu(dpa)2SiF6-i], a metal-organic material (MOM) consisting of an interpenetrated square grid of Cu2+ ions coordinated to 4,4′-dipyridylacetylene (dpa) rings and pillars of SiF6 2

  17. Fluorescent detection of dipicolinic acid as a biomarker of bacterial spores using lanthanide-chelated gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Donmez, Mert [Department of Chemistry, Faculty of Art and Sciences, Duzce University, Duzce 81620 (Turkey); Yilmaz, M. Deniz, E-mail: deniz.yilmaz@gidatarim.edu.tr [Department of Bioengineering, Faculty of Engineering and Architecture, Konya Food and Agriculture University, Konya 42080 (Turkey); Kilbas, Benan, E-mail: benankilbas@duzce.edu.tr [Department of Chemistry, Faculty of Art and Sciences, Duzce University, Duzce 81620 (Turkey)

    2017-02-15

    Highlights: • The nanosensors based on gold nanoparticles functionalized with lanthanide complexes were synthesized. • The nanosensors selectively and sensitively detected DPA, a biomarker of bacterial spores. • Ratiometric sensing of DPA by a ternary complex was achieved by ligand displacement strategy. - Abstract: Gold nanoparticles (GNPs) functionalized with ethylenediamine-lanthanide complexes (Eu-GNPs and Tb-GNPs) were used for the selective fluorescent detection of dipicolinic acid (DPA), a unique biomarker of bacterial spores, in water. Particles were characterized by transmission electron microscopy and zeta potential measurements. The coordination of DPA to the lanthanides resulted in the enhancement of the fluorescence. A selective response to DPA was observed over the nonselective binding of aromatic ligands. The ligand displacement strategy were also employed for the ratiometric fluorescent detection of DPA. 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedion (TFNB) was chosen as an antenna to synthesize ternary complexes. The addition of DPA on EuGNP:TFNB ternary complex quenched the initial emission of the complex at 615 nm and increased the TFNB emission at 450 nm when excited at 350 nm. The results demonstrated that the ratiometric fluorescent detection of DPA was achieved by ligand displacement strategy.

  18. Enantiopure Chiral Coordination Polymers Based on Polynuclear Paddlewheel Helices and Arsenyl Tartrate

    Directory of Open Access Journals (Sweden)

    Ángela Valentín-Pérez

    2018-03-01

    Full Text Available Herein, we report the preparation of chiral, one-dimensional coordination polymers based on trinuclear paddlewheel helices [M3(dpa4]2+ (M = Co(II and Ni(II; dpa = the anion of 2,2′-dipyridylamine. Enantiomeric resolution of a racemic mixture of [M3(dpa4]2+ complexes was achieved by chiral recognition of the respective enantiomer by [Δ-As2(tartrate2]2− or [Λ-As2(tartrate2]2− in N,N-dimethylformamide (DMF, affording crystalline coordination polymers formed from [(Δ-Co3(dpa4(Λ-As2(tartrate2]·3DMF (Δ-1, [(Λ-Co3(dpa4(Δ-As2(tartrate2]·3DMF (Λ-1, [(Δ-Ni3(dpa4(Λ-As2(tartrate2]·(4 − nDMF∙nEt2O (Δ-2 or [(Λ-Ni3(dpa4(Δ-As2(tartrate2]·(4 − nDMF∙nEt2O (Λ-2 repeating units. UV-visible circular dichroism spectra of the complexes in DMF solutions demonstrate the efficient isolation of optically active species. The helicoidal [M3(dpa4]2+ units that were obtained display high stability towards racemization as shown by the absence of an evolution of the dichroic signals after several days at room temperature and only a small decrease of the signal after 3 h at 80 °C.

  19. Has the Alberta daily physical activity initiative been successfully implemented in Calgary schools?

    NARCIS (Netherlands)

    Kennedy, Christine Diane; Cantell, Marja; Dewey, Deborah

    INTRODUCTION: In September 2005, the Alberta government introduced the daily physical activity (DPA) initiative, which requires that students from grades 1 to 9 be physically active in school for a minimum of 30 min per day. OBJECTIVE: To obtain information on whether and how the DPA initiative has

  20. Swelling, mechanical properties, and microstructure of Type 316 stainless steel at fusion reactor damage levels

    International Nuclear Information System (INIS)

    Horak, J.A.; Bloom, E.E.; Grossbeck, M.L.; Maziasz, P.J.; Stiegler, J.O.; Wiffen, F.W.

    1979-01-01

    Alloys such as AISI 316 stainless steel exhibit more swelling and larger decreases in ductility when irradiated to produce fusion reactor He and dpa levels than at fast reactor He and dpa levels. For T approx. 0 C to ensure adequate ductility for long-term service

  1. PHEMT Distributed Power Amplifier Adopting Broadband Impedance Transformer

    DEFF Research Database (Denmark)

    Narendra, K.; Limiti, E.; Paoloni, C.

    2013-01-01

    A non-uniform drain line distributed power amplifier (DPA) employing a broadband impedance transformer is presented. The DPA is based on GaAs PHEMT technology. The impedance transformer employs asymmetric coupled lines and transforms a low output impedance of the amplifier to a standard 50 Ω...

  2. A mobile phone application to stimulate daily physical activity in patients with chronic obstructive pulmonary disease: development, feasibility and pilot studies

    NARCIS (Netherlands)

    Jan-Willem J. Lammers; Dr. H.S.M. Kort; Sigrid N.W. Vorrink; Thierry Troosters

    2016-01-01

    Background: Patients with chronic obstructive pulmonary disease (COPD) demonstrate reduced levels of daily physical activity (DPA) compared to healthy controls. This results in a higher risk of hospital admission and shorter survival. Performing regular DPA reduces these risks. Objective: To develop

  3. Optimization of the synthesis of SAPO-11 for the methylation of naphthalene with methanol by varying templates and template content

    International Nuclear Information System (INIS)

    Wang, Xiaoxiao; Zhang, Wei; Zhao, Liangfu; Xiang, Hongwei; Guo, Shaoqing

    2013-01-01

    SAPO-11 zeolites were successfully synthesized by using three different templates (diethylamine (DEA), di-n-propylamine (DPA) and di-isopropylamine (DIPA)) and varying DPA contents (nDPA/Al 2 O 3 = 0.8, 1.2, 1.6 and 2.0) under hydrothermal conditions. The samples were characterized by powder X-ray diffractometry (XRD), scanning electron microscopy (SEM), N 2 adsorption-desorption, temperature programmed desorption of ammonia (NH 3 -TPD) and 29 Si magic angle spinning (MAS) nuclear magnetic resonance (NMR). The samples were also evaluated towards the methylation of naphthalene with methanol to produce 2,6-dimethylnaphthalene (2,6-DMN). XRD results indicated that the directing effect of the different templates for AEL (Aluminophosphate-ELeven) structure decreased in the order DPA > DEA > DIPA and the most suitable DPA content was nDPA/Al 2 O 3 = 1.2. N 2 adsorption-desorption results showed that SAPO-11(DPA,1.2) exhibited the broadest pore size distribution, the highest BET specific surface area and the largest pore volume among all the SAPO-11 samples. SAPO-11(DPA,1.2) exhibited high catalytic performances in the methylation of naphthalene due to its high crystallinity, high external surface and broad pore size distribution. The pore structure of SAPO-11 zeolite, rather than its acidity, played an important role in achieving high catalytic performances in the methylation of naphthalene with methanol. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-10-01

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

  5. Plastic deformation of the cladding of Fortissimo fuel elements

    International Nuclear Information System (INIS)

    Marbach, G.; Millet, P.; Blanchard, F.

    1979-07-01

    A study of a large number of standard Fortissimo pins, clad in solution treated 316 steel, shows that the plastic strain depends linearly on the fission gas pressure and the dose (in dpaF). The derived modulus of irradiation creep ranges from 1 to 2 x 10 -6 (MPa dpaF) -1 at 450 0 C and increases steadily with temperature. (author)

  6. Scientific Opinion on the substantiation of health claims related to eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), docosapentaenoic acid (DPA) and maintenance of normal cardiac function (ID 504, 506, 516, 527, 538, 703, 1128, 1317, 1324, 1325), maintenance of normal blood glucose, -cholesterol concentrations (ID 527, 538, 1317, 1325, 4689), protection of the skin from photo-oxidative (UV-induced) damage (ID 530), improved absorption of EPA and DHA (ID 522, 523)

    DEFF Research Database (Denmark)

    Tetens, Inge

    EFSA-Q-2008-1291 , EFSA-Q-2008-1293 , EFSA-Q-2008-1303 , EFSA-Q-2008-1307 , EFSA-Q-2008-1309 , EFSA-Q-2008-1310 , EFSA-Q-2008-1314 , EFSA-Q-2008-1317 , EFSA-Q-2008-1325 , EFSA-Q-2008-1353 , EFSA-Q-2008-1490 , EFSA-Q-2008-1867 , EFSA-Q-2008-2054 , EFSA-Q-2008-2061 , EFSA-Q-2008-2062 , EFSA-Q-2008-...

  7. Accuracy of dual photon absorptiometry for assessment of bone mineral and body composition

    International Nuclear Information System (INIS)

    Aoki, Manabu; Iwamura, Akira; Goto, Eisuke; Mori, Yutaka; Kawakami, Kenji; Soshi, Shigeru

    1991-01-01

    Accuracy of bone mineral measurement by the dual photon absorptiometry (DPA) was studied in comparison to ashed bone mineral (ash) on the lumbar spine of 23 cada vars. There was a high correlation (r=0.896) between the value of DPA and ash weight. Bone mineral content in the radius by the single photon absorptiometry (SPA) did not correlate to bone mineral density (BMD) by DPA in the patients with hemodialysis. SPA may be less useful to assess BMD of the whole body. Fat mass and lean mass measured by DPA were well correlated to the value obtained by the electrical impedance method. Precision in measurement of fat mass and lean mass was also confirmed by the electrical impedance method. These results suggest that DPA has a high precision for measurements of the bone mineral and the body composition. (author)

  8. Calculation of atom displacement cross section for structure material

    International Nuclear Information System (INIS)

    Liu Ping; Xu Yiping

    2015-01-01

    The neutron radiation damage in material is an important consideration of the reactor design. The radiation damage of materials mainly comes from atom displacements of crystal structure materials. The reaction cross sections of charged particles, cross sections of displacements per atom (DPA) and KERMA are the basis of radiation damage calculation. In order to study the differences of DPA cross sections with different codes and different evaluated nuclear data libraries, the DPA cross sections for structure materials were calculated with UNF and NJOY codes, and the comparisons of results were given. The DPA cross sections from different evaluated nuclear data libraries were compared. And the comparison of DPA cross sections between NJOY and Monte Carlo codes was also done. The results show that the differences among these evaluated nuclear data libraries exist. (authors)

  9. A two-step transport pathway allows the mother cell to nurture the developing spore in Bacillus subtilis.

    Science.gov (United States)

    Ramírez-Guadiana, Fernando H; Meeske, Alexander J; Rodrigues, Christopher D A; Barajas-Ornelas, Rocío Del Carmen; Kruse, Andrew C; Rudner, David Z

    2017-09-01

    One of the hallmarks of bacterial endospore formation is the accumulation of high concentrations of pyridine-2,6-dicarboxylic acid (dipicolinic acid or DPA) in the developing spore. This small molecule comprises 5-15% of the dry weight of dormant spores and plays a central role in resistance to both wet heat and desiccation. DPA is synthesized in the mother cell at a late stage in sporulation and must be translocated across two membranes (the inner and outer forespore membranes) that separate the mother cell and forespore. The enzymes that synthesize DPA and the proteins required to translocate it across the inner forespore membrane were identified over two decades ago but the factors that transport DPA across the outer forespore membrane have remained mysterious. Here, we report that SpoVV (formerly YlbJ) is the missing DPA transporter. SpoVV is produced in the mother cell during the morphological process of engulfment and specifically localizes in the outer forespore membrane. Sporulating cells lacking SpoVV produce spores with low levels of DPA and cells engineered to express SpoVV and the DPA synthase during vegetative growth accumulate high levels of DPA in the culture medium. SpoVV resembles concentrative nucleoside transporters and mutagenesis of residues predicted to form the substrate-binding pocket supports the idea that SpoVV has a similar structure and could therefore function similarly. These findings provide a simple two-step transport mechanism by which the mother cell nurtures the developing spore. DPA produced in the mother cell is first translocated into the intermembrane space by SpoVV and is then imported into the forespore by the SpoVA complex. This pathway is likely to be broadly conserved as DPA synthase, SpoVV, and SpoVA proteins can be found in virtually all endospore forming bacteria.

  10. Radiation damage simulation studies in the Harwell VEC of selected austenitic and ferritic alloys for fusion applications

    Energy Technology Data Exchange (ETDEWEB)

    Mazey, D J; Walters, G P; Buckley, S N; Hanks, W; Bolster, D E.J.; Murphy, S M

    1988-07-01

    Three austenitic (316 L, 316-Ti, 316-Nb); four high-nickel (IN 625, IN 706, PE 16, Fe-25Ni-8Cr) and four ferritic (CRM 12, FV 448, FV 607, FI) alloys have been irradiated with 46 MeV Ni or 20 MeV Cr ions in the Harwell VEC to simulated fusion-reactor doses up to 110 dpa (proportional to 10 MW-yr m/sup -2/) at temperatures from 425 to 625/sup 0/C. Gas production rates appropriate to fusion were obtained from a mixed beam of He+H/sub 2/ in the ratio 1:4 He:H with gas/dpa ratios of 13 appm He/dpa and 52 appm H/dpa. The 316 alloys showed irradiation-induced precipitation and swelling as high as 40% in ST 316-Ti after 110 dpa at 625/sup 0/C. Low swelling (e.g. <2% at 110 dpa) was observed in the high-nickel alloys. The ferritic/martensitic alloys showed negligible swelling (e.g. <0.2% in FV 607 after 100 dpa at 475/sup 0/C). The results demonstrate the high swelling behaviour of 316 alloys and the better swelling resistance of high-nickel and ferritic alloys under simulated fusion conditions.

  11. Exciton dynamics in an energy up-converting solid state system based on diphenylanthracene doped with platinum octaethylporphyrin

    Energy Technology Data Exchange (ETDEWEB)

    Karpicz, R., E-mail: renata.karpicz@ftmc.lt [Center for Physical Sciences and Technology, Savanoriu Ave. 231, LT-02300 Vilnius (Lithuania); Puzinas, S.; Gulbinas, V. [Center for Physical Sciences and Technology, Savanoriu Ave. 231, LT-02300 Vilnius (Lithuania); Vakhnin, A. [Institute of Physics, National Academy of Sciences of Ukraine, 03028 Kyiv (Ukraine); Kadashchuk, A. [Institute of Physics, National Academy of Sciences of Ukraine, 03028 Kyiv (Ukraine); IMEC, Kapeldreef 75, B-3001 Heverlee-Leuven (Belgium); Rand, B.P. [IMEC, Kapeldreef 75, B-3001 Heverlee-Leuven (Belgium); Department of Electrical Engineering and the Andlinger Center for Energy and the Environment, Princeton University, Princeton, NJ 08544 (United States)

    2014-01-31

    Highlights: • We study exciton dynamics by ultrafast spectroscopies in DPA:PtOEP host–guest films. • Aggregation of PtOEP affects considerably the triplet energy transfer to DPA host. • No significant triplet loss due to TTA occurs within PtOEP aggregates. • Triplet energy transfer from PtOEP to DPA is slow and thermally activated process. • The ISC time in PtOEP is shorter than 100 fs. - Abstract: Photophysics of composite solid films based on 9,10-diphenylanthracene (DPA) doped with Pt(II)octaethylporphyrin (PtOEP) has been investigated by means of transient absorption and luminescence spectroscopy. The DPA:PtOEP host:guest system is a benchmark for incoherent energy up-conversion via triplet fusion in solution and we focus here on photophysical processes of this system in solid films. The triplet energy transfer from PtOEP to DPA takes place during tens of ns, featuring a thermally activated behavior. This implies that, before being transferred to the host, triplets migrate within PtOEP aggregates, defining a rate limiting step for the overall energy transfer to DPA. In contrast to other porphyrin-based sensitizers, no significant triplet–triplet annihilation was found to happen during triplet migration within PtOEP aggregates, implying that such a triplet loss mechanism does not universally apply to porphyrin-based organometallic complexes.

  12. The transcriptome of the developing grain: a resource for understanding seed development and the molecular control of the functional and nutritional properties of wheat.

    Science.gov (United States)

    Rangan, Parimalan; Furtado, Agnelo; Henry, Robert J

    2017-10-11

    Wheat is one of the three major cereals that have been domesticated to feed human populations. The composition of the wheat grain determines the functional properties of wheat including milling efficiency, bread making, and nutritional value. Transcriptome analysis of the developing wheat grain provides key insights into the molecular basis for grain development and quality. The transcriptome of 35 genotypes was analysed by RNA-Seq at two development stages (14 and 30 days-post-anthesis, dpa) corresponding to the mid stage of development (stage Z75) and the almost mature seed (stage Z85). At 14dpa, most of the transcripts were associated with the synthesis of the major seed components including storage proteins and starch. At 30dpa, a diverse range of genes were expressed at low levels with a predominance of genes associated with seed defence and stress tolerance. RNA-Seq analysis of changes in expression between 14dpa and 30dpa stages revealed 26,477 transcripts that were significantly differentially expressed at a FDR corrected p-value cut-off at ≤0.01. Functional annotation and gene ontology mapping was performed and KEGG pathway mapping allowed grouping based upon biochemical linkages. This analysis demonstrated that photosynthesis associated with the pericarp was very active at 14dpa but had ceased by 30dpa. Recently reported genes for flour yield in milling and bread quality were found to influence wheat quality largely due to expression patterns at the earlier seed development stage. This study serves as a resource providing an overview of gene expression during wheat grain development at the early (14dpa) and late (30dpa) grain filling stages for use in studies of grain quality and nutritional value and in understanding seed biology.

  13. Fundamental radiation effects studies in the fusion-materials program

    International Nuclear Information System (INIS)

    Doran, D.G.

    1981-10-01

    Some examples of progress being made in DAFS studies are given. The primary parameters in which most damage models are expressed are total displacements per atom (dpa), total helium concentration (appm), and the helium-to-dpa ratio. The concentrations of other transmutation products than helium have assumed significance in certain cases as will be seen below. The number of dpa is generally taken proportional to the damage energy, the total energy deposited in a material, corrected for the fraction dissipated in electronic excitation and ionization

  14. Improved swelling resistance for PCA austenitic stainless steel under HFIR irradiation through microstructural control

    International Nuclear Information System (INIS)

    Maziasz, P.J.; Braski, D.N.

    1984-01-01

    Swelling evaluation of PCA variants and 20%-cold-worked (N-Lot) type 316 stainless steel (CW 316) at 300 to 600 0 C was extended to 44 dpa. Swelling was negligible in all the steels at 300 0 C after approx. 44 dpa. At 500 to 600 0 C 25%-cold-worked PCA showed better void swelling resistance than type 316 at approx. 44 dpa. There was less swelling variation among alloys at 400 0 C, but again 25%-cold-worked PCA was the best

  15. DFT studies of the effectiveness of p-substituted diphenyl amine antioxidants in styrene-butadiene rubber through their Cu(II) coordination ability

    Science.gov (United States)

    Puškárová, Ingrid; Breza, Martin

    2017-07-01

    Structures of a series of diphenyl amine (DPA) antioxidants and of their complexes with Cu2+ were optimized at B3LYP level of theory. DPAs may be divided into two groups according to their molar antioxidant effectiveness (AEM). The effectiveness of high-AEM DPA antioxidants at 130 °C rises with decreasing spin densities at Cu atoms and with the increasing electron density Laplacian at Cu-N bond critical points in the 2[DPA…Cu]2+ complexes similarly as in the case of p-phenylene diamine antioxidants. No such trends are observed at 25 °C and for low- AEM DPA antioxidants.

  16. Follow-up of bone mineral contents by single and dual photon absorptiometry

    International Nuclear Information System (INIS)

    Krasznai, Istvan; Lakatos, Peter; Horvath, Csaba; Hollo, Istvan

    1988-01-01

    Quality control, performance and long-range reproducibility of SPA and DPA techniques were tested in model experiments. The relative minimum detectable change in bone mineral content, determined with appropriately checked and calibrated instrument amounts to 2.5-3.0 percent by SPA and 4.0-6.0 percent by DPA. To achieve this potential at least two parallel measurements are needed but in case of long-range measurements following-up measurements have to be repeated at least quarterly. DPA requires the same person to evaluate. (author) 6 refs.; 5 tabs

  17. Complexes of uranyl nitrate with 2,6-pyridinedicarboxamides: synthesis, crystal structure, and DFT study

    Energy Technology Data Exchange (ETDEWEB)

    Alyapyshev, Mikhail; Babain, Vasiliy [ITMO University, 49, Kronverksky pr., 197101, St. Petersburg (Russian Federation); ThreeArc Mining Ltd., 5, Stary Tolmachevskiy per., 115184, Moscow (Russian Federation); Tkachenko, Lyudmila; Lumpov, Alexander [Khlopin Radium Institute, 28, 2nd Murinskiy pr., 194021, St. Petersburg (Russian Federation); Gurzhiy, Vladislav; Zolotarev, Andrey; Dar' in, Dmitriy [St. Petersburg State University, 7-9, Universitetskaya nab., 199034, St. Petersburg (Russian Federation); Ustynyuk, Yuriy; Gloriozov, Igor [M.V. Lomonosov Moscow State University, 119991, Moscow (Russian Federation); Paulenova, Alena [Department of Nuclear Engineering, Oregon State University, Corvallis, OR (United States)

    2017-05-04

    Two complexes of uranyl nitrate with N,N,N',N'-tetrabutyl-2,6-pyridinedicarboxamide (TBuDPA) and N,N'-diethyl-N,N'-diphenyl-2,6-pyridinedicarboxamide (EtPhDPA) were synthesized and studied. The complex of tetraalkyl-2,6-pyridinedicarboxamide with metal nitrate was synthesized for the first time. XRD analysis revealed the different type of complexation: a 1:1 metal:ligand complex for EtPhDPA and complex with polymeric structure for TBuDPA. The quantum chemical calculations (DFT) confirm that both ligands form the most stable complexes that match the minimal values pre-organization energy of the ligands. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Damage clustering in metals: Importance, advances and challenges

    International Nuclear Information System (INIS)

    Nordlund, K.; Sand, A.E.; Granberg, F.; Levo, E.; Djurabekova, F.

    2016-01-01

    The damage produced in metals has traditionally been primarily characterized in terms of the total damage production, which typically is first estimated with the dpa number. As discussed in previous meetings of this CRP, the dpa is not actually very well suited for typical dense metals, since the number it gives is typically about 3 times larger than the number of actual defects produced, and 30 times smaller than the actual number of defects produced. Hence we developed the improved arc-dpa and rpa standards, that give in a simple analytical form a defect number that does correspond well to MD and experimental data. Section 2 summarizes the development of the arc-dpa and rpa standards. In sections 3 and 4 we discuss the role of damage clustering in damage production

  19. Quantification of bone mineral density at 3rd lumbar vertebra by dual photon absorptiometry in healthy subjects

    International Nuclear Information System (INIS)

    Fukunaga, Masao; Otsuka, Nobuaki; Ono, Shimato

    1987-01-01

    Bone mineral density (BMD), by dual photon absorptiometry (DPA), at the 3rd lumbar vertebra (L 3 ) was measured in healthy subjects (37 males and 49 females). BMD values on 1 slice of vertebral body (L 3 ), employed as a routine, showed good correlation to the mean BMD values, calculated from multiple slices of whole L 3 . BMD values, by DPA, at L 3 were better correlation to concentrations of bone mineral equivalent material, by quantitative computed tomography, at the trabecular bone of L 3 than to BMD values, by single photon absorptiometry, at distal radius (predominantly cortical bone). Furthermore, by this DPA technique, bone diminution at L 3 with aging was shown in both sexes. These data suggest that measurements of BMD by DPA is greatly useful for evaluating the spinal bone mineral content. (author)

  20. Two Dimensional Multiwavelength Fluorescence Spectra of Dipicolinic Acid and Calcium Dipicolinate

    National Research Council Canada - National Science Library

    Sarasanandarajah, Sivananthan

    2004-01-01

    .... In this paper we report in some detail on the room temperature fluorescence excitation and emission spectra of DPA and its calcium ion complex and comparison of the excitation-emission spectrum...

  1. Characterization of irradiation damage distribution near TiO2/SrTiO3 interfaces using coherent acoustic phonon interferometry

    International Nuclear Information System (INIS)

    Yarotski, Dmitry; Yan Li; Jia Quanxi; Taylor, Antoinette J.; Fu Engang; Wang Yongqiang; Uberuaga, Blas P.

    2012-01-01

    We apply ultrafast coherent acoustic phonon interferometry to characterize the distribution of the radiation damage near the TiO 2 /SrTiO 3 interfaces. We show that the optical and mechanical properties of anatase TiO 2 remain unaffected by the radiation dosages in the 0.1÷5 dpa (displacements per atom) range, while the degraded optical response indicates a significant defect accumulation in the interfacial region of SrTiO 3 at 0.1 dpa and subsequent amorphization at 3 dpa. Comparison between the theoretical simulations and the experimental results reveals an almost threefold reduction of the sound velocity in the irradiated SrTiO 3 layer with peak damage levels of 3 and 5 dpa.

  2. The behaviour of ferritic steels under fast neutron irradiation

    International Nuclear Information System (INIS)

    Erler, J.; Maillard, A.; Brun, G.; Lehmann, J.; Dupouy, J.M.

    1979-07-01

    Ferritic steels have been irradiated in Rapsodie and Phenix to doses up to 150 dpa F. The swelling and irradiation creep characteristics and the mechanical properties of these materials are reported. (author)

  3. A Decade-Bandwidth Distributed Power Amplifier MMIC Using 0.25 μm GaN HEMT Technology

    Directory of Open Access Journals (Sweden)

    Dong-Hwan Shin

    2017-10-01

    Full Text Available This study presents a 2–20 GHz monolithic distributed power amplifier (DPA using a 0.25 μm AlGaN/GaN on SiC high electron mobility transistor (HEMT technology. The gate width of the HEMT was selected after considering the input capacitance of the unit cell that guarantees decade bandwidth. To achieve high output power using small transistors, a 12-stage DPA was designed with a nonuniform drain line impedance to provide optimal output power matching. The maximum operating frequency of the proposed DPA is above 20 GHz, which is higher than those of other DPAs manufactured with the same gate-length process. The measured output power and power-added efficiency of the DPA monolithic microwave integrated circuit (MMIC are 35.3–38.6 dBm and 11.4%–31%, respectively, for 2–20 GHz.

  4. High mobility emissive organic semiconductor

    Science.gov (United States)

    Liu, Jie; Zhang, Hantang; Dong, Huanli; Meng, Lingqiang; Jiang, Longfeng; Jiang, Lang; Wang, Ying; Yu, Junsheng; Sun, Yanming; Hu, Wenping; Heeger, Alan J.

    2015-01-01

    The integration of high charge carrier mobility and high luminescence in an organic semiconductor is challenging. However, there is need of such materials for organic light-emitting transistors and organic electrically pumped lasers. Here we show a novel organic semiconductor, 2,6-diphenylanthracene (DPA), which exhibits not only high emission with single crystal absolute florescence quantum yield of 41.2% but also high charge carrier mobility with single crystal mobility of 34 cm2 V−1 s−1. Organic light-emitting diodes (OLEDs) based on DPA give pure blue emission with brightness up to 6,627 cd m−2 and turn-on voltage of 2.8 V. 2,6-Diphenylanthracene OLED arrays are successfully driven by DPA field-effect transistor arrays, demonstrating that DPA is a high mobility emissive organic semiconductor with potential in organic optoelectronics. PMID:26620323

  5. Diversion Path Analysis handbook. Volume 3 (of 4 volumes). Computer Program 1

    International Nuclear Information System (INIS)

    Schleter, J.C.

    1978-11-01

    The FORTRAN IV computer program, DPA Computer Program 1 (DPACP-1), is used to assemble and tabulate the data for Specific Diversion Paths (SDPs) identified when performing a Diversion Path Analysis (DPA) in accord with the methodology given in Volume 1. The program requires 255498 bytes exclusive of the operating system. The data assembled and tabulated by DPACP-1 are used by the DPA team to assist in analyzing vulnerabilities, in a plant's material control and material accounting subsystems, to diversion of special nuclear material (SNM) by a knowledgable insider. Based on this analysis, the DPA team can identify, and propose to plant management, modifications to the plant's safeguards system that would eliminate, or reduce the severity of, the identified vulnerabilities. The data are also used by plant supervision when investigating a potential diversion

  6. Mechanistic aspects of Os(VIII) catalysed oxidation of loop diuretic ...

    Indian Academy of Sciences (India)

    furosemide by Ag(III) periodate complex in aqueous alkaline medium. SHWETA J .... Os(VIII) catalysed DPA oxidation, the order in [OH. −. ] ... Victoria-3170, Australia) connected to a rapid ..... follows. The furosemide, periodate and hydroxide ion.

  7. Metabolomic Characterization of Hot Pepper (Capsicum annuum "CM334") during Fruit Development.

    Science.gov (United States)

    Jang, Yu Kyung; Jung, Eun Sung; Lee, Hyun-Ah; Choi, Doil; Lee, Choong Hwan

    2015-11-04

    Non-targeted metabolomic analysis of hot pepper (Capsicum annuum "CM334") was performed at six development stages [16, 25, 36, 38, 43, and 48 days post-anthesis (DPA)] to analyze biochemical changes. Distinct distribution patterns were observed in the changes of metabolites, gene expressions, and antioxidant activities by early (16-25 DPA), breaker (36-38 DPA), and later (43-48 DPA) stages. In the early stages, glycosides of luteolin, apigenin, and quercetin, shikimic acid, γ-aminobutyric acid (GABA), and putrescine were highly distributed but gradually decreased over the breaker stage. At later stages, leucine, isoleucine, proline, phenylalanine, capsaicin, dihydrocapsaicin, and kaempferol glycosides were significantly increased. Pathway analysis revealed metabolite-gene interactions in the biosynthesis of amino acids, capsaicinoids, fatty acid chains, and flavonoids. The changes in antioxidant activity were highly reflective of alterations in metabolites. The present study could provide useful information about nutrient content at each stage of pepper cultivation.

  8. NEUTRON-INDUCED SWELLING OF Fe-Cr BINARY ALLOYS IN FFTF AT ∼400 DEGREES C

    International Nuclear Information System (INIS)

    Garner, Francis A.; Greenwood, Lawrence R.; Okita, Taira; Sekimura, Naoto; Wolfer, W. G.

    2002-01-01

    The purpose of this effort is to determine the influence of dpa rate, He/dpa ratio and composition on the void swelling of simple binary Fe-Cr alloys. Contrary to the behavior of swelling of model fcc Fe-Cr-Ni alloys irradiated in the same FFTF-MOTA experiment, model bcc Fe-Cr alloys do not exhibit a dependence of swelling on dpa rate at approximately 400 degrees C. This is surprising in that an apparent flux-sensitivity was observed in an earlier comparative irradiation of Fe-Cr binaries conducted in EBR-II and FFTF. The difference in behavior is ascribed to the higher helium generation rates of Fe-Cr alloys in EBR-II compared to that of FFTF, and also the fact that lower dpa rates in FFTF are accompanied by progressively lower helium generation rates.

  9. Characterization of ion beam irradiated 304 stainless steel utilizing nanoindentation and Laue microdiffraction

    Energy Technology Data Exchange (ETDEWEB)

    Lupinacci, A. [Department of Materials Science and Engineering, University of California, Berkeley, CA (United States); Chen, K., E-mail: kchenlbl@gmail.com [Center for Advancing Materials Performance from the Nanoscale (CAMP-Nano), State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China); Li, Y. [Center for Advancing Materials Performance from the Nanoscale (CAMP-Nano), State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China); Kunz, M. [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Jiao, Z.; Was, G.S. [Department of Nuclear Engineering, University of Michigan, Ann Arbor, MI (United States); Abad, M.D. [Department of Nuclear Engineering, University of California, Berkeley, CA (United States); Minor, A.M. [Department of Materials Science and Engineering, University of California, Berkeley, CA (United States); National Center for Electron Microscopy, The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Hosemann, P., E-mail: Peterh@berkeley.edu [Department of Nuclear Engineering, University of California, Berkeley, CA (United States)

    2015-03-15

    Characterizing irradiation damage in materials utilized in light water reactors is critical for both material development and application reliability. Here we use both nanoindentation and Laue microdiffraction to characterize both the mechanical response and microstructure evolution due to irradiation. Two different irradiation conditions were considered in 304 stainless steel: 1 dpa and 10 dpa. In addition, an annealed condition of the 10 dpa specimen for 1 h at 500 °C was evaluated. Nanoindentation revealed an increase in hardness due to irradiation and also revealed that hardness saturated in the 10 dpa case. Broadening using Laue microdiffraction peaks indicates a significant plastic deformation in the irradiated area that is in good agreement with both the SRIM calculations and the nanoindentation results.

  10. Variant Branching Pattern of Dorsalis Pedis Artery Accompanied with Anomalous Presence of Extensor Hallucis Brevis Muscle

    Directory of Open Access Journals (Sweden)

    Ashwini Aithal Padur

    2017-10-01

    Full Text Available During routine dissection, we came across multiple variations in the dorsum of the right foot. Dorsalis pedis artery (DPA presented with an unusual branching pattern. The arcuate artery was completely absent, and hence three tarsal branches arose from lateral side of DPA. The first branch continued as first dorsal metatarsal artery, the second branch continued as the second dorsal metatarsal artery, and the third branch continued as third dorsal metatarsal artery which also provided a small twig to the fourth intermetatarsal space as the fourth dorsal metatarsal artery. We also observed the unique presence of extensor hallucis brevis muscle with the origin from the medial part of superior surface of the calcaneus and inserted to proximal phalanx of great toe. Since the DPA was just beneath this muscle, anomalous presence of the muscle may lead to compression of DPA. Awareness regarding such variations is critical for angiographers, vascular surgeons, reconstructive and plastic surgeons.

  11. Supply Chain Viability for the North American Microwave Power Tube Industry

    National Research Council Canada - National Science Library

    Philippi, Therese M

    2002-01-01

    The DoD Defense Production (DPA) Act Title III program sponsored this project in response to a critical supply base issue with the objective of strengthening the supplier base to ensure it's future viability...

  12. Microstructural characterization and density change of 304 stainless steel reflector blocks after long-term irradiation in EBR-II

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Y., E-mail: yina.huang@materials.ox.ac.uk [University of Wisconsin, Madison, WI 53706 (United States); Wiezorek, J.M.K. [University of Pittsburgh, Pittsburgh, PA 15260 (United States); Garner, F.A. [Radiation Effects Consulting, 2003 Howell Ave., Richland, WA 99354 (United States); Freyer, P.D. [Westinghouse Electric Company LLC, Pittsburgh, PA 15235 (United States); Okita, T. [University of Tokyo, Tokyo (Japan); Sagisaka, M.; Isobe, Y. [Nuclear Fuel Industries, Ltd., Osaka (Japan); Allen, T.R. [University of Wisconsin, Madison, WI 53706 (United States)

    2015-10-15

    While thin reactor structural components such as cladding and ducts do not experience significant gradients in dpa rate, gamma heating rate, temperature or stress, thick components can develop strong local variations in void swelling and irradiation creep in response to gradients in these variables. In this study we conducted microstructural investigations by transmission electron microscopy of two 52 mm thick 304-type stainless steel hex-blocks irradiated for 12 years in the EBR-II reactor with accumulated doses ranging from ∼0.4 to 33 dpa. Spatial variations in the populations of voids, precipitates, Frank loops and dislocation lines have been determined for 304 stainless steel sections exposed to different temperatures, different dpa levels and at different dpa rates, demonstrating the existence of spatial gradients in the resulting void swelling. The microstructural measurements compare very well with complementary density change measurements regarding void swelling gradients in the 304 stainless steel hex-block components. The TEM studies revealed that the original cold-worked-state microstructure of the unirradiated blocks was completely erased by irradiation, replaced by high densities of interstitial Frank loops, voids and carbide precipitates at both the lowest and highest doses. At large dose levels the amount of volumetric void swelling correlated directly with the gamma heating gradient-related temperature increase (e.g. for 28 dpa, ∼2% swelling at 418 °C and ∼2.9% swelling at 448 °C). Under approximately iso-thermal local conditions, volumetric void swelling was found to increase with dose level (e.g. ∼0.2% swelling at 0.4 dpa, ∼0.5% swelling at 4 dpa and ∼2% swelling at 28 dpa). Carbide precipitate formation levels were found to be relatively independent of both dpa level and temperature and induced a measurable densification. Void swelling was dominant at the higher dose levels and caused measurable decreases in density. Void

  13. Microstructural characterization and density change of 304 stainless steel reflector blocks after long-term irradiation in EBR-II

    Science.gov (United States)

    Huang, Y.; Wiezorek, J. M. K.; Garner, F. A.; Freyer, P. D.; Okita, T.; Sagisaka, M.; Isobe, Y.; Allen, T. R.

    2015-10-01

    While thin reactor structural components such as cladding and ducts do not experience significant gradients in dpa rate, gamma heating rate, temperature or stress, thick components can develop strong local variations in void swelling and irradiation creep in response to gradients in these variables. In this study we conducted microstructural investigations by transmission electron microscopy of two 52 mm thick 304-type stainless steel hex-blocks irradiated for 12 years in the EBR-II reactor with accumulated doses ranging from ∼0.4 to 33 dpa. Spatial variations in the populations of voids, precipitates, Frank loops and dislocation lines have been determined for 304 stainless steel sections exposed to different temperatures, different dpa levels and at different dpa rates, demonstrating the existence of spatial gradients in the resulting void swelling. The microstructural measurements compare very well with complementary density change measurements regarding void swelling gradients in the 304 stainless steel hex-block components. The TEM studies revealed that the original cold-worked-state microstructure of the unirradiated blocks was completely erased by irradiation, replaced by high densities of interstitial Frank loops, voids and carbide precipitates at both the lowest and highest doses. At large dose levels the amount of volumetric void swelling correlated directly with the gamma heating gradient-related temperature increase (e.g. for 28 dpa, ∼2% swelling at 418 °C and ∼2.9% swelling at 448 °C). Under approximately iso-thermal local conditions, volumetric void swelling was found to increase with dose level (e.g. ∼0.2% swelling at 0.4 dpa, ∼0.5% swelling at 4 dpa and ∼2% swelling at 28 dpa). Carbide precipitate formation levels were found to be relatively independent of both dpa level and temperature and induced a measurable densification. Void swelling was dominant at the higher dose levels and caused measurable decreases in density. Void swelling

  14. Optimization of the synthesis of SAPO-11 for the methylation of naphthalene with methanol by varying templates and template content

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaoxiao [University of Chinese Academy of Sciences, Beijing (China); Zhang, Wei; Zhao, Liangfu; Xiang, Hongwei, E-mail: zw7234@sxicc.ac.cn, E-mail: lfzhao@sxicc.ac.cn [Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan (China); Guo, Shaoqing [Taiyuan University of Science and Technology, Taiyuan (China)

    2013-07-15

    SAPO-11 zeolites were successfully synthesized by using three different templates (diethylamine (DEA), di-n-propylamine (DPA) and di-isopropylamine (DIPA)) and varying DPA contents (nDPA/Al{sub 2}O{sub 3} = 0.8, 1.2, 1.6 and 2.0) under hydrothermal conditions. The samples were characterized by powder X-ray diffractometry (XRD), scanning electron microscopy (SEM), N{sub 2} adsorption-desorption, temperature programmed desorption of ammonia (NH{sub 3} -TPD) and {sup 29}Si magic angle spinning (MAS) nuclear magnetic resonance (NMR). The samples were also evaluated towards the methylation of naphthalene with methanol to produce 2,6-dimethylnaphthalene (2,6-DMN). XRD results indicated that the directing effect of the different templates for AEL (Aluminophosphate-ELeven) structure decreased in the order DPA > DEA > DIPA and the most suitable DPA content was nDPA/Al{sub 2}O{sub 3} = 1.2. N{sub 2} adsorption-desorption results showed that SAPO-11(DPA,1.2) exhibited the broadest pore size distribution, the highest BET specific surface area and the largest pore volume among all the SAPO-11 samples. SAPO-11(DPA,1.2) exhibited high catalytic performances in the methylation of naphthalene due to its high crystallinity, high external surface and broad pore size distribution. The pore structure of SAPO-11 zeolite, rather than its acidity, played an important role in achieving high catalytic performances in the methylation of naphthalene with methanol. (author)

  15. Swelling of Fe-Mn and Fe-Cr-Mn alloys at high neutron fluence

    International Nuclear Information System (INIS)

    Garner, F.A.; Brager, H.R.

    1986-06-01

    Swelling data on neutron-irradiated simple Fe-Cr-Mn and Fe-Mn alloys, as well as commercial Fe-Cr-Mn base alloys are now becoming available at exposure levels approaching 50 dpa. The swelling rate decreases from the ∼1%/dpa found at lower exposures, probably due to the extensive formation of ferritic phases. As expected, commercial alloys swell less than the simple alloys

  16. Elastic and inelastic light scattering from single bacterial spores in an optical trap allows the monitoring of spore germination dynamics

    Science.gov (United States)

    Peng, Lixin; Chen, De; Setlow, Peter; Li, Yong-qing

    2009-01-01

    Raman scattering spectroscopy and elastic light scattering intensity (ESLI) were used to simultaneously measure levels of Ca-dipicolinic acid (CaDPA) and changes in spore morphology and refractive index during germination of individual B. subtilis spores with and without the two redundant enzymes (CLEs), CwlJ and SleB, that degrade spores’ peptidoglycan cortex. Conclusions from these measurements include: 1) CaDPA release from individual wild-type germinating spores was biphasic; in a first heterogeneous slow phase, Tlag, CaDPA levels decreased ∼15% and in the second phase ending at Trelease, remaining CaDPA was released rapidly; 2) in L-alanine germination of wild-type spores and spores lacking SleB: a) the ESLI rose ∼2-fold shortly before Tlag at T1; b) following Tlag, the ESLI again rose ∼2-fold at T2 when CaDPA levels had decreased ∼50%; and c) the ESLI reached its maximum value at ∼Trelease and then decreased; 3) in CaDPA germination of wild-type spores: a) Tlag increased and the first increase in ESLI occurred well before Tlag, consistent with different pathways for CaDPA and L-alanine germination; b) at Trelease the ESLI again reached its maximum value; 4) in L-alanine germination of spores lacking both CLEs and unable to degrade their cortex, the time ΔTrelease (Trelease–Tlag) for excretion of ≥75% of CaDPA was ∼15-fold higher than that for wild-type or sleB spores; and 5) spores lacking only CwlJ exhibited a similar, but not identical ESLI pattern during L-alanine germination to that seen with cwlJ sleB spores, and the high value for ΔTrelease. PMID:19374431

  17. Elastic and inelastic light scattering from single bacterial spores in an optical trap allows the monitoring of spore germination dynamics

    OpenAIRE

    Peng, Lixin; Chen, De; Setlow, Peter; Li, Yong-qing

    2009-01-01

    Raman scattering spectroscopy and elastic light scattering intensity (ESLI) were used to simultaneously measure levels of Ca-dipicolinic acid (CaDPA) and changes in spore morphology and refractive index during germination of individual B. subtilis spores with and without the two redundant enzymes (CLEs), CwlJ and SleB, that degrade spores’ peptidoglycan cortex. Conclusions from these measurements include: 1) CaDPA release from individual wild-type germinating spores was biphasic; in a first h...

  18. Analysis of the DHCE experiment in the position A10 of the ATR reactor

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, I.C.; Smith, D.L.; Tsai, H. [Argonne National Lab., IL (United States)

    1997-08-01

    Calculations were performed to assess the possibility of performing DHCE experiments in mixed spectrum fission reactors. Calculated values of key parameters were compared with limit values for each quantity. The values calculated were: He-4 production from the {sup 6}Li(n,t){sup 4}He reaction, tritium leakage, required tritium concentration in lithium, initial tritium charge per capsule, and helium to dpa ratio after 10 dpa of irradiation.

  19. Implementing displacement damage calculations for electrons and gamma rays in the Particle and Heavy-Ion Transport code System

    Science.gov (United States)

    Iwamoto, Yosuke

    2018-03-01

    In this study, the Monte Carlo displacement damage calculation method in the Particle and Heavy-Ion Transport code System (PHITS) was improved to calculate displacements per atom (DPA) values due to irradiation by electrons (or positrons) and gamma rays. For the damage due to electrons and gamma rays, PHITS simulates electromagnetic cascades using the Electron Gamma Shower version 5 (EGS5) algorithm and calculates DPA values using the recoil energies and the McKinley-Feshbach cross section. A comparison of DPA values calculated by PHITS and the Monte Carlo assisted Classical Method (MCCM) reveals that they were in good agreement for gamma-ray irradiations of silicon and iron at energies that were less than 10 MeV. Above 10 MeV, PHITS can calculate DPA values not only for electrons but also for charged particles produced by photonuclear reactions. In DPA depth distributions under electron and gamma-ray irradiations, build-up effects can be observed near the target's surface. For irradiation of 90-cm-thick carbon by protons with energies of more than 30 GeV, the ratio of the secondary electron DPA values to the total DPA values is more than 10% and increases with an increase in incident energy. In summary, PHITS can calculate DPA values for all particles and materials over a wide energy range between 1 keV and 1 TeV for electrons, gamma rays, and charged particles and between 10-5 eV and 1 TeV for neutrons.

  20. Dual photon absorptiometry of the spine

    International Nuclear Information System (INIS)

    Guaydier-Souquieres, G.; Sabatier, J.P.

    1987-01-01

    Dual photon absorptiometry allows quantitative investigation of the vertebral mineral content. The authors report the bone mineralization regression curves they obtained with their prototype in male and female controle subjects. There is a fracture threshold, unconnected with age, between normal and osteoporotic subjects. DPA results correlate well with those of Quantitative Computed Tomography. DPA can be used to monitor patient's mineralization and detect subjects at increased risk for fractures [fr

  1. JCSC_129_10_1627_1637_SI.doc

    Indian Academy of Sciences (India)

    Contents. Figure S1. UV-Vis spectrum of the [Cu(dpa)2(OAc)](ClO4) complex in ethanol. Figure S2. EPR plot of [Cu(dpa)2(OAc)](ClO4) in frozen acetonitrile (left) and in powder state (right) at low temperature (77K). Figure S3. Cyclic voltammogram of 10-3 M Cu(II) complex in acetonitrile solution containing 0.1 M TBAP at 25 ...

  2. Dual lanthanide-doped complexes: the development of a time-resolved ratiometric fluorescent probe for anthrax biomarker and a paper-based visual sensor.

    Science.gov (United States)

    Wang, Qi-Xian; Xue, Shi-Fan; Chen, Zi-Han; Ma, Shi-Hui; Zhang, Shengqiang; Shi, Guoyue; Zhang, Min

    2017-08-15

    In this work, a novel time-resolved ratiometric fluorescent probe based on dual lanthanide (Tb: terbium, and Eu: europium)-doped complexes (Tb/DPA@SiO 2 -Eu/GMP) has been designed for detecting anthrax biomarker (dipicolinic acid, DPA), a unique and major component of anthrax spores. In such complexes-based probe, Tb/DPA@SiO 2 can serve as a stable reference signal with green fluorescence and Eu/GMP act as a sensitive response signal with red fluorescence for ratiometric fluorescent sensing DPA. Additionally, the probe exhibits long fluorescence lifetime, which can significantly reduce the autofluorescence interferences from biological samples by using time-resolved fluorescence measurement. More significantly, a paper-based visual sensor for DPA has been devised by using filter paper embedded with Tb/DPA@SiO 2 -Eu/GMP, and we have proved its utility for fluorescent detection of DPA, in which only a handheld UV lamp is used. In the presence of DPA, the paper-based visual sensor, illuminated by a handheld UV lamp, would result in an obvious fluorescence color change from green to red, which can be easily observed with naked eyes. The paper-based visual sensor is stable, portable, disposable, cost-effective and easy-to-use. The feasibility of using a smartphone with easy-to-access color-scanning APP as the detection platform for quantitative scanometric assays has been also demonstrated by coupled with our proposed paper-based visual sensor. This work unveils an effective method for accurate, sensitive and selective monitoring anthrax biomarker with backgroud-free and self-calibrating properties. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Radiation-induced grain subdivision and bubble formation in U3Si2 at LWR temperature

    Science.gov (United States)

    Yao, Tiankai; Gong, Bowen; He, Lingfeng; Harp, Jason; Tonks, Michael; Lian, Jie

    2018-01-01

    U3Si2, an advanced fuel form proposed for light water reactors (LWRs), has excellent thermal conductivity and a high fissile element density. However, limited understanding of the radiation performance and fission gas behavior of U3Si2 is available at LWR conditions. This study explores the irradiation behavior of U3Si2 by 300 keV Xe+ ion beam bombardment combining with in-situ transmission electron microscopy (TEM) observation. The crystal structure of U3Si2 is stable against radiation-induced amorphization at 350 °C even up to a very high dose of 64 displacements per atom (dpa). Grain subdivision of U3Si2 occurs at a relatively low dose of 0.8 dpa and continues to above 48 dpa, leading to the formation of high-density nanoparticles. Nano-sized Xe gas bubbles prevail at a dose of 24 dpa, and Xe bubble coalescence was identified with the increase of irradiation dose. The volumetric swelling resulting from Xe gas bubble formation and coalescence was estimated with respect to radiation dose, and a 2.2% volumetric swelling was observed for U3Si2 irradiated at 64 dpa. Due to extremely high susceptibility to oxidation, the nano-sized U3Si2 grains upon radiation-induced grain subdivision were oxidized to nanocrystalline UO2 in a high vacuum chamber for TEM observation, eventually leading to the formation of UO2 nanocrystallites stable up to 80 dpa.

  4. A low molecular weight zinc2+-dipicolylamine-based probe detects apoptosis during tumour treatment better than an annexin V-based probe

    International Nuclear Information System (INIS)

    Palmowski, Karin; Rix, Anne; Lederle, Wiltrud; Kiessling, Fabian; Behrendt, Florian F.; Mottaghy, Felix M.; Gray, Brian D.; Pak, Koon Y.; Palmowski, Moritz

    2014-01-01

    Molecular imaging of apoptosis is frequently discussed for monitoring cancer therapies. Here, we compare the low molecular weight phosphatidylserine-targeting ligand zinc 2+ -dipicolylamine (Zn 2+ -DPA) with the established but reasonably larger protein annexin V. Molecular apoptosis imaging with the fluorescently labelled probes annexin V (750 nm, 36 kDa) and Zn 2+ -DPA (794 nm, 1.84 kDa) was performed in tumour-bearing mice (A431). Three animal groups were investigated: untreated controls and treated tumours after 1 or 4 days of anti-angiogenic therapy (SU11248). Additionally, μPET with 18 F-FDG was performed. Imaging data were displayed as tumour-to-muscle ratio (TMR) and validated by quantitative immunohistochemistry. Compared with untreated control tumours, TUNEL staining indicated significant apoptosis after 1 day (P 2+ -DPA uptake increased significantly after 1 day (P 2+ -DPA, 18 F-FDG tumour uptake decreased significantly at days 1 (P 2+ -DPA than with the annexin V-based probe. Additionally, significant treatment effects were detectable as early using Zn 2+ -DPA as with measurements of the glucose metabolism using 18 F-FDG. (orig.)

  5. Differences in bone mineral density between mildly and definitively osteoporotic women

    International Nuclear Information System (INIS)

    Heuck, A.F.; Steiger, P.; Block, J.E.; Glueer, C.C.; Steiger, S.; Genant, H.K.

    1988-01-01

    The authors studied 68 postmenopausal women to determine the ability of three bone densitometry techniques (QCT and DPA of the spine and SPA of the radius) for discriminating patients with mild wedge deformities (20%-25% wedge) from definitive compression fractures (≥25% wedge or crush fracture). Decrements of bone density between mildly osteoporotic women and osteoporotic women were -20% (P<.001) for QCT, -11% (P<.01) for DPA, and -5.5% (not significant) for SPA. Z-scores were -0.7 (P<.001) for QCT, -0.6 (P<.01) for DPA, and -0.4 (not significant) for SPA. The group was divided into quartiles of bone density with odds ratios calculated and the highest quartile acting as the reference group (risk=1). Odds ratios for the lower quartiles were 2.3, 5.3, and 10.7 for QCT; 0.4, 2.9, and 3.7 for DPA; and 0.7, 0.7, and 2.7 for SPA, respectively. Only the odds ratio for the lowest quartile of QCT (10.7) was found to be significant (P<.01). Receiver operating characteristic curves were calculated for each modality, with QCT showing the greatest area under the curve (0.70), followed by DPA (0.67) and SPA (0.60). The authors' results show that QCT and DPA are sensitive in discriminating mild from advanced forms of osteoporosis, whereas SPA has limited discriminatory capability

  6. Transmission electron microscope study of fusion-environment radiation damage in iron and iron-chromium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Horton, L.L.S.

    1982-07-01

    A transmission electron microscopy study of radiation damage microstructures in iron and iron-chromium alloys has been performed. This study consisted of both qualitative and quantitative characterization of the dislocation and cavity microstructures, including determination of vacancy/interstitial character and Burgers vectors for dislocation loops and analysis of the cavity morphology. The effects of irradiation temperature, fluence, helium implantation, and chromium content were investigated. Neutron irradiation (iron specimens, 1 dpa, 455 to 1000 K) and triple-beam ion irradiation (Fe-10% Cr specimens, 10 dpa, 725 to 950 K; Fe-10% Cr specimens, 850 K, 0.3 to 100 dpa; and Fe, Fe-5% Cr, Fe-10% Cr specimens, 850 K, 10 dpa) were employed. In the triple-beam ion irradiation procedure, simultaneous bombardment with 4 MeV Fe/sup + +/ ions and energetic He/sup +/ and D/sub 2//sup +/ ions was used to simulate the fusion environment (10 at. ppM He/dpa and 41 at. ppM D/dpa). In addition, single-beam 4 MeV Fe/sup + +/ ion irradiations of Fe-10% Cr both with and without pre-injection of helium and deuterium were performed.

  7. Transmission electron microscope study of fusion-environment radiation damage in iron and iron-chromium alloys

    International Nuclear Information System (INIS)

    Horton, L.L.S.

    1982-07-01

    A transmission electron microscopy study of radiation damage microstructures in iron and iron-chromium alloys has been performed. This study consisted of both qualitative and quantitative characterization of the dislocation and cavity microstructures, including determination of vacancy/interstitial character and Burgers vectors for dislocation loops and analysis of the cavity morphology. The effects of irradiation temperature, fluence, helium implantation, and chromium content were investigated. Neutron irradiation (iron specimens, 1 dpa, 455 to 1000 K) and triple-beam ion irradiation (Fe-10% Cr specimens, 10 dpa, 725 to 950 K; Fe-10% Cr specimens, 850 K, 0.3 to 100 dpa; and Fe, Fe-5% Cr, Fe-10% Cr specimens, 850 K, 10 dpa) were employed. In the triple-beam ion irradiation procedure, simultaneous bombardment with 4 MeV Fe ++ ions and energetic He + and D 2 + ions was used to simulate the fusion environment (10 at. ppM He/dpa and 41 at. ppM D/dpa). In addition, single-beam 4 MeV Fe ++ ion irradiations of Fe-10% Cr both with and without pre-injection of helium and deuterium were performed

  8. Delinquent peer affiliation as an etiological moderator of childhood delinquency.

    Science.gov (United States)

    Burt, S A; Klump, K L

    2013-06-01

    Prior research has indicated that affiliation with delinquent peers activates genetic influences on delinquency during adolescence. However, because other studies have indicated that the socializing effects of delinquent peers vary dramatically across childhood and adolescence, it is unclear whether delinquent peer affiliation (DPA) also moderates genetic influences on delinquency during childhood. Method The current study sought to evaluate whether and how DPA moderated the etiology of delinquency in a sample of 726 child twins from the Michigan State University Twin Registry (MSUTR). The results robustly supported etiological moderation of childhood delinquency by DPA. However, this effect was observed for shared environmental, rather than genetic, influences. Shared environmental influences on delinquency were found to be several-fold larger in those with higher levels of DPA as compared to those with lower levels. This pattern of results persisted even when controlling for the overlap between delinquency and DPA. Our findings bolster prior work in suggesting that, during childhood, the association between DPA and delinquency is largely (although not solely) attributable to the effects of socialization as compared to selection. They also suggest that the process of etiological moderation is not specific to genetic influences. Latent environmental influences are also amenable to moderation by measured environmental factors.

  9. Synthesis, crystal structure, and magnetic properties of two-dimensional divalent metal glutarate/dipyridylamine coordination polymers, with a single crystal-to-single crystal transformation in the copper derivative

    International Nuclear Information System (INIS)

    Montney, Matthew R.; Supkowski, Ronald M.; Staples, Richard J.; LaDuca, Robert L.

    2009-01-01

    Hydrothermal reaction of divalent metal chlorides with glutaric acid and 4,4'-dipyridylamine (dpa) has afforded an isostructural family of coordination polymers with formulation [M(glu)(dpa)] n (M=Co (1), Ni (2), Cu (3); glu=glutarate). Square pyramidal coordination is seen in 1-3, with semi-ligation of a sixth donor to produce a '5+1' extended coordination sphere. Neighboring metal atoms are linked into 1D [M(glu)] n neutral chains through chelating/monodentate bridging glutarate moieties with a syn-anti binding mode, and semi-chelation of the pendant carboxylate oxygen. These chains further connect into 2D layers through dipodal dpa ligands. Neighboring layers stack into the pseudo 3D crystal structure of 1-3 through supramolecular hydrogen bonding between dpa amine units and the semi-chelated glutarate oxygen atoms. The variable temperature magnetic behavior of 1-3 was explored and modeled as infinite 1D Heisenberg chains. Notably, complex 3 undergoes a thermally induced single crystal-to-single crystal transformation between centric and acentric space groups, with a conformationally disordered unilayer structure at 293 K and an ordered bilayer structure at 173 K. All materials were further characterized via infrared spectroscopy and elemental and thermogravimetric analyses. - Graphical abstract: The coordination polymers [M(glu)(dpa)] n (M=Co (1), Ni (2), Cu (3); glu=glutarate, dpa=4,4'-dipyridylamine) exhibit 2D layer structures based on 1D [M(glu)] n chains linked through dpa tethers. Antiferromagnetic coupling is observed for 2 and 3, while ferromagnetism is predominant in 1. Compound 3 undergoes a thermally induced single crystal-to-single crystal transformation from an acentric to a centrosymmetric space group

  10. Fluoxetine potentiation of omega-3 fatty acid antidepressant effect: evaluating pharmacokinetic and brain fatty acid-related aspects in rodents.

    Science.gov (United States)

    Laino, Carlos Horacio; Garcia, Pilar; Podestá, María Fernanda; Höcht, Christian; Slobodianik, Nora; Reinés, Analía

    2014-10-01

    We previously reported that combined fluoxetine administration at antidepressant doses renders additive antidepressant effects, whereas non-antidepressant doses potentiate the omega-3 fatty acid antidepressant effect. In the present study, we aimed to evaluate putative pharmacokinetic and brain omega-3 fatty acid-related aspects for fluoxetine potentiation of omega-3 fatty acid antidepressant effect in rats. Coadministration of omega-3 fatty acids with a non-antidepressant dose of fluoxetine (1 mg/kg day) failed to affect both brain fluoxetine concentration and norfluoxetine plasma concentration profile. Fluoxetine plasma concentrations remained below the sensitivity limit of the detection method. Either antidepressant (10 mg/kg day) or non-antidepressant (1 mg/kg day) doses of fluoxetine in combination with omega-3 fatty acids increased hippocampal docosapentaenoic acid (DPA, 22:5 omega-3) levels. Although individual treatments had no effects on DPA concentration, DPA increase was higher when omega-3 were combined with the non-antidepressant dose of fluoxetine. Chronic DPA administration exerted antidepressant-like effects in the forced swimming test while increasing hippocampal docosahexaenoic (22:6 omega-3) and DPA levels. Our results suggest no pharmacokinetic interaction and reveal specific hippocampal DPA changes after fluoxetine and omega-3 combined treatments in our experimental conditions. The DPA role in the synergistic effect of fluoxetine and omega-3 combined treatments will be for sure the focus of future studies. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 103:3316-3325, 2014. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

  11. Sustained hypoxia leads to the emergence of cells with enhanced growth, migratory, and promitogenic potentials within the distal pulmonary artery wall.

    Science.gov (United States)

    Frid, Maria G; Li, Min; Gnanasekharan, Meena; Burke, Danielle L; Fragoso, Miguel; Strassheim, Derek; Sylman, Joanna L; Stenmark, Kurt R

    2009-12-01

    All forms of chronic pulmonary hypertension (PH) are characterized by structural remodeling of the pulmonary artery (PA) media, a process previously attributed solely to changes in the phenotype of resident smooth muscle cells (SMC). However, recent experimental evidence in both systemic and pulmonary circulations suggests that other cell types, including circulating and local progenitors, contribute significantly to this process. The goal of this study was to determine if hypoxia-induced remodeling of distal PA (dPA) media involves the emergence of cells with phenotypic and functional characteristics distinct from those of resident dPA SMC and fibroblasts. In vivo, in contrast to the phenotypically uniform SMC composition of dPA media in control calves, the remodeled dPA media of neonatal calves with severe hypoxia-induced PH comprised cells exhibiting a distinct phenotype, including the expression of hematopoetic (CD45), leukocytic/monocytic (CD11b, CD14), progenitor (cKit), and motility-associated (S100A4) cell markers. Consistent with these in vivo observations, primary cell cultures isolated from dPA media of hypertensive calves yielded not only differentiated SMC, but also smaller, morphologically rhomboidal (thus termed here "R") cells that transiently expressed CD11b, constitutively expressed the mesenchymal cell marker type I procollagen, expressed high mRNA levels of progenitor cell markers cKit, CD34, CD73, as well as for inflammatory mediators, IL-6 and MCP-1, and, with time in culture, gained expression of a myofibroblast marker, alpha-SM-actin. R cells exhibited highly augmented proliferative, migratory, invasive, and potent promitogenic capabilities, which were due, at least in part, to the production of PDGFs, SDF-1/CXCL12, and S100A4. These data suggest that the cellular mechanisms of dPA remodeling include the emergence of cells with phenotypic and functional characteristics markedly distinct from those of resident dPA cells.

  12. Primary Radiation Damage in Materials. Review of Current Understanding and Proposed New Standard Displacement Damage Model to Incorporate in Cascade Defect Production Efficiency and Mixing Effects

    International Nuclear Information System (INIS)

    Nordlund, Kai; Sand, Andrea E.; Granberg, Fredric; Zinkle, Steven J.; Stoller, Roger; Averback, Robert S.; Suzudo, Tomoaki; Malerba, Lorenzo; Banhart, Florian; Weber, William J.; Willaime, Francois; Dudarev, Sergei; Simeone, David

    2015-01-01

    Under the auspices of the NEA Nuclear Science Committee (NSC), the Working Party on Multi-scale Modelling of Fuels and Structural Materials for Nuclear Systems (WPMM) was established in 2008 to assess the scientific and engineering aspects of fuels and structural materials, aiming at evaluating multi-scale models and simulations as validated predictive tools for the design of nuclear systems, fuel fabrication and performance. The WPMM's objective is to promote the exchange of information on models and simulations of nuclear materials, theoretical and computational methods, experimental validation, and related topics. It also provides member countries with up-to-date information, shared data, models and expertise. The WPMM Expert Group on Primary Radiation Damage (PRD) was established in 2009 to determine the limitations of the NRT-dpa standard, in the light of both atomistic simulations and known experimental discrepancies, to revisit the NRT-dpa standard and to examine the possibility of proposing a new improved standard of primary damage characteristics. This report reviews the current understanding of primary radiation damage from neutrons, ions and electrons (excluding photons, atomic clusters and more exotic particles), with emphasis on the range of validity of the 'displacement per atom' (dpa) concept in all major classes of materials with the exception of organics. The report also introduces an 'athermal recombination-corrected dpa' (arc-dpa) relation that uses a relatively simple functional to address the well-known issue that 'displacement per atom' (dpa) overestimates damage production in metals under energetic displacement cascade conditions, as well as a 'replacements-per-atom' (rpa) equation, also using a relatively simple functional, that accounts for the fact that dpa is understood to severely underestimate actual atom relocation (ion beam mixing) in metals. (authors)

  13. Precipitate evolution in low-nickel austenitic stainless steels during neutron irradiation at very low dose rates

    International Nuclear Information System (INIS)

    Isobe, Y.; Sagisaka, M.; Garner, F.; Okita, T.

    2007-01-01

    Full text of publication follows: Not all components of a fusion reactor will be subjected to high atomic displacement rates. Some components outside the plasma containment may experience relatively low displacement rates but data generated under long-term irradiation at low dpa rates is hard to obtain. In another study the neutron-induced microstructural evolution in response to long term irradiation at very low dose rates was studied for a Russian low-nickel austenitic stainless steel that is analogous to AISI 304. The irradiated samples were obtained from an out-of-core anti-crush support column for the BN-600 fast reactor with doses ranging from 1.5 to 22 dpa generated at 3x10 -9 to 4x10 -8 dpa/s. The irradiation temperatures were in a very narrow range of 370-375 deg. C. Microstructural observation showed that in addition to voids and dislocations, an unexpectedly high density of small carbide precipitates was formed that are not usually observed at higher dpa rates in this temperature range. These results required us to ask if such unexpected precipitation was anomalous or was a general feature of low-flux, long-term irradiation. It is shown in this paper that a similar behavior was observed in a western stainless steel, namely AISI 304 stainless steel, irradiated at similar temperatures and dpa rates in the EBR-II fast reactor, indicating that irradiation at low dpa rates for many years leads to a different precipitate microstructure and therefore different associated changes in matrix composition than are generated at higher dpa rates. One consequence of this precipitation is a reduced lattice parameter of the alloy matrix, leading to densification that increases in strength with increasing temperature and dose. A. non-destructive method to evaluate these precipitates is under development and is also discussed in this paper. (authors)

  14. Spatial investigation of the elemental distribution in Wilson's disease liver after d-penicillamine treatment by LA-ICP-MS.

    Science.gov (United States)

    Hachmöller, Oliver; Zibert, Andree; Zischka, Hans; Sperling, Michael; Groba, Sara Reinartz; Grünewald, Inga; Wardelmann, Eva; Schmidt, Hartmut H-J; Karst, Uwe

    2017-12-01

    At present, the copper chelator d-penicillamine (DPA) is the first-line therapy of Wilson's disease (WD), which is characterized by an excessive copper overload. Lifelong DPA treatments aim to reduce the amount of detrimental excess copper retention in the liver and other organs. Although DPA shows beneficial effect in many patients, it may cause severe adverse effects. Despite several years of copper chelation therapy, discontinuation of DPA therapy can be linked to a rapidly progressing liver failure, indicating a high residual liver copper load. In order to investigate the spatial distribution of remaining copper and additional elements, such as zinc and iron, in rat and human liver samples after DPA treatment, a high resolution (spotsize of 10μm) laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) imaging method was applied. Untreated LPP -/- rats, an established animal model for WD, appeared with a high overall copper concentration and a copper distribution of hotspots distributed over the liver tissue. In contrast, a low (>2-fold decreased) overall copper concentration was detected in liver of DPA treated animals. Importantly, however, copper distribution was highly inhomogeneous with lowest concentrations in direct proximity to blood vessels, as observed using novel zonal analysis. A human liver needle biopsy of a DPA treated WD patient substantiated the finding of an inhomogeneous copper deposition upon chelation therapy. In contrast, comparatively homogenous distributions of zinc and iron were observed. Our study indicates that a high resolution LA-ICP-MS analysis of liver samples is excellently suited to follow efficacy of chelator therapy in WD patients. Copyright © 2017 Elsevier GmbH. All rights reserved.

  15. Synthesis and characterization of an MRI Gd-based probe designed to target the translocator protein

    International Nuclear Information System (INIS)

    Cerutti, Erika; Aime, Silvio; Damont, Annelaure; Dolle, Frederic; Baroni, Simona

    2013-01-01

    DPA-713 is the lead compound of a recently reported pyrazolo[1,5-a]pyrimidine acetamide series, targeting the translocator protein (TSPO 18 kDa), and as such, this structure, as well as closely related derivatives, have been already successfully used as positron emission tomography radioligands. On the basis of the pharmacological core of this ligands series, a new magnetic resonance imaging probe, coded DPA-C6-(Gd)DOTAMA was designed and successfully synthesized in six steps and 13% overall yield from DPA-713. The Gd-DOTA monoamide cage (DOTA = 1,4,7,10-tetraaza-cyclododecane-1,4,7,10-tetraacetic acid) represents the magnetic resonance imaging reporter, which is spaced from the phenyl-pyrazolo[1,5-a]pyrimidine acetamide moiety (DPA-713 motif) by a six carbon-atom chain. DPA-C6-(Gd)DOTAMA relaxometric characterization showed the typical behavior of a small-sized molecule (relaxivity value: 6.02 mM -1 s -1 at 20 MHz). The good hydrophilicity of the metal chelate makes DPAC6-(Gd)DOTAMA soluble in water, affecting thus its biodistribution with respect to the parent lipophilic DPA-713 molecule. For this reason, it was deemed of interest to load the probe to a large carrier in order to increase its residence lifetime in blood. Whereas DPA-C6-(Gd)DOTAMA binds to serum albumin with a low affinity constant, it can be entrapped into liposomes (both in the membrane and in the inner aqueous cavity). The stability of the supramolecular adduct formed by the Gd-complex and liposomes was assessed by a competition test with albumin. (authors)

  16. Characterization of Wet-Heat Inactivation of Single Spores of Bacillus Species by Dual-Trap Raman Spectroscopy and Elastic Light Scattering▿

    Science.gov (United States)

    Zhang, Pengfei; Kong, Lingbo; Setlow, Peter; Li, Yong-qing

    2010-01-01

    Dual-trap laser tweezers Raman spectroscopy (LTRS) and elastic light scattering (ELS) were used to investigate dynamic processes during high-temperature treatment of individual spores of Bacillus cereus, Bacillus megaterium, and Bacillus subtilis in water. Major conclusions from these studies included the following. (i) After spores of all three species were added to water at 80 to 90°C, the level of the 1:1 complex of Ca2+ and dipicolinic acid (CaDPA; ∼25% of the dry weight of the spore core) in individual spores remained relatively constant during a highly variable lag time (Tlag), and then CaDPA was released within 1 to 2 min. (ii) The Tlag values prior to rapid CaDPA release and thus the times for wet-heat killing of individual spores of all three species were very heterogeneous. (iii) The heterogeneity in kinetics of wet-heat killing of individual spores was not due to differences in the microscopic physical environments during heat treatment. (iv) During the wet-heat treatment of spores of all three species, spore protein denaturation largely but not completely accompanied rapid CaDPA release, as some changes in protein structure preceded rapid CaDPA release. (v) Changes in the ELS from individual spores of all three species were strongly correlated with the release of CaDPA. The ELS intensities of B. cereus and B. megaterium spores decreased gradually and reached minima at T1 when ∼80% of spore CaDPA was released, then increased rapidly until T2 when full CaDPA release was complete, and then remained nearly constant. The ELS intensity of B. subtilis spores showed similar features, although the intensity changed minimally, if at all, prior to T1. (vi) Carotenoids in B. megaterium spores' inner membranes exhibited two changes during heat treatment. First, the carotenoid's two Raman bands at 1,155 and 1,516 cm−1 decreased rapidly to a low value and to zero, respectively, well before Tlag, and then the residual 1,155-cm−1 band disappeared, in parallel

  17. Effects of neutron irradiation of Ti{sub 3}SiC{sub 2} and Ti{sub 3}AlC{sub 2} in the 121–1085 °C temperature range

    Energy Technology Data Exchange (ETDEWEB)

    Tallman, Darin J. [Department of Materials Science and Engineering, Drexel University, Philadelphia, PA 19104 (United States); He, Lingfeng; Gan, Jian [Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Caspi, El' ad N. [Department of Materials Science and Engineering, Drexel University, Philadelphia, PA 19104 (United States); Physics Department, Nuclear Research Centre – Negev, 84190 Israel (Israel); Hoffman, Elizabeth N. [Savannah River National Laboratory, Savannah River Site, Aiken, SC 29808 (United States); Barsoum, Michel W., E-mail: barsoumw@drexel.edu [Department of Materials Science and Engineering, Drexel University, Philadelphia, PA 19104 (United States)

    2017-02-15

    Herein we report on the formation of defects in response to neutron irradiation of polycrystalline Ti{sub 3}SiC{sub 2} and Ti{sub 3}AlC{sub 2} samples exposed to total fluences of ≈6 × 10{sup 20} n/m{sup 2}, 5 × 10{sup 21} n/m{sup 2} and 1.7 × 10{sup 22} n/m{sup 2} at irradiation temperatures of 121(12), 735(6) and 1085(68)°C. These fluences correspond to 0.14, 1.6 and 3.4 dpa, respectively. After irradiation to 0.14 dpa at 121 °C and 735 °C, black spots are observed via transmission electron microscopy in both Ti{sub 3}SiC{sub 2} and Ti{sub 3}AlC{sub 2}. After irradiation to 1.6 and 3.4 dpa at 735 °C, basal dislocation loops, with a Burgers vector of b = ½ [0001] are observed in Ti{sub 3}SiC{sub 2}, with loop diameters of 21(6) and 30(8) nm after 1.6 dpa and 3.4 dpa, respectively. In Ti{sub 3}AlC{sub 2}, larger dislocation loops, 75(34) nm in diameter are observed after 3.4 dpa at 735 °C, in addition to stacking faults. Impurity particles of TiC, as well as stacking fault TiC platelets in the MAX phases, are seen to form extensive dislocation loops under all conditions. Cavities were observed at grain boundaries and within stacking faults after 3.4 dpa irradiation, with extensive cavity formation in the TiC regions at 1085 °C. Remarkably, denuded zones on the order of 1 μm are observed in Ti{sub 3}SiC{sub 2} after irradiation to 3.4 dpa at 735 °C. Small grains, 3–5 μm in diameter, are damage free after irradiation at 1085 °C at this dose. The results shown herein confirm once again that the presence of the A-layers in the MAX phases considerably enhance their irradiation tolerance. Based on these results, and up to 3.4 dpa, Ti{sub 3}SiC{sub 2} remains a promising candidate for high temperature nuclear applications as long as the temperature remains >700 °C.

  18. Ion irradiation-induced swelling and hardening effect of Hastelloy N alloy

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, S.J. [Key Laboratory of Artificial Micro-and Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Li, D.H.; Chen, H.C.; Lei, G.H.; Huang, H.F.; Zhang, W.; Wang, C.B. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Yan, L., E-mail: yanlong@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Fu, D.J. [Key Laboratory of Artificial Micro-and Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Tang, M. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2017-06-15

    The volumetric swelling and hardening effect of irradiated Hastelloy N alloy were investigated in this paper. 7 MeV and 1 MeV Xe ions irradiations were performed at room temperature (RT) with irradiation dose ranging from 0.5 to 27 dpa. The volumetric swelling increases with increasing irradiation dose, and reaches up to 3.2% at 27 dpa. And the irradiation induced lattice expansion is also observed. The irradiation induced hardening initiates at low ion dose (≤1dpa) then saturates with higher ion dose. The irradiation induced volumetric swelling may be ascribed to excess atomic volume of defects. The irradiation induced hardening may be explained by the pinning effect where the defects can act as obstacles for the free movement of dislocation lines. And the evolution of the defects' size and number density could be responsible for the saturation of hardness. - Highlights: •Irradiation Swelling: The irradiation induced volumetric swelling increases with ion dose. •Irradiation Hardening: The irradiation hardening initiates below 1 dpa, then saturates with higher ion dose (1–10 dpa). •Irradiation Mechanism: The irradiation phenomena are ascribed to the microstructural evolution of the irradiation defects.

  19. Measurements of Pulmonary Artery Size for Assessment of Pulmonary Hypertension by Cardiovascular Magnetic Resonance and Clinical Application

    Directory of Open Access Journals (Sweden)

    Fan YANG

    2017-02-01

    Full Text Available Background and objective Pulmonary hypertension (PH often leads to dilatation of main pulmonary artery (MPA. MPA measurements can be used to predict PH. This aim of this study is to investigate power of MPA vessel indices, which are acquired from cardiovascular magnetic resonance, to evaluate PH. Methods Cardiovascular-magnetic-resonance-determined parameters of MPA were acquired and calculated in 83 PH patients, whose diagnosis were confirmed with right heart catheterization and 49 healthy volunteers; these parameters included MPA diameter (DPA, ratio of DPA and ascending aorta diameter (DPA/DAo, max mean diameter (MDmax, min mean diameter (MDmin, fraction transverse diameter (fTD, fraction longitudinal diameter (fLD, and distensibility. Results Compared with control group, DPA, DPA/DAo, MDmax, and MDmin were significantly higher in patients with PH (P28.4 mm, and MDmax>32.4 mm (area under the curve, AUC=0.979, 0.981 showed best performance in predicting PH, yielding highest specificity at 100%. Conclusion Noninvasive cardiovascular-magnetic-resonance-derived MPA measurements provide excellent and practical reference in clinical settings for detecting PH.

  20. Improved calculation of displacements per atom cross section in solids by gamma and electron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Piñera, Ibrahin, E-mail: ipinera@ceaden.edu.cu [Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear, CEADEN, 30 St. 502, Playa 11300, Havana (Cuba); Cruz, Carlos M.; Leyva, Antonio; Abreu, Yamiel; Cabal, Ana E. [Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear, CEADEN, 30 St. 502, Playa 11300, Havana (Cuba); Espen, Piet Van; Remortel, Nick Van [University of Antwerp, CGB, Groenenborgerlaan 171, 2020 Antwerpen (Belgium)

    2014-11-15

    Highlights: • We present a calculation procedure for dpa cross section in solids under irradiation. • Improvement about 10–90% for the gamma irradiation induced dpa cross section. • Improvement about 5–50% for the electron irradiation induced dpa cross section. • More precise results (20–70%) for thin samples irradiated with electrons. - Abstract: Several authors had estimated the displacements per atom cross sections under different approximations and models, including most of the main gamma- and electron-material interaction processes. These previous works used numerical approximation formulas which are applicable for limited energy ranges. We proposed the Monte Carlo assisted Classical Method (MCCM), which relates the established theories about atom displacements to the electron and positron secondary fluence distributions calculated from the Monte Carlo simulation. In this study the MCCM procedure is adapted in order to estimate the displacements per atom cross sections for gamma and electron irradiation. The results obtained through this procedure are compared with previous theoretical calculations. An improvement in about 10–90% for the gamma irradiation induced dpa cross section is observed in our results on regard to the previous evaluations for the studied incident energies. On the other hand, the dpa cross section values produced by irradiation with electrons are improved by our calculations in about 5–50% when compared with the theoretical approximations. When thin samples are irradiated with electrons, more precise results are obtained through the MCCM (in about 20–70%) with respect to the previous studies.

  1. A Doherty Power Amplifier with Large Back-Off Power Range Using Integrated Enhancing Reactance

    Directory of Open Access Journals (Sweden)

    Wa Kong

    2018-01-01

    Full Text Available A symmetric Doherty power amplifier (DPA based on integrated enhancing reactance (IER was proposed for large back-off applications. The IER was generated using the peaking amplifier with the help of a desired impedance transformation in the low-power region to enhance the back-off efficiency of the carrier amplifier. To convert the impedances properly, both in the low-power region and at saturation, a two-impedance matching method was employed to design the output matching networks. For verification, a symmetric DPA with large back-off power range over 2.2–2.5 GHz was designed and fabricated. Measurement results show that the designed DPA has the 9 dB back-off efficiency of higher than 45%, while the saturated output power is higher than 44 dBm over the whole operation bandwidth. When driven by a 20 MHz LTE signal, the DPA can achieve good average efficiency of around 50% with adjacent channel leakage ratio of about –50 dBc after linearization over the frequency band of interest. The linearity improvement of the DPA for multistandard wireless communication system was also verified with a dual-band modulated signal.

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

    International Nuclear Information System (INIS)

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

    1998-01-01

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

  3. Estimation of irradiation-induced material damage measure of FCM fuel in LWR core

    International Nuclear Information System (INIS)

    Lee, Kyung-Hoon; Lee, Chungchan; Park, Sang-Yoon; Cho, Jin-Young; Chang, Jonghwa; Lee, Won Jae

    2014-01-01

    An irradiation-induced material damage measure on tri-isotropic (TRISO) multi-coating layers of fully ceramic micro-encapsulated (FCM) fuel to replace conventional uranium dioxide (UO 2 ) fuel for existing light water reactors (LWRs) has been estimated using a displacement per atom (DPA) cross section for a FCM fuel performance analysis. The DPA cross sections in 47 and 190 energy groups for both silicon carbide (SiC) and graphite are generated based on the molecular dynamics simulation by SRIM/TRIM. For the selected FCM fuel assembly design with FeCrAl cladding, a core depletion analysis was carried out using the DeCART2D/MASTER code system with the prepared DPA cross sections to evaluate the irradiation effect in the Korean OPR-1000. The DPA of the SiC and IPyC coating layers is estimated by comparing the discharge burnup obtained from the MASTER calculation with the burnup-dependent DPA for each coating layer calculated using DeCART2D. The results show that low uranium loading and hardened neutron spectrum compared to that of high temperature gas-cooled reactor (HTGR) result in high discharge burnup and high fast neutron fluence. In conclusion, it can be seen that the irradiation-induced material damage measure is noticeably increased under LWR operating conditions compared to HTGRs. (author)

  4. Expression analysis of fiber related genes in cotton (gossypium hirsutum l.) through real time pcr

    International Nuclear Information System (INIS)

    Iqbal, N.; Khatoon, A.; Asif, M.; Bashir, A.

    2016-01-01

    Cotton fibers are unicellular seed trichomes and the largest known plant cells. Fiber morphogenesis in cotton is a complex process involving a large number of genes expressed throughout fiber development process. The expression profiling of five gene families in various cotton tissues was carried out through real time PCR. Expression analysis revealed that transcripts of expansin, tubulin and E6 were elevated from 5 to 20 days post anthesis (DPA) fibers. Three Lipid transfer proteins (LTPs) including LTP1, LTP3, LTP7 exhibited highest expression in 10 - 20 DPA fibers. Transcripts of LTP3 were detected in fibers and non fiber tissues that of LTP7 were almost negligible in non fiber tissues. Sucrose phosphate synthase gene showed highest expression in 10 DPA fibers while sucrose synthse (susy) expressed at higher rate in 5-20 DPA fibers as well as roots. The results reveal that most of fiber related genes showed high expression in 5-20 DPA fibers. Comprehensive expression study may help to determine tissue and stage specificity of genes under study. The study may also help to explore complex process of fiber development and understand the role of these genes in fiber development process. Highly expressed genes in fibers may be transformed in cotton for improvement of fiber quality traits. Genes that were expressed specifically in fibers or other tissues could be used for isolation of upstream regulatory sequences. (author)

  5. Tensile properties of a titanium modified austenitic stainless steel and the weld joints after neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Shiba, K.; Ioka, I.; Jitsukawa, S.; Hamada, A.; Hishinuma, A. [and others

    1996-10-01

    Tensile specimens of a titanium modified austenitic stainless steel and its weldments fabricated with Tungsten Inert Gas (TIG) and Electron Beam (EB) welding techniques were irradiated to a peak dose of 19 dpa and a peak helium level of 250 appm in the temperature range between 200 and 400{degrees}C in spectrally tailored capsules in the Oak Ridge Research Reactor (ORR) and the High Flux Isotope Reactor (HFIR). The He/dpa ratio of about 13 appm/dpa is similar to the typical helium/dpa ratio of a fusion reactor environment. The tensile tests were carried out at the irradiation temperature in vacuum. The irradiation caused an increase in yield stress to levels between 670 and 800 MPa depending on the irradiation temperature. Total elongation was reduced to less than 10%, however the specimens failed in a ductile manner. The results were compared with those of the specimens irradiated using irradiation capsules producing larger amount of He. Although the He/dpa ratio affected the microstructural change, the impact on the post irradiation tensile behavior was rather small for not only base metal specimens but also for the weld joint and the weld metal specimens.

  6. Direct high-pressure NMR observation of dipicolinic acid leaking from bacterial spore: A crucial step for thermal inactivation.

    Science.gov (United States)

    Akasaka, Kazuyuki; Maeno, Akihiro; Yamazaki, Akira

    2017-12-01

    A bacterial spore protects itself with an unusually high concentration (~10% in dry weight of spore) of dipicolinic acid (DPA), the release of which is considered the crucial step for inactivating it under mild pressure and temperature conditions. However, the process of how the spore releases DPA in response to pressure remains obscure. Here we apply 1 H high-resolution high-pressure NMR spectroscopy, for the first time, to the spore suspension of Bacillus subtilis natto and monitor directly and in real-time the leaking process of DPA in response to pressure of 200MPa at 20°C. We find that about one third of the total DPA leaks immediately upon applying pressure, but that the rest leaks slowly in hrs upon decreasing the pressure. Once DPA is fully released from the spore, the proteins of the spore become easily denatured at a mild temperature, e.g., 80°C, much below the temperature commonly used to inactivate spores (121°C). The success of the present experiment opens a new avenue for studying bacterial spores and cells at the molecular level in response to pressure, temperature and other perturbations. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Distance-dependent energy transfer between indole and anthracene moieties in Langmuir Blodgett films

    Science.gov (United States)

    Saha, D. C.; Bhattacharjee, D.; Misra, T. N.

    1998-09-01

    1,2-Diphenyl indole (DPI) and 9,10-diphenyl anthracene (DPA) are non-amphiphilic molecules but form excellent LB films when mixed with stearic acid (SA). Spectroscopic investigations of these films indicate formation of aggregates of DPI and DPA in the mixed LB films. DPA has been used as the quencher of the fluorescence of the DPI donor. Distance-dependent energy transfer between donor and acceptor monolayers in the LB film, where they can be precisely separated by inert spacers of stearic acid layers of varied thickness, is shown to satisfy Khun's quadratic equation. This suggests that the donor excitations are delocalized. The large critical transfer distance estimated from the experimental results has been attributed to the formation of aggregates of the molecules in a LB monolayer.

  8. PKA spectrum file

    Energy Technology Data Exchange (ETDEWEB)

    Kawai, M. [Toshiba Corp., Kawasaki, Kanagawa (Japan). Nuclear Engineering Lab.

    1997-03-01

    In the Japanese Nuclear Data Committee, the PKA/KERMA file containing PKA spectra, KERMA factors and DPA cross sections in the energy range between 10{sup -5} eV and 50 MeV is being prepared from the evaluated nuclear data. The processing code ESPERANT was developed to calculate quantities of PKA, KERMA and DPA from evaluated nuclear data for medium and heavy elements by using the effective single particle emission approximation (ESPEA). For light elements, the PKA spectra are evaluated by the SCINFUL/DDX and EXIFON codes, simultaneously with other neutron cross sections. The DPA cross sections due to charged particle emitted from light elements are evaluated for high neutron energy above 20 MeV. (author)

  9. Preparation of 2H- and 3H-labeled phaseic acid and dihydrophaseic acid as standards for determination of abscisic acid metabolites in tomato fruit

    International Nuclear Information System (INIS)

    Kubik, M.; Buta, J.G.

    1990-01-01

    There have been reports that the level of abscisic acid (ABA) increases during the cold storage of tomatoes. However, the important ABA metabolites, phaseic acid (PA) and dihydrophaseic acid (DPA) were never quantitatively determined in such a system. In order to obtain the labeled standards for quantitative determination of those compounds by GC-MS-SIM, we fed bean plants with 6,6,6-[ 2 H 3 ]-ABA (mean isotopic enrichment 60%) with addition of about 10 5 Bq per mg of [ 3 H]-ABA. After 100 hours the plants were harvested and extracted with acetone. The extract were purified by solvent partitioning and, Prep-Sep amino column and on an HPLC C 18 reverse phase column. Two major radioactive metabolites of ABA were obtained and identified by GC-MS as PA and DPA. Some results on the quantitation of ABA, PA and DPA in tomato fruit after cold storage will be presented

  10. A New Approach of Parallelism and Load Balance for the Apriori Algorithm

    Directory of Open Access Journals (Sweden)

    BOLINA, A. C.

    2013-06-01

    Full Text Available The main goal of data mining is to discover relevant information on digital content. The Apriori algorithm is widely used to this objective, but its sequential version has a low performance when execu- ted over large volumes of data. Among the solutions for this problem is the parallel implementation of the algorithm, and among the parallel implementations presented in the literature that based on Apriori, it highlights the DPA (Distributed Parallel Apriori [10]. This paper presents the DMTA (Distributed Multithread Apriori algorithm, which is based on DPA and exploits the parallelism level of threads in order to increase the performance. Besides, DMTA can be executed over heterogeneous hardware platform, using different number of cores. The results showed that DMTA outperforms DPA, presents load balance among processes and threads, and it is effective in current multicore architectures.

  11. Microstructure and Nano-Hardness of 10 MeV Cl-Ion Irradiated T91 Steel

    International Nuclear Information System (INIS)

    Hu Jing; Wang Xianping; Gao Yunxia; Zhuang Zhong; Zhang Tao; Fang Qianfeng; Liu Changsong

    2015-01-01

    Hardening and elemental segregation of T91 martenstic steel irradiated by 10 MeV Cl ions to doses from 0.06 dpa to 0.83 dpa were investigated with the nanoindentation technique and transmission electron microscopy (TEM). The results demonstrated that the irradiation hardening was closely related with irradiation dose. By increasing the dose, the hardness increased rapidly at first from the initial value of 3.15 GPa before irradiation, and then tended to saturate at a value of 3.58 GPa at the highest dose of 0.83 dpa. Combined with TEM observation, the mechanism of hardening was preliminary attributed to the formation of M(Fe,Cr) 2 3C 6 carbides induced by the high energy Cl-ion irradiation. (paper)

  12. Calculations on neutron irradiation damage in reactor materials

    International Nuclear Information System (INIS)

    Sone, Kazuho; Shiraishi, Kensuke

    1976-01-01

    Neutron irradiation damage calculations were made for Mo, Nb, V, Fe, Ni and Cr. Firstly, damage functions were calculated as a function of neutron energy with neutron cross sections of elastic and inelastic scatterings, and (n,2n) and (n,γ) reactions filed in ENDF/B-III. Secondly, displacement damage expressed in displacements per atom (DPA) was estimated for neutron environments such as fission spectrum, thermal neutron reactor (JMTR), fast breeder reactor (MONJU) and two fusion reactors (The Conceptual Design of Fusion Reactor in JAERI and ORNL-Benchmark). then, damage cross section in units of dpa. barn was defined as a factor to convert a given neutron fluence to the DPA value, and was calculated for the materials in the above neutron environments. Finally, production rates of helium and hydrogen atoms were calculated with (n,α) and (n,p) cross sections in ENDF/B-III for the materials irradiated in the above reactors. (auth.)

  13. On Monte Carlo estimation of radiation damage in light water reactor systems

    International Nuclear Information System (INIS)

    Read, Edward A.; Oliveira, Cassiano R.E. de

    2010-01-01

    There has been a growing need in recent years for the development of methodologies to calculate damage factors, namely displacements per atom (dpa), of structural components for Light Water Reactors (LWRs). The aim of this paper is discuss and highlight the main issues associated with the calculation of radiation damage factors utilizing the Monte Carlo method. Among these issues are: particle tracking and tallying in complex geometries, dpa calculation methodology, coupled fuel depletion and uncertainty propagation. The capabilities of the Monte Carlo code Serpent such as Woodcock tracking and burnup are assessed for radiation damage calculations and its capability demonstrated and compared to those of the MCNP code for dpa calculations of a typical LWR configuration involving the core vessel and the downcomer. (author)

  14. Detection of Bacterial Endospores in Soil by Terbium Fluorescence

    Directory of Open Access Journals (Sweden)

    Andrea Brandes Ammann

    2011-01-01

    Full Text Available Spore formation is a survival mechanism of microorganisms when facing unfavorable environmental conditions resulting in “dormant” states. We investigated the occurrence of bacterial endospores in soils from various locations including grasslands (pasture, meadow, allotment gardens, and forests, as well as fluvial sediments. Bacterial spores are characterized by their high content of dipicolinic acid (DPA. In the presence of terbium, DPA forms a complex showing a distinctive photoluminescence spectrum. DPA was released from soil by microwaving or autoclaving. The addition of aluminium chloride reduced signal quenching by interfering compounds such as phosphate. The highest spore content (up to 109 spores per gram of dry soil was found in grassland soils. Spore content is related to soil type, to soil depth, and to soil carbon-to-nitrogen ratio. Our study might provide a basis for the detection of “hot spots” of bacterial spores in soil.

  15. 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

  16. Empirical relations for tensile properties of austenitic stainless steels irradiated in mixed-spectrum reactors

    International Nuclear Information System (INIS)

    Grossbeck, M.L.

    1991-01-01

    An assessment has been made of available tensile property data relevant to the design of fusion reactors, especially near term devices expected to operate at lower temperatures than power reactors. Empirical relations have been developed for the tensile properties as a functions of irradiation temperature for neutron exposures of 10-15, 20, 30, and 50 dpa. It was found that yield strength depends little on the particular austenitic alloy and little on the helium concentration. Strength depends upon initial condition of the alloy only for exposures of less than 30 dpa. Uniform elongation was found to be more sensitive to alloy and condition. It was also more sensitive than strength to helium level. However, below 500deg C, helium only appeared to have an efect at 10-15 dpa. At higher temperatures, helium embrittlement was apparent, and its threshold temperature decreased with increasing neutron exposure level. (orig.)

  17. Self-Assembly Behavior and pH-Stimuli-Responsive Property of POSS-Based Amphiphilic Block Copolymers in Solution

    Directory of Open Access Journals (Sweden)

    Yiting Xu

    2018-05-01

    Full Text Available Stimuli-responsive polymeric systems containing special responsive moieties can undergo alteration of chemical structures and physical properties in response to external stimulus. We synthesized a hybrid amphiphilic block copolymer containing methoxy polyethylene glycol (MePEG, methacrylate isobutyl polyhedral oligomeric silsesquioxane (MAPOSS and 2-(diisopropylaminoethyl methacrylate (DPA named MePEG-b-P(MAPOSS-co-DPA via atom transfer radical polymerization (ATRP. Spherical micelles with a core-shell structure were obtained by a self-assembly process based on MePEG-b-P(MAPOSS-co-DPA, which showed a pH-responsive property. The influence of hydrophobic chain length on the self-assembly behavior was also studied. The pyrene release properties of micelles and their ability of antifouling were further studied.

  18. Microstructural design of PCA austenitic stainless steel for improved resistance to helium embrittlement under HFIR irradiation

    International Nuclear Information System (INIS)

    Maziasz, P.J.; Braski, D.N.

    1983-01-01

    Several variants of Prime Candidate Alloy (PCA) with different preirradiation thermal-mechanical treatments were irradiated in HFIR and were evaluated for embrittlement resistance via disk-bend tensile testing. Comparison tests were made on two heats of 20%-cold-worked type 316 stainless steel. None of the alloys were brittle after irradiation at 300 to 400 0 C to approx. 44 dpa and helium levels of 3000 to approx.3600 at. ppm. However, all were quite brittle after similar exposure at 600 0 C. Embrittlement varied with alloy and pretreatment for irradiation to 44 dpa at 500 0 C and to 22 dpa at 600 0 C. Better relative embrittlement resistance among PCA variants was found in alloys which contained prior grain boundary MC carbide particles that remained stable under irradiation

  19. Influence of heat and radiation on the germinability and viability of B. cereus BIS-59 spores

    International Nuclear Information System (INIS)

    Kamat, A.S.; Lewis, N.F.

    1983-01-01

    Spores of Bicillus cereus BIS-59, isolated in this laboratory from shrimps, exhibited an exponential gamma radiation survival curve with a d 10 value of 400 krad as compared with a D 10 value of 30 krad for the vegetative cells. The D 10 value of DPA-depleted spores was also 400 krad indicating that DPA does not influence the radiation response of these spores. Maximum germination monitored with irradiated spores was 60 percent as compared with 80 percent in case of unirradiated spores. Radiation-induced inhibition of the germination processes was not dose dependent. Heat treatment (15 min at 80 C) to spores resulted in activation of the germination process; however, increase in heating time (30 min and 60 min) increased the germination lag period. DPA-depleted spores were less heat resistant than normal spores and exhibited biphasic exponential inactivation. (author)

  20. Irradiation-induced stress relaxation of Eurofer97 steel

    International Nuclear Information System (INIS)

    Luzginova, N.V.; Jong, M.; Rensman, J.W.; Hegeman, J.B.J.; Laan, J.G. van der

    2011-01-01

    The irradiation-induced stress relaxation behavior of Eurofer97 at 300 deg. C up to 3.4 dpa and under pre-stress loads typical for the ITER applications is investigated. The bolt specimens are pre-loaded from 30% to 90% of the yield strength. To verify the results obtained with the pre-stressed bolts, bent strips were investigated as well. The strips are bent into a pre-defined radius in order to achieve similar pre-stress levels. The irradiation-induced stress relaxation is found to be independent of the pre-stress level. 10-12% of the stress relaxation in Eurofer97 may be reached after a dose of 0.1 dpa, and after an irradiation dose of 2.7 dpa 42-47% of the original pre-stress is retained.

  1. Impacts of friction stir processing on irradiation effects in vacuum-plasma-spray coated tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Ozawa, Kazumi, E-mail: ozawa.kazumi@jaea.go.jp [Fusion Research and Development Directorate, Japan Atomic Energy Agency, 2-166 Obuchi-Omotedate, Rokkasho, Aomori 039-3212 (Japan); Tanigawa, Hiroyasu [Fusion Research and Development Directorate, Japan Atomic Energy Agency, 2-166 Obuchi-Omotedate, Rokkasho, Aomori 039-3212 (Japan); Morisada, Yoshiaki; Fujii, Hidetoshi [Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan)

    2015-10-15

    In order to examine the impacts of friction stir processing (FSP) on irradiation effects in vacuum-plasma-spray (VPS) coated tungsten (W), nano indentation hardness was evaluated of three kinds of W materials after self-ion-irradiation to 5.0–5.4 dpa at 500 and 800 °C. The VPS-FSP clearly got grains refined and isotropic compared to bulk-W and the as-VPS-W. Nano indentation hardness remains unchanged for the as-VPS-W and VPS-FSP × 2-W irradiated to 5.4 dpa at 500 °C and it decreased from 1 dpa at 800 °C, while typical irradiation induced hardening was observed for the bulk-W irradiated at 500 °C.

  2. Swelling of pure copper and copper alloys after high fluence irradiation in FFTF [Fast Flux Test Facility] at approximately 4500C

    International Nuclear Information System (INIS)

    Garner, F.A.; Brager, H.R.

    1986-03-01

    The swelling of pure copper and various copper-base alloys has been determined at 47.2 dpa after irradiation in FFTF-MOTA at ∼450 0 C. Data are also becoming available at 63.3 dpa. The alloys tend to fall into two broad categories, those that swell appreciably, sometimes with an S-shaped behavior, and those that resist swelling to very high neutron exposures. It appears that copper may have an intrinsic swelling rate of ∼1%/dpa that is often not reached due to its tendency toward saturation of swelling. The most swelling-resistant alloys examined to date are CuAl25, MZC and Cu-2.0Be

  3. Damage structure in Nimonic PE16 alloy ion bombarded to high doses and gas levels

    International Nuclear Information System (INIS)

    Farrell, K.; Packan, N.H.

    1981-01-01

    The Nimonic PE16 alloy in solution-treated-and-aged condition was bombarded simultaneously with nickel ions and α and deuteron beams at 625 0 C to doses of 80 to 313 dpa at He/dpa = 10 and D/dpa = 25. Microstructural changes consisted of the introduction of dislocations and of cavities, and the redistribuion of γ' precipitates to these defects. Cavitational swelling remained below 1%. Cavities were represented by several distinct size classes, the smaller ones believed to be gas bubbles, and some larger ones associated with preferred growth of precipitate. Formation of bubbles at grain boundaries, and large cavities at incoherent twins intensified the possibility of mechanical separation of interfaces under high-gas irradiation conditions

  4. THE MAIN QUESTION OF FIXED ASSETS

    Directory of Open Access Journals (Sweden)

    Kogan A. B.

    2015-03-01

    Full Text Available The article deals with the methods of selecting the best type of fixed assets (real investment. Explore the current situation where the investor has to compare the different-parametrical alternatives (DPA. The DPA are the fixed assets which have similar functions, but different in price, durability and periodic effects. In the general case the DPA are the investment projects which have different amounts of investment, accounting periods and net cash flow. Net present value (NPV and internal rate of return (IRR are criticized. The author describes his indicator «speed index of unit value increase» (IS. The author proves on numerical examples that the economy, the subjects of which use IS instead of NPV and IRR, has accelerated the pace of development.

  5. Picosecond absorption studies of photoinduced charge separation in polyelectrolyte bound aromatic chromophores

    Science.gov (United States)

    Shand, M. A.; Rodgers, M. A. J.; Webber, S. E.

    1991-02-01

    Picosecond absorption studies of photoinduced electron transfer between aromatic chromophores bound to polymethacrylic acid (P) and methylviologen (MV 2+ have been carried out in aqueous solution. The diphenylanthracene copolymer/viologen system at pH 2.8 shows the corresponding redox products DPA + rad and MV + rad arising from the singlet state of DPA with a forward rate constant of electron transfer of 2.6 × 10 9 s -1. At pH 9.0 the quenching of the S 1 state of DPA occurs with no charge separated products being observed. The pyrene copolymer shows no evidence of charge separated products at any pH in the range 2.8-9.0. It is proposed that the differences in the radical pair kinetics arise from differences in the degree of binding of the ground state complexes formed by the donor and acceptor species.

  6. The effect of low temperature neutron irradiation and annealing on the thermal conductivity of advanced carbon-based materials

    International Nuclear Information System (INIS)

    Barabash, V.; Mazul, I.; Latypov, R.; Pokrovsky, A.; Wu, C.H.

    2002-01-01

    Several carbon-based materials (carbon fibre composites NB 31, NS 31 and UAM-92, doped graphite RGTi-91), were irradiated at about 90 deg. C in the damage dose range 0.0021-0.13 dpa. Significant reduction of the thermal conductivity of all materials was observed (e.g. at damage dose of ∼0.13 dpa the thermal conductivity degraded up to level of ∼2-3% of the initial values). However, saturation of this effect was observed starting at a dose of ∼0.06 dpa. The effect of annealing at 250 and 350 deg. C on the recovery of thermal conductivity of NB 31 and NS 31 was studied and it was shown this annealing can significantly improve thermal conductivity (∼2.5-3 times). The data on the degradation of the thermal conductivity after additional irradiation after annealing is also reported

  7. Longitudinal variation in adolescent physical activity patterns and the emergence of tobacco use.

    Science.gov (United States)

    Audrain-McGovern, Janet; Rodriguez, Daniel; Rodgers, Kelli; Cuevas, Jocelyn; Sass, Joseph

    2012-07-01

    The objective of this investigation was to examine how variation in adolescent physical activity is related to smoking and alternative tobacco use. Adolescents (N = 1,384) completed a self-report survey every 6 months from ages 14- to 18-years old in a prospective study of health behaviors. The 8 waves of data were analyzed using General Growth Mixture Modeling (GGMM) RESULTS: GGMM identified five physical activity trajectories including stable higher (SHPA), decreased (DPA), stable regular (SRPA), curvilinear (CPA), and stable low (SLPA). Across 4 years, the likelihood of smoking was greater among adolescents in the DPA, SLPA and SRPA trajectories compared to adolescents belonging to the SHPA trajectory. Alternative tobacco use was greatest among adolescents in the DPA and SRPA trajectories. Adolescents with decreasing physical activity and even adolescents averaging an hour of physical activity a day (SRPA) are important groups to target for tobacco use prevention and intervention efforts.

  8. Effect of irradiation temperature and strain rate on the mechanical properties of V-4Cr-4Ti irradiated to low doses in fission reactors

    International Nuclear Information System (INIS)

    Zinkle, S.J.; Snead, L.L.; Rowcliffe, A.F.; Alexander, D.J.; Gibson, L.T.

    1998-01-01

    Tensile tests performed on irradiated V-(3-6%)Cr-(3-6%)Ti alloys indicate that pronounced hardening and loss of strain hardening capacity occurs for doses of 0.1--20 dpa at irradiation temperatures below ∼330 C. The amount of radiation hardening decreases rapidly for irradiation temperatures above 400 C, with a concomitant increase in strain hardening capacity. Low-dose (0.1--0.5 dpa) irradiation shifts the dynamic strain aging regime to higher temperatures and lower strain rates compared to unirradiated specimens. Very low fracture toughness values were observed in miniature disk compact specimens irradiated at 200--320 C to ∼1.5--15 dpa and tested at 200 C

  9. Gold nanoparticles having dipicolinic acid imprinted nanoshell for Bacillus cereus spores recognition

    International Nuclear Information System (INIS)

    Gueltekin, Aytac; Ersoez, Arzu; Huer, Deniz; Sarioezlue, Nalan Yilmaz; Denizli, Adil; Say, Ridvan

    2009-01-01

    Taking into account the recognition element for sensors linked to molecular imprinted polymers (MIPs), a proliferation of interest has been witnessed by those who are interested in this subject. Indeed, MIP nanoparticles are theme which recently has come to light in the literature. In this study, we have proposed a novel thiol ligand-capping method with polymerizable methacryloylamidocysteine (MAC) attached to gold nanoparticles, reminiscent of a self-assembled monolayer. Furthermore, a surface shell by synthetic host polymers based on molecular imprinting method for recognition has been reconstructed. In this method, methacryloyl iminodiacetic acid-chrome (MAIDA-Cr(III)) has been used as a new metal-chelating monomer via metal coordination-chelation interactions and dipicolinic acid (DPA) which is the main participant of Bacillus cereus spores has been used as a template. Nanoshell sensors with templates produce a cavity that is selective for DPA. The DPA can simultaneously chelate to Cr(III) metal ion and fit into the shape-selective cavity. Thus, the interaction between Cr(III) ion and free coordination spheres has an effect on the binding ability of the gold nanoparticles nanosensor. The interactions between DPA and MIP particles were studied observing fluorescence measurements. DPA addition caused significant decreases in fluorescence intensity because they induced photoluminescence emission from Au nanoparticles through the specific binding to the recognition sites of the crosslinked nanoshell polymer matrix. The binding affinity of the DPA imprinted nanoparticles has been explored by using the Langmuir and Scatchard methods and the analysis of the quenching results has been performed in terms of the Stern-Volmer equation.

  10. Heroin purchasing is income and price sensitive.

    Science.gov (United States)

    Roddy, Juliette; Steinmiller, Caren L; Greenwald, Mark K

    2011-06-01

    Semi-structured interviews were used to assess behavioral economic drug demand in heroin dependent research volunteers. Findings on drug price, competing purchases, and past 30-day income and consumption, established in a previous study, are replicated. We extended these findings by having participants indicate whether hypothetical environmental changes would alter heroin purchasing. Participants (n = 109) reported they would significantly (p purchasing amounts (DPA) from past 30-day levels (M = $60/day) if: (a) they encountered a 33% decrease in income (DPA = $34), (b) family/friends no longer paid their living expenses (DPA = $32), or (c) they faced four-fold greater likelihood of police arrest at their purchasing location (DPA = $42). Participants in higher income quartiles (who purchase more heroin) show greater DPA reductions (but would still buy more heroin) than those in lower income quartiles. For participants receiving government aid (n = 31), heroin purchasing would decrease if those subsidies were eliminated (DPA = $28). Compared to participants whose urine tested negative for cocaine (n = 31), cocaine-positive subjects (n = 32) reported more efficient heroin purchasing, that is, they live closer to their primary dealer; are more likely to have heroin delivered or walk to obtain it (and less likely to ride the bus), thus reducing purchasing time (52 vs. 31 min, respectively); and purchase more heroin per episode. These simulation results have treatment and policy implications: Daily heroin users' purchasing repertoire is very cost-effective, more so for those also using cocaine, and only potent environmental changes (income reductions or increased legal sanctions) may impact this behavior. (PsycINFO Database Record (c) 2011 APA, all rights reserved).

  11. Dual-Analyte Fluorescent Sensor Based on [5]Helicene Derivative with Super Large Stokes Shift for the Selective Determinations of Cu2+ or Zn2+ in Buffer Solutions and Its Application in a Living Cell.

    Science.gov (United States)

    Sakunkaewkasem, Siwakorn; Petdum, Anuwut; Panchan, Waraporn; Sirirak, Jitnapa; Charoenpanich, Adisri; Sooksimuang, Thanasat; Wanichacheva, Nantanit

    2018-05-10

    A new fluorescent sensor, M201-DPA, based on [5]helicene derivative was utilized as dual-analyte sensor for determination of Cu 2+ or Zn 2+ in different media and different emission wavelengths. The sensor could provide selective and bifunctional determination of Cu 2+ in HEPES buffer containing Triton-X100 and Zn 2+ in Tris buffer/methanol without interference from each other and other ions. In HEPES buffer, M201-DPA demonstrated the selective ON-OFF fluorescence quenching at 524 nm toward Cu 2+ . On the other hand, in Tris buffer/methanol, M201-DPA showed the selective OFF-ON fluorescence enhancement upon the addition of Zn 2+ , which was specified by the hypsochromic shift at 448 nm. Additionally, M201-DPA showed extremely large Stokes shifts up to ∼150 nm. By controlling the concentration of Zn 2+ and Cu 2+ in a living cell, the imaging of a HepG2 cellular system was performed, in which the fluorescence of M201-DPA in the blue channel was decreased upon addition of Cu 2+ and was enhanced in UV channel upon addition of Zn 2+ . The detection limits of M201-DPA for Cu 2+ and Zn 2+ in buffer solutions were 5.6 and 3.8 ppb, respectively. Importantly, the Cu 2+ and Zn 2+ detection limits of the developed sensors were significantly lower than permitted Cu 2+ and Zn 2+ concentrations in drinking water as established by the U.S. EPA and WHO.

  12. PET molecular imaging of peripheral and central inflammatory processes targeting the TSPO 18 kDa

    International Nuclear Information System (INIS)

    Bernards, Nicholas

    2014-01-01

    The purpose of this study was to determine the in vivo potential of the TSPO 18 kDa as a bio-marker of inflammation, with the use of its radioligand [ 18 F]DPA-714, to non-invasively quantify the inflammatory state within the scope of various pathologies. Multiple animal models of various inflammatory diseases, to include: inflammatory bowel disease, neuro-inflammation, and septic shock, were developed and put in place by adapted measures. The animals well-being and the subsequent inflammation was evaluated. The inflammatory state was measured using quantitative PET imaging with the TSPO radioligand [ 18 F]DPA-714 and correlated to the expression of conventional inflammatory markers using microscopy. Based on the observed data, we were able to distinguish control groups from treated groups when using [ 18 F]DPA-714. This TSPO radioligand permitted us to quantify the inflammatory level and to observe evolutionary changes in the inflammatory state of the disease in multiple models. The PET results, using the [ 18 F]DPA-714 signal was correlated with an increased TSPO expression at cellular level. Results indicate that [ 18 F]DPA-714 is a suitable tracer for studying inflammation of multiple diseases. [ 18 F]DPA-714 could be a good molecular probe to non-invasively evaluate the level and localization of inflammation. Moreover, in vivo imaging using this TSPO ligand is potentially a powerful tool to stage and certainly to follow the evolution and therapeutic efficiency at molecular level in inflammatory diseases. (author) [fr

  13. A low molecular weight zinc{sup 2+}-dipicolylamine-based probe detects apoptosis during tumour treatment better than an annexin V-based probe

    Energy Technology Data Exchange (ETDEWEB)

    Palmowski, Karin [RWTH-Aachen University, Department of Experimental Molecular Imaging, Aachen (Germany); University of Heidelberg, Department of Pneumology, Thoraxklinik Heidelberg, Heidelberg (Germany); Rix, Anne; Lederle, Wiltrud; Kiessling, Fabian [RWTH-Aachen University, Department of Experimental Molecular Imaging, Aachen (Germany); Behrendt, Florian F. [RWTH-Aachen University, Department of Nuclear Medicine, Aachen (Germany); Mottaghy, Felix M. [RWTH-Aachen University, Department of Nuclear Medicine, Aachen (Germany); Maastricht University Medical Center, Department of Nuclear Medicine, Maastricht (Netherlands); Gray, Brian D. [Molecular Targeting Technologies, Inc., West Chester, PA (United States); Pak, Koon Y. [University Medical Center Heidelberg, Academic Radiology Baden-Baden, Diagnostic and Interventional Radiology, Heidelberg (Germany); Palmowski, Moritz [RWTH-Aachen University, Department of Experimental Molecular Imaging, Aachen (Germany); RWTH-Aachen University, Department of Nuclear Medicine, Aachen (Germany); University Medical Center Heidelberg, Academic Radiology Baden-Baden, Diagnostic and Interventional Radiology, Heidelberg (Germany)

    2014-02-15

    Molecular imaging of apoptosis is frequently discussed for monitoring cancer therapies. Here, we compare the low molecular weight phosphatidylserine-targeting ligand zinc{sup 2+}-dipicolylamine (Zn{sup 2+}-DPA) with the established but reasonably larger protein annexin V. Molecular apoptosis imaging with the fluorescently labelled probes annexin V (750 nm, 36 kDa) and Zn{sup 2+}-DPA (794 nm, 1.84 kDa) was performed in tumour-bearing mice (A431). Three animal groups were investigated: untreated controls and treated tumours after 1 or 4 days of anti-angiogenic therapy (SU11248). Additionally, μPET with {sup 18} F-FDG was performed. Imaging data were displayed as tumour-to-muscle ratio (TMR) and validated by quantitative immunohistochemistry. Compared with untreated control tumours, TUNEL staining indicated significant apoptosis after 1 day (P < 0.05) and 4 days (P < 0.01) of treatment. Concordantly, Zn{sup 2+}-DPA uptake increased significantly after 1 day (P < 0.05) and 4 days (P < 0.01). Surprisingly, annexin V failed to detect significant differences between control and treated animals. Contrary to the increasing uptake of Zn{sup 2+}-DPA, {sup 18} F-FDG tumour uptake decreased significantly at days 1 (P < 0.05) and 4 (P < 0.01). Increase in apoptosis during anti-angiogenic therapy was detected significantly better with the low molecular weight probe Zn{sup 2+}-DPA than with the annexin V-based probe. Additionally, significant treatment effects were detectable as early using Zn{sup 2+}-DPA as with measurements of the glucose metabolism using {sup 18} F-FDG. (orig.)

  14. Dorsalis pedis arterial pressure is lower than noninvasive arm blood pressure in normotensive patients under sevoflurane anesthesia.

    Science.gov (United States)

    Chen, Yan; Wang, Enqin; Zhu, Yuan; Li, Yongshuai; Lu, Kaizhi

    2016-02-01

    It is widely known that blood pressure (BP) in the lower extremity is higher than in the upper extremity. However, whether this phenomenon remains the same during general anesthesia is still unclear. This study aims to investigate the difference between invasive dorsalis pedis artery (DPA) pressure and the most commonly used noninvasive arm pressure during sevoflurane anesthesia. A total of 50 normotensive Chinese patients were enrolled in this observational study. Invasive DPA pressure, noninvasive arm pressure, and systemic vascular resistance index were assessed simultaneously. BP data during the entire surgery were analyzed through a Bland-Altman plot for repeated measures. The concordance of BP variation in the DPA and the arm was analyzed using four-quadrant plots and linear regression. The time-dependent changes in BP and the systemic vascular resistance index were also evaluated. Data from 46 effective cases were analyzed. Bias (95% limits of agreement) was -7.40 mmHg (-20.36 to +5.57 mmHg) for mean blood pressure, +3.54 mmHg (-20.32 to +27.41 mmHg) for systolic blood pressure, and -10.20 mmHg (-23.66 to +3.26 mmHg) for diastolic blood pressure, respectively. The concordance of BP variation at the two measurement sites was clinically acceptable. DPA pressure and vascular resistance in the lower limb decreased gradually during surgery. DPA pressure tends to be lower than arm pressure under sevoflurane anesthesia, especially the mean blood pressure and the diastolic blood pressure. Hence, noninvasive arm BP monitoring is recommend to be retained when invasive BP is measured at the DPA, so as to allow clinicians to comprehensively evaluate the BP condition of the patients and make appropriate therapeutic decisions.

  15. Synthesis of new molecular probes radiolabelled with fluorine-18 for imaging neuro-inflammation with Positon Emission Tomography

    International Nuclear Information System (INIS)

    Medran-Navarrete, Vincent

    2014-01-01

    The work presented in this manuscript aims to describe the synthesis of new ligands of the translocation protein 18 kDa (TSPO), their in vitro evaluation and, for the most promising candidates, their isotopic radiolabelling with the short-lived positron emitter fluorine-18 (t 1/2 : 109.8 minutes). The ultimate goal of this work consists in developing new molecular probes, or bio-markers, for imaging neuro-inflammation in a non-invasive and atraumatic manor using Positron Emission Tomography (PET). Neuro-inflammatory processes have been identified in Alzheimer and Parkinson diseases, MS and various psychiatric pathologies. The radioligand of choice for imaging TSPO is currently [ 18 F]DPA-714, a pyr-azolo[1,5-a]pyrimidine radiolabelled with fluorine-18 which has been recently prepared in our laboratories. However, [ 18 F]DPA-714 undergoes a rapid in vivo loss of the radioactive fluorine by cleavage of the fluoro-alkoxy chain as demonstrated in metabolic studies. Therefore, my PhD project aimed to design and develop new structurally related analogues of DPA-714 where the linkage between the main backbone and the fluorine-18 would be reinforced. To this extent, nineteen compounds were prepared and their affinity towards the TSPO was evaluated. Two promising candidates, coded DPA-C5yne and CfO-DPA-714, were radiolabelled with fluorine-18 with good radiochemical yields (20-30 %) and high specific radioactivities (50-90 GBq/μmol). These radioligands were also evaluated by PET imaging at the preclinical stage and displayed equivalent or slightly improved results when compared to [ 18 F]DPA- 714. (author) [fr

  16. Fluorescent zinc sensor with minimized proton-induced interferences: photophysical mechanism for fluorescence turn-on response and detection of endogenous free zinc ions.

    Science.gov (United States)

    Kwon, Ji Eon; Lee, Sumin; You, Youngmin; Baek, Kyung-Hwa; Ohkubo, Kei; Cho, Jaeheung; Fukuzumi, Shunichi; Shin, Injae; Park, Soo Young; Nam, Wonwoo

    2012-08-20

    A new fluorescent zinc sensor (HNBO-DPA) consisting of 2-(2'-hydroxy-3'-naphthyl)benzoxazole (HNBO) chromophore and a di(2-picolyl)amine (DPA) metal chelator has been prepared and examined for zinc bioimaging. The probe exhibits zinc-induced fluorescence turn-on without any spectral shifts. Its crystal structure reveals that HNBO-DPA binds a zinc ion in a pentacoordinative fashion through the DPA and HNBO moieties. Steady-state photophysical studies establish zinc-induced deprotonation of the HNBO group. Nanosecond and femtosecond laser flash photolysis and electrochemical measurements provide evidence for zinc-induced modulation of photoinduced electron transfer (PeT) from DPA to HNBO. Thus, the zinc-responsive fluorescence turn-on is attributed to suppression of PeT exerted by deprotonation of HNBO and occupation of the electron pair of DPA, a conclusion that is further supported by density functional theory and time-dependent density functional theory (DFT/TD-DFT) calculations. Under physiological conditions (pH 7.0), the probe displays a 44-fold fluorescence turn-on in response to zinc ions with a K(d) value of 12 pM. The fluorescent response of the probe to zinc ions is conserved over a broad pH range with its excellent selectivity for zinc ions among biologically relevant metal ions. In particular, its sensing ability is not altered by divalent transition metal ions such as Fe(II), Cu(II), Cd(II), and Hg(II). Cell experiments using HNBO-DPA show its suitability for monitoring intracellular zinc ions. We have also demonstrated applicability of the probe to visualize intact zinc ions released from cells that undergo apoptosis. More interestingly, zinc-rich pools in zebrafish embryos are traced with HNBO-DPA during early developmental stages. The results obtained from the in vitro and in vivo imaging studies demonstrate the practical usefulness of the probe to detect zinc ions.

  17. Effect of Ar9+ irradiation on Zr-1Nb-1Sn-0.1Fe alloy characterized by Grazing Incidence X-ray diffraction technique

    Science.gov (United States)

    Dutta, Argha; Das, Kalipada; Gayathri, N.; Menon, Ranjini; Nabhiraj, P. Y.; Mukherjee, Paramita

    2018-03-01

    The microstructural parameters such as domain size and microstrain have been estimated from Grazing Incidence X-ray Diffraction (GIXRD) data for Ar9+ irradiated Zr-1Nb-1Sn-0.1Fe sample as a function of dpa (dose). Detail studies using X-ray Diffraction Line Profile Analysis (XRDLPA) from GIXRD data has been carried out to characterize the microstructural parameters like domain size and microstrain. The reorientation of the grains due to effect of irradiation at high dpa (dose) has been qualitatively assessed by the texture parameter P(hkl).

  18. Swelling variability of reference steels in HVEM studies

    International Nuclear Information System (INIS)

    Garner, F.A.; Mastel, B.

    1975-09-01

    A series of low-fluence electron irradiation experiments (0-15 dpa) were conducted on 316 stainless steels to explore the effects of the following variables: heat variations, FTR duct vs tubes, fabrication, annealing, Si content. Conclusions: the swelling rate became constant (max 1.3 percent/dpa) in all irradiations after an incubation period, which is variable. There is no difference in the steady-state swelling rate between various FTR heats, for annealing temperature variations, or for variation of Si content from 0.4 to 2 percent

  19. EURAC: the JRC proposal for an European fusion reactor materials test and development facility

    International Nuclear Information System (INIS)

    Kley, W.; Bishop, G.R.

    1986-01-01

    For the last 7 years we examined the use of a Spallation Neutron Source (SNS) as an altenative European Option to FMIT. For an optimized spallation neutron source design we find now for the same beam power the following design parameters: - Linear Accelerator: 600 MeV, 6 m-A-proton beam on liquid lead target - irradiation parameters: 320 dpa/year in 20 cm 3 or 274 dpa/year in 31.5 cm 3 6 -1 sec -1 in order to simulate the Pulsed Mode of Tokamak Power Reactors. The deflected beam can be used for other experiments

  20. DNA polymorphism of HLA class II genes in primary biliary cirrhosis

    DEFF Research Database (Denmark)

    Morling, Niels; Dalhoff, K; Fugger, L

    1992-01-01

    We investigated the DNA restriction fragment length polymorphism of the major histocompatibility complex class II genes: HLA-DRB, -DQA, -DQB, DPA, -DPB, the serologically defined HLA-A, B, C, DR antigens, and the primed lymphocyte typing defined HLA-DP antigens in 23 Danish patients with primary...... than 0.05, 'corrected' P greater than 0.05). No DNA fragments specific for DRB1*0301 (DR3) could be identified. The frequencies in PBC of other genetic markers including DRw8, DRB1*08, HLA-DP antigens, DPA, and DPB genes did not differ significantly from those in controls. The associations between PBC...

  1. A novel aggregation induced emission active cyclometalated Ir(III) complex as a luminescent probe for detection of copper(II) ion in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Wei; Yan, Liqiang; Tian, Wenwen; Cui, Xia; Qi, Zhengjian, E-mail: qizhengjian@seu.edu.cn; Sun, Yueming, E-mail: sun@seu.edu.cn

    2016-09-15

    We report the synthesis and characterization of a novel aggregation induced emission (AIE) active cyclometalated Ir(III) complex, namely [Ir(dfppy){sub 2}(phen-DPA)]PF{sub 6}, where dfppy and phen-DPA represent 2-(2,4-difluorophenyl)pyridine and 2-(bis(pyridin-2-ylmethyl)amino)-N-(1,10-phenanthrolin-5-yl)acetamide, respectively. The complex showed remarkable selectivity for copper(II) in aqueous solution over other competitive ions. Furthermore, this sensor showed a rapid and reversible response to copper(II) in aqueous solution with a detection limit of 65 nM.

  2. A comparison of microstructures in copper irradiated with fission, fusion, and spallation neutrons

    International Nuclear Information System (INIS)

    Muroga, T.; Heinisch, H.L.; Sommer, W.F.; Ferguson, P.D.

    1992-01-01

    The objective of this work is to investigate the effects of the neutron energy spectrum in low dose irradiations on the microstructure and mechanical properties of metals. The microstructures of pure copper irradiated to low doses at 36-90 C with spallation neutrons, fusion neutrons and fission neutrons are compared. The defect cluster densities for the spallation and fusion neutrons are very similar when compared on the basis of displacements per atom (dpa). In both cases, the density increases in proportion to the square root of the dpa. The difference in defect density between fusion neutrons and fission neutrons corresponds with differences observed in data on yield stress changes

  3. Void swelling behaviour of austenitic stainless steel during electron irradiation

    International Nuclear Information System (INIS)

    Sheng Zhongqi; Xiao Hong; Peng Feng; Ti Zhongxin

    1994-04-01

    The irradiation swelling behaviour of 00Cr17Ni14Mo2 austenitic stainless steel (AISI 316L) was investigated by means of high voltage electron microscope. Results showed that in solution annealed condition almost no swelling incubation period existed, and the swelling shifted from the transition period to the steady-state one when the displacement damage was around 40 dpa. In cold rolled condition there was evidently incubation period, and when the displacement damage was up to 84 dpa the swelling still remained in the transition period. The average size and density of voids in both conditions were measured, and the factors, which influenced the void swelling, were discussed. (3 figs.)

  4. Nucleonic calculations for possible irradiation experiments in SAPHIR

    International Nuclear Information System (INIS)

    Caro, M.; Pelloni, S.

    1990-01-01

    Accurate two-dimensional calculations show that a 'neutronic environment' exists in the SAPHIR reactor at the Paul Scherrer Institute (PSI) to simulate the inner surface of a given trepan of the Gundremmingen reactor. Neutron fluences and DPA rates were calculated at two positions in SAPHIR using the modern codes and nuclear data (from JEF-1). A particular region of the reactor can be found in which fluences and DPA rates agree well within a few percent with the Gundremmingen reference case. (author) 13 figs., 4 tabs., 18 refs

  5. Proteasome activity related with the daily physical activity of COPD patients

    Directory of Open Access Journals (Sweden)

    Lee KY

    2017-05-01

    Full Text Available Kang-Yun Lee,1,2,* Tzu-Tao Chen,1,* Ling-Ling Chiang,1,3 Hsiao-Chi Chuang,1,3 Po-Hao Feng,1,2 Wen-Te Liu,1–3 Kuan-Yuan Chen,1 Shu-Chuan Ho1,3 1Division of Pulmonary Medicine, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, 2Division of Pulmonary Medicine, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, 3School of Respiratory Therapy, College of Medicine, Taipei Medical University, Taipei, Taiwan *These authors contributed equally to this work Background: COPD is a debilitating disease that affects patients’ daily lives. One’s daily physical activity (DPA decreases due to multifactorial causes, and this decrease is correlated with a poor prognosis in COPD patients. Muscle wasting may at least be partly due to increased activity of the ubiquitin proteasome pathway and apoptosis.Methods: This study investigated the relationships among DPA, circulating proteasome activity, and protein carbonyl in COPD patients and healthy subjects (HSs. This study included 57 participants (42 patients and 15 healthy subjects. Ambulatory DPA was measured using actigraphy, and oxygen saturation was measured with a pulse oximeter.Results: COPD patients had lower DPA, lower 6 min walking distance (6MWD, lower delta saturation pulse oxygenation (SpO2 during the 6MWT, and lower delta SpO2 during DPA than HSs. COPD patients had higher proteasome activity and protein carbonyl than HSs. Circulating proteasome activity was significantly negatively correlated with DPA (r=−0.568, P<0.05 in COPD patients, whereas delta SpO2 during the 6MWT was significantly positively correlated with proteasome activity (r=0.685, P<0.05 in HSs. Protein carbonyl was significantly negatively correlated with the body mass index (r=−0.318, P<0.05, mid-arm circumference (r=0.350, P<0.05, calf circumference (r=0.322, P<0.05, forced expiratory volume in the first second (r=−0.441, P<0

  6. Response of solute and precipitation-strengthened copper alloys at high neutron exposure

    International Nuclear Information System (INIS)

    Garner, F.A.; Hamilton, M.L.; Shikama, T.; Edwards, D.J.; Newkirk, J.W.

    1991-11-01

    A variety of solute and precipitation strengthened copper base alloys have been irradiated to neutron-induced displacement levels of 34 to 150 dpa at 415 degrees C and 32 dpa at 529 degrees C in the Fast Flux Test Facility to assess their potential for high heat flux applications in fusion reactors. Several MZC-type alloys appear to offer the most promise for further study. For low fluence applications CuBeNi and spinodally strengthened CuNiTi alloys may also be suitable. Although Cu-2Be resists swelling, it is not recommended for fusion reactor applications because of its low conductivity

  7. Response of solute and precipitation-strengthened copper alloys at high neutron exposure

    Energy Technology Data Exchange (ETDEWEB)

    Garner, F.A.; Hamilton, M.L. [Pacific Northwest Lab., Richland, WA (United States); Shikama, T. [Tohoku Univ., Oarai Branch (Japan); Edwards, D.J.; Newkirk, J.W. [Missouri Univ., Rolla, MO (United States)

    1991-11-01

    A variety of solute and precipitation strengthened copper base alloys have been irradiated to neutron-induced displacement levels of 34 to 150 dpa at 415{degrees}C and 32 dpa at 529{degrees}C in the Fast Flux Test Facility to assess their potential for high heat flux applications in fusion reactors. Several MZC-type alloys appear to offer the most promise for further study. For low fluence applications CuBeNi and spinodally strengthened CuNiTi alloys may also be suitable. Although Cu-2Be resists swelling, it is not recommended for fusion reactor applications because of its low conductivity.

  8. Charpy impact test results of ferritic alloys from the HFIR[High Flux Isotope Reactor]-MFE-RB2 test

    International Nuclear Information System (INIS)

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

    1987-03-01

    Miniature Charpy specimens of HT-9 in base metal, weld metal and heat affected zone (HAZ) metal conditions, and 9Cr-1Mo in base metal and weld metal conditions have been tested following irradiation in HFIR-MFE-RB2 at 55 0 C to ≅10 dpa. All specimen conditions have degraded properties (both DBTT and USE) in comparison with specimens irradiated to lower dose. 9Cr-Mo degraded more than HT-9 and weld metal performed worse than base metal which performed worse than HAZ material. Property degradation was approximately linear as a function of dose, indicating that degradation response had not saturated by 10 dpa

  9. 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

  10. (n-3) fatty acids and cardiovascular health: are effects of EPA and DHA shared or complementary?

    Science.gov (United States)

    Mozaffarian, Dariush; Wu, Jason H Y

    2012-03-01

    Considerable research supports cardiovascular benefits of consuming omega-3 PUFA, also known as (n-3) PUFA, from fish or fish oil. Whether individual long-chain (n-3) PUFA have shared or complementary effects is not well established. We reviewed evidence for dietary and endogenous sources and cardiovascular effects on biologic pathways, physiologic risk factors, and clinical endpoints of EPA [20:5(n-3)], docosapentaenoic acid [DPA, 22:5(n-3)], and DHA [22:6(n-3)]. DHA requires direct dietary consumption, with little synthesis from or retroconversion to DPA or EPA. Whereas EPA is also largely derived from direct consumption, EPA can also be synthesized in small amounts from plant (n-3) precursors, especially stearidonic acid. In contrast, DPA appears principally derived from endogenous elongation from EPA, and DPA can also undergo retroconversion back to EPA. In experimental and animal models, both EPA and DHA modulate several relevant biologic pathways, with evidence for some differential benefits. In humans, both fatty acids lower TG levels and, based on more limited studies, favorably affect cardiac diastolic filling, arterial compliance, and some metrics of inflammation and oxidative stress. All three (n-3) PUFA reduce ex vivo platelet aggregation and DHA also modestly increases LDL and HDL particle size; the clinical relevance of such findings is uncertain. Combined EPA+DHA or DPA+DHA levels are associated with lower risk of fatal cardiac events and DHA with lower risk of atrial fibrillation, suggesting direct or indirect benefits of DHA for cardiac arrhythmias (although not excluding similar benefits of EPA or DPA). Conversely, EPA and DPA, but not DHA, are associated with lower risk of nonfatal cardiovascular endpoints in some studies, and purified EPA reduced risk of nonfatal coronary syndromes in one large clinical trial. Overall, for many cardiovascular pathways and outcomes, identified studies of individual (n-3) PUFA were relatively limited, especially

  11. (n-3) Fatty Acids and Cardiovascular Health: Are Effects of EPA and DHA Shared or Complementary?123

    Science.gov (United States)

    Mozaffarian, Dariush; Wu, Jason H. Y.

    2012-01-01

    Considerable research supports cardiovascular benefits of consuming omega-3 PUFA, also known as (n-3) PUFA, from fish or fish oil. Whether individual long-chain (n-3) PUFA have shared or complementary effects is not well established. We reviewed evidence for dietary and endogenous sources and cardiovascular effects on biologic pathways, physiologic risk factors, and clinical endpoints of EPA [20:5(n-3)], docosapentaenoic acid [DPA, 22:5(n-3)], and DHA [22:6(n-3)]. DHA requires direct dietary consumption, with little synthesis from or retroconversion to DPA or EPA. Whereas EPA is also largely derived from direct consumption, EPA can also be synthesized in small amounts from plant (n-3) precursors, especially stearidonic acid. In contrast, DPA appears principally derived from endogenous elongation from EPA, and DPA can also undergo retroconversion back to EPA. In experimental and animal models, both EPA and DHA modulate several relevant biologic pathways, with evidence for some differential benefits. In humans, both fatty acids lower TG levels and, based on more limited studies, favorably affect cardiac diastolic filling, arterial compliance, and some metrics of inflammation and oxidative stress. All three (n-3) PUFA reduce ex vivo platelet aggregation and DHA also modestly increases LDL and HDL particle size; the clinical relevance of such findings is uncertain. Combined EPA+DHA or DPA+DHA levels are associated with lower risk of fatal cardiac events and DHA with lower risk of atrial fibrillation, suggesting direct or indirect benefits of DHA for cardiac arrhythmias (although not excluding similar benefits of EPA or DPA). Conversely, EPA and DPA, but not DHA, are associated with lower risk of nonfatal cardiovascular endpoints in some studies, and purified EPA reduced risk of nonfatal coronary syndromes in one large clinical trial. Overall, for many cardiovascular pathways and outcomes, identified studies of individual (n-3) PUFA were relatively limited, especially

  12. Influence of helium generation rate and temperature history on mechanical properties of model Fe-Cr-Ni alloys irradiated in FFTF at relatively low displacement rates

    International Nuclear Information System (INIS)

    Hamilton, M.L.; Garner, F.A.; Edwards, D.J.

    1993-01-01

    In agreement with earlier studies conducted at higher displacement rates, evolution of mechanical properties of model Fe-Cr-Ni alloys irradiated at lower displacement rates in the 59 Ni isotopic doping experiment does not appear to be strongly affected by large differences in helium generation rate. This insensitivity to helium/dpa ratio is exhibited during both isothermal and non-isothermal irradiation. The overall behavior of the model alloys used in this study is dominated by the tendency to converge to a saturation strength level that is independent of thermomechanical starting state and helium/dpa ratio, but which is dependent on irradiation temperature and alloy composition

  13. Application of uncertainty analysis in conceptual fusion reactor design

    International Nuclear Information System (INIS)

    Wu, T.; Maynard, C.W.

    1979-01-01

    The theories of sensitivity and uncertainty analysis are described and applied to a new conceptual tokamak fusion reactor design--NUWMAK. The responses investigated in this study include the tritium breeding ratio, first wall Ti dpa and gas productions, nuclear heating in the blanket, energy leakage to the magnet, and the dpa rate in the superconducting magnet aluminum stabilizer. The sensitivities and uncertainties of these responses are calculated. The cost/benefit feature of proposed integral measurements is also studied through the uncertainty reductions of these responses

  14. Nuclear medicine and densitometry

    International Nuclear Information System (INIS)

    Mazess, R.B.; Wahner, H.M.

    1988-01-01

    Several reports and books over the past decade have summarized bone measurement methods. This chapter serves as an update on those with particular reference to nuclear medicine approaches to bone density and skeletal uptake. Bone densitometry approaches include singe-photon absorptiometry(SPA) and dual-photon absortiometry neutron activation (DPA) of calcium, Compton scattering, ultrasound measurements and uptake of diphosphonates. Of these only SPA and DPA are used clinically; the other methods are largely experimental or investigational. Radiographic morphometry, radiographic indices, and X-ray QCT are dealt with

  15. Characterization of BOR-60 Irradiated 14YWT-NFA1 Tubes

    Energy Technology Data Exchange (ETDEWEB)

    Saleh, Tarik A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Maloy, Stuart Andrew [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Aydogan, Eda [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Quintana, Matthew Estevan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Romero, Tobias J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-15

    Tubes of FCRD 14YWT-NFA1 Alloy were placed in the BOR-60 reactor and irradiated under a fast flux neutron environment to two conditions: 7 dpa at 360-370 °C and 6 dpa at 385-430 °C. Small sections of the tube were cut and sent to UC Berkeley for nanohardness testing and focused ion beam (FIB) milling of TEM specimens. FIB specimens were sent back to LANL for final FIB milling and TEM imaging. Hardness data and TEM images are presented in this report. This is the first fast reactor neutron irradiated information on the 14YWT-NFA1 alloy.

  16. Pramana – Journal of Physics | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics. G PANDIKUMAR. Articles written in Pramana – Journal of Physics. Volume 90 Issue 4 April 2018 pp 46 Research Article. Neutron radiation damage studies in the structural materials of a 500 MWe fast breeder reactor using DPA cross-sections from ENDF/B-VII.1.

  17. Towards a reduced activation structural materials database for fusion DEMO reactors

    International Nuclear Information System (INIS)

    Moeslang, A.; Diegele, E.; Laesser, R.; Klimiankou, M.; Lindau, R.; Materna-Morris, E.; Rieth, M.; Lucon, E.; Petersen, C.; Schneider, H.-C.; Pippan, R.; Rensman, J.W.; Schaaf, B. van der; Tavassoli, F.

    2005-01-01

    The development of First Wall, Blanket and Divertor materials which are capable of withstanding many years the high neutron and heat fluxes, is a critical path to fusion power. Therefore, the timely availability of a sound materials database has become an indispensable element in international fusion road maps. In order to provide materials design data for short term needs of ITER Test Blanket Modules and for a DEMOnstration fusion reactor, a wealth of R and D results on the European reduced activation ferritic-martensitic steel EUROFER, and on oxide dispersion strengthened variants are being characterized, mainly in the temperature window 250-650 deg. C. The characterisation includes irradiations up to 15 dpa in the mixed spectrum reactor HFR and up to 75 dpa in the fast breeder reactor BOR60. Industrial EUROFER-batches of 3.5 and 7.5 tons have been produced with a variety of semi-finished, quality-assured product forms. To increase thermal efficiency of blankets, high temperature resistant SiC f /SiC channel inserts for liquid metal coolant tubes are also developed. Regarding radiation damage resistance, a broad based reactor irradiation programs counts several steps from ≤5dpa (ITER TBMs) up to 75 dpa (DEMO). For the European divertor designers, a materials data base is presently being set up for pure W and W alloys, and related reactor irradiations are foreseen with temperatures from 650-1000 deg. C. (author)

  18. High temperature tensile testing of modified 9Cr-1Mo after irradiation with high energy protons

    International Nuclear Information System (INIS)

    Toloczko, M.B.; Hamilton, M.L.; Maloy, S.A.

    2003-01-01

    This study examines the effect of tensile test temperatures ranging from 50 to 600 deg. C on the tensile properties of a modified 9Cr-1Mo ferritic steel after high energy proton irradiation at about 35-67 deg. C to doses from 1 to 3 dpa and 9 dpa. For the specimens irradiated to doses between 1 and 3 dpa, it was observed that the yield strength and ultimate strength decreased monotonically as a function of tensile test temperature, whereas the uniform elongation (UE) remained at approximately 1% for tensile test temperatures up to 250 deg. C and then increased for tensile test temperatures up to and including 500 deg. C. At 600 deg. C, the UE was observed to be less than the values at 400 and 500 deg. C. UE of the irradiated material tensile tested at 400-600 deg. C was observed to be greater than the values for the unirradiated material at the same temperatures. Tensile tests on the 9 dpa specimens followed similar trends

  19. A Realistic Digital Deteriorating Patient to Foster Emergency Decision-Making Skills in Medical Students

    DEFF Research Database (Denmark)

    Blanchard, Emmanuel G.; Wiseman, Jeffrey; Naismith, Laura

    2012-01-01

    and effective in improving student decision making, DPA is difficult to carry out since it requires students and medical instructors, all busy people, to be available at the same time and location. The present paper describes the “Digital” Deteriorating Patient Activity (DDPA), an agent-based tutoring system...

  20. Total synthesis of 4-F3t-neuroprostane and its 4-epimer

    Czech Academy of Sciences Publication Activity Database

    Auvinet, A. L.; Eignerová, Barbara; Guy, A.; Kotora, Martin; Durand, T.

    2009-01-01

    Roč. 50, č. 13 (2009), s. 1498-1500 ISSN 0040-4039 R&D Projects: GA MŠk 1M0508 Institutional research plan: CEZ:AV0Z40550506 Keywords : DPA * oxidative stress * neuroprostane * total synthesis Subject RIV: CC - Organic Chemistry Impact factor: 2.660, year: 2009

  1. Comparison of bone densitometry methods in healthy and osteoporotic women

    International Nuclear Information System (INIS)

    Reinbold, W.D.; Dinkel, E.; Genant, H.K.

    1988-01-01

    To compare methods of noninvasive measurement of bone mineral content, 40 healthy early postmenopausal women and 68 postmenopausal women with osteoporosis were studied. The methods included mono- and dual-energy quantitative computed tomography (QCT) and dual-photon absorptiometry (DPA) of the lumbar spine, single-photon absorptiometry (SPA) of the distal third of the radius, and combined cortical thickness (CCT) of the second metacarpal shaft. Lateral thoracolumbar radiographic studies were performed and the spinal fracture index calculated. There was good correlation between QCT and DPA methods in early postmenopausal women and moderate correlation in postmenopausal osteoporotic women. Correlations between spinal measurements (QCT or DPA) and appendicular cortical measurements (SPA or CCT) were moderate in healthy women and poor in osteoporotic women. Measurements resulting from one method were not predictive of measurements obtained by another method for individual patients. The strongest correlation with severity of vertebral fracture was provided by QCT and the weakest by SPA. There was good correlation between single- and dual-energy QCT results. Osteoporotic women and younger healthy women can be distinguished by the measurement of spinal trabecular bone density using QCT, and this method is more sensitive than the measurement of spinal integral bone by DPA or of appendicular cortical bone by SPA or CCT. (orig.) [de

  2. Bone mineral content in early-postmenopausal and postmenopausal osteoporotic women: comparison of measurement methods

    International Nuclear Information System (INIS)

    Reinbold, W.D.; Genant, H.K.; Reiser, U.J.; Harris, S.T.; Ettinger, B.

    1986-01-01

    To investigate associations among methods for noninvasive measurement of skeletal bone mass, we studied 40 healthy early postmenopausal women and 68 older postmenopausal women with osteoporosis. Methods included single- and dual-energy quantitative computed tomography (QCT) and dual-photon absorptiometry (DPA) of the lumbar spine, single-photon absorptiometry (SPA) of the distal third of the radius, and combined cortical thickness (CCT) of the second metacarpal shaft. Lateral thoracolumbar radiography was performed, and a spinal fracture index was calculated. There was good correlation between QCT and DPA methods in early postmenopausal women and modest correlation in postmenopausal osteoporotic women. Correlations between spinal measurements (QCT or DPA) and appendicular cortical measurements (SPA or CCT) were modest in healthy women and poor in osteoporotic women. Measurements resulting from one method are not predictive of those by another method for the individual patient. The strongest correlation with severity of vertebral fracture is provided by QCT; the weakest, by SPA. There was a high correlation between single- and dual-energy QCT results, indicating that errors due to vertebral fat are not substantial in these postmenopausal women. Single-energy QCT may be adequate and perhaps preferable for assessing postmenopausal women. The measurement of spinal trabecular bone density by QCT discriminates between osteoporotic women and younger healthy women with more sensitivity than measurements of spinal integral bone by DPA or of appendicular cortical bone by SPA or CCT

  3. Radiation damage simulation studies of selected austenitic and ferritic/martensitic alloys for fusion reactor structural applications

    International Nuclear Information System (INIS)

    Mazey, D.J.; Walters, G.P.; Buckley, S.N.; Bullough, R.; Hanks, W.; Bolster, D.E.J.; Sowden, B.C.; Lurcook, D.; Murphy, S.M.

    1985-03-01

    Results are given of an investigation of the radiation damage stability of selected austenitic and ferritic alloys following ion bombardment in the Harwell VEC to simulate fusion-reactor exposures up to 110 dpa at temperatures from 425 deg to 625 deg C. Gas production rates appropriate to CTR conditions were simulated using a mixed beam of (4 MeV He + 2 MeV H 2 ) in the ratio 1:4 He:H. A beam of 46 MeV Ni or 20 MeV Cr ions was used in sequence with the mixed gas beam to provide a gas/damage ratio of 13 appm He/dpa at a damage rate of approx. 1 dpa/hr. The materials were investigated using TEM and comprised three austenitic alloys: European reference 316L, 316-Ti, 316-Nb; four high-nickel alloys: Fe/25 Ni/8Cr, Inconel 625, Inconel 706 and Nimonic PE16, and four ferritic/martensitic alloys: FV 448, FV 607, CRM 12 and FI. Some data were obtained for a non-magnetic structural alloy Nonmagne-30. The swelling behaviour is reported. The overall results of the study indicate that on a comparative basis the ferritic alloys are the most swelling-resistant, whilst the high-nickel alloys have an acceptable low swelling response up to 110 dpa. The 316 alloys tested have shown an unfavourable swelling response. (author)

  4. 10 CFR 216.7 - Conflict in priority orders.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 3 2010-01-01 2010-01-01 false Conflict in priority orders. 216.7 Section 216.7 Energy... DOMESTIC ENERGY SUPPLIES § 216.7 Conflict in priority orders. If it appears that the use of assistance pursuant to DPA section 101(c) creates or threatens to create a conflict with priorities and allocation...

  5. Dual photon absorptiometry in hemodialyzed patients

    International Nuclear Information System (INIS)

    Viron, B.; Dosquet, P.; Haddoum, F.; Mignon, F.; Talbot, J.N.; Kiffel, T.; Coutris, G.; Milhaud, G.

    1988-01-01

    Dual photon absorptiometry (DPA) was performed in 25 uremic patients (mean age: 8) undergoing dialysis for 1 month to 10 years. Mean bone mineral content (BMC), expressed as a percentage of normal value, was significantly lower in hemodialyzed patients (-10 ± 17%) than in control subjects (p [fr

  6. Diversion path analysis handbook. Volume I. Methodology

    International Nuclear Information System (INIS)

    Maltese, M.D.K.; Goodwin, K.E.; Schleter, J.C.

    1976-10-01

    Diversion Path Analysis (DPA) is a procedure for analyzing internal controls of a facility in order to identify vulnerabilities to successful diversion of material by an adversary. The internal covert threat is addressed but the results are also applicable to the external overt threat. The diversion paths are identified. Complexity parameters include records alteration or falsification, multiple removals of sub-threshold quantities, collusion, and access authorization of the individual. Indicators, or data elements and information of significance to detection of unprevented theft, are identified by means of DPA. Indicator sensitivity is developed in terms of the threshold quantity, the elapsed time between removal and indication and the degree of localization of facility area and personnel given by the indicator. Evaluation of facility internal controls in light of these sensitivities defines the capability of interrupting identified adversary action sequences related to acquisition of material at fixed sites associated with the identified potential vulnerabilities. Corrective measures can, in many cases, also be prescribed for management consideration and action. DPA theory and concepts have been developing over the last several years, and initial field testing proved both the feasibility and practicality of the procedure. Follow-on implementation testing verified the ability of facility personnel to perform DPA

  7. Formation of austenite in high Cr ferritic/martensitic steels by high fluence neutron irradiation

    Science.gov (United States)

    Lu, Z.; Faulkner, R. G.; Morgan, T. S.

    2008-12-01

    High Cr ferritic/martensitic steels are leading candidates for structural components of future fusion reactors and new generation fission reactors due to their excellent swelling resistance and thermal properties. A commercial grade 12%CrMoVNb ferritic/martensitic stainless steel in the form of parent plate and off-normal weld materials was fast neutron irradiated up to 33 dpa (1.1 × 10 -6 dpa/s) at 400 °C and 28 dpa (1.7 × 10 -6 dpa/s) at 465 °C, respectively. TEM investigation shows that the fully martensitic weld metal transformed to a duplex austenite/ferrite structure due to high fluence neutron irradiation, the austenite was heavily voided (˜15 vol.%) and the ferrite was relatively void-free; whilst no austenite phases were detected in plate steel. Thermodynamic and phase equilibria software MTDATA has been employed for the first time to investigate neutron irradiation-induced phase transformations. The neutron irradiation effect is introduced by adding additional Gibbs free energy into the system. This additional energy is produced by high energy neutron irradiation and can be estimated from the increased dislocation loop density caused by irradiation. Modelling results show that neutron irradiation reduces the ferrite/austenite transformation temperature, especially for high Ni weld metal. The calculated results exhibit good agreement with experimental observation.

  8. Chemotaxonomic study of the demosponge Cinachyrella cavernosa (Lamarck)

    Digital Repository Service at National Institute of Oceanography (India)

    Wahidullah, S.; Naik, B.G.; Al-Fadhli, A.A

    previously been identified in Cinachyrella australiensis. To our knowledge, this is the first report of 4α-methyl gorgostanol from a sponge and DPA from a marine source. The probable origin and chemotaxonomic importance of some of the metabolites is discussed...

  9. Chain elongation and cyclization in type III PKS DpgA.

    Science.gov (United States)

    Wu, Hai-Chen; Li, Yi-San; Liu, Yu-Chen; Lyu, Syue-Yi; Wu, Chang-Jer; Li, Tsung-Lin

    2012-04-16

    Chain elongation and cyclization of precursors of dihydroxyphenylacetyl-CoA (DPA-CoA) catalyzed by the bacterial type III polyketide synthase DpgA were studied. Two labile intermediates, di- and tri-ketidyl-CoA (DK- and TK-CoA), were proposed and chemically synthesized. In the presence of DpgABD, each of these with [(13)C(3)]malonyl-CoA (MA-CoA) was able to form partially (13)C-enriched DPA-CoA. By NMR and MS analysis, the distribution of (13)C atoms in the partially (13)C-enriched DPA-CoA shed light on how the polyketide chain elongates and cyclizes in the DpgA-catalyzed reaction. Polyketone intermediates elongate in a manner different from that which had been believed: two molecules of DK-CoA, or one DK-CoA plus one acetoacetyl-CoA (AA-CoA), but not two molecules of AA-CoA can form one molecule of DPA-CoA. As a result, polyketidyl-CoA serves as both the starter and extender, whereas polyketone-CoA without the terminal carboxyl group can only act as an extender. The terminal carboxyl group is crucial for the cyclization that likely takes place on CoA. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Voltammetric sensor for D-penicillamine determination based on its electrocatalytic oxidation at the surface of ferrocenes modified carbon paste electrodes · Jahan-Bakhsh Raoof Reza Ojani Fereshteh Chekin · More Details Abstract Fulltext PDF. Electrocatalytic oxidation of D-penicillamine (D-PA) at the surface of ferrocene ...

  11. Effects of oversized solutes on radiation-induced segregation in austenitic stainless steels

    Science.gov (United States)

    Hackett, M. J.; Busby, J. T.; Miller, M. K.; Was, G. S.

    2009-06-01

    Zirconium or hafnium additions to austenitic stainless steels caused a reduction in grain boundary Cr depletion after proton irradiations for up to 3 dpa at 400 °C and 1 dpa at 500 °C. The predictions of a radiation-induced segregation (RIS) model were also consistent with experiments in showing greater effectiveness of Zr relative to Hf due to a larger binding energy. However, the experiments showed that the effectiveness of the solute additions disappeared above 3 dpa at 400 °C and above 1 dpa at 500 °C. The loss of solute effectiveness with increasing dose is attributed to a reduction in the amount of oversized solute from the matrix due to growth of carbide precipitates. Atom probe tomography measurements indicated a reduction in amount of oversized solute in solution as a function of irradiation dose. The observations were supported by diffusion analysis suggesting that significant solute diffusion by the vacancy flux to precipitate surfaces occurs on the time scales of proton irradiations. With a decrease in available solute in solution, improved agreement between the predictions of the RIS model and measurements were consistent with the solute-vacancy trapping process, as the mechanism for enhanced recombination and suppression of RIS.

  12. Experiment CATETO II

    International Nuclear Information System (INIS)

    Hendriks, J.A.; Freudenreich, W.E.

    1994-03-01

    In the irradiation experiment CATETO II different reduced activation (RA) steels will be irradiated up to 2.5 dpa at a temperature of 300 C. The results of the calculation of the nuclear constants, the reactivity effect, and the activity of the steel samples are presented. (orig.)

  13. Properties and mechanical behaviour of fuel cans of fast neutron reactors

    International Nuclear Information System (INIS)

    Cauvin, R.; Boutard, J.L.

    1983-06-01

    Mechanical properties of Stainless steel-316 irradiated up to 100 dpa in fast neutron reactors are examined. Microscopic phenomena involved are reviewed: precipitation, segregation, dislocations, vacancies. Influence on mechanical behaviour of materials are examined: tensile properties, creep, ductility. Consequences on reactor dimensioning are given in conclusion [fr

  14. 75 FR 52594 - Voluntary Intermodal Sealift Agreement (VISA)

    Science.gov (United States)

    2010-08-26

    ... antitrust laws in accordance with the DPA. CCAs must be submitted to the Maritime Administration for... non-participants. Participation Any U.S.-flag vessel operator organized under the laws of a state of... Incorporation and/or By Laws; Copies of loadline documents from a recognized classification society to validate...

  15. D-penicillamine-templated copper nanoparticles via ascorbic acid reduction as a mercury ion sensor.

    Science.gov (United States)

    Lin, Shu Min; Geng, Shuo; Li, Na; Li, Nian Bing; Luo, Hong Qun

    2016-05-01

    Mercury ion is one of the most hazardous metal pollutants that can cause deleterious effects on human health and the environment even at low concentrations. It is necessary to develop new mercury detection methods with high sensitivity, specificity and rapidity. In this study, a novel and green strategy for synthesizing D-penicillamine-capped copper nanoparticles (DPA-CuNPs) was successfully established by a chemical reduction method, in which D-penicillamine and ascorbic acid were used as stabilizing agent and reducing agent, respectively. The as-prepared DPA-CuNPs showed strong red fluorescence and had a large Stoke's shift (270nm). Scanning electron microscopy, transmission electron microscopy, Fourier-transform infrared spectroscopy, fluorescence spectroscopy, and ultraviolet-visible spectrophotometry were utilized to elucidate the possible fluorescence mechanism, which could be aggregation-induced emission effect. Based on the phenomenon that trace mercury ion can disperse the aggregated DPA-CuNPs, resulting in great fluorescence quench of the system, a sensitive and selective assay for mercury ion in aqueous solution with the DPA-CuNPs was developed. Under optimum conditions, this assay can be applied to the quantification of Hg(2+) in the 1.0-30μM concentration range and the detection limit (3σ/slope) is 32nM. The method was successfully applied to determine Hg(2+) in real water samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Passivation of aluminum with alkyl phosphonic acids for biochip applications

    Science.gov (United States)

    Attavar, Sachin; Diwekar, Mohit; Linford, Matthew R.; Davis, Mark A.; Blair, Steve

    2010-09-01

    Self-assembly of decylphosphonic acid (DPA) and octadecylphosphonic acid (ODPA) was studied on aluminum films using XPS, ToF-SIMS and surface wettability. Modified aluminum films were tested for passivation against silanization and subsequent oligonucleotide attachment. Passivation ratios of at least 450:1 compared to unprotected aluminum were obtained, as quantified by attachment of radio-labeled oligos.

  17. 10 CFR 216.3 - Requests for assistance.

    Science.gov (United States)

    2010-01-01

    ... DOMESTIC ENERGY SUPPLIES § 216.3 Requests for assistance. (a) Persons who believe that they perform work..., performance data (capacity, life duration, etc.), standards, acceptable tolerances in dimensions and.... (10) Any known conflicts with rated orders already issued pursuant to the DPA for supplies of the...

  18. Pramana – Journal of Physics | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Abstract. The radiation damage in the structural materials of a 500 MWe Indian prototype fast breeder reactor (PFBR) is re-assessed by computing the neutron displacement per atom (dpa) cross-sections from the recent nuclear data library evaluated by the USA,ENDF/B-VII.1, wherein revisions were taken place in the new ...

  19. Dose dependence of the microstructural evolution in neutron-irradiated austenitic stainless steel

    International Nuclear Information System (INIS)

    Zinkle, S.J.; Maziasz, P.J.; Stoller, R.E.

    1993-01-01

    Microstructural data on the evolution of the dislocation loop, cavity, and precipitate populations in neutron-irradiated austenitic stainless steels are reviewed in order to estimate the displacement damage levels needed to achieve the 'steady state' condition. The microstructural data can be conveniently divided into two temperature regimes. In the low temperature regime (below about 200 degrees C) the microstructure of austenitic stainless steel is dominated by 'black spot' defect clusters and faulted interstitial dislocation loops. The dose needed to approach saturation of the loop and defect cluster densities is generally on the order of 1 displacement per atom (dpa) in this regime. In the high temperature regime (∼300 to 700 degrees C), cavities, precipitates, loops and network dislocations are all produced during irradiation; doses in excess of 10 dpa are generally required to approach a 'steady state' microstructural condition. Due to complex interactions between the various microstructural components that form during irradiation, a secondary transient regime is typically observed in commercial stainless steels during irradiation at elevated temperatures. This slowly evolving secondary transient may extend to damage levels in excess of 50 dpa in typical 300-series stainless steels, and to >100 dpa in radiation-resistant developmental steels. The detailed evolution of any given microstructural component in the high-temperature regime is sensitive to slight variations in numerous experimental variables, including heat-to-heat composition changes and neutron spectrum

  20. Effect of minor elements on microstructure evolution in Ni alloys irradiated with neutrons

    International Nuclear Information System (INIS)

    Xu, Q.; Yoshiie, T.

    2001-01-01

    The minor elements, Si (-5.81%), Cu (7.18%), Ge (14.76%) and Sn (74.08%) were chosen to investigate the effects of volume size factor as shown in the parentheses on void swelling in neutron irradiated Ni alloys. Neutron irradiation temperature and dose were changed widely from 473 K to 703 K, and 0.001 dpa to 1 dpa, respectively. Voids were observed by transmission electron microscopy (TEM) in Ni even after a very small irradiation dose of 0.026 dpa at 573 K. With increasing dose, the number density of voids was nearly constant while void size increased. The microstructure evolution in Ni-2 at%Cu and Ni-2 at%Ge alloys was similar to that in Ni. However, in Ni-2 at%Si and Ni-2 at%Sn alloys, no voids were observed by TEM even at 703 K to 1 dpa. The minor elements, Si and Sn, play an important role for the suppression of vacancy clusters. Vacancies are annihilated by mutual recombination with interstitials in Si and Sn added alloys. (orig.)

  1. Development of High-Temperature Ferritic Alloys and Performance Prediction Methods for Advanced Fission Energy Systems

    Energy Technology Data Exchange (ETDEWEB)

    G. RObert Odette; Takuya Yamamoto

    2009-08-14

    Reports the results of a comprehensive development and analysis of a database on irradiation hardening and embrittlement of tempered martensitic steels (TMS). Alloy specific quantitative semi-empirical models were derived for the dpa dose, irradiation temperature (ti) and test (Tt) temperature of yield stress hardening (or softening) .

  2. Sensitive and selective determination of Cu2+ at D-penicillamine functionalized nano-cellulose modified pencil graphite electrode

    Science.gov (United States)

    Taheri, M.; Ahour, F.; Keshipour, S.

    2018-06-01

    A novel electrochemical sensor based on D-penicillamine anchored nano-cellulose (DPA-NC) modified pencil graphite electrode was fabricated and used for highly selective and sensitive determination of copper (II) ions in the picomolar concentration by square wave adsorptive stripping voltammetric (SWV) method. The modified electrode showed better and increased SWV response compared to the bare and NC modified electrodes which may be related to the porous structure of modifier along with formation of complex between Cu2+ ions and nitrogen or oxygen containing groups in DPA-NC. Optimization of various experimental parameters influence the performance of the sensor, were investigated. Under optimized condition, DPA-NC modified electrode was used for the analysis of Cu2+ in the concentration range from 0.2 to 50 pM, and a lower detection limit of 0.048 pM with good stability, repeatability, and selectivity. Finally, the practical applicability of DPA-NC-PGE was confirmed via measuring trace amount of Cu (II) in tap and river water samples.

  3. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    The rate of the reaction increases with increasing pH due to the deprotonation equilibria of the complex. The experimental rate law is consistent with a mechanism in which the deprotonated form [CrIII(DPA)(OX)(OH)]2− is more reactive than the conjugated acid. It is proposed that electron transfer proceeds through an ...

  4. Hardening and microstructural evolution of A533b steels irradiated with Fe ions and electrons

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, H., E-mail: watanabe@riam.kyushu-u.ac.jp [Research Institute for Applied Mechanics, Kyushu University, 6-1, Kasuga-kouenn, Kasugashi, Fukuoka, 816-8580 (Japan); Arase, S. [Interdisciplinary Graduate School of Kyushu University, 6-1, Kasuga-kouenn, Kasugashi, Fukuoka, 816-8580 (Japan); Yamamoto, T.; Wells, P. [Dept. Chemical Engineering, UCSB Engineering II, RM3357, Santa Barbara, CA, 93106-5080 (United States); Onishi, T. [Interdisciplinary Graduate School of Kyushu University, 6-1, Kasuga-kouenn, Kasugashi, Fukuoka, 816-8580 (Japan); Odette, G.R. [Dept. Chemical Engineering, UCSB Engineering II, RM3357, Santa Barbara, CA, 93106-5080 (United States)

    2016-04-01

    Radiation hardening and embrittlement of A533B steels is heavily dependent on the Cu content. In this study, to investigate the effect of copper on the microstructural evolution of these materials, A533B steels with different Cu levels were irradiated with 2.4 MeV Fe ions and 1.0 MeV electrons. Ion irradiation was performed from room temperature (RT) to 350 °C with doses up to 1 dpa. At RT and 290 °C, low dose (<0.1 dpa) hardening trend corresponded with ΔH ∝ (dpa){sup n}, with n initially approximately 0.5 and consistent with a barrier hardening mechanism, but saturating at ≈0.1 dpa. At higher dose levels, the radiation-induced hardening exhibited a strong Cu content dependence at 290 °C, but not at 350 °C. Electron irradiation using high-voltage electron microscopy revealed the growth of interstitial-type dislocation loops and enrichment of Ni, Mn, and Si in the vicinities of pre-existing dislocations at doses for which the radiation-induced hardness due to ion irradiation was prominent.

  5. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Electrocatalytic oxidation of D-penicillamine (D-PA) at the surface of ferrocene modified carbon paste electrode (FCCPE) was thoroughly investigated in aqueous solution with various pH. The performance of this modified electrode was compared with those of 2,7-bis(ferrocenyl ethyl) fluoren-9-one modified carbon paste ...

  6. Formation of Cavities at and Away from Grain Boundaries during 600 MeV Proton Irradiation

    DEFF Research Database (Denmark)

    Singh, Bachu Narain; Leffers, Torben; Green, W. V.

    1982-01-01

    High-purity aluminium (99.9999%) was irradiated with 600 MeV protons at the Swiss Institute for Nuclear Research (SIN) with a damage rate of 3,5 x 10^-6 dpa/s. Irradiation with 600 MeV protons produces helium, hydrogen, and other impurities through mutational reactions. The irradiation experiment...

  7. Mechanistic study of ruthenium (III) catalysed oxidation of L-lysine by ...

    Indian Academy of Sciences (India)

    Administrator

    MS received 15 April 2008; revised 2 July 2008. Abstract. The kinetics of Ru(III) catalysed oxidation of L-lysine by diperiodatoargentate (III) (DPA) in alkaline medium at 298 K and a constant ionic strength of 0⋅50 mol dm. –3 was studied spectrophotometri- cally. The oxidation products are aldehyde (5-aminopentanal) and ...

  8. Pramana – Journal of Physics | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Bäcklund transformation and soliton solutions in terms of the Wronskian for the Kadomtsev–Petviashvili-based system in fluid dynamics · ZHONG DU BO TIAN ... 46 Research Article. Neutron radiation damage studies in the structural materials of a 500 MWe fast breeder reactor using DPA cross-sections from ENDF/B-VII.1.

  9. The Scholarly Practitioner: Connections of Research and Practice in the Classroom

    Science.gov (United States)

    Godwin, Marcia L.; Meek, Jack W.

    2016-01-01

    This article outlines how Master of Public Administration (MPA) and Doctor of Public Administration (DPA) programs from one university in the United States approach the integration of theory, research, and practice. The article reviews the historic missions of US public administration programs that focus on the development of public service…

  10. AHP 24: A Multi-ethnic Village in Northeast Tibet - History, Ritual, and Daily Life in Chu cha

    Directory of Open Access Journals (Sweden)

    Stobs stag lha སྟོབས་སྟག་ལྷ།

    2013-09-01

    Full Text Available Multi-ethnic Chu cha Village in Mchod rten thang Township, Dpa' ris Tibetan Autonomous County, Gansu Province, China is described in terms of location; population; clothing; language; religion; history; and personal, family, and community rituals. Photographs provide additional information.

  11. Spectroscopy and viability of Bacillus subtilis spores after ultraviolet irradiation: implications for the detection of potential bacterial life on Europa.

    Science.gov (United States)

    Noell, Aaron C; Ely, Tucker; Bolser, Diana K; Darrach, Halley; Hodyss, Robert; Johnson, Paul V; Hein, Jeffrey D; Ponce, Adrian

    2015-01-01

    One of the most habitable environments in the Solar System outside of Earth may exist underneath the ice on Europa. In the near future, our best chance to look for chemical signatures of a habitable environment (or life itself) will likely be at the inhospitable icy surface. Therefore, it is important to understand the ability of organic signatures of life and life itself to persist under simulated europan surface conditions. Toward that end, this work examined the UV photolysis of Bacillus subtilis spores and their chemical marker dipicolinic acid (DPA) at temperatures and pressures relevant to Europa. In addition, inactivation curves for the spores at 100 K, 100 K covered in one micron of ice, and 298 K were measured to determine the probability for spore survival at the surface. Fourier transform infrared spectra of irradiated DPA showed a loss of carboxyl groups to CO2 as expected but unexpectedly showed significant opening of the heterocyclic ring, even for wavelengths>200 nm. Both DPA and B. subtilis spores showed identical unknown spectral bands of photoproducts after irradiation, further highlighting the importance of DPA in the photochemistry of spores. Spore survival was enhanced at 100 K by ∼5× relative to 298 K, but 99.9% of spores were still inactivated after the equivalent of ∼25 h of exposure on the europan surface.

  12. Dual-photon absorptiometry: A new method of determining bone mineral content. Pt. 1

    International Nuclear Information System (INIS)

    Buttermann, G.; Eiber, J.; Hennig, J.; Pabst, H.W.

    1988-01-01

    Cortical (neck of femur) and trabecular (L 2-4) bone mass has been determined repeatedly with DPA using 153 Gd (NOVO Lab 22 a) in 545 females and 112 males with no evidence of bone diseases. Measured 'normal' (age- and sex-related average) values for bone mineral content (BMC) differed significantly (p [de

  13. OBJECT KINETIC MONTE CARLO SIMULATIONS OF RADIATION DAMAGE ACCUMULATION IN TUNGSTEN

    Energy Technology Data Exchange (ETDEWEB)

    Nandipati, Giridhar; Setyawan, Wahyu; Roche, Kenneth J.; Kurtz, Richard J.; Wirth, Brian D.

    2016-09-01

    The objective of this work is to understand the accumulation of radiation damage created by primary knock-on atoms (PKAs) of various energies, at 300 K and for a dose rate of 10-4 dpa/s in bulk tungsten using the object kinetic Monte Carlo (OKMC) method.

  14. Positioning for vertical integration through clinics "without walls".

    Science.gov (United States)

    Johnson, B A; Schryver, D L

    1994-01-01

    Authors Bruce A. Johnson, J.D., M.P.A., and Darrell Schryver, D.P.A., offer the clinic without walls model as a transitory step to full vertical integration. They write that this model "may enable physicians to address the key issues associated with managed care and integration in a more gradual, controlled fashion.

  15. uttiyoarnab saha

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics. UTTIYOARNAB SAHA. Articles written in Pramana – Journal of Physics. Volume 90 Issue 4 April 2018 pp 46 Research Article. Neutron radiation damage studies in the structural materials of a 500 MWe fast breeder reactor using DPA cross-sections from ENDF/B-VII.1.

  16. Void swelling of proton-irradiated stainless steel at large displacement levels

    International Nuclear Information System (INIS)

    Kumar, A.; Garner, F.A.

    1982-01-01

    The purpose of this study is to determine whether saturation of void swelling in AISI 316 stainless steel can be made to occur at any level relevant to engineering design and to decide whether saturation is sensitive to irradiation variables such as helium/dpa ratio or simulation artifacts such as injected interstitials

  17. Solute segregation and void formation in ion-irradiated vanadium-base alloys

    International Nuclear Information System (INIS)

    Loomis, B.A.; Smith, D.L.

    1985-01-01

    The radiation-induced segregation of solute atoms in the V-15Cr-5Ti alloys was determined after either single- dual-, or helium implantation followed by single-ion irradiation at 725 0 C to radiation damage levels ranging from 103 to 169 dpa. Also, the effect of irradiation temperature (600-750 0 C) on the microstructure in the V-15Cr-5Ti alloy was determined after single-ion irradiation to 200 and 300 dpa. The solute segregation results for the single- and dual-ion irradiated alloy showed that the simultaneous production of irradiation damage and deposition of helium resulted in enhanced depletion of Cr solute and enrichment of Ti, C and S solute in the near-surface layers of irradiated specimens. The observations of the irradiation-damaged microstructures in V-15Cr-5Ti specimens showed an absence of voids for irradiations of the alloy at 600-750 0 C to 200 dpa and at 725 0 C to 300 dpa. The principle effect on the microstructure of these irradiations was to induce the formation of a high density of disc-like precipitates in the vicinity of grain boundaries and intrinsic precipitates and on the dislocation structure. 8 references, 4 figures

  18. Two-dimensional coordination polymer matrix for solid-phase extraction of pesticide residues from plant Cordia salicifolia.

    Science.gov (United States)

    de Carvalho, Pedro Henrique Viana; Barreto, Alysson Santos; Rodrigues, Marcelo O; Prata, Vanessa de Menezes; Alves, Péricles Barreto; de Mesquita, Maria Eliane; Alves, Severino; Navickiene, Sandro

    2009-06-01

    The 2D coordination polymer (infinity[Gd(DPA)(HDPA)]) was tested for extraction of acephate, chlorpropham, pirimicarb, bifenthrin, tetradifon, and phosalone from the medicinal plant Cordia salicifolia, whose extracts are commercialized in Brazil as diuretic, appetite suppressant, and weight loss products, using GC/MS, SIM. Considering that there are no Brazilian regulations concerning maximum permissible pesticide residue concentrations in medicinal herbs, recovery experiments were carried out (seven replicates), at two arbitrary fortification levels (0.5 and 1.0 mg/kg), resulting in recoveries in range of 20 to 107.7% and SDRSDs were between 5.6 and 29.1% for infinity[Gd(DPA)(HDPA)] sorbent. Detection and quantification limits for herb ranged from 0.10 to 0.15 mg/kg and from 0.15 to 0.25 mg/kg, respectively, for the different pesticides studied. The developed method is linear over the range assayed, 0.5-10.0 microg/mL, with correlation coefficients ranging from 0.9975 to 0.9986 for all pesticides. Comparison between infinity[Gd(DPA)(HDPA)] sorbent and conventional sorbent (neutral alumina) showed similar performance of infinity[Gd(DPA)(HDPA)] polymeric sorbent for three (bifenthrin, tetradifon, and phosalone) out of six pesticides tested.

  19. Supramolecular dendritic pi-conjugated systems: synthesis of glycinylurea functionalized pi-conjugated diphenylanthracene guests and their complexation with dendritic hosts. Part I.

    NARCIS (Netherlands)

    Precup, F.S.; Schenning, A.P.H.J.; Meijer, E.W.; Hubca, G.

    2007-01-01

    Glycinylurea functionalized p-conjugated diphenylanthracene guests (DPA guests) that bind to adamantyl urea modified dendritic hosts were synthesized and fully characterized by NMR spectroscopy (1H-NMR, 13C-NMR) and MALDI-TOF-MS. The resulting supramolecular assemblies have been investigated with

  20. DNA polymorphism of HLA class II genes in pauciarticular juvenile rheumatoid arthritis

    DEFF Research Database (Denmark)

    Morling, N; Friis, J; Fugger, L

    1991-01-01

    We investigated the DNA restriction fragment length polymorphism (RFLP) of the major histocompatibility complex (MHC) class II genes: HLA-DRB, -DQA, -DQB, DPA, and -DPB in 54 patients with pauciarticular juvenile rheumatoid arthritis (PJRA) and in healthy Danes. The frequencies of DNA fragments a...

  1. Quasi-morphine abstinence behaviour GABA-ergic mechanisms and their localization

    NARCIS (Netherlands)

    J.W. van der Laan

    1981-01-01

    textabstractDi-n-propylacetate (DPA), generally known to be an anti-epileptic drug, induces a behavioural syndrome in rats resembling morphine abstinence behaviour, which is called, therefore, quasi-morphine abstinence beh~viour. An increase in GABA-ergic activity is probably responsible for this

  2. Can flavonoid-rich chocolate modulate arterial elasticity and pathological uterine artery Doppler blood flow in pregnant women? A pilot study.

    Science.gov (United States)

    von Wowern, Emma; Olofsson, Per

    2018-09-01

    Dark chocolate has shown beneficial effects on cardiovascular health and might also modulate hypertensive complications in pregnancy and uteroplacental blood flow. Increased uteroplacental resistance is associated with systemic arterial stiffness. We aimed to investigate the short-term effect of flavonoid-rich chocolate on arterial stiffness and Doppler blood flow velocimetry indexes in pregnant women with compromised uteroplacental blood flow. Doppler blood flow velocimetry and digital pulse wave analysis (DPA) were performed in 25 women pregnant in the second and third trimesters with uterine artery (UtA) score (UAS) 3-4, before and after 3 days of ingestion of chocolate with high flavonoid and antioxidant contents. UtA pulsatility index (PI), UtA diastolic notching, UAS (semiquantitative measure of PI and notching combined), and umbilical artery PI were calculated, and DPA variables representing central and peripheral maternal arteries were recorded. Mean UtA PI (p = .049) and UAS (p = .025) significantly decreased after chocolate consumption. There were no significant changes in UtA diastolic notching or any DPA indexes of arterial stiffness/vascular tone. Chocolate may have beneficial effects on the uteroplacental circulation, but in this pilot study, we could not demonstrate effects on arterial vascular tone as assessed by DPA.

  3. In-situ measurement of the electrical conductivity of aluminum oxide in HFIR

    Energy Technology Data Exchange (ETDEWEB)

    Zinkle, S.J.; White, D.P.; Snead, L.L. [Oak Ridge National Lab., TN (United States)] [and others

    1996-10-01

    A collaborative DOE/Monbusho irradiation experiment has been completed which measured the in-situ electrical resistivity of 12 different grades of aluminum oxide during HFIR neutron irradiation at 450{degrees}C. No evidence for bulk RIED was observed following irradiation to a maximum dose of 3 dpa with an applied dc electric field of 200 V/mm.

  4. The effect of low dose rate irradiation on the swelling of 12% cold-worked 316 stainless steel

    International Nuclear Information System (INIS)

    Allen, T. R.

    1999-01-01

    In pressurized water reactors (PWRs), stainless steel components are irradiated at temperatures that may reach 400 C due to gamma heating. If large amounts of swelling (>10%) occur in these reactor internals, significant swelling related embrittlement may occur. Although fast reactor studies indicate that swelling should be insignificant at PWR temperatures, the low dose rate conditions experienced by PWR components may possibly lead to significant swelling. To address these issues, JNC and ANL have collaborated to analyze swelling in 316 stainless steel, irradiated in the EBR-II reactor at temperatures from 376-444 C, at dose rates between 4.9 x 10 -8 and 5.8 x 10 -7 dpa/s, and to doses of 56 dpa. For these irradiation conditions, the swelling decreases markedly at temperatures less than approximately 386 C, with the extrapolated swelling at 100 dpa being around 3%. For temperatures greater than 386 C, the swelling extrapolated to 100 dpa is around 9%. For a factor of two difference in dose rate, no statistically significant effect of dose rate on swelling was seen. For the range of dose rates analyzed, the swelling measurements do not support significant (>10%) swelling of 316 stainless steel in PWRs

  5. Overview of the IFMIF test cell design

    International Nuclear Information System (INIS)

    Moeslang, A.; Daum, E.; Jitsukawa, S.; Noda, K.; Viola, R.

    1996-01-01

    The Conceptual Design Activity (CDA) for the International Fusion Materials Irradiation Facility (IFMIF) has entered its second and final year, and an outline design has been developed. Initial evaluations of the potential of this high flux, high intensity D-Li source have shown that the main materials testing needs can be fulfilled. According to these needs, Vertical Test Assemblies will accommodate test modules for the high flux (0.5 liter, 20 dpa/a, 250-1000 C), the medium flux (6 liter, 1-20 dpa/a, 250-1000 C), the low flux (7.5 liter, 0.1-1 dpa/a), and the very low flux (> 100 liter, 0.01-0.1 dpa/a) regions. Detailed test matrices have been defined for the high and medium flux regions, showing that on the basis of small specimen test technologies, a database for an engineering design of an advanced fusion reactor (DEMO) can be established for a variety of structural materials and ceramic breeders. The design concepts for the Test Cell, including test assemblies, remote handling equipment and Hot Cell Facilities with capacity for investigating all irradiation specimens at the IFMIF site are described

  6. Compositional effects on the development of damage structures in accelerator

    International Nuclear Information System (INIS)

    Williams, T.M.

    A study of the development of dislocation structures in charged particle irradiated austenitic alloys has shown that the effects of irradiation and materials variables may be apparent at doses of the order approximately 1 dpa. Irradiation of identical specimens to much higher doses indicates that low and high dose behaviour are closely related

  7. The Status of Daily Physical Activity in Northern Ontario's Elementary Public Schools

    Science.gov (United States)

    Rickwood, Greg

    2015-01-01

    The importance of daily physical activity (DPA) for children and youth is highlighted in Canada's Active Healthy Kids annual report on fitness. Since 2005, this report has revealed that elementary-aged students are spending most of their waking hours stationary, in front of screens (phones, televisions, computers). To counteract this trend, the…

  8. Data protection authority perspectives on the impact of data protection reform on cooperation in the EU

    NARCIS (Netherlands)

    Barnard-Wills, David; Pauner Chulvi, Cristina; de Hert, Paul

    2016-01-01

    This article presents the findings of interviews with representatives from the majority of EU data protection authorities in the context of the ongoing data protection reform process. It not only identifies commonalities between the authorities to the extent it is possible to speak about an EU DPA

  9. The RaDIATE High-Energy Proton Materials Irradiation Experiment at the Brookhaven Linac Isotope Producer Facility

    Energy Technology Data Exchange (ETDEWEB)

    Ammigan, Kavin; et al.

    2017-05-01

    The RaDIATE collaboration (Radiation Damage In Accelerator Target Environments) was founded in 2012 to bring together the high-energy accelerator target and nuclear materials communities to address the challenging issue of radiation damage effects in beam-intercepting materials. Success of current and future high intensity accelerator target facilities requires a fundamental understanding of these effects including measurement of materials property data. Toward this goal, the RaDIATE collaboration organized and carried out a materials irradiation run at the Brookhaven Linac Isotope Producer facility (BLIP). The experiment utilized a 181 MeV proton beam to irradiate several capsules, each containing many candidate material samples for various accelerator components. Materials included various grades/alloys of beryllium, graphite, silicon, iridium, titanium, TZM, CuCrZr, and aluminum. Attainable peak damage from an 8-week irradiation run ranges from 0.03 DPA (Be) to 7 DPA (Ir). Helium production is expected to range from 5 appm/DPA (Ir) to 3,000 appm/DPA (Be). The motivation, experimental parameters, as well as the post-irradiation examination plans of this experiment are described.

  10. Radiation damage in stainless steel under varying temperature neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Naoaki [Kyushu Univ., Kasuga, Fukuoka (Japan). Research Inst. for Applied Mechanics

    1998-03-01

    Microstructural evolution of model alloys of 316SS was examined by neutron irradiation at JMTR under cyclic temperature varying condition. In the case of Fe-16Cr-17Ni, formation of interstitial loops and voids are strongly suppressed by varying the temperature from 473K to 673K. By adding Ti as miner element (0.25wt%), however, abnormal accumulation of vacancies (void swelling of 11%dpa at 0.1dpa) was observed. Theoretical analysis standing on the rate theory of defect clustering and simulation irradiation experiments with heavy ions indicates that the vacancy-rich condition which appears temporally during and after changing the temperature from low to high brings these results. It was also shown that only 1 dpa pre-irradiation at low temperature changes swelling behavior at high temperature above several 10 dpa. The understanding of non-steady-state defect processes under temperature varying irradiation is very important to estimate the radiation damage under fusion environment where short-term and long-term temperature variation is expected. (author)

  11. An update on the side channel cryptanalysis of MACs based on cryptographic hash functions

    DEFF Research Database (Denmark)

    Gauravaram, Praveen; Okeya, Katsuyuki

    2007-01-01

    Okeya has established that HMAC/NMAC implementations based on only Matyas-Meyer-Oseas (MMO) PGV scheme and his two refined PGV schemes are secure against side channel DPA attacks when the block cipher in these constructions is secure against these attacks. The significant result of Okeya's analys...

  12. [Raman spectra of endospores of Bacillus subtilis by alkali stress].

    Science.gov (United States)

    Dong, Rong; Lu, Ming-qian; Li, Feng; Shi, Gui-yu; Huang, Shu-shi

    2013-09-01

    To research the lethal mechanism of spores stressed by alkali, laser tweezers Raman spectroscopy (LTRS) combined with principal components analysis (PCA) was used to study the physiological process of single spore with alkali stress. The results showed that both spores and germinated spores had tolerance with alkali in a certain range, but the ability of spores was obviously lower than that of spores due to the release of their Ca2+ -DPA which plays a key role in spores resistance as well as spores resistance to many stresses; A small amount of Ca2+ -DPA of spores was observed to release after alkali stress, however, the behavior of release was different with the normal Ca2+ -DPA release behavior induced by L-alanine; The data before and after alkali stress of the spores and g. spores with PCA reflected that alkali mainly injured the membrane of spores, and alkali could be easily enter into the inner structure of spores to damage the structure of protein backbone and injure the nucleic acid of spores. We show that the alkali could result in the small amount of Ca2+ -DPA released by destroying the member channel of spores.

  13. Postirradiation tensile properties of Mo and Mo alloys irradiated with 600 MeV protons

    International Nuclear Information System (INIS)

    Mueller, G.V.; Gavillet, D.; Victoria, M.; Martin, J.L.

    1994-01-01

    Tensile specimens of pure Mo and Mo-5 Re, Mo-41 Re and TZM alloys have been irradiated with 600 MeV protons in the PIREX facility at 300 and 660 K to 0.5 dpa. Results of the postirradiation tensile testing show a strong radiation hardening and a severe loss of ductility for all the materials tested at room temperature. ((orig.))

  14. Directeur, Gestion du risque et audit interne | CRDI - Centre de ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Résumé des fonctions En qualité de dirigeant principal de l'audit (DPA), ... président du Centre et au président du Comité des finances et de l'audit une assurance et des ... Il fournit des services de gestion du risque organisationnel et d'autres ...

  15. [{sup 18}F]D.P.A.-714: a novel fluorine-18-labelled pyrazolo[1,5-a]pyrimidine acetamide for imaging the peripheral benzodiazepine receptors with PET - radiosynthesis on a zymate-xp robotic system

    Energy Technology Data Exchange (ETDEWEB)

    Dolle, F.; Damont, A.; Hinnen, F.; Kuhnast, B.; Chauveau, F.; Van camp, N.; Hantraye, P.; Tavitian, B. [Servvice Hospitalier Frederic Joliot, I2BM/DSV, 91 - Orsay (France); James, M.; Creelman, A.; Fulton, R.; Kassiou, M. [Sydney Univ., Brain and Mind Research Institute, NSW (Australia); Vercouillie, J.; Guilloteau, D. [Universite Francois Rabelais de Tours, 37 (France); Vercouillie, J.; Guilloteau, D. [Centre Hospitalier Regional Universitaire, 37 - Tours (France); Selleri, S.; Kassiou, M. [Sydney Univ., Discipline of Medical Radiations, Sciences and School of Chemistry, NSW (Australia)

    2008-02-15

    {sup 11}C D.P.A.-713 (N,N-diethyl-2-[2-(4-[{sup 11}C]methoxy-phenyl)-5,7-dimethyl-pyrazolo [1,5-a]pyrimidin-3-yl]acetamide) is a recently developed carbon-11-labelled (half life: 20.4 min)pyrazolo[1,5-a]pyrimidine acetamide for the in vivo imaging of the peripheral benzodiazepine receptors (P.B.R. or translocator protein (18 kDa, T.S.P.O.)). Preliminary results obtained in a rodent-model demonstrates that {sup 11}C D.P.A.-713 showed a high potential to in vivo image neuro-inflammation and additionally, this radioligand allowed a higher contrast between the lesioned area and the corresponding area in the intact contralateral hemisphere when compared to the radioligand of reference. D.P.A-714 (N,N-diethyl-2-[2-[4-(2-fluoro-ethoxy)phenyl] -5,7-dimethyl-pyrazolo[1,5-a]pyrimidin-3-yl]acetamide), a chemically closely related derivative of D.P.A.-713, had been designed with a fluorine atom in its structure, allowing ultimate labelling with fluorine-18, a longer-lived positron-emitter (half life:109.8 min) and today one of the most attractive PET isotopes for radiopharmaceutical chemistry. D.P.A.-714 as well as its corresponding tosylated derivative have been re-synthesized in 2 chemicals steps from D.P.A.-713. D.P.A.-714 has then been labelled at its aromatic fluoro-ethoxy group from the corresponding tosyl-derivative using the K{sup 18}FF-kryptofix{sub 222} (in CH{sub 3}CN (3 mL) at 85 degrees C for 5 min or D.M.S.O. (600 {mu}L) at 130 degrees C for 5 min). {sup 18}FD.P.A.-714 was then purified using semi preparative X terra reverse phase H.P.L.C., adequately formulated for i.v. injection and was found to be > 95% chemically and radiochemically pure. The total synthesis time was less than 90 min and the specific radioactivities at the end of the radiosynthesis ranged from 1 to 3 Ci/micro-mole. (N.C.)

  16. Experience and results of material science research conducted on spent fuel assemblies from the BN-350 fast reactor

    Energy Technology Data Exchange (ETDEWEB)

    Maksimkin, O.; Gusev, M.; Turubarova, L.G.; Tsai, K.V.; Yarovchuk, A.V. [Institute of Nuclear Physics, Almaty (Kazakhstan)

    2007-07-01

    Full text of publication follows: The BN-350 fast reactor was commissioned in 1973, ran successfully for many years and is now in the decommission stage. Its unique operational parameters (low temperature of sodium at the input, wide range of damage rates, etc. ) allowed the investigation of a number of new radiation effects on both austenitic and ferritic-martensitic steels. The latter class of steel was extensively employed as wrappers for fuel assemblies. Much of the accumulated experience in BN-350 is relevant to development of fusion devices. Results are presented on post-operational research of steels 12Cr18Ni10Ti, 08Cr16Ni11Mo3, and 12Cr13Mo2BFR, all serving as hexagonal shrouds of fuel assemblies. Structural materials in the active core zone operated at temperatures of 280-430 deg. C, and were irradiated the range of 0.25-83 dpa with damage rates of 10{sup -9} - 10{sup -6} dpa/s). Investigations of irradiated hexagonal shroud materials were performed with using traditional techniques of transmission and scanning electron microscopy, metallography, mechanical tests, hydrostatic weighing, magnetometry, etc. Additionally, new techniques have been developed and employed with great success on these highly irradiated materials, such as optical computer extensometry, and magnetization cartography. Typical results to be covered in this presentation are: a) In 12Cr18Ni10Ti steel irradiated at a low dose rate of 0.12 x 10{sup -8} dpa/s voids were found at 281 deg. C after only 0.65 dpa, demonstrating once again the acceleration of swelling at low dpa rates observed in other steels. b) Data on helium release during annealing of highly irradiated sample are presented. c) Differences in deformation-induced hardening between the shroud's corners and faces leads to post-irradiation differences in swelling and mechanical properties. d) During room temperature mechanical tests of 12Cr18Ni10Ti steel at {approx}56 dpa at 350 deg. C it was found that ductility lost at

  17. Theoretical Investigations of CO 2 and H 2 Sorption in an Interpenetrated Square-Pillared Metal–Organic Material

    KAUST Repository

    Pham, Tony

    2013-05-16

    Simulations of CO2 and H2 sorption and separation were performed in [Cu(dpa)2SiF6-i], a metal-organic material (MOM) consisting of an interpenetrated square grid of Cu2+ ions coordinated to 4,4′-dipyridylacetylene (dpa) rings and pillars of SiF6 2- ions. This class of water stable MOMs shows great promise in practical gas sorption/separation with especially high selectivity for CO2 and variable selectivity for other energy related gases. Simulated CO2 sorption isotherms and isosteric heats of adsorption, Qst, at ambient temperatures were in excellent agreement with the experimental measurements at all pressures considered. Further, it was observed that the Qst for CO2 increases as a function of uptake in [Cu(dpa)2SiF6-i]. This suggests that nascently sorbed CO2 molecules within a channel contribute to a more energetically favorable site for additional CO2 molecules, i.e., in stark contrast to typical behavior, sorbate intermolecular interactions enhance sorption energetics with increased loading. The simulated structure at CO2 saturation shows a loading with tight packing of 8 CO2 molecules per unit cell. The CO2 molecules can be seen alternating between a vertical and horizontal alignment within a channel, with each CO2 molecule coordinating to an equatorial fluorine MOM atom. Calculated H 2 sorption isotherms and Qst values were also in good agreement with the experimental measurements in [Cu(dpa)2SiF 6-i]. H2 saturation corresponds to 10 H2 molecules per unit cell for the studied structure. Moreover, there were two observed binding sites for hydrogen sorption in [Cu(dpa)2SiF 6-i]. Simulations of a 30:70 CO2/H2 mixture, typical of syngas, in [Cu(dpa)2SiF6-i] showed that the MOM exhibited a high uptake and selectivity for CO2. In addition, it was observed that the presence of H2O had a negligible effect on the CO2 uptake and selectivity in [Cu(dpa)2SiF6-i], as simulations of a mixture containing CO2, H2, and small amounts of CO, N2, and H2O produced comparable

  18. Geographic Data as Personal Data in Four EU Member States

    Science.gov (United States)

    de Jong, A. J.; van Loenen, B.; Zevenbergen, J. A.

    2016-06-01

    The EU Directive 95/46/EC on the protection of individuals with regard to the processing of personal data and on the free movement of such data aims at harmonising data protection legislation in the European Union. This should promote the free flow of products and services within the EU. This research found a wide variety of interpretations of the application of data protection legislation to geographic data. The variety was found among the different EU Member States, the different stakeholders and the different types of geographic data. In the Netherlands, the Data Protection Authority (DPA) states that panoramic images of streets are considered personal data. While Dutch case law judges that the data protection legislation does not apply if certain features are blurred and no link to an address is provided. The topographic datasets studied in the case studies do not contain personal data, according to the Dutch DPA, while the German DPA and the Belgian DPA judge that topographic maps of a large scale can contain personal data, and impose conditions on the processing of topographic maps. The UK DPA does consider this data outside of the scope of legal definition of personal data. The patchwork of differences in data protection legislation can be harmonised by using a traffic light model. This model focuses on the context in which the processing of the data takes place and has four categories of data: (1) sensitive personal data, (2) personal data, (3), data that can possibly lead to identification, and (4) non-personal data. For some geographic data, for example factual data that does not reveal sensitive information about a person, can be categorised in the third category giving room to opening up data under the INSPIRE Directive.

  19. Neutron displacement damage cross sections for SiC

    International Nuclear Information System (INIS)

    Huang Hanchen; Ghoniem, N.

    1993-01-01

    Calculations of neutron displacement damage cross sections for SiC are presented. We use Biersack and Haggmark's empirical formula in constructing the electronic stopping power, which combines Lindhard's model at low PKA energies and Bethe-Bloch's model at high PKA energies. The electronic stopping power for polyatomic materials is computed on the basis of Bragg's Additivity Rule. A continuous form of the inverse power law potential is used for nuclear scattering. Coupled integro-differential equations for the number of displaced atoms j, caused by PKA i, are then derived. The procedure outlined above gives partial displacement cross sections, displacement cross sections for each specie of the lattice, and for each PKA type. The corresponding damage rates for several fusion and fission neutron spectra are calculated. The stoichiometry of the irradiated material is investigated by finding the ratio of displacements among various atomic species. The role of each specie in displacing atoms is also investigated by calculating the fraction of displacements caused by each PKA type. The study shows that neutron displacement damage rates of SiC in typical magnetic fusion reactor first walls will be ∝10-15 dpa MW -1 m 2 ; in typical lead-protected inertial confinement fusion reactor first walls they will be ∝15-20 dpa MW -1 m 2 . For fission spectra, we find that the neutron displacement damage rate of SiC is ∝74 dpa per 10 27 n/m 2 in FFTF, ∝39 dpa per 10 27 n/m 2 in HFIR, and 25 dpa per 10 27 n/m 2 in NRU. Approximately 80% of displacement atoms are shown to be of the carbon-type. (orig.)

  20. Primary Damage Characteristics in Metals Under Irradiation in the Cores of Thermal and Fast Reactors

    International Nuclear Information System (INIS)

    Pechenkin, V.A.

    2012-01-01

    For an analysis and forecasting of radiation-induced phenomena in structural materials of WWERs, PWRs and BN reactors the fast neutron fluence is usually used (for structural materials of the reactor cores and internals the fluence of neutrons with energy > 0.1 MeV, for WWER and PWRs vessel steels the fluence of neutrons with energy > 0.5 MeV in Russia and East Europe, and with energy > 1.0 MeV in USA and France). Displacements per atom (dpa) seem to be a more appropriate correlation parameter, because it allows comparing the results of materials irradiation in different neutron energy spectra or with different types of particles (neutrons, ions, fast electrons). Energy spectra of primary knocked atoms (PKA) and 'effective' dpa, which are introduced to take into account the point defect recombination during the relaxation stage of a displacement cascade, can be still better representation of the effect of irradiation on material properties. In this work the results of calculating dose rates (dpa/s, NRT-model), PKA energy spectra and PKA mean energies in metals under irradiation in the cores of Russian reactors WWER-440, WWER-1000 (both power thermal reactors) and BN-600 (power fast reactor) and BR-10 (test fast reactor) are presented. In all the reactors Fe and Zr are considered, with addition of Ti and W in BN-600. 'Effective' dose rates in these metals are calculated. Limitations and uncertainties in the standard dpa formulation (the NRT-dpa) are discussed. IPPE activities in the fields related to the TM subject are considered

  1. Self-ion emulation of high dose neutron irradiated microstructure in stainless steels

    Science.gov (United States)

    Jiao, Z.; Michalicka, J.; Was, G. S.

    2018-04-01

    Solution-annealed 304L stainless steel (SS) was irradiated to 130 dpa at 380 °C, and to 15 dpa at 500 °C and 600 °C, and cold-worked 316 SS (CW 316 SS) was irradiated to 130 dpa at 380 °C using 5 MeV Fe++/Ni++ to produce microstructures and radiation-induced segregation (RIS) for comparison with that from neutron irradiation at 320 °C to 46 dpa in the BOR60 reactor. For the 304L SS alloy, self-ion irradiation at 380 °C produced a dislocation loop microstructure that was comparable to that by neutron irradiation. No voids were observed in either the 380 °C self-ion irradiation or the neutron irradiation conditions. Irradiation at 600 °C produced the best match to radiation-induced segregation of Cr and Ni with the neutron irradiation, consistent with the prediction of a large temperature shift by Mansur's invariant relations for RIS. For the CW 316 SS alloy irradiated to 130 dpa at 380 °C, both the irradiated microstructure (dislocation loops, precipitates and voids) and RIS reasonably matched the neutron-irradiated sample. The smaller temperature shift for RIS in CW 316 SS was likely due to the high sink (dislocation) density induced by the cold work. A single self-ion irradiation condition at a dose rate ∼1000× that in reactor does not match both dislocation loops and RIS in solution-annealed 304L SS. However, a single irradiation temperature produced a reasonable match with both the dislocation/precipitate microstructure and RIS in CW 316 SS, indicating that sink density is a critical factor in determining the temperature shift for self-ion irradiations.

  2. Microstructural characterization and model of hardening for the irradiated austenitic stainless steels of the internals of pressurized water reactors

    International Nuclear Information System (INIS)

    Pokor, C.

    2003-01-01

    The core internals of Pressurized Water Reactors (PWR) are composed of SA 304 stainless steel plates and CW 316 stainless steel bolts. These internals undergo a neutron flux at a temperature between 280 deg C and 380 deg C which modifies their mechanical properties. These modifications are due to the changes in the microstructure of these materials under irradiation which depend on flux, dose and irradiation temperature. We have studied, by Transmission Electron Microscopy, the microstructure of stainless steels SA 304, CW 316 and CW 316Ti irradiated in a mixed flux reactor (OSIRIS at 330 deg C between 0,8 dpa et 3,4 dpa) and in a fast breeder reactor at 330 deg C (BOR-60) up to doses of 40 dpa. Moreover, samples have been irradiated at 375 deg C in a fast breeder reactor (EBR-II) up to doses of 10 dpa. The microstructure of the irradiated stainless steels consists in faulted Frank dislocation loops in the [111] planes of austenitic, with a Burgers vector of [111]. It is possible to find some voids in the solution annealed samples irradiated at 375 deg C. The evolution of the dislocations loops and voids has been simulated with a 'cluster dynamic' model. The fit of the model parameters has allowed us to have a quantitative description of our experimental results. This description of the microstructure after irradiation was coupled together with a hardening model by Frank loops that has permitted us to make a quantitative description of the hardening of SA 304, CW 316 and CW 316Ti stainless steels after irradiation at a certain dose, flux and temperature. The irradiation doses studied grow up to 90 dpa, dose of the end of life of PWR internals. (author)

  3. Levels of small molecules and enzymes in the mother cell compartment and the forespore of sporulating Bacillus megaterium.

    Science.gov (United States)

    Singh, R P; Setlow, B; Setlow, P

    1977-06-01

    We have determined the amounts of a number of small molecules and enzymes in the mother cell compartment and the developing forespore during sporulation of Bacillus megaterium. Significant amounts of adenosine 5'-triphosphate and reduced nicotinamide adenine dinucleotide were present in the forespore compartment before accumulation of dipicolinic acid (DPA), but these compounds disappeared as DPA was accumulated. 3-Phosphoglyceric acid (3-PGA) accumulated only within the developing forespore, beginning 1 to 2 h before DPA accumulation. Throughout its development the forespore contained constant levels of enzymes of both 3-PGA synthesis (phosphoglycerate kinase and glyceraldehyde-3-phosphate dehydrogenase) and 3-PGA utilization (phosphoglycerate mutase, enolase, and pyruvate kinase) at levels similar to those in the mother cell and the dormant spore. Despite the presence of enzymes for 3-PGA utilization, this compound was stable within isolated forespores. Two acid-soluble proteins (A and B proteins) also accumulated only in the forespore, beginning 1 to 2 h before DPA accumulation. At this time the specific protease involved in degradation of the A and B proteins during germination also appeared, but only in the forespore compartment. Nevertheless, the A and B proteins were stable within isolated forespores. Arginine and glutamic acid accumulated within the forespore in parallel with DPA accumulation. The forespore also contained the enzyme arginase at a level similar to that in the mother cell and a level of glutamic acid decarboxylase 2- to 25-fold higher than that in the mother cell, depending on when in sporulation the forespores were isolated. The specific activities of several other enzymes (protease active on hemoglobin, ornithine transcarbamylase, malate dehydrogenase, aconitase, and isocitrate dehydrogenase) in forespores were about 10% or less of the values in the mother cell. Aminopeptidase was present at similar levels in both compartments; threonine

  4. Controllable Synthesis of Lindqvist Alkoxopolyoxovanadate Clusters as Heterogeneous Catalysts for Sulfoxidation of Sulfides.

    Science.gov (United States)

    Li, Ji-Kun; Dong, Jing; Wei, Chuan-Ping; Yang, Song; Chi, Ying-Nan; Xu, Yan-Qing; Hu, Chang-Wen

    2017-05-15

    Six alkoxohexavanadate-based Cu- or Co-POVs [Cu(dpa)(acac)(H 2 O)] 2 [V 6 O 13 (OMe) 6 ] (1), [Cu(phen)(acac)(MeOH)] 2 [V 6 O 13 (OMe) 6 ] (2), [Co(dpa)(acac) 2 ] 2 [V 6 O 13 (OMe) 6 ]·2MeOH (3), [Co(phen)(acac) 2 ] 2 [V 6 O 13 (OMe) 6 ] (4), [Cu(dpa)(acac)] 2 [V IV 2 V V 4 O 12 (OMe) 7 ] (5), and [Cu(dpa)(acac)(MeOH)] 2 [V IV 2 V V 4 O 11 (OMe) 8 ] (6) (POV = polyoxovanadate; dpa = 2,2'-dipyridine amine; phen = 1,10-phenanthroline; acac = acetylacetone anion) have been synthesized by controlling the reaction conditions and characterized by single-crystal X-ray diffraction and powder X-ray diffraction analyses, FT-IR spectroscopy, element analyses, and X-ray photoelectron spectroscopy. In compounds 1-4 and 6, Cu or Co complexes and alkoxohexavanadate anions are assembled through electrostatic interactions. Differently, in compound 5, seven-methoxo-substituted Lindqvist-type [V 6 O 12 (OMe) 7 ] 2- are bridged to Cu complex via terminal O atoms by coordination bonds. All compounds 1-6 exhibit excellent heterogeneous catalytic performance in oxidative desulfurization and CEES ((2-chloroethyl) ethyl sulfide, a sulfur mustard simulant) abatement with H 2 O 2 as oxidant. Among them, the catalytic activity of 6 [conv. of DBT (dibenzothiophene) up to 100% in 6 h; conv. of CEES reached 100% and selectivity of CEESO ((2-chloroethyl) ethyl sulfoxide) up to 85% after 4 h] outperforms others and can be reused without losing its activity.

  5. Use of double and triple-ion irradiation to study the influence of high levels of helium and hydrogen on void swelling of 8-12% Cr ferritic-martensitic steels

    Science.gov (United States)

    Kupriiyanova, Y. E.; Bryk, V. V.; Borodin, O. V.; Kalchenko, A. S.; Voyevodin, V. N.; Tolstolutskaya, G. D.; Garner, F. A.

    2016-01-01

    In accelerator-driven spallation (ADS) devices, some of the structural materials will be exposed to intense fluxes of very high energy protons and neutrons, producing not only displacement damage, but very high levels of helium and hydrogen. Unlike fission flux-spectra where most helium and hydrogen are generated by transmutation in nickel and only secondarily in iron or chromium, gas production in ADS flux-spectra are rather insensitive to alloy composition, such that Fe-Cr base ferritic alloys also generate very large gas levels. While ferritic alloys are known to swell less than austenitic alloys in fission spectra, there is a concern that high gas levels in fusion and especially ADS facilities may strongly accelerate void swelling in ferritic alloys. In this study of void swelling in response to helium and hydrogen generation, irradiation was conducted on three ferritic-martensitic steels using the Electrostatic Accelerator with External Injector (ESUVI) facility that can easily produce any combination of helium to dpa and/or hydrogen to dpa ratios. Irradiation was conducted under single, dual and triple beam modes using 1.8 MeV Cr+3, 40 keV He+, and 20 keV H+. In the first part of this study we investigated the response of dual-phase EP-450 to variations in He/dpa and H/dpa ratio, focusing first on dual ion studies and then triple ion studies, showing that there is a diminishing influence on swelling with increasing total gas content. In the second part we investigated the relative response of three alloys spanning a range of starting microstructure and composition. In addition to observing various synergisms between He and H, the most important conclusion was that the tempered martensite phase, known to lag behind the ferrite phase in swelling in the absence of gases, loses much of its resistance to void nucleation when irradiated at large gas/dpa levels.

  6. Use of double and triple-ion irradiation to study the influence of high levels of helium and hydrogen on void swelling of 8–12% Cr ferritic-martensitic steels

    Energy Technology Data Exchange (ETDEWEB)

    Kupriiyanova, Y.E., E-mail: fomenkoj@kipt.kharkov.ua [National Science Centre Kharkov Institute of Physics and Technology, 1, Akademicheskaya St., Kharkov, 61108 (Ukraine); Bryk, V.V.; Borodin, O.V.; Kalchenko, A.S.; Voyevodin, V.N.; Tolstolutskaya, G.D. [National Science Centre Kharkov Institute of Physics and Technology, 1, Akademicheskaya St., Kharkov, 61108 (Ukraine); Garner, F.A. [Radiation Effects Consulting, Richland, WA 99354 (United States)

    2016-01-15

    In accelerator-driven spallation (ADS) devices, some of the structural materials will be exposed to intense fluxes of very high energy protons and neutrons, producing not only displacement damage, but very high levels of helium and hydrogen. Unlike fission flux-spectra where most helium and hydrogen are generated by transmutation in nickel and only secondarily in iron or chromium, gas production in ADS flux-spectra are rather insensitive to alloy composition, such that Fe–Cr base ferritic alloys also generate very large gas levels. While ferritic alloys are known to swell less than austenitic alloys in fission spectra, there is a concern that high gas levels in fusion and especially ADS facilities may strongly accelerate void swelling in ferritic alloys. In this study of void swelling in response to helium and hydrogen generation, irradiation was conducted on three ferritic-martensitic steels using the Electrostatic Accelerator with External Injector (ESUVI) facility that can easily produce any combination of helium to dpa and/or hydrogen to dpa ratios. Irradiation was conducted under single, dual and triple beam modes using 1.8 MeV Cr{sup +3}, 40 keV He{sup +}, and 20 keV H{sup +}. In the first part of this study we investigated the response of dual-phase EP-450 to variations in He/dpa and H/dpa ratio, focusing first on dual ion studies and then triple ion studies, showing that there is a diminishing influence on swelling with increasing total gas content. In the second part we investigated the relative response of three alloys spanning a range of starting microstructure and composition. In addition to observing various synergisms between He and H, the most important conclusion was that the tempered martensite phase, known to lag behind the ferrite phase in swelling in the absence of gases, loses much of its resistance to void nucleation when irradiated at large gas/dpa levels.

  7. Proton irradiation effects on tensile and bend-fatigue properties of welded F82H specimens

    Energy Technology Data Exchange (ETDEWEB)

    Saito, S., E-mail: saito.shigeru@jaea.go.j [JAEA Tokai, J-PARC Center, 2-4 Shirakata-shirane, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan); Kikuchi, K.; Hamaguchi, D. [JAEA Tokai, J-PARC Center, 2-4 Shirakata-shirane, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan); Usami, K.; Ishikawa, A.; Nishino, Y.; Endo, S. [JAEA Tokai, Department of Hot Laboratories, Tokai-mura, Ibaraki-ken 319-1195 (Japan); Kawai, M. [KEK, Tsukuba-shi, Ibaraki-ken 305-0801 (Japan); Dai, Y. [PSI, Spallation Source Division, 5232 Villigen PSI (Switzerland)

    2010-03-15

    In several institutes, research and development for an accelerator-driven transmutation system (ADS) have been progressed. Ferritic/martensitic (FM) steels are the candidate materials for the beam window of ADS. To evaluate of the mechanical properties of the irradiated materials, the post irradiation examination (PIE) work of the SINQ (Swiss spallation neutron source) target irradiation program (STIP) specimens was carried out at JAEA. In present study, the results of PIE on FM steel F82H and its welded joint have been reported. The present irradiation conditions of the specimens were as follows: proton energy was 580 MeV. Irradiation temperatures were ranged from 130 to 380 deg. C, and displacement damage level was ranged from 5.7 to 11.8 dpa. The results of tensile tests performed at 22 deg. C indicated that the irradiation hardening occurred with increasing the displacement damage up to 10.1 dpa at 320 deg. C irradiation. At higher dose (11.8 dpa) and higher temperature (380 deg. C), irradiation hardening was observed, but degradation of ductility was relaxed in F82H welded joint. In present study, all specimens kept its ductility after irradiation and fractured in ductile manner. The results on bend-fatigue tests showed that the fatigue life (N{sub f}) of F82H base metal irradiated up to 6.3 dpa was almost the same with that of unirradiated specimens. The N{sub f} of the specimens irradiated up to 9.1 dpa was smaller than that of unirradiated specimens. Though the number of specimen was limited, the N{sub f} of F82H EB (15 mm) and EB (3.3 mm) welded joints seemed to increase after irradiation and the fracture surfaces of the specimens showed transgranular morphology. While F82H TIG welded specimens were not fractured by 10{sup 7} cycles.

  8. Omega-3 Fatty Acids and Incident Ischemic Stroke and Its Atherothrombotic and Cardioembolic Subtypes in 3 US Cohorts.

    Science.gov (United States)

    Saber, Hamidreza; Yakoob, Mohammad Yawar; Shi, Peilin; Longstreth, W T; Lemaitre, Rozenn N; Siscovick, David; Rexrode, Kathryn M; Willett, Walter C; Mozaffarian, Dariush

    2017-10-01

    The associations of individual long-chain n-3 polyunsaturated fatty acids with incident ischemic stroke and its main subtypes are not well established. We aimed to investigate prospectively the relationship of circulating eicosapentaenoic acid, docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA) with risk of total ischemic, atherothrombotic, and cardioembolic stroke. We measured circulating phospholipid fatty acids at baseline in 3 separate US cohorts: CHS (Cardiovascular Health Study), NHS (Nurses' Health Study), and HPFS (Health Professionals Follow-Up Study). Ischemic strokes were prospectively adjudicated and classified into atherothrombotic (large- and small-vessel infarctions) or cardioembolic by imaging studies and medical records. Risk according to fatty acid levels was assessed using Cox proportional hazards (CHS) or conditional logistic regression (NHS, HPFS) according to study design. Cohort findings were pooled using fixed-effects meta-analysis. A total of 953 incident ischemic strokes were identified (408 atherothrombotic, 256 cardioembolic, and 289 undetermined subtypes) during median follow-up of 11.2 years (CHS) and 8.3 years (pooled, NHS and HPFS). After multivariable adjustment, lower risk of total ischemic stroke was seen with higher DPA (highest versus lowest quartiles; pooled hazard ratio [HR], 0.74; 95% confidence interval [CI], 0.58-0.92) and DHA (HR, 0.80; 95% CI, 0.64-1.00) but not eicosapentaenoic acid (HR, 0.94; 95% CI, 0.77-1.19). DHA was associated with lower risk of atherothrombotic stroke (HR, 0.53; 95% CI, 0.34-0.83) and DPA with lower risk of cardioembolic stroke (HR, 0.58; 95% CI, 0.37-0.92). Findings in each individual cohort were consistent with pooled results. In 3 large US cohorts, higher circulating levels of DHA were inversely associated with incident atherothrombotic stroke and DPA with cardioembolic stroke. These novel findings suggest differential pathways of benefit for DHA, DPA, and eicosapentaenoic acid. © 2017

  9. Microstructural characterization and model of hardening for the irradiated austenitic stainless steels of the internals of pressurized water reactors; Caracterisation microstructurale et modelisation du durcissement des aciers austenitiques irradies des structures internes des reacteurs a eau pressurisee

    Energy Technology Data Exchange (ETDEWEB)

    Pokor, C

    2003-07-01

    The core internals of Pressurized Water Reactors (PWR) are composed of SA 304 stainless steel plates and CW 316 stainless steel bolts. These internals undergo a neutron flux at a temperature between 280 deg C and 380 deg C which modifies their mechanical properties. These modifications are due to the changes in the microstructure of these materials under irradiation which depend on flux, dose and irradiation temperature. We have studied, by Transmission Electron Microscopy, the microstructure of stainless steels SA 304, CW 316 and CW 316Ti irradiated in a mixed flux reactor (OSIRIS at 330 deg C between 0,8 dpa et 3,4 dpa) and in a fast breeder reactor at 330 deg C (BOR-60) up to doses of 40 dpa. Moreover, samples have been irradiated at 375 deg C in a fast breeder reactor (EBR-II) up to doses of 10 dpa. The microstructure of the irradiated stainless steels consists in faulted Frank dislocation loops in the [111] planes of austenitic, with a Burgers vector of [111]. It is possible to find some voids in the solution annealed samples irradiated at 375 deg C. The evolution of the dislocations loops and voids has been simulated with a 'cluster dynamic' model. The fit of the model parameters has allowed us to have a quantitative description of our experimental results. This description of the microstructure after irradiation was coupled together with a hardening model by Frank loops that has permitted us to make a quantitative description of the hardening of SA 304, CW 316 and CW 316Ti stainless steels after irradiation at a certain dose, flux and temperature. The irradiation doses studied grow up to 90 dpa, dose of the end of life of PWR internals. (author)

  10. Microstructure and mechanical properties of FeCrAl alloys under heavy ion irradiations

    Science.gov (United States)

    Aydogan, E.; Weaver, J. S.; Maloy, S. A.; El-Atwani, O.; Wang, Y. Q.; Mara, N. A.

    2018-05-01

    FeCrAl ferritic alloys are excellent cladding candidates for accident tolerant fuel systems due to their high resistance to oxidation as a result of formation of a protective Al2O3 scale at high temperatures in steam. In this study, we report the irradiation response of the 10Cr and 13Cr FeCrAl cladding tubes under Fe2+ ion irradiation up to ∼16 dpa at 300 °C. Dislocation loop size, density and characteristics were determined using both two-beam bright field transmission electron microscopy and on-zone scanning transmission electron microscopy techniques. 10Cr (C06M2) tube has a lower dislocation density, larger grain size and a slightly weaker texture compared to the 13Cr (C36M3) tube before irradiation. After irradiation to 0.7 dpa and 16 dpa, the fraction of type sessile dislocations decreases with increasing Cr amount in the alloys. It has been found that there is neither void formation nor α‧ precipitation as a result of ion irradiations in either alloy. Therefore, dislocation loops were determined to be the only irradiation induced defects contributing to the hardening. Nanoindentation testing before the irradiation revealed that the average nanohardness of the C36M3 tube is higher than that of the C06M2 tube. The average nanohardness of irradiated tube samples saturated at 1.6-2.0 GPa hardening for both tubes between ∼3.4 dpa and ∼16 dpa. The hardening calculated based on transmission electron microscopy was found to be consistent with nanohardness measurements.

  11. Ion irradiation effects on high purity bcc Fe and model FeCr alloys

    International Nuclear Information System (INIS)

    Bhattacharya, Arunodaya

    2014-01-01

    FeCr binary alloys are a simple representative of the reduced activation ferritic/martensitic (F-M) steels, which are currently the most promising candidates as structural materials for the sodium cooled fast reactors (SFR) and future fusion systems. However, the impact of Cr on the evolution of the irradiated microstructure in these materials is not well understood in these materials. Moreover, particularly for fusion applications, the radiation damage scenario is expected to be complicated further by the presence of large quantities of He produced by the nuclear transmutation (∼ 10 appm He/dpa). Within this context, an elaborate ion irradiation study was performed at 500 C on a wide variety of high purity FeCr alloys (with Cr content ranging from ∼ 3 wt.% to 14 wt.%) and a bcc Fe, to probe in detail the influence of Cr and He on the evolution of microstructure. The irradiations were performed using Fe self-ions, in single beam mode and in dual beam mode (damage by Fe ions and co-implantation of He), to separate ballistic damage effect from the impact of simultaneous He injection. Three different dose ranges were studied: high dose (157 dpa, 17 appm He/dpa for the dual beam case), intermediate dose (45 dpa, 57 appm He/dpa for dual beam case) and in-situ low dose (0.33 dpa, 3030 appm He/dpa for the dual beam case). The experiments were performed at the JANNuS triple beam facility and dual beam in situ irradiation facility at CEA-Saclay and CSNSM, Orsay respectively. The microstructure was principally characterized by conventional TEM, APT and EDS in STEM mode. The main results are as follows: 1) A comparison of the cavity microstructure in high dose irradiated Fe revealed strong swelling reduction by the addition of He. It was achieved by a drastic reduction in cavity sizes and an increased number density. This behaviour was observed all along the damage depth, up to the damage peak. 2) Cavity microstructure was also studied in the dual beam high dose

  12. Computational screening of Six Antigens for potential MHC class II restricted epitopes and evaluating its CD4+ T-Cell Responsiveness against Visceral Leishmaniasis

    Directory of Open Access Journals (Sweden)

    Manas Ranjan

    2017-12-01

    Full Text Available Visceral leishmaniasis is one of the most neglected tropical diseases for which no vaccine exists. In spite of extensive efforts, no successful vaccine is available against this dreadful infectious disease. To support the vaccine development, immunoinformatics approach was applied to search for potential MHC-classII restricted epitopes that can activate the immune cells. Initially, a total of 37 epitopes derived from six, stage dependent over expressed antigens were predicted, which were presented by at least 26 diverse MHC class II alleles including: DRB10101, DRB10301, DRB10401, DRB10404, DRB10405, DRB10701, DRB10802, DRB10901, DRB11101, DRB11302, DRB11501, DRB30101, DRB40101, DRB50101, DPA10103-DPB10401, DPA10103-DPB10201, DPA10201-DPB10101, DPA10103-DPB10301_DPB10401, DPA10301-DPB10402, DPA10201-DPB105021, DQA10102-DQB10602, DQA10401-DQB10402, DQA10501-QB10201, DQA10501-DQB10301, DQA10301-DQB10302 and DQA10101-DQB10501. Based on the population coverage analysis and HLA cross presentation ability, six epitopes namely, FDLFLFSNGAVVWWG (P1, YPVYPFLASNAALLN (P2, VYPFLASNAALLNLI (P3, LALLIMLYALIATQF (P4, LIMLYALIATQFSDD (P5, IMLYALIATQFSDDA (P6 were selected for further analysis. Stimulation with synthetic peptide alone or as a cocktail triggered the intracellular IFN-γ production. Moreover, specific IgG class of antibodies was detected in the serum of active VL cases against P1, P4, P and P6 in order to evaluate peptide effect on humoral immune response. Additionally, most of the peptides, except P2, were found to be non-inducer of CD4+ IL-10 against both active VL as well as treated VL subjects. Peptide immunogenicity was validated in BALB/c mice immunized with cocktail of synthetic peptide emulsified in complete Freund’s adjuvant/incomplete Freund’s adjuvant. The immunized splenocytes induced strong spleen cell proliferation upon parasite re-stimulation. Furthermore, an increased IFN-γ, IL-12, IL-17 and IL-22 production augmented with

  13. Dietary nutrients associated with preservation of lung function in Hispanic and non-Hispanic white smokers from New Mexico

    Directory of Open Access Journals (Sweden)

    Leng S

    2017-10-01

    Full Text Available Shuguang Leng,1,2 Maria A Picchi,1 Yohannes Tesfaigzi,3 Guodong Wu,1 W James Gauderman,4 Fadi Xu,5 Frank D Gilliland,4 Steven A Belinsky1,2,6 1The Lung Cancer Program, Lovelace Respiratory Research Institute, 2Cancer Control Research Program, University of New Mexico Comprehensive Cancer Center, 3COPD Program, Lovelace Respiratory Research Institute, Albuquerque, NM, 4Keck School of Medicine, University of Southern California, Los Angeles, CA, 5Pathophysiology Program, Lovelace Respiratory Research Institute, 6Cancer Genetics and Epigenetics Program, University of New Mexico Comprehensive Cancer Center, Albuquerque, NM, USA Background: COPD is the third leading cause of death in the United States. Cigarette smoking accelerates the age-related forced expiratory volume in 1 s (FEV1 decline, an important determinant for the genesis of COPD. Hispanic smokers have lower COPD prevalence and FEV1 decline than non-Hispanic whites (NHWs. Patients and methods: A nutritional epidemiological study was conducted in the Lovelace Smokers cohort (LSC; n=1,829 and the Veterans Smokers cohort (n=508 to identify dietary nutrients (n=139 associated with average FEV1 and its decline and to assess whether nutrient intakes could explain ethnic disparity in FEV1 decline between Hispanics and NHW smokers. Results: Nutrients discovered and replicated to be significantly associated with better average FEV1 included magnesium, folate, niacin, vitamins A and D, eicosenoic fatty acid (20:1n9, eicosapentaenoic acid (20:5n3, docosapentaenoic acid (DPA; 22:5n3, docosahexaenoic acid (22:6n3, and fiber. In addition, greater intakes of eicosenoic fatty acid and DPA were associated with slower FEV1 decline in the LSC. Among omega 3 polyunsaturated fatty acids, DPA is the most potent nutrient associated with better average FEV1 and slower FEV1 decline. Adverse effect of continuous current smoking on FEV1 decline was completely negated in LSC members with high DPA intake (>20

  14. Deuterium trapping at vacancy clusters in electron/neutron-irradiated tungsten studied by positron annihilation spectroscopy

    Science.gov (United States)

    Toyama, T.; Ami, K.; Inoue, K.; Nagai, Y.; Sato, K.; Xu, Q.; Hatano, Y.

    2018-02-01

    Deuterium trapping at irradiation-induced defects in tungsten, a candidate material for plasma facing components in fusion reactors, was revealed by positron annihilation spectroscopy. Pure tungsten was electron-irradiated (8.5 MeV at ∼373 K and to a dose of ∼1 × 10-3 dpa) or neutron-irradiated (at 573 K to a dose of ∼0.3 dpa), followed by post-irradiation annealing at 573 K for 100 h in deuterium gas of ∼0.1 MPa. In both cases of electron- or neutron-irradiation, vacancy clusters were found by positron lifetime measurements. In addition, positron annihilation with deuterium electrons was demonstrated by coincidence Doppler broadening measurements, directly indicating deuterium trapping at vacancy-type defects. This is expected to cause significant increase in deuterium retention in irradiated-tungsten.

  15. Swelling and swelling resistance possibilities of austenitic stainless steels in fusion reactors

    International Nuclear Information System (INIS)

    Maziasz, P.J.

    1983-01-01

    Fusion reactor helium generation rates in stainless steels are intermediate to those found in EBR-II and HFIR, and swelling in fusion reactors may differ from the fission swelling behavior. Advanced titanium-modified austenitic stainless steels exhibit much better void swelling resistance than AISI 316 under EBR-II (up to approx. 120 dpa) and HFIR (up to approx. 44 dpa) irradiations. The stability of fine titanium carbide (MC) precipitates plays an important role in void swelling resistance for the cold-worked titanium-modified steels irradiated in EBR-II. Futhermore, increased helium generation in these steels can (a) suppress void conversion, (b) suppress radiation-induced solute segregation (RIS), and (c) stabilize fine MC particles, if sufficient bubble nucleation occurs early in the irradation. The combined effects of helium-enhanced MC stability and helium-suppressed RIS suggest better void swelling resistance in these steels for fusion service than under EBR-II irradiation

  16. Intake of Sweets, Snacks and Soft Drinks Predicts Weight Gain in Obese Pregnant Women

    DEFF Research Database (Denmark)

    Renault, Kristina M; Carlsen, Emma M; Nørgaard, Kirsten

    2015-01-01

    factors targeted. OBJECTIVE: To evaluate improvements and relevance of different dietary factors targeted with respect to gestational weight gain in a 3-arm Randomised Controlled Trial (n=342) among obese pregnant women with BMI≥30 kg/m2. METHODS: Randomisation 1:1:1 to either hypocaloric Mediterranean...... type of diet and physical activity intervention (D+PA); physical activity intervention alone (PA); or control (C). Diet was assessed at baseline (weeks 11-14) and endpoint (weeks 36-37) using a validated food frequency questionnaire. RESULTS: During the intervention women in the D+PA group...... for limiting gestational weight gain than encouraging strict compliance to more specific diets. TRIAL REGISTRATION: ClinicalTrials.gov NCT01345149....

  17. Irradiation Microstructure of Austenitic Steels and Cast Steels Irradiated in the BOR-60 Reactor at 320°C

    Science.gov (United States)

    Yang, Yong; Chen, Yiren; Huang, Yina; Allen, Todd; Rao, Appajosula

    Reactor internal components are subjected to neutron irradiation in light water reactors, and with the aging of nuclear power plants around the world, irradiation-induced material degradations are of concern for reactor internals. Irradiation-induced defects resulting from displacement damage are critical for understanding degradation in structural materials. In the present work, microstructural changes due to irradiation in austenitic stainless steels and cast steels were characterized using transmission electron microscopy. The specimens were irradiated in the BOR-60 reactor, a fast breeder reactor, up to 40 dpa at 320°C. The dose rate was approximately 9.4x10-7 dpa/s. Void swelling and irradiation defects were analyzed for these specimens. A high density of faulted loops dominated the irradiated-altered microstructures. Along with previous TEM results, a dose dependence of the defect structure was established at 320°C.

  18. Effect of gas atoms on swelling of austenitic stainless steel

    International Nuclear Information System (INIS)

    Igata, N.; Eguchi, N.; Nishibe, E.; Naito, A.

    1994-01-01

    There have been many studies on the effect of He on swelling, however not so many on the effect of nitrogen on swelling. In this study the effect of nitrogen on swelling of 316 steel was investigated under HVEM irradiation for establishing a model of swelling. The nitrogen content was changed from 0.083 to 0.002 wt%, and for the comparison 321 steel containing Ti was used. Irradiation was performed by HVEM at 500 C under 2x10 -3 dpa/s. The dislocation loop number density in the early stage was nearly equal to the cavity number density formed later and both increased with nitrogen content. The swelling increased and decreased through the maximum as the nitrogen content increased. The result was explained by the model of swelling. As for 321 steel, no cavities were found under HVEM until 6 dpa at 500 C. This suggests the effect of scavenging of nitrogen by Ti. ((orig.))

  19. Nuclear medical methods for determination of bone mineral content

    International Nuclear Information System (INIS)

    Fischer, M.; Kempers, B.; Tschepke, H.D.; Spitz, J.

    1988-01-01

    Osteoporosis is becoming recognized as a major social and economical health problem. Bone mineral content (BMC) depends on many hormonal and metabolic factors. The pathophysiological mechanism of the loss of bone mass is still unclear. For preventive diagnosis and treatment of osteoporosis, quantitative technology is required that will measure BMC with high precision and reproducibility. Nuclear medical methods permit the BMC of the appendicular skeleton to be measured by single photon absorptiometry. Whole-body BMC, as well as spine and femur BMC, can be measured by dual photon absorptiometry. The results from both procedures are reasonably precise and correlate well with the ash weight of isolated bone. The radiation exposure level in both SPA and DPA is low. SPA and DPA may be used for cost-effective screening of high-risk patients to predict the likelihood of future fractures and control osteoporosis therapy. (orig.) [de

  20. Highly red-shifted NIR emission from a novel anthracene conjugated polymer backbone containing Pt( ii ) porphyrins

    KAUST Repository

    Freeman, D. M. E.

    2015-11-30

    © The Royal Society of Chemistry 2016. We present the synthesis of a novel diphenylanthracene (DPA) based semiconducting polymer. The polymer is solubilised by alkoxy groups attached directly to a DPA monomer, meaning the choice of co-monomer is not limited to exclusively highly solubilising moieties. Interestingly, the polymer shows a red-shifted elecroluminescence maximum (510 nm) when compared to its photoluminescence maximum (450 nm) which we attribute to excimer formation. The novel polymer was utilised as a host for a covalently-linked platinum(ii) complexed porphyrin dopant. Emission from these polymers was observed in the NIR and again showed almost a 100 nm red shift from photoluminescence to electroluminescence. This work demonstrates that utilising highly aggregating host materials is an effective tool for inducing red-shifted emission in OLEDs.

  1. Irradiation creep and stress-enhanced swelling of Fe-16Cr-15Ni-Nb austenitic stainless steel in BN-350

    Energy Technology Data Exchange (ETDEWEB)

    Vorobjev, A.N.; Porollo, S.I.; Konobeev, Yu.V. [Institute of Physics and Power Engineering, Obninsk (Russian Federation)] [and others

    1997-04-01

    Irradiation creep and void swelling will be important damage processes for stainless steels when subjected to fusion neutron irradiation at elevated temperatures. The absence of an irradiation device with fusion-relevant neutron spectra requires that data on these processes be collected in surrogate devices such as fast reactors. This paper presents the response of an annealed austenitic steel when exposed to 60 dpa at 480{degrees}C and to 20 dpa at 520{degrees}C. This material was irradiated as thin-walled argon-pressurized tubes in the BN-350 reactor located in Kazakhstan. These tubes were irradiated at hoop stresses ranging from 0 to 200 MPa. After irradiation both destructive and non-destructive examination was conducted.

  2. Spatial variations of damage parameters in FMIT and their implications

    International Nuclear Information System (INIS)

    Schiffgens, J.O.; Simons, R.L.; Mann, F.M.; Carter, L.L.

    1978-12-01

    The major conclusion is that the variation in damage rates in FMIT will be dominated by changes in flux, not spectrum. Throughout the test region where the flux is greater than 10 14 n/cm 2 .s, the flux varies by a factor of about 20, while the spectral-averaged displacement and helium production cross sections for copper vary by less than factors of two and four, respectively. The corresponding helium-to-dpa ratios bracket a fusion reactor first wall value for copper (i.e., 7.7 appm He/dpa). With the Li(d,n) yields and copper damage energy and helium production cross sections used in this study, the test volumes for which the displacement and total helium production rates are greater than those at a D-T fusion reactor first wall, with a loading of 1.25 MW/m 2 , are about 100 and 130 cm 3 , respectively

  3. Correlation of yield strength with irradiation-induced microstructure in AISI 316 stainless steel

    International Nuclear Information System (INIS)

    Simons, R.L.; Hulbert, L.A.

    1985-10-01

    Improvements in the correlation of radiation-induced change in yield strength in AISI 316 stainless steel with microstructure were made by re-examining the role of short-range obstacles. Effects due to the size of the obstacles relative to their spacing and shape of the obstacles were applied. The concept of shearing the precipitates instead of bowing around them was used to explain the effects of precipitate hardening. It is concluded that large changes in yield strength may be produced in high swelling materials. Voids will dominate the hardening at high dpa. The increase in hardening will depend on the diameter of the voids even though the swelling in the material is the same. Precipitate hardening at high fluence (>15 dpa) make a significant contribution for irradiation temperatures above 500 0 C

  4. Magnetic properties of a stainless steel irradiated with 6 MeV Xe ions

    Science.gov (United States)

    Xu, Chaoliang; Liu, Xiangbing; Qian, Wangjie; Li, Yuanfei

    2017-11-01

    Specimens of austenitic stainless steel were irradiated with 6 MeV Xe ions at room temperature to 2, 7, 15 and 25 dpa. The vibrating sample magnetometer (VSM), grazing incidence X-ray diffraction (GIXRD) and positron annihilation lifetime spectroscopy (PLS) were carried out to analysis the magnetic properties and microstructural variations. The magnetic hysteresis loops indicated that higher irradiation damage causes more significant magnetization phenomenon. The equivalent saturated magnetization Mes and coercive force Hc were obtained from magnetic hysteresis loops. It is indicated that the Mes increases with irradiation damage. While Hc increases first to 2 dpa and then decreases continuously with irradiation damage. The different contributions of irradiation defects and ferrite precipitates on Mes and Hc can explain these phenomena.

  5. Alexandre - a multi-project, multi-material and multi-technique action for an irradiation experiment in Osiris and post irradiation examination

    International Nuclear Information System (INIS)

    Averty, X.; Brachet, J.C.; Bertin, J.L.; Pizzanelli, J.P.; Rozenblum, F.

    1999-01-01

    This paper presents the data obtained on different classes of steels neutron irradiated at 325 deg C in pressurized water with a PWR-type chemistry. This irradiation, nicknamed 'Alexandre', took place in the OSIRIS reactor and finished in November 1999, for a maximum irradiation damage of ∼9 dpa. The preliminary results (up to 3.4 dpa), discussed in relation to chemical composition and initial metallurgical conditions, are listed below: - Evolution of the mechanical properties as a function of irradiation dose including the measurements of the Reduction-in-Area to failure by image analysis. - Comparison between out-of-pile and in-pile uniform corrosion. - Microstructural aspects (fractography, Transmission Electron Microscopy, and Small Angle Neutron Scattering measurements). - Post-irradiation evolution of residual. activity. (authors)

  6. Emulation of neutron irradiation effects with protons: validation of principle

    International Nuclear Information System (INIS)

    Was, G.S.; Busby, J.T.; Allen, T.; Kenik, E.A.; Jensson, A.; Bruemmer, S.M.; Gan, J.; Edwards, A.D.; Scott, P.M.; Andreson, P.L.

    2002-01-01

    This paper presents the results of the irradiation, characterization and irradiation assisted stress corrosion cracking (IASCC) behavior of proton- and neutron-irradiated samples of 304SS and 316SS from the same heats. The objective of the study was to determine whether proton irradiation does indeed emulate the full range of effects of in-reactor neutron irradiation: radiation-induced segregation (RIS), irradiated microstructure, radiation hardening and IASCC susceptibility. The work focused on commercial heats of 304 stainless steel (heat B) and 316 stainless steel (heat P). Irradiation with protons was conducted at 360 deg. C to doses between 0.3 and 5.0 dpa to approximate those by neutron irradiation at 275 deg. C over the same dose range. Characterization consisted of grain boundary microchemistry, dislocation loop microstructure, hardness as well as stress corrosion cracking (SCC) susceptibility of both un-irradiated and irradiated samples in oxygenated and de-oxygenated water environments at 288 deg. C. Overall, microchemistry, microstructure, hardening and SCC behavior of proton- and neutron-irradiated samples were in excellent agreement. RIS analysis showed that in both heats and for both irradiating particles, the pre-existing grain boundary Cr enrichment transformed into a 'W' shaped profile at 1.0 dpa and then into a 'V' shaped profile between 3.0 and 5.0 dpa. Grain boundary segregation of Cr, Ni, Si, and Mo all followed the same trends and agreed well in magnitude. The microstructure of both proton- and neutron-irradiated samples was dominated by small, faulted dislocation loops. Loop size distributions were nearly identical in both heats over a range of doses. Saturated loop size following neutron irradiation was about 30% larger than that following proton irradiation. Loop density increased with dose through 5.0 dpa for both particle irradiations and was a factor of 3 greater in neutron-irradiated samples vs. proton-irradiated samples. Grain boundary

  7. The irradiation hardening of Ni-Mo-Cr and Ni-W-Cr alloy under Xe26+ ion irradiation

    Science.gov (United States)

    Chen, Huaican; Hai, Yang; Liu, Renduo; Jiang, Li; Ye, Xiang-xi; Li, Jianjian; Xue, Wandong; Wang, Wanxia; Tang, Ming; Yan, Long; Yin, Wen; Zhou, Xingtai

    2018-04-01

    The irradiation hardening of Ni-Mo-Cr and Ni-W-Cr alloy was investigated. 7 MeV Xe26+ ion irradiation was performed at room temperature and 650 °C with peak damage dose from 0.05 to 10 dpa. With the increase of damage dose, the hardness of Ni-Mo-Cr and Ni-W-Cr alloy increases, and reaches saturation at damage dose ≥1 dpa. Moreover, the damage dose dependence of hardness in both alloys can be described by the Makin and Minter's equation, where the effective critical volume of obstacles can be used to represent irradiation hardening resistance of the alloys. Our results also show that Ni-W-Cr alloy has better irradiation hardening resistance than Ni-Mo-Cr alloy. This is ascribed to the fact that the W, instead of Mo in the alloy, can suppress the formation of defects under ion irradiation.

  8. Light ions cyclotron bombardment to simulate fast neutron radiation damage in nuclear materials

    International Nuclear Information System (INIS)

    Segura, E.; Lucki, G.; Aguiar, D.

    1984-01-01

    The applicability and limitations of the use of cyclotron light ions bombardment to simulate the effects of the neutron irradiation are presented. Light ions with energies of about 10 MeV are capable to produce homogeneous damage in specimens suitable for measuring bulk mechanical properties although their low damage rate of 10 -5 dpa.sec -1 limit the dose range to a few dpa. On the other hand, cyclotron alpha particle implantation provides a fast and convenient way of introducing helium with a minimum of side effects so that we can take advantage of this technique to get better understanding of the mechanism by which this insoluble gas produces high temperature embrittlement. Some experimental details such as dimensions and cooling techniques are described. Finally a description of the infrastructure for cyclotron alpha particle implantation and a creep-test facility of the Division of Radiation Damage at IPEN-CNEN/SP are presented. (Author) [pt

  9. Scintigraphic findings of bone and bone-marrow and determination of bone mineral density using photon absorptiometry in osteopetrosis

    International Nuclear Information System (INIS)

    Otsuka, Nobuaki; Fukunaga, Masao; Morita, Koichi

    1988-01-01

    On a 15-year-old girl with osteopetrosis, bone and bonemarrow scintigraphy were performed. Also, bone mineral density (BMD) with quantitative CT (QCT), single photon absorptiometry (SPA) and dual photon absorptiometry (DPA) were measured. On bone scintigraphy the diffusely increased skeletal uptake and relatively diminished renal uptake were noted. On the other hand, on bone marrow scintigraphy poor accumulation in central marrow and peripheral expansion were shown. BMD value by QCT and DPA (mainly trabecular bone) was markedly high, while BMD by SPA (mainly cortical bone) was within normal range. Thus, it was shown that bone and bone-marrow scintigraphy combined with BMD measurement by photon absorptiometry were useful and essential in evaluating the pathophysiology of osteosclerosis. (author)

  10. Reevaluation of ferritic steel ΔDBTT data used in damage function analysis

    International Nuclear Information System (INIS)

    Simons, R.L.

    1980-01-01

    Damage functions for the change in ductile-brittle transition temperature (ΔDBTT) in ferritic steels for application to Light Water Reactor (LWR) pressure vessels were re-evaluated. Two improvements in the analysis of the data resulted in a reduction in data scatter from the 15-30% range to the 4-15% range. These improvements were in the form of an improved fluence dependence function and correction of errors in the fluence values themselves. A comparison of several spectral indices used to correlate the data showed that the A-212 and A-302 steels favored the use of the displacement cross section (dpa) while the A-350 steels favored the use of an interstitial cluster cross section which is spectrally more sensitive to neutron energy than the dpa cross section

  11. Radiation induced phosphorus segregation in austenitic and ferritic alloys

    International Nuclear Information System (INIS)

    Brimhall, J.L.; Baer, D.R.; Jones, R.H.

    1984-01-01

    The radiation induced surface segregation (RIS) of phosphorus in stainless steel attained a maximum at a dose of 0.8 dpa then decreased continually with dose. This decrease in the surface segregation of phosphorus at high dose levels has been attributed to removal of the phosphorus layer by ion sputtering. Phosphorus is not replenished since essentially all of the phosphorus within the irradiation zone has been segregated to the surface. Sputter removal can explain the previously reported absence of phosphorus segregation in ferritic alloys irradiated at high dosessup(1,2) (>1 dpa) since irradiation of ferritic alloys to low doses has shown measurable RIS. This sputtering phenomenon places an inherent limitation to the heavy ion irradiation technique for the study of surface segregation of impurity elements. The magnitude of the segregation in ferritics is still much less than in stainless steel which can be related to the low damage accumulation in these alloys. (orig.)

  12. A Pebble-Bed Breed-and-Burn Reactor

    International Nuclear Information System (INIS)

    Greenspan, Ehud

    2016-01-01

    The primary objective of this project is to use three-dimensional fuel shuffling in order to reduce the minimum peak radiation damage of ~550 dpa present Breed-and-Burn (B&B) fast nuclear reactor cores designs (they feature 2-D fuel shuffling) call for to as close as possible to the presently accepted value of 200 dpa thereby enabling earlier commercialization of B&B reactors which could make substantial contribution to energy sustainability and economic stability without need for fuel recycling. Another objective is increasing the average discharge burnup for the same peak discharge burnup thereby (1) increasing the fuel utilization of 2-D shuffled B&B reactors and (2) reducing the reprocessing capacity required to support a given capacity of FRs that are to recycle fuel.

  13. A broadband high-efficiency Doherty power amplifier using symmetrical devices

    Science.gov (United States)

    Cheng, Zhiqun; Zhang, Ming; Li, Jiangzhou; Liu, Guohua

    2018-04-01

    This paper proposes a method for broadband and high-efficiency amplification of Doherty power amplifier (DPA) using symmetric devices. In order to achieve the perfect load modulation, the carrier amplifier output circuit total power length is designed to odd multiple of 90°, and the peak amplifier output total power length is designed to even multiple of 180°. The proposed method is demonstrated by designing a broadband high-efficiency DPA using identical 10-W packaged GaN HEMT devices. Measurement results show that over 51% drain efficiency is achieved at 6-dB back-off power, over the frequency band of 1.9–2.4 GHz. Project supported by the National Natural Science Foundation of China (No. 60123456), the Zhejiang Provincial Natural Science Foundation of China (No. LZ16F010001), and the Zhejiang Provincial Public Technology Research Project (No. 2016C31070).

  14. Microstructural evolution of pure tungsten neutron irradiated with a mixed energy spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Koyanagi, Takaaki, E-mail: koyanagit@ornl.gov [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Kumar, N.A.P. Kiran [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Hwang, Taehyun [Tohoku University, Sendai, 980-8579 (Japan); Garrison, Lauren M.; Hu, Xunxiang [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Snead, Lance L. [Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Katoh, Yutai [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2017-07-15

    Microstructures of single-crystal bulk tungsten (W) and polycrystalline W foil with a strong grain texture were investigated using transmission electron microscopy following neutron irradiation at ∼90–800 °C to 0.03–4.6 displacements per atom (dpa) in the High Flux Isotope Reactor with a mixed energy spectrum. The dominant irradiation defects were dislocation loops and small clusters at ∼90 °C. Additional voids were formed in W irradiated at above 460 °C. Voids and precipitates involving transmutation rhenium and osmium were the dominant defects at more than ∼1 dpa. We found a new phenomenon of microstructural evolution in irradiated polycrystalline W: Re- and Os-rich precipitation along grain boundaries. Comparison of results between this study and previous studies using different irradiation facilities revealed that the microstructural evolution of pure W is highly dependent on the neutron energy spectrum in addition to the irradiation temperature and dose.

  15. Minaturized disk bend tests of neutron-irradiated path A type alloys

    International Nuclear Information System (INIS)

    Lee, M.; Sohn, D.S.; Grant, N.J.; Harling, O.K.

    1983-01-01

    Path A Prime Candidate Alloy (PCA) has been rapidly solidified and consoliated by extrusion. Twenty percent CW samples, precision TEM disks, 3 phi x 0.254 mm, were irradiated in the mixed flux of the Oak Ridge HFIR reactor up to approx. 8.5 dpa (360 appm He) and approx. 34 dpa (3100 appm He) at 300, 400, 500 and 600 0 C. Similar samples of conventionally processed PCA were also irradiated for comparison. Mechanical properties were characterized using a minaturized disk bend test (MDBT) developed at MIT. These tests indicate major decreases in strength and ductility especially for the 500 and 600 0 C irradiations. No major differences were found between this first version of a rapidly solidified and extruded PCA type alloy and conventionally processed PCA

  16. Evaluation of hardening by ion irradiation in molybdenum using nanoindentation techniques

    International Nuclear Information System (INIS)

    Iwakiri, Hirotomi; Watanabe, Hideo; Yoshida, Naoaki

    1997-01-01

    As a part of fundamental research on interaction of plasma and wall, some model experiments on loading of particles such as He, H and so forth suffered by plasma facing material were conducted for Mo in high Z material. As an evaluation method for it, nanoindentation technique was proposed. By this method, the hardness evaluation in surface neighboring damage range was conducted. As a result, in the helium irradiated materials, sufficient hardening was observed even at low dpa range impossible to recognize hardening on heavy ion and deuterium irradiated materials, and extreme hardening was established by formation of helium bubble at high dpa region. Furthermore, in the helium irradiated materials, recovery of hardening could not be observed even for annealed materials at 1173 K for 1 hr after irradiation. From such results, hardening promotion work due to helium and extreme thermal stability of the formed defects were elucidated. (B.K.)

  17. Influence of ion irradiation on internal residual stress in DLC films

    Energy Technology Data Exchange (ETDEWEB)

    Karaseov, Platon A., E-mail: platon.karaseov@rphf.spbstu.r [St. Petersburg State Polytechnic University, Polytechnicheskaya St. 29, 195251 St. Petersburg (Russian Federation); Podsvirov, Oleg A.; Karabeshkin, Konstantin V. [St. Petersburg State Polytechnic University, Polytechnicheskaya St. 29, 195251 St. Petersburg (Russian Federation); Vinogradov, Andrei Ya. [Ioffe Physicotechnical Institute RAS, Polytechnicheskaya 26, 195252 St. Petersburg (Russian Federation); Azarov, Alexander Yu. [St. Petersburg State Polytechnic University, Polytechnicheskaya St. 29, 195251 St. Petersburg (Russian Federation); Karasev, Nikita N. [State University of Information Technologies, Mechanics and Optics, Sablinskaya Str. 14, 197101 St. Petersburg (Russian Federation); Titov, Andrei I.; Smirnov, Alexander S. [St. Petersburg State Polytechnic University, Polytechnicheskaya St. 29, 195251 St. Petersburg (Russian Federation)

    2010-10-01

    The dependence of internal residual stress in thin diamond-like carbon films grown on Si substrate by PECVD technique on most important growth parameters, namely RF-power, DC bias voltage and substrate temperature, is described. Results show that compressive stress reaches the highest value of 2.7 GPa at low RF-power and DC bias. Increase of substrate temperature from 250 to 350 {sup o}C leads to nonlinear increase of stress value. Inhomogeneity of residual stress along the film surface disappears when film is deposited at temperatures above 275 {sup o}C. Post-growth film irradiation by P{sup +} and In{sup +} ions cause decrease of compressive stress followed by its inversion to tensile. For all ion energy combinations used residual stress changes linearly with normalized fluence up to 0.2 DPA with slope (8.7 {+-} 1.3) GPa/DPA.

  18. Effects of neutron irradiation on mechanical properties of silicon carbide composites fabricated by nano-infiltration and transient eutectic-phase process

    International Nuclear Information System (INIS)

    Koyanagi, T.; Hinoki, T.; Shimoda, K.; Ozawa, K.; Katoh, Y.

    2014-01-01

    Unidirectional silicon carbide (SiC)-fiber-reinforced SiC matrix (SiC/SiC) composites fabricated by a nano-infiltration and transient eutectic-phase (NITE) process were irradiated with neutrons at 830°C to 5.9 dpa, and at 1270°C to 5.8 dpa. The in-plane and trans-thickness tensile and the inter-laminar shear properties were evaluated at ambient temperature. The mechanical characteristics, including the quasi-ductile behavior, the proportional limit stress, and the ultimate tensile strength, were retained subsequent to irradiation. Analysis of the stress–strain hysteresis loop indicated the increased fiber/matrix interface friction and the decreased residual stresses. The inter-laminar shear strength exhibited a significant decrease following irradiation. (author)

  19. Radiation-induced segregation and phase stability in ferritic-martensitic alloy T 91

    Energy Technology Data Exchange (ETDEWEB)

    Wharry, Janelle P.; Jiao Zhijie; Shankar, Vani [University of Michigan, 2355 Bonisteel Blvd, Ann Arbor, MI 48109-2104 (United States); Busby, Jeremy T. [Oak Ridge National Laboratory, 1 Bethel Valley Rd, Oak Ridge, TN 37831 (United States); Was, Gary S., E-mail: gsw@umich.edu [University of Michigan, 2355 Bonisteel Blvd, Ann Arbor, MI 48109-2104 (United States)

    2011-10-01

    Radiation-induced segregation in ferritic-martensitic alloy T 91 was studied to understand the behavior of solutes as a function of dose and temperature. Irradiations were conducted using 2 MeV protons to doses of 1, 3, 7 and 10 dpa at 400 deg. C. Radiation-induced segregation at prior austenite grain boundaries was measured, and various features of the irradiated microstructure were characterized, including grain boundary carbide coverage, the dislocation microstructure, radiation-induced precipitation and irradiation hardening. Results showed that Cr, Ni and Si segregate to prior austenite grain boundaries at low dose, but segregation ceases and redistribution occurs above 3 dpa. Grain boundary carbide coverage mirrors radiation-induced segregation. Irradiation induces formation of Ni-Si-Mn and Cu-rich precipitates that account for the majority of irradiation hardening. Radiation-induced segregation behavior is likely linked to the evolution of the precipitate and dislocation microstructures.

  20. Dose dependence of radiation-induced segregation in Ni-1 at% Si

    International Nuclear Information System (INIS)

    Rehn, L.E.; Okamoto, P.R.; Wiedersich, H.

    1979-01-01

    Measurements have been made of alloy composition as a function of depth from the external surface in Ni-1 at% Si specimens after irradiation with 3-MeV 58 Ni + ions to several different doses at nominal temperatures of 525 and 600 0 C. Very rapid segregation of Si toward the external surface ocurred during irradiation. Surface concentrations of Si in excess of the 10 at% solubility limit were found at both irradiation temperatures after a dose of only approximately 0.05 dpa. The rate of segregation decreased markedly in the dose range from approximately 1-10 dpa. Qualitative agreement was found between the experimental observations and calculations made using a modified Johnson-Lam segregation mode (1976). The present investigation suggests that radiation-induced segregation may significantly alter the mechanical behavior of irradiated alloys long before the onset of void swelling. (Auth.)

  1. Irradiation creep of candidate materials for advanced nuclear plants

    Energy Technology Data Exchange (ETDEWEB)

    Chen, J., E-mail: jiachao.chen@psi.ch; Jung, P.; Hoffelner, W.

    2013-10-15

    In the present paper, irradiation creep results of an intermetallic TiAl alloy and two ferritic oxide dispersion strengthened (ODS) steels are summarized. In situ irradiation creep measurements were performed using homogeneous implantation with α- and p-particles to maximum doses of 0.8 dpa at displacement damage rates of 2–8 × 10{sup −6} dpa/s. The strains of miniaturized flat dog-bone specimens were monitored under uniaxial tensile stresses ranging from 20 to 400 MPa at temperatures of 573, 673 and 773 K, respectively. The effects of material composition, ODS particle size, and bombarding particle on the irradiation creep compliance was studied and results are compared to literature data. Evolution of microstructure during helium implantation was investigated in detail by TEM and is discussed with respect to irradiation creep models.

  2. Microstructures of neutron-irradiated Fe-12Cr-XMn (X=15-30) ternary alloys

    International Nuclear Information System (INIS)

    Miyahara, K.; Hosoi, Y.; Garner, F.A.

    1992-01-01

    The objective of this effort is to determine the factors which control the stability of irradiated alloys proposed for reduced activation applications. The Fe-Cr-Mn alloy system is being studied as an alternative to the Fe-Cr-Ni system because of the need to reduce long-term radioactivation in fusion-power devices. In this study, four Fe-12Cr-XMn (X =15, 20, 25, 30 wt%) alloys were irradiated in the Fast Flux Test Facility to 20 dpa at 643K and 40 dpa at 679, 793, and 873K to investigate the influence of manganese content on void swelling and phase stability. The results confirm and expand the results of earlier studies that indicate that the Fe-Cr-Mn system is relatively unstable compared to that of the Fe-Cr-Ni system, with alpha and sigma phases forming as a consequence of thermal aging or high temperature irradiation

  3. Ductility loss of ion-irradiated zircaloy-2 in iodine

    International Nuclear Information System (INIS)

    Shimada, M.; Terasawa, M.; Yamamoto, S.; Kamei, H.; Koizumi, K.

    1981-01-01

    An ion bombardment simulation technique for neutron irradiation was applied to 'thick' materials to study the effect of radiation damage on the ductility change in Zircaloy-2 in an iodine environment. Specimens were prepared from actual cladding tubes and, prior to the irradiation, they were heat-treated in vacuo at 450, 580, and 700/degree/C for 2 h. Irradiation was performed by 52-MeV alpha particles up to the 0.32 displacements per atom (dpa) at 340/degree/C. Ductility loss begins to appear after 0.03 dpa irradiation, both in iodine and argon gas environments. The iodine presence resulted in ductility reduction, compared with the argon result in all irradiation dose ranges examined. The stress applied during irradiation caused ductility loss to commence at lower dosage than in the case of stress-free irradiation. These results are discussed in relation to the existing stress corrosion cracking models

  4. Some stress-related issues in tokamak fusion reactor first walls

    International Nuclear Information System (INIS)

    Majumdar, S.; Pai, B.; Ryder, R.H.

    1987-01-01

    Recent design studies of a tokamak fusion power reactor and of various blankets have envisioned surface heat fluxes on the first wall ranging from 0.1 to 1.0 MW/m 2 , and end-of-life irradiation fluences ranging from 100 dpa for the austenitic stainless steels to as high as 250 dpa for postulated vanadium alloys. Some tokamak blankets, particularly those using helium or liquid metal as coolant/breeder, may have to operate at relatively high coolant pressures so that the first wall may be subjected to high primary stress in addition to high secondary stresses such as thermal stresses or stresses due to constrained swelling. The present paper focusses on the various problems that may arise in the first wall because of stress and high neutron fluence, and discusses some of the design solutions that have been proposed to overcome these problems

  5. Ductile electroless Ni-P coating onto flexible printed circuit board

    Science.gov (United States)

    Wang, Wenchang; Zhang, Weiwei; Wang, Yurong; Mitsuzak, Naotoshi; Chen, Zhidong

    2016-03-01

    In this study, a ductile electroless Ni-P coating on the flexible printed circuit board (FPCB) was prepared in an acidic nickel plating bath. The addition of dipropylamine (DPA) in electroless plating not only improves the ductility of the Ni-P coating, but also enhances the corrosion resistance. The further analysis reveals that the ductility improvement and enhancement of corrosion resistance for the Ni-P coating may be due to the fact that the addition of DPA significantly refines the volume of columnar nodule and reduce the porosity, thus leading to the released internal stress. In addition, it was found that the nodule within the Ni-P coating grew into a columnar structure, which may be also contribute to the improvement of ductility.

  6. Effect of neutron radiation on the dielectric, mechanical and thermal properties of ceramics for RF transmission windows

    International Nuclear Information System (INIS)

    Hazelton, C.; Rice, J.; Snead, L.L.; Zinkle, S.J.

    1998-01-01

    The behavior of electrically insulating ceramics was investigated before and after exposure to neutron radiation. Mechanical, thermal and dielectric specimens were studied after exposure to a fast neutron dose of 0.1 displacements per atom (dpa) at Oak Ridge National Laboratory (ORNL). Four materials were compared to alumina: polycrystalline spinel, aluminum nitride, sialon and silicon nitride. Mechanical bend tests were performed before and after irradiation. Thermal diffusivity was measured using a room temperature laser flash technique. Dielectric loss factor was measured at 105 MHz with a special high resolution resonance cavity. The materials exhibited a significant degradation of thermal diffusivity and an increase in dielectric loss tangent. The flexural strength and physical dimensions were not significantly affected by the 0.1 dpa level of neutron radiation. The aluminum nitride and S silicon nitride showed superior RF window performance over the sialon and the alumina. The results are compared to radiation studies on similar materials

  7. Monochromatic computed tomography of the human brain using synchrotron x rays: Technical feasibility

    International Nuclear Information System (INIS)

    Nachaliel, E.; Dilmanian, F.A.; Garrett, R.F.; Thomlinson, W.C.; Chapman, L.D.; Gmuer, N.F.; Lazarz, N.M.; Moulin, H.R.; Rivers, M.L.; Rarback, H.; Stefan, P.M.; Spanne, P.; Luke, P.N.; Pehl, R.; Thompson, A.C.; Miller, M.

    1991-01-01

    A monochromatic computed tomography (CT) scanner is being developed at the X17 superconducting wiggler beamline at the National Synchrotron Light Source (NSLS), Brookhaven National Laboratory, to image the human head and neck. The system configuration is one of a horizontal fan beam and an upright seated rotating subject. The purpose of the project are to demonstrate improvement in the image contrast and in the image quantitative accuracy that can be obtained in monochromatic CT and to apply the system to specific clinical research programs in neuroradiology. This paper describes the first phantom studies carried out with a prototype system, using the dual photon absorptiometry (DPA) method at energies of 20 and 39 Kev. The results show that improvements in image contrast and quantitative accuracy are possible with monochromatic DPA CT. Estimates of the clinical performance of the planned CT system are made on the basis of these initial results

  8. Thermal conductivity degradation of graphites due to neutron irradiation at low temperature

    International Nuclear Information System (INIS)

    Snead, L.L.; Burchell, T.D.

    1995-01-01

    Several graphites and carbon/carbon composites (C/C's) have been irradiated with fission neutrons near 150 C and at fluences up to a displacement level of 0.24 dpa. The unirradiated room temperature thermal conductivity of these materials varied from 114 W/m K for H-451 isotropic graphite, to 670 W/m K for a unidirectional FMI-1D C/C composite. At the irradiation temperature a saturation reduction in thermal conductivity was seen to occur at displacement levels of approximately 0.1 dpa. All materials were seen to degrade to approximately 10 to 14% of their original thermal conductivity after irradiation. The significant recovery of thermal conductivity due to post-irradiation isochronal anneals is also presented. (orig.)

  9. Assessment of helium effects on swelling by reirradiation in FFTF of Path A alloys previously irradiated in HFIR

    International Nuclear Information System (INIS)

    Maziasz, P.J.; Garner, F.A.; Brager, H.R.

    1985-01-01

    Specimens of the Path A Prime Candidate Alloys and of N-lot SS 316 were irradiated in HFIR at 400 to 600 0 C to fluences producing approximately 10 to 44 dpa and 500 to 3600 at. ppm He, in both the solution annealed and 20 to 25% cold-worked conditions. The cavity swelling and total microstructural evolution of most samples were observed via transmission electron microscopy on identical disks irradiated side by side in HFIR, and immersion densities were also measured prior to insertion into FFTF/MOTA (Materials Open Test Assembly of the Fast Flux Test Facility). These disks are being irradiated in the FFTF/MOTA (cycles 5 and 6), side by side with disks of the same materials which were not previously irradiated in HFIR. These specimens have been divided into two subsets for discharges after 30 and 60 dpa. 4 references, 1 table

  10. A Pebble-Bed Breed-and-Burn Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Greenspan, Ehud [Univ. of California, Berkeley, CA (United States)

    2016-03-31

    The primary objective of this project is to use three-dimensional fuel shuffling in order to reduce the minimum peak radiation damage of ~550 dpa present Breed-and-Burn (B&B) fast nuclear reactor cores designs (they feature 2-D fuel shuffling) call for to as close as possible to the presently accepted value of 200 dpa thereby enabling earlier commercialization of B&B reactors which could make substantial contribution to energy sustainability and economic stability without need for fuel recycling. Another objective is increasing the average discharge burnup for the same peak discharge burnup thereby (1) increasing the fuel utilization of 2-D shuffled B&B reactors and (2) reducing the reprocessing capacity required to support a given capacity of FRs that are to recycle fuel.

  11. Microstructural defects in EUROFER 97 after different neutron irradiation conditions

    Directory of Open Access Journals (Sweden)

    Christian Dethloff

    2016-12-01

    Full Text Available Characterization of irradiation induced microstructural evolution is essential for assessing the applicability of structural steels like the Reduced Activation Ferritic/Martensitic steel EUROFER 97 in upcoming fusion reactors. In this work Transmission Electron Microscopy (TEM is used to determine the defect microstructure after different neutron irradiation conditions. In particular dislocation loops, voids and precipitates are analyzed concerning defect nature, density and size distribution after irradiation to 15 dpa at 300 °C in the mixed spectrum High Flux Reactor (HFR. New results are combined with previously obtained data from irradiation in the fast spectrum BOR-60 reactor (15 and 32 dpa, 330 °C, which allows for assessment of dose and dose rate effects on the aforementioned irradiation induced defects and microstructural characteristics.

  12. Temperature dependence of damage accumulation in α-zirconium

    International Nuclear Information System (INIS)

    Arevalo, C.; Caturla, M.J.; Perlado, J.M.

    2007-01-01

    Using the input data obtained from molecular dynamics (MD) simulations on defect energetics and cascade damage, we present results obtained on irradiation of hexagonal-close-packed (hcp) α-zirconium under different conditions with a kinetic Monte Carlo (kMC) model. We used three 25 keV cascade databases at temperatures of 100 K, 300 K and 600 K respectively. The evolution of the microstructure during irradiation for a dose rate of 10 -6 dpa/s, at temperatures of 100 K, 300 K and 600 K until a final dose of 0.1 dpa has been studied. We have considered isotropic motion for vacancies and one dimensional movement for interstitials and we have studied how the accumulation of damage is affected considering different temperatures. We present preliminary comparisons with experimental data

  13. High sensitive detection of copper II ions using D-penicillamine-coated gold nanorods based on localized surface plasmon resonance

    Science.gov (United States)

    Hong, Yoochan; Jo, Seongjae; Park, Joohyung; Park, Jinsung; Yang, Jaemoon

    2018-05-01

    In this paper, we describe the development of a nanoplasmonic biosensor based on the localized surface plasmon resonance (LSPR) effect that enables a sensitive and selective recognition of copper II ions. First, we fabricated the nanoplasmonics as LSPR substrates using gold nanorods (GNR) and the nano-adsorption method. The LSPR sensitivity of the nanoplasmonics was evaluated using various solvents with different refractive indexes. Subsequently, D-penicillamine (DPA)—a chelating agent of copper II ions—was conjugated to the surface of the GNR. The limit of detection (LOD) for the DPA-conjugated nanoplasmonics was 100 pM. Furthermore, selectivity tests were conducted using various divalent cations, and sensitivity tests were conducted on the nanoplasmonics under blood-like environments. Finally, the developed nanoplasmonic biosensor based on GNR shows great potential for the effective recognition of copper II ions, even in human blood conditions.

  14. Enhanced photovoltaic performance of Sb2S3-sensitized solar cells through surface treatments

    Science.gov (United States)

    Ye, Qing; Xu, Yafeng; Chen, Wenyong; Yang, Shangfeng; Zhu, Jun; Weng, Jian

    2018-05-01

    Efficient antimony sulfide (Sb2S3)-sensitized solar cells were obtained by a sequential treatment with thioacetamide (TA) and 1-decylphosphonic acid (DPA). Compared with the untreated Sb2S3-sensitized solar cells, the power conversion efficiency of the treated Sb2S3 solar cells was improved by 1.80% to 3.23%. The TA treatment improved the Sb2S3 films by reducing impurities and decreasing the film's surface defects, which inhibited the emergence of recombination centers. The DPA treatment reduced the recombination between hole transport materials (HTMs) and the Sb2S3. Therefore, we have presented an efficient strategy to improve the performance of Sb2S3-sensitized solar cells.

  15. Nuclear irradiation parameters of beryllium under fusion, fission and IFMIF irradiation conditions

    International Nuclear Information System (INIS)

    Fischer, U.; Chen, Y.; Leichtle, D.; Simakov, S.; Moeslang, A.; Vladimirov, P.

    2004-01-01

    A computational analysis is presented of the nuclear irradiation parameters for Beryllium under irradiation in typical neutron environments of fission and fusion reactors, and of the presently designed intense fusion neutron source IFMIF. The analysis shows that dpa and Tritium production rates at fusion relevant levels can be achieved with existing high flux fission reactors while the achievable Helium production is too low. The resulting He-Tritium and He/dpa ratios do not meet typical fusion irradiation conditions. Irradiation simulations in the medium flux test modules of the IFMIF neutron source facility were shown to be more suitable to match fusion typical irradiation conditions. To achieve sufficiently high production rates it is suggested to remove the creep-fatigue testing machine together with the W spectra shifter plate and move the tritium release module upstream towards the high flux test module. (author)

  16. Effects of pulsed dual-ion irradiation of microstructural development

    International Nuclear Information System (INIS)

    Packan, N.H.

    1981-01-01

    The effect of pulsed irradiation on the development of microstructure during Ni ion bombardment has been investigated in a simple austenitic alloy similar to type 316 stainless steel. Bombardment conditions were 10 dpa, 940 K, pulsing with equal on/off times of either 0.5 or 60 s, and the addition of 20 appM He/dpa to some specimens either by room temperature preimplantation or by dual-beam coimplantation. Particular care was taken to minimize thermal pulses from beam heating (to 0 C). The results show that pulsing has a subtle influence, and the effects on specific cavity parameters are complex. Pulsing produced a small increase in swelling in the helium-free case, but a slight decrease for helium-implanted specimens, and it seems to have counteracted the usual stimulative effects of helium on cavity nucleation

  17. French R&D on Materials for the Core Components of SFRs

    International Nuclear Information System (INIS)

    Le Flem, M.; Séran, J.L.; Blat-Yrieix, M.; Garat, V.

    2013-01-01

    ASTRID demonstrator 480-700°C, 110 dpa. • Use of reference materials benefiniting from a large feed-back from the previous French SFRs (Rapsodie, Phénix, SuperPhénix) • Austenitic steels (cladding), Martensitic steels (wrapper tube), B4C (absorbers). • Improving the description of their behavior (swelling, high temperature) • Qualifying the materials regarding the specificities of ASTRID core. Future SFRs 530-750, 180 dpa. • Use of advanced materials with improved properties • ODS ferritic/martensitic steels (cladding), Other metallic solutions as V alloys (cladding), SiC/SiC composites (wrapper tube), Innovative absorbers and reflectors. • R&D to develop/fabricate suitable grades • Qualifying these materials in ASTRID

  18. Effect of helium preinjection and prior thermomechanical treatment on the microstructure of Type 316 SS

    International Nuclear Information System (INIS)

    Kohyama, A.; Ayrault, G.; Turner, A.P.L.; Igata, N.

    1982-10-01

    Samples of 316 SS were preinjected with 15 appM helium either hot (650 0 C) or cold (room temperature) and irradiated with 3 MeV Ni + ions to a dose level of 25 dpa at 625 0 C in order to test the validity of helium preinjection as a means of simulation of transmutant helium production. Results for preinjected and single-ion irradiated samples were compared to samples irradiated with 3 MeV Ni + and simultaneously injected with helium at a rate of 15 appM He/dpa (dual-ion irradiated samples). Preinjected samples exhibited bimodal cavity size distributions. Preinjected samples of solution annealed or solution annealed and aged material showed lower swelling than dual-ion irradiated samples. However, He preinjection in 20% cold worked samples showed greater swelling than dual-ion irradiated samples 9 figures, 1 table

  19. Improved swelling resistance for PCA austenitic stainless steel under HFIR irradiation through microstructural control

    International Nuclear Information System (INIS)

    Maziasz, P.J.; Braski, D.N.

    1983-01-01

    Six microstructural variants of Prime Candidate Alloy (PCA) were evaluated for swelling resistance during HFIR irradiation, together with several heats of type 316 stainless steel (316). Swelling was negligible in all the steels at 300 0 C after approx. 44 dpa. At 500 to 600 0 C 25%-cold-worked PCA showed better void swelling resistance than type 316 at approx. 44 dpa. There was less swelling variability among alloys at 400 0 C, but again 25%-cold-worked PCA was the best. Microstructurally, swelling resistance correlated with development of fine, stable bubbles whereas high swelling was due to coarser distributions of bubbles becoming unstable and converting to voids (bias-driven cavities)

  20. In situ study of heavy ion induced radiation damage in NF616 (P92) alloy

    International Nuclear Information System (INIS)

    Topbasi, Cem; Motta, Arthur T.; Kirk, Mark A.

    2012-01-01

    Highlights: ► The ferritic–martensitic alloy NF616 was irradiated in situ with 1 MeV Kr ions at 50 K and 473 K. ► The defect cluster density increases with dose and saturates at ∼6 dpa at 50 K and 473 K. ► The defect size distributions do not change with dose at this temperature range. ► Results indicate that defect cluster formation and destruction is governed by cascade impact. - Abstract: NF616 is a nominal 9Cr ferritic–martensitic steel that is amongst the primary candidates for cladding and duct applications in the Sodium-Cooled Fast Reactor, one of the Generation IV nuclear energy systems. In this study, an in situ investigation of the microstructure evolution in NF616 under heavy ion irradiation has been conducted. NF616 was irradiated to 8.4 dpa at 50 K and to 7.6 dpa at 473 K with 1 MeV Kr ions. Nano-sized defects first appeared as white dots in dark-field TEM images and their areal density increased until saturation (∼6 dpa). Dynamic observations at 50 K and 473 K showed appearance and disappearance of TEM-visible defect clusters under irradiation that continued above saturation dose. Quantitative analysis showed no significant change in the average size (∼3–4 nm) and distribution of defect clusters with increasing dose at 50 K and 473 K. These results indicate a cascade-driven process of microstructure evolution under irradiation in these alloys that involves both the formation of TEM-visible defect clusters by various degrees of cascade overlap and cascade induced defect cluster elimination. According to this mechanism, saturation of defect cluster density is reached when the rate of defect cluster formation by overlap is equal to the rate of cluster elimination during irradiation.

  1. Group constant preparation for the estimate of neutron induced damage in structural materials

    International Nuclear Information System (INIS)

    Panini, G.C.

    1996-01-01

    Neutron heating (kerma), displacement per atom cross sections (DPA), gas and γ-ray production are important parameters for the estimate of the damage produced by neutron induced nuclear reactions in the structural materials. The NJOY System for Nuclear Data Processing has been extensively used in order to compute the above quantities; here the theory, the algorithms and the connected problems are described. (author). 6 refs, 3 tabs

  2. Microstructural evolution of CANDU spacer material Inconel X-750 under in situ ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, He Ken [Department of Mechanical and Materials Engineering, Queen’s University Kingston, Ontario K7L 3N6 (Canada); Yao, Zhongwen, E-mail: yaoz@me.queensu.ca [Department of Mechanical and Materials Engineering, Queen’s University Kingston, Ontario K7L 3N6 (Canada); Judge, Colin; Griffiths, Malcolm [Deformation Technology Branch, AECL, Chalk River Laboratories Chalk River, Ontario K0J 1J0 (Canada)

    2013-11-15

    Highlights: •γ′ Disordered at low dose. •Cascade induced SFTs were observed in alloy X-750. •No cavities were found from mono heavy ions irradiated samples. -- Abstract: Work on Inconel® X-750 spacers removed from CANDU® reactors has shown that they become embrittled and there is development of many small cavities within the metal matrix and along grain boundaries. In order to emulate the neutron irradiation induced microstructural changes, heavy ion irradiations (1 MeV Kr{sup 2+} ions) were performed while observing the damage evolution using an intermediate voltage electron microscope (IVEM) operating at 200 kV. The irradiations were carried out at various temperatures 60–400 °C. The principal strengthening phase, γ′, was disordered at low doses (∼0.06 dpa) during the irradiation. M{sub 23}C{sub 6} carbides were found to be stable up to 5.4 dpa. Lattice defects consisted mostly of stacking fault tetrahedras (SFTs), 1/2<1 1 0> perfect loops and small 1/3<1 1 1> faulted Frank loops. The ratio of SFT number density to loop number density for each irradiation condition was found to be neither temperature nor dose dependent. Under the operation of the ion beam the SFT production was very rapid, with no evidence for further growth once formed, indicating that they probably formed as a result of cascade collapse in a single cascade. The number density of the defects was found to saturate at low dose (∼0.68 dpa). No cavities were observed regardless of the irradiation temperature between 60 °C and 400 °C for doses up to 5.4 dpa. In contrast, cavities have been observed after neutron irradiation in the same material at similar doses and temperatures indicating that helium, produce during neutron irradiation, may be essential for the nucleation and growth of cavities.

  3. Results and Prospects of Development of Works on Structural Core Materials for Russian Fast Reactors

    International Nuclear Information System (INIS)

    Nikitina, A.A.; Ageev, V.S.; Leontyeva-Smirnova, M.V.; Mitrofanova, N.M.; Tselishchev, A.V.

    2015-01-01

    The strategy of development of atomic energy in Russia in the first half of XXI century contemplates construction and putting in operation of fast reactors of new generation with different types of coolant: sodium (BN-800, BN-1200, MBIR), lead (BREST-OD-300) and lead-bismuth eutectic (SVBR-100). For assurance of the working capacity of reactors that are under construction and achievement of economically reasonable burn-up of nuclear fuel the structural core materials with necessary level of radiation resistance, heat resistance, corrosion resistance to products of fuel fission, corrosion resistance in coolant and in water must be developed and justified. For sodium cooled reactors the key challenge is creation of radiation resistant and heat resistant cladding materials, which must ensure the achievement of damage doses at least 140 dpa. The solution of this problem is provided by phased use as cladding materials of austenitic steels ChS68 and EK164 (maximum damage doses ~ 92 and ~110-115 dpa, respectively), precipitation-hardening heat resistant ferritic-martensitic steels EK181 and ChS139 (maximum damage dose ~140 dpa) and oxide dispersion strengthened (ODS) steels (maximum damage dose more than 140 dpa). For development of core materials for reactors with lead and lead-bismuth eutectic coolants the most serious challenge is corrosion resistance of materials in coolant. Therefore at present time a very wide range of works on study of corrosion resistance of candidate materials is carrying out. As the basic material for the cladding tubes is considered a ferritic-martensitic steel EP823 with high silicon content. In this report the main results of works on justification of the working capacity of materials of different classes in respect to use it in cores of operating and prospective fast reactors with different types of coolant and prospects of further development of works are presented. (author)

  4. Radiation enhanced copper clustering processes in Fe-Cu alloys during electron and ion irradiations as measured by electrical resistivity

    International Nuclear Information System (INIS)

    Ishino, S.; Chimi, Y.; Bagiyono; Tobita, T.; Ishikawa, N.; Suzuki, M.; Iwase, A.

    2003-01-01

    To study the mechanism of radiation-enhanced clustering of copper atoms in Fe-Cu alloys, in situ electrical resistivity measurements are performed during irradiation with 100 MeV carbon ions and with 2 MeV electrons at 300 K. Two kinds of highly pure Fe-Cu alloys with Cu content of 0.02 and 0.6 wt% are used. The results are summarized as follows: - Although there is a steep initial resistivity increase below about 10 μdpa, the resistivity steadily decreases after this initial transient in Fe-0.6wt%Cu alloy, while in Fe-0.02wt%Cu alloy, the resistivity either decreases slowly or stays almost constant. The rate of change in resistivity depends on copper concentration. - The rate of change in resistivity per dpa is larger for electron irradiation than for ion irradiation. - Change in dose rate from 10 -8 to 10 -9 dpa/s slightly enhances the rate of resistivity change per dpa. The decrease in resistivity with dose is considered to be due to clustering or precipitation of copper atoms. The initial abrupt increase in resistivity is too large to be accounted for by initial introduction of point defects before copper clustering. Tentatively the phenomenon is explained as due to the formation of embryos of copper precipitates with a large strain field around them. Quantitative evaluation of the results using resistivity contribution of a unit concentration of Frenkel pairs and that of copper atoms gives an important conclusion that more than one copper atom are removed from solid solution by one Frenkel pair. The clustering efficiency is surprisingly high in the present case compared with the ordinary radiation-induced or radiation-enhanced precipitation processes

  5. MANIA (276-3/4/5). Nuclear analysis

    International Nuclear Information System (INIS)

    Sciolla, C.M.

    1993-11-01

    This report contains the results of the nuclear calculations performed for the MANIA-276 experiment, sample holders 3, 4 and 5. The codes MICROFLUX-2, GAM, HFR-TEDDI and ORIGEN-S have been used for this analysis. Nuclear constants, dpa, reactivity effect and activity of the samples and of the structural materials have been calculated. The results are given in the tables and appendices of the present report. (orig.)

  6. Specimen Machining for the Study of the Effect of Swelling on CGR in PWR Environment.

    Energy Technology Data Exchange (ETDEWEB)

    Teysseyre, Sebastien Paul [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-06-01

    This report describes the preparation of ten specimens to be used for the study of the effect of swelling on the propagation of irradiation assisted stress corrosion cracking cracks. Four compact tension specimens, four microscopy plates and two tensile specimens were machined from a AISI 304 material that was irradiated up to 33 dpa. The specimens had been machined such as to represent the behavior of materials with 3.7%swelling and <2% swelling.

  7. Study of the Effect of Swelling on Irradiation Assisted Stress Corrosion Cracking

    Energy Technology Data Exchange (ETDEWEB)

    Teysseyre, Sebastien Paul [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-09-01

    This report describes the methodology used to study the effect of swelling on the crack growth rate of an irradiation-assisted stress corrosion crack that is propagating in highly irradiated stainless steel 304 material irradiated to 33 dpa in the Experimental Breeder Reactor-II. The material selection, specimens design, experimental apparatus and processes are described. The results of the current test are presented.

  8. Precipitation response of austenitic stainless steel to simulated fusion irradiation

    International Nuclear Information System (INIS)

    Maziasz, P.J.

    1978-01-01

    The precipitation response of annealed type 316 stainless steel irradiated in HFIR is studied and compared to previously observed thermal aging and fast reactor irradiation responses. Irradiation in HFIR simultaneously produces high levels of helium and displacement damage and partially simulates a fusion environment. Samples have been irradiated at temperatures from 550 to 680 0 C to fluences producing up to 3300 appm He and 47 dpa

  9. Enantiomeric resolution and X-ray optical activity of a tricobalt extended metal atom chain† †Electronic supplementary information (ESI) available: Bond distances and angles for 2 and 3, thermal ellipsoid plots, packing diagrams, PXRD data, magnetization curves, thermogravimetric analysis, and additional XNCD and XMCD plots and CD spectra. CCDC 1574514–1574516 and 1588703. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7sc04131d

    Science.gov (United States)

    Srinivasan, Anandi; Cortijo, Miguel; Bulicanu, Vladimir; Naim, Ahmad; Clérac, Rodolphe; Rogalev, Andrei; Wilhelm, Fabrice; Rosa, Patrick

    2017-01-01

    A simple procedure based on anion exchange was employed for the enantiomeric resolution of the extended metal atom chain (EMAC) [Co3(dpa)4(MeCN)2]2+. Use of the chiral salt (NBu4)2[As2(tartrate)2], (Λ-1 or Δ-1), resulted in the selective crystallization of the EMAC enantiomers as [Δ-Co3(dpa)4(MeCN)2](NBu4)2[Λ-As2(tartarte)2]2, (Δ-2) and [Λ-Co3(dpa)4(MeCN)2](NBu4)2[Δ-As2(tartrate)2]2 (Λ-2), respectively, in the P4212 space group, whereas a racemic mixture of 1 yielded [Co3(dpa)4(MeCN)2][As2(tartrate)2]·2MeCN (rac-3), which crystallized in the C2/c space group. The local electronic and magnetic structure of the EMAC enantiomers was studied, exploiting a variety of dichroisms in single crystals. A strong linear dichroism at the Co K-edge was observed in the orthoaxial configuration, whereas it vanished in the axial orientation, thus spectroscopically confirming the D4 crystal symmetry. Compounds Δ-2 and Λ-2 are shown to be enantiopure materials as evidenced by mirror-image natural circular dichroism spectra in the UV/vis in solution and in the X-ray range at the Co K-edge in single crystals. The surprising absence of detectable X-ray magnetic circular dichroism or X-ray magnetochiral dichroism signals at the Co K-edge, even at low temperature (3 K) and a high magnetic field (17 T), is ascribed to a strongly delocalized spin density on the tricobalt core. PMID:29675158

  10. 100 group displacement cross sections from RECOIL data base

    International Nuclear Information System (INIS)

    Gopalakrishnan, V.

    1995-01-01

    Displacement cross sections in 100 neutron energy groups were calculated from the RECOIL data base using the RECOIL program, for use in DPA (Displacement Per Atom) calculations for FBTR and PFBR materials. 100 group displacement cross sections were calculated using RECOIL-Data Base and RECOIL Program. Modifications were made in the data base to reduce space requirement, and in the program for easy handling on a PC. 2 refs

  11. Ion-irradiation-induced phase transformation in rare earth sesquioxides (Dy2O3,Er2O3,Lu2O3)

    International Nuclear Information System (INIS)

    Tang, M.; Lu, P.; Valdez, J.A.; Sickafus, K.E.

    2006-01-01

    Polycrystalline pellets of cubic C-type rare earth structure (Ia3) Dy 2 O 3 , Er 2 O 3 , and Lu 2 O 3 were irradiated at cryogenic temperature (120 K) with 300 keV Kr ++ ions to a maximum fluence of 1x10 20 Kr/m 2 . Irradiated specimens were examined using grazing incidence x-ray diffraction and transmission electron microscopy. Ion irradiation leads to different radiation effects in these three materials. First, Dy 2 O 3 begins to transform to a monoclinic B-type rare earth structure (C2/m) at a peak dose of ∼5 displacements per atom (dpa) (corresponding to a fluence of 2x10 19 Kr/m 2 ). This transformation is nearly complete at a peak dose of 25 dpa (a fluence of 1x10 20 Kr/m 2 ). Er 2 O 3 also transforms to the B-type structure, but the transformation starts at a higher irradiation dose of about 15-20 dpa [a fluence of about (6-8)x10 19 Kr/m 2 ]. Lu 2 O 3 was found to maintain the C-type structure even at the highest irradiation dose of 25 dpa (a fluence of 1x10 20 Kr/m 2 ). No C-to-B transformation was observed in Lu 2 O 3 . The irradiation dose dependence of the C-to-B phase transformation observed in Dy 2 O 3 , Er 2 O 3 , and Lu 2 O 3 is closely related to the temperature dependence of the C-to-B phase transformation found in phase diagrams for these three materials

  12. Neutronics analysis of the DHCE experiment in ATR-ITV

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, I.C.; Smith, D.L.; Tsai, H. [Argonne National Lab., IL (United States)

    1997-08-01

    The preliminary analysis of the DHCE experiments in the ITV and ATR was performed and its was concluded that such a vehicle is suitable for this kind of experiment. It is recommended to place an extra filter material in the thermocouple sleeve (such as B-10), to improve the helium to dpa ratio profile during irradiation. Also, it was concluded that a preliminary estimation of period of time for replacement of the external filter would be around 5 dps`s.

  13. Comparison of damage microstructures in neutron-irradiated vanadium and iron

    International Nuclear Information System (INIS)

    Horton, L.L.; Farrell, K.

    1983-01-01

    The cavity morphology and dislocation loop geometry in bcc vanadium are compared with the previously reported observations for neutron-irradiated iron. The specimens were vanadium (V) with 100 wppM of interstitial impurities and vanadium with boron carbide additions (V-B 4 C) which were irradiated to approx. 1 dpa in the same Oak Ridge Research Reactor capsules as the iron specimens

  14. Properties of vanadium-base alloys irradiated in the Dynamic Helium Charging Experiment*1

    Science.gov (United States)

    Chung, H. M.; Loomis, B. A.; Smith, D. L.

    1996-10-01

    One property of vanadium-base alloys that is not well understood in terms of their potential use a fusion reactor structural materials, is the effect of simultaneous generation of helium and neutron damage. In the present Dynamic Helium Charging Experiment (DHCE), helium was produced uniformly in the specimen at linear rates of ≈ 0.4 to 4.2 appm helium/dpa by the decay of tritium during irradiation to 18-31 dpa at 425-600°C in Li-filled capsules in a sodium-cooled fast reactor. This paper presents results of postirradiation examination and tests of microstructure and mechanical properties of V5Ti, V3Ti1Si, V8Cr6Ti, and V4Cr4Ti (the latter alloy has been identified as the most promising candidate vanadium alloy). Effects of helium on tensile strength and ductility were insignificant after irradiation and testing at > 420°C. However, postirradiation ductilities at irradiation. Ductile—brittle transition behavior of the DHCE specimens was also determined from bend tests and fracture appearance of transmission electron microscopy (TEM) disks and broken tensile specimens. No brittle behavior was observed at temperatures > - 150°C in DHCE specimens. Predominantly brittle-cleavage fracture morphologies were observed only at - 196°C in some specimens that were irradiated to 31 dpa at 425°C during the DHCE. For the helium generation rates in this experiment (≈ 0.4-4.2 appm He/dpa), grain-boundary coalescence of helium microcavities was negligible and intergranular fracture was not observed.

  15. A simple phenotypic method for screening of MCR-1-mediated colistin resistance.

    Science.gov (United States)

    Coppi, M; Cannatelli, A; Antonelli, A; Baccani, I; Di Pilato, V; Sennati, S; Giani, T; Rossolini, G M

    2018-02-01

    To evaluate a novel method, the colistin-MAC test, for phenotypic screening of acquired colistin resistance mediated by transferable mcr-1 resistance determinants, based on colistin MIC reduction in the presence of dipicolinic acid (DPA). The colistin-MAC test consists in a broth microdilution method, in which colistin MIC is tested in the absence or presence of DPA (900 μg/mL). Overall, 74 colistin-resistant strains of Enterobacteriaceae (65 Escherichia coli and nine other species), including 61 strains carrying mcr-1-like genes and 13 strains negative for mcr genes, were evaluated with the colistin-MAC test. The presence of mcr-1-like and mcr-2-like genes was assessed by real-time PCR and end-point PCR. For 20 strains, whole-genome sequencing data were also available. A ≥8-fold reduction of colistin MIC in the presence of DPA was observed with 59 mcr-1-positive strains, including 53 E. coli of clinical origin, three E. coli transconjugants carrying MCR-1-encoding plasmids, one Enterobacter cloacae complex and two Citrobacter spp. Colistin MICs were unchanged, increased or at most reduced by twofold with the 13 mcr-negative colistin-resistant strains (nine E. coli and four Klebsiella pneumoniae), but also with two mcr-1-like-positive K. pneumoniae strains. The colistin-MAC test could be a simple phenotypic test for presumptive identification of mcr-1-positive strains among isolates of colistin-resistant E. coli, based on a ≥8-fold reduction of colistin MIC in the presence of DPA. Evaluation of the test with a larger number of strains, species and mcr-type resistance determinants would be of interest. Copyright © 2017 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  16. Analysis of stress-induced Burgers vector anisotropy in pressurized tube specimens of irradiated ferritic-martensitic steel: JLF-1

    International Nuclear Information System (INIS)

    Gelles, D.S.; Shibayama, T.

    1998-01-01

    A procedure for determining the Burgers vector anisotropy in irradiated ferritic steels allowing identification of all a and all a/2 dislocations in a region of interest is applied to a pressurized tube specimen of JLF-1 irradiated at 430 C to 14.3 x 10 22 n/cm 2 (E > 0.1 MeV) or 61 dpa. Analysis of micrographs indicates large anisotropy in Burgers vector populations develop during irradiation creep

  17. Tensile properties of neutron irradiated 316Ti and 15-15Ti steels

    International Nuclear Information System (INIS)

    Fissolo, A.; Levy, V.; Seran, J.L.; Maillard, A.; Royer, J.; Rabouille, O.

    1992-01-01

    This paper deals with the tensile behavior of CW316Ti and CW15-15Ti Phenix fuel pin cladding. The tensile tests were conducted on defueled tubes irradiated up to 115 dpa 3 in the 400-640 deg C temperature range. Test temperature corresponds essentially to irradiation temperature. The results emphasize that although irradiation induces a reduction of ductility, failure always occurs with significant plastic deformation even for the most irradiated clads. (author). 15 refs., 12 figs., 1 tab

  18. Gamma spectrometry of 285-04 ILAS gamma scan wires

    International Nuclear Information System (INIS)

    Dassel, G.; Buurveld, H.A.; Plakman, J.C.

    1996-12-01

    In the frame work of their on-going sustain programme for the material development and characterization of fusion reactors, ECN is investigating the irradiation behaviour of ferritic/martensitic steels. In the fourth irradiation experiment 285-04, 55 steel tensile samples have been irradiated up to 2.5 dpa. Four gamma scan wires from this experiment have been examined by gamma scanning. The results of the measurements have been described in this report. (orig.)

  19. Gamma spectrometry of 285-03 ILAS gamma scan wires

    International Nuclear Information System (INIS)

    Dassel, G.; Buurveld, H.A.; Plakman, J.C.

    1996-12-01

    In the frame work of their on-going sustain programme for the material development and characterization of fusion reactors, ECN is investigating the irradiation behaviour of ferritic/martensitic steels. In the third irradiation experiment 285-03, 55 vanadium (V-4Cr-4Ti) tensile samples have been irradiated up to 6 dpa. Four gamma scan wires from this experiment have been examined by gamma scanning. The results of the measurements have been described in this report. (orig.)

  20. Potential for bioremediation of agro-industrial effluents with high loads of pesticides by selected fungi.

    Science.gov (United States)

    Karas, Panagiotis A; Perruchon, Chiara; Exarhou, Katerina; Ehaliotis, Constantinos; Karpouzas, Dimitrios G

    2011-02-01

    Wastewaters from the fruit packaging industry contain a high pesticide load and require treatment before their environmental discharge. We provide first evidence for the potential bioremediation of these wastewaters. Three white rot fungi (WRF) (Phanerochaete chrysosporium, Trametes versicolor, Pleurotus ostreatus) and an Aspergillus niger strain were tested in straw extract medium (StEM) and soil extract medium (SEM) for degrading the pesticides thiabendazole (TBZ), imazalil (IMZ), thiophanate methyl (TM), ortho-phenylphenol (OPP), diphenylamine (DPA) and chlorpyrifos (CHL). Peroxidase (LiP, MnP) and laccase (Lac) activity was also determined to investigate their involvement in pesticide degradation. T. versicolor and P. ostreatus were the most efficient degraders and degraded all pesticides (10 mg l⁻¹) except TBZ, with maximum efficiency in StEM. The phenolic pesticides OPP and DPA were rapidly degraded by these two fungi with a concurrent increase in MnP and Lac activity. In contrast, these enzymes were not associated with the degradation of CHL, IMZ and TM implying the involvement of other enzymes. T. versicolor degraded spillage-level pesticide concentrations (50 mg l⁻¹) either fully (DPA, OPP) or partially (TBZ, IMZ). The fungus was also able to rapidly degrade a mixture of TM/DPA (50 mg l⁻¹), whereas it failed to degrade IMZ and TBZ when supplied in a mixture with OPP. Overall, T. versicolor and P. ostreatus showed great potential for the bioremediation of wastewaters from the fruit packaging industry. However, degradation of TBZ should be also achieved before further scaling up.

  1. Changes to the school food and physical activity environment after guideline implementation in British Columbia, Canada

    OpenAIRE

    Watts, Allison W; Mâsse, Louise C; Naylor, Patti-Jean

    2014-01-01

    Background High rates of childhood obesity have generated interest among policy makers to improve the school food environment and increase students’ levels of physical activity. The purpose of this study was to examine school-level changes associated with implementation of the Food and Beverage Sales in Schools (FBSS) and Daily Physical Activity (DPA) guidelines in British Columbia, Canada. Methods Elementary and middle/high school principals completed a survey on the school food and physical...

  2. Biotic nitrosation of diclofenac in a soil aquifer system (Katari watershed, Bolivia).

    Science.gov (United States)

    Chiron, Serge; Duwig, Céline

    2016-09-15

    Up till now, the diclofenac (DCF) transformation into its nitrogen-derivatives, N-nitroso-DCF (NO-DCF) and 5-nitro-DCF (NO2-DCF), has been mainly investigated in wastewater treatment plant under nitrification or denitrification processes. This work reports, for the first time, an additional DCF microbial mediated nitrosation pathway of DCF in soil under strictly anoxic conditions probably involving codenitrification processes and fungal activities. This transformation pathway was investigated by using field observations data at a soil aquifer system (Katari watershed, Bolivia) and by carrying out soil slurry batch experiments. It was also observed for diphenylamine (DPA). Field measurements revealed the occurrence of NO-DCF, NO2-DCF and NO-DPA in groundwater samples at concentration levels in the 6-68s/L range. These concentration levels are more significant than those previously reported in wastewater treatment plant effluents taking into account dilution processes in soil. Interestingly, the p-benzoquinone imine of 5-OH-DCF was also found to be rather stable in surface water. In laboratory batch experiments under strictly anoxic conditions, the transformation of DCF and DPA into their corresponding N-nitroso derivatives was well correlated to denitrification processes. It was also observed that NO-DCF evolved into NO2-DCF while NO-DPA was stable. In vitro experiments showed that the Fisher-Hepp rearrangement could not account for NO2-DCF formation. One possible mechanism might be that NO-DCF underwent spontaneous NO loss to give the resulting intermediates diphenylaminyl radical or nitrenium cation which might evolve into NO2-DCF in presence of NO2 radical or nitrite ion, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Power spectral density of velocity fluctuations estimated from phase Doppler data

    OpenAIRE

    Jicha Miroslav; Lizal Frantisek; Jedelsky Jan

    2012-01-01

    Laser Doppler Anemometry (LDA) and its modifications such as PhaseDoppler Particle Anemometry (P/DPA) is point-wise method for optical nonintrusive measurement of particle velocity with high data rate. Conversion of the LDA velocity data from temporal to frequency domain – calculation of power spectral density (PSD) of velocity fluctuations, is a non trivial task due to nonequidistant data sampling in time. We briefly discuss possibilities for the PSD estimation and specify limitations caused...

  4. Vertebral bone mineral measurement using dual photon absorptiometry and computed tomography

    International Nuclear Information System (INIS)

    Eriksson, S.; Isberg, B.; Lindgren, U.; Huddinge Univ. Hospital

    1988-01-01

    The lumbar spine of 14 cadavers was studied both by 153 Gd dual photon absorptiometry (DPA) and quantitative computed tomography (QCT) at 96 and 125 kVp. The intact spine and the individual vertebrae were analyzed. After these measurements the ash content of the vertebral body, the posterior elements, and the transverse processes was determined. The fat content of the vertebral body as well as its volume was also measured. With DPA, the bone mineral content (BMC) determined in situ as well as on excised spine specimens correlated highly with the amount of total vertebral ash (r > 0.92, SEE 0.81, SEE 3 ). The so-called corpus density and central density determinations were less accurate. No difference in accuracy was found between measurements when using 3 mm and 4.5 mm step intervals. Variations in the distribution of mineral between the vertebral body and the posterior elements contribute to the error in predicting vertebral body mineral with DPA. QCT gave a smaller error when a cylindric portion of the vertebral body with a 20 diameter was measured compared with one with a 9 mm diameter, when the dual energy technique was used (p 3 ). Single energy QCT was insignificantly less accurate than dual energy QCT. Only small differences were found between vertebrae with high fat density of the vertebral body when single or dual QCT was used. QCT was more accurate than DPA in the prediction of the mineral density of individual vertebral bodies (p < 0.05) but no difference was found when the average values for the lumbar spine were calculated. (orig.)

  5. Microstructural evolution in fast-neutron-irradiated austenitic stainless steels

    International Nuclear Information System (INIS)

    Stoller, R.E.

    1987-12-01

    The present work has focused on the specific problem of fast-neutron-induced radiation damage to austenitic stainless steels. These steels are used as structural materials in current fast fission reactors and are proposed for use in future fusion reactors. Two primary components of the radiation damage are atomic displacements (in units of displacements per atom, or dpa) and the generation of helium by nuclear transmutation reactions. The radiation environment can be characterized by the ratio of helium to displacement production, the so-called He/dpa ratio. Radiation damage is evidenced microscopically by a complex microstructural evolution and macroscopically by density changes and altered mechanical properties. The purpose of this work was to provide additional understanding about mechanisms that determine microstructural evolution in current fast reactor environments and to identify the sensitivity of this evolution to changes in the He/dpa ratio. This latter sensitivity is of interest because the He/dpa ratio in a fusion reactor first wall will be about 30 times that in fast reactor fuel cladding. The approach followed in the present work was to use a combination of theoretical and experimental analysis. The experimental component of the work primarily involved the examination by transmission electron microscopy of specimens of a model austenitic alloy that had been irradiated in the Oak Ridge Research Reactor. A major aspect of the theoretical work was the development of a comprehensive model of microstructural evolution. This included explicit models for the evolution of the major extended defects observed in neutron irradiated steels: cavities, Frank faulted loops and the dislocation network. 340 refs., 95 figs., 18 tabs

  6. Neutron-exposure parameters for the fourth HSST series of metallurgical irradiation capsules

    International Nuclear Information System (INIS)

    Kam, F.B.K.; Stallmann, F.W.; Baldwin, C.A.; Fabry, A.

    1982-01-01

    The neutron exposure parameters for the Heavy Section Steel Technology (HSST) Experiments performed at the Oak Ridge National Laboratory (ORNL) can be determined conservatively to +-10% (1sigma) variance. The neutron exposure parameters used for this study were fluence greater than 1 MeV, fluence greater than 0.1 MeV, and displacements per atom (dpa). Measured reaction rates, calculated neutron transport fluxes, and cross sections values were combined in the logarithmic least square adjustment code LSL

  7. PAPER ON MISCELLANEOUS ISSUES, INCLUDING WORKPLACE PRIVACY

    OpenAIRE

    Richards, G. W.

    2014-01-01

    EU directives give member states a certain period – say 2 or 3 years – to implement rules at national level. In fact the DPA 1998 replaces earlier UK legislation, the Data Protection Act 1984, so it does more than simply reproduce the directive. Other examples of subjects covered by directives are redundancy information/ consultation, equal treatment, insolvency protection, pregnancy protection, European and domestic works councils and agency work

  8. Damage energy functions for compounds and alloys

    International Nuclear Information System (INIS)

    Parkin, D.M.; Coulter, C.A.

    1977-01-01

    The concept of the damage energy of an energetic primary knock-on atom in a material is a central component in the procedure used to calculate dpa for metals exposed to neutron and charged particle radiation. Coefficients for analytic fits to the calculated damage energy functions are given for Al 2 O 3 , Si 3 N 4 , Y 2 O 3 , and NbTi. Damage efficiencies are given for Al 2 O 3

  9. Correlation of mechanical property changes in neutron-irradiated pressure vessel steels on the basis of spectral effects

    International Nuclear Information System (INIS)

    Heinisch, H.L.

    1991-01-01

    Comparisons are made of tensile data on specimens of A212B and A302B pressure vessel steels irradiated at low temperatures (40-90degC) and to low doses (<0.1 dpa) with 14 MeV D-T fusion neutrons in the Rotating Target Neutron Source (RTNS-II), with fission reactor neutrons in the Omega West Reactor (OWR) and the Oak Ridge Research Reactor (ORR), and with the highly thermal spectrum at the pressure vessel surveillance positions of the High Flux Isotope Reactor (HFIR). For each neutron spectrum, damage cross sections are determined for several defect production functions derived from atomistic computer simulations of collision cascades. Displacements per atom (dpa) and the numbers of freely migrating defects are tested as damage correlation parameters for the tensile data. The data from RTNS-II, OWR and ORR correlate fairly well when compared on the basis of dpa, but the data from HFIR show only about one sixth as many dpa are needed to produce the same radiation-induced yield stress changes as in the other neutron spectra. In the HFIR surveillance position a significant fraction of the displacements is produced by recoils resulting from thermal neutron captures. Having energies of about 400 eV, these recoils are much more efficient per unit energy at producing freely migrating defects than the high energy recoils responsible for most of the displacements in the other neutron spectra considered. A significantly better correlation of data from HFIR with those from the other spectra is achieved when the property changes are compared on the basis of the production of freely migrating self-interstitial defects. (orig./MM)

  10. Reactor calculation benchmark PCA blind test results

    International Nuclear Information System (INIS)

    Kam, F.B.K.; Stallmann, F.W.

    1980-01-01

    Further improvement in calculational procedures or a combination of calculations and measurements is necessary to attain 10 to 15% (1 sigma) accuracy for neutron exposure parameters (flux greater than 0.1 MeV, flux greater than 1.0 MeV, and dpa). The calculational modeling of power reactors should be benchmarked in an actual LWR plant to provide final uncertainty estimates for end-of-life predictions and limitations for plant operations. 26 references, 14 figures, 6 tables

  11. Reactor calculation benchmark PCA blind test results

    Energy Technology Data Exchange (ETDEWEB)

    Kam, F.B.K.; Stallmann, F.W.

    1980-01-01

    Further improvement in calculational procedures or a combination of calculations and measurements is necessary to attain 10 to 15% (1 sigma) accuracy for neutron exposure parameters (flux greater than 0.1 MeV, flux greater than 1.0 MeV, and dpa). The calculational modeling of power reactors should be benchmarked in an actual LWR plant to provide final uncertainty estimates for end-of-life predictions and limitations for plant operations. 26 references, 14 figures, 6 tables.

  12. Dose dependence of nano-hardness of 6H-SiC crystal under irradiation with inert gas ions

    Science.gov (United States)

    Yang, Yitao; Zhang, Chonghong; Su, Changhao; Ding, Zhaonan; Song, Yin

    2018-05-01

    Single crystal 6H-SiC was irradiated by inert gas ions (He, Ne, Kr and Xe ions) to various damage levels at room temperature. Nano-indentation test was performed to investigate the hardness change behavior with damage. The depth profile of nano-hardness for 6H-SiC decreased with increasing depth for both the pristine and irradiated samples, which was known as indentation size effect (ISE). Nix-Gao model was proposed to determine an asymptotic value of nano-hardness by taking account of ISE for both the pristine and irradiated samples. In this study, nano-hardness of the irradiated samples showed a strong dependence on damage level and showed a weak dependence on ions species. From the dependence of hardness on damage, it was found that the change of hardness demonstrated three distinguishable stages with damage: (I) The hardness increased with damage from 0 to 0.2 dpa and achieved a maximum of hardening fraction ∼20% at 0.2 dpa. The increase of hardness in this damage range was contributed to defects produced by ion irradiation, which can be described well by Taylor relation. (II) The hardness reduced rapidly with large decrement in the damage range from 0.2 to 0.5 dpa, which was considered to be from the covalent bond breaking. (III) The hardness reduced with small decrement in the damage range from 0.5 to 2.2 dpa, which was induced by extension of the amorphous layer around damage peak.

  13. Temperature Effects on the Mechanical Properties of Candidate SNS Target Container Materials after Proton and Neutron Irradiation; TOPICAL

    International Nuclear Information System (INIS)

    Byun, T.S.

    2001-01-01

    This report presents the tensile properties of EC316LN austenitic stainless steel and 9Cr-2WVTa ferritic/martensitic steel after 800 MeV proton and spallation neutron irradiation to doses in the range 0.54 to 2.53 dpa. Irradiation temperatures were in the range 30 to 100 C. Tensile testing was performed at room temperature (20 C) and 164 C to study the effects of test temperature on the tensile properties. Test materials displayed significant radiation-induced hardening and loss of ductility due to irradiation. The EC316LN stainless steel maintained notable strain-hardening capability after irradiation, while the 9Cr-2WVTa ferritic/martensitic steel posted negative strain hardening. In the EC316LN stainless steel, increasing the test temperature from 20 C to 164 C decreased the strength by 13 to 18% and the ductility by 8 to 36%. The tensile data for the EC316LN stainless steel irradiated in spallation conditions were in line with the values in a database for 316 stainless steels for doses up to 1 dpa irradiated in fission reactors at temperatures below 200 C. However, extra strengthening induced by helium and hydrogen contents is evident in some specimens irradiated to above about 1 dpa. The effect of test temperature for the 9Cr-2WVTa ferritic/martensitic steel was less significant than for the EC316LN stainless steel. In addition, strain-hardening behaviors were analyzed for EC316LN and 316L stainless steels. The strain-hardening rate of the 316 stainless steels was largely dependent on test temperature. It was estimated that the 316 stainless steels would retain more than 1% true stains to necking at 164 C after irradiation to 5 dpa. A calculation using reduction of area (RA) measurements and stress-strain data predicted positive strain hardening during plastic instability

  14. Neutron irradiation creep in stainless steel alloys

    Energy Technology Data Exchange (ETDEWEB)

    Schuele, Wolfgang (Commission of the European Union, Institute for Advanced Materials, I-21020 Ispra (Vatican City State, Holy See) (Italy)); Hausen, Hermann (Commission of the European Union, Institute for Advanced Materials, I-21020 Ispra (Vatican City State, Holy See) (Italy))

    1994-09-01

    Irradiation creep elongations were measured in the HFR at Petten on AMCR steels, on 316 CE-reference steels, and on US-316 and US-PCA steels varying the irradiation temperature between 300 C and 500 C and the stress between 25 and 300 MPa. At the beginning of an irradiation a type of primary'' creep stage is observed for doses up to 3-5 dpa after which dose the secondary'' creep stage begins. The primary'' creep strain decreases in cold-worked steel materials with decreasing stress and decreasing irradiation temperature achieving also negative creep strains depending also on the pre-treatment of the materials. These primary'' creep strains are mainly attributed to volume changes due to the formation of radiation-induced phases, e.g. to the formation of [alpha]-ferrite below about 400 C and of carbides below about 700 C, and not to irradiation creep. The secondary'' creep stage is found for doses larger than 3 to 5 dpa and is attributed mainly to irradiation creep. The irradiation creep rate is almost independent of the irradiation temperature (Q[sub irr]=0.132 eV) and linearly dependent on the stress. The total creep elongations normalized to about 8 dpa are equal for almost every type of steel irradiated in the HFR at Petten or in ORR or in EBR II. The negative creep elongations are more pronounced in PCA- and in AMCR-steels and for this reason the total creep elongation is slightly smaller at 8 dpa for these two steels than for the other steels. ((orig.))

  15. Diffusion Couple Alloying of Refractory Metals in Austenitic and Ferritic/Martensitic Steels

    Science.gov (United States)

    2012-03-01

    stainless steel and ferritic/ martensitic steel can vary from structural and support components in the reactor core to reactor fuel...of ferritic/ martensitic steels compared to type 316 stainless steel after irradiation in Experimental Breeder Reactor-II at 420 ºC to ~80dpa (From...ferritic martensitic steel at Sandia National Laboratories. The 316 stainless steel had a certified composition of:

  16. Promising Cu-Ni-Cr-Si alloy for first wall ITER applications

    International Nuclear Information System (INIS)

    Ivanov, A.; Abramov, V.; Rodin, M.

    1996-01-01

    Precipitation-hardened Cu-Ni-Cr-Si alloy, a promising material for ITER applications, is considered. Available commercial products, chemical composition, physical and mechanical properties are presented. Embrittlement of Cu-Ni-Cr-Si alloy at 250-300 C is observed. Mechanical properties of Cu-Ni-Cr-Si alloy neutron irradiated to a dose of ∝0.2 dpa at 293 C are investigated. Embrittlement of Cu-Ni-Cr-Si alloy can be avoided by annealing. (orig.)

  17. Developmental and hormonal regulation of fiber quality in two natural-colored cotton cultivars

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiang; HU Da-peng; LI Yuan; CHEN Yuan; Eltayib H.M.A.Abidallha; DONG Zhao-di; CHEN De-hua; ZHANG Lei

    2017-01-01

    Cotton cultivars with brown (Xiangcaimian 2),green (Wanmian 39) and white (Sumian 9) fiber were investigated to study fiber developmental characteristics of natural-colored cotton and the effect of hormones on fiber quality at different stages after anthesis.Fiber lengths of both natural-colored cottons were lower than the white-fibered control,with brown-flbered cotton longer than green.Fiber strength,micronaire and maturation of natural-colored cotton were also lower than the control.The shorter fiber of the green cultivar was due to slower growth during 10 to 30 days post-anthesis (DPA).Likewise,the lower fiber strength,micronaire and maturation of natured-colored cotton were also due to slower growth during this pivotal stage.Indole-3-acetic acid (IAA) content at 10 DPA,and abscisic acid (ABA) content at 30 to 40 DPA were lower in the fibers of the natural-colored than that of the white-flbered cotton.After applying 20 mg L-1 gibberellic acid (GA3),the IAA content at 20 DPA in the brown and green-fibered cottons increased by 51.07 and 64.33%,fiber ABA content increased by 38.96 and 24.40%,and fiber length increased by 8.13 and 13.96%,respectively.Fiber strength,micronaire and maturation were also enhanced at boll opening stage.Those results suggest that the level of endogenous hormones affect fiber quality.Application of external hormones can increase hormone content in natural-colored cotton fiber,improving its quality.

  18. Radiation hardening of metals irradiated by heavy ions

    International Nuclear Information System (INIS)

    Didyk, A.Yu.; Skuratov, V.A.; Mikhajlova, N.Yu.; Regel', V.R.

    1988-01-01

    The damage dose dependence in the 10 -4 -10 -2 dpa region of radiation hardening of Al, V, Ni, Cu irradiated by xenon ions with 124 MeV energy is investigated using the microhardness technique and transmission electron microscope. It is shown that the pure metals radiation hardening is stimulated for defects clusters with the typical size less than 5 nm, as in the case of neutron and the light charge ion irradiation

  19. High-energy-neutron damage in Nb3Sn: changes in critical properties, and damage-energy analysis

    International Nuclear Information System (INIS)

    Snead, C.L. Jr.; Parkin, D.M.; Guinan, M.W.

    1981-01-01

    Filamentary wires of Nb 3 Sn have been irradiated with fission-reactor, 14.8-MeV, and d-Be neutrons and the changes in critical properties measured. The changes observed scale reasonably well with the calculated damage energies for the irradiations. A critical dose for operation of these conductors in fusion-magnet applications is determined to be 0.19 eV/atom damage energy or 0.0019 dpa

  20. Dislocation and void segregation in copper during neutron irradiation

    DEFF Research Database (Denmark)

    Singh, Bachu Narain; Leffers, Torben; Horsewell, Andy

    1986-01-01

    ); the irradiation experiments were carried out at 250 degree C. The irradiated specimens were examined by transmission electron microscopy. At both doses, the irradiation-induced structure was found to be highly segregated; the dislocation loops and segments were present in the form of irregular walls and the voids...... density, the void swelling rate was very high (approximately 2. 5% per dpa). The implications of the segregated distribution of sinks for void formation and growth are briefly discussed....

  1. Neutron-irradiation + helium hardening and embrittlement modeling of 9% Cr-steels in an engineering perspective (HELENA)

    Energy Technology Data Exchange (ETDEWEB)

    Chaouadi, Rachid

    2008-07-01

    This report provides a physically-based engineering model to estimate the radiation hardening of 9%Cr-steels under both displacement damage (dpa) and helium. The model is essentially based on the dispersed barrier hardening theory and the dynamic re-solution of helium under displacement cascades. However, a number of assumptions and simplifications were considered to obtain a simple description of irradiation hardening and embrittlement primarily relying on the available experimental data. As a result, two components were basically identified, the dpa component that can be associated with black dots and small loops and the He-component accounting for helium bubbles. The dpa component is strongly dependent on the irradiation temperature and its dependence law was based on a first-order annealing kinetics. The damage accumulation law was also modified to take saturation into account. Finally, the global kinetics of the damage accumulation kept defined, its amplitude is fitted to one experimental condition. The model was rationalized on an experimental database that mainly consists of {proportional_to}9%Cr-steels irradiated in the technologically important temperature range of 50 to 600 C up do 50 dpa and with a He-content up to {proportional_to}5000 appm, including neutron and proton irradiation as well as implantation. The test temperature effect is taken into account through a normalization procedure based on the change of the Young's modulus and the anelastic deformation that occurs at high temperature. Finally, the hardening-to-embrittlement correlation is obtained using the load diagram approach. Despite the large experimental scatter, inherent to the variety of the materials and irradiation as well as testing conditions, the obtained results are very promising. Improvement of the model performance is still possible by including He-hardening saturation and high temperature softening but unfortunately, at this stage, a number of conflicting experimental data

  2. 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

  3. Comparative Transcriptomics Reveals Jasmonic Acid-Associated Metabolism Related to Cotton Fiber Initiation.

    Directory of Open Access Journals (Sweden)

    Liman Wang

    Full Text Available Analysis of mutants and gene expression patterns provides a powerful approach for investigating genes involved in key stages of plant fiber development. In this study, lintless-fuzzless XinWX and linted-fuzzless XinFLM with a single genetic locus difference for lint were used to identify differentially expressed genes. Scanning electron microscopy showed fiber initiation in XinFLM at 0 days post anthesis (DPA. Fiber transcriptional profiling of the lines at three initiation developmental stages (-1, 0, 1 DPA was performed using an oligonucleotide microarray. Loop comparisons of the differentially expressed genes within and between the lines was carried out, and functional classification and enrichment analysis showed that gene expression patterns during fiber initiation were heavily associated with hormone metabolism, transcription factor regulation, lipid transport, and asparagine biosynthetic processes, as previously reported. Further, four members of the allene-oxide cyclase (AOC family that function in jasmonate biosynthesis were parallel up-regulation in fiber initiation, especially at -1 DPA, compared to other tissues and organs in linted-fuzzed TM-1. Real time-quantitative PCR (RT-qPCR analysis in different fiber mutant lines revealed that AOCs were up-regulated higher at -1 DPA in lintless-fuzzless than that in linted-fuzzless and linted-fuzzed materials, and transcription of the AOCs was increased under jasmonic acid (JA treatment. Expression analysis of JA biosynthesis-associated genes between XinWX and XinFLM showed that they were up-regulated during fiber initiation in the fuzzless-lintless mutant. Taken together, jasmonic acid-associated metabolism was related to cotton fiber initiation. Parallel up-regulation of AOCs expression may be important for normal fiber initiation development, while overproduction of AOCs might disrupt normal fiber development.

  4. THE COMBINED EFFECT OF ORGANIC PHOSPHINATE BASED FLAME RETARDANT AND ZINC BORATE ON THE FIRE BEHAVIOR OF POLY(BUTYLENE TEREPHTHALATE

    Directory of Open Access Journals (Sweden)

    Mustafa Erdem ÜREYEN

    2016-12-01

    Full Text Available Neat poly(butylene terephthalate is highly combustible. It is not self-extinguishing, and after ignition it burns with dripping. To meet the fire safety requirements, it should be rendered flame retardant. The most common flame retardants for PBT are based on halogenated (most often brominated or phosphorus compounds. Although their efficiency is lower than halogen based flame retardants, expensive phosphorus based flame retardants for polyester are preferred, because of low smoke generation, nontoxicity and low corrosion properties. Zinc borate has been widely used with other flame retardants in wood products and in several polymers. In this work the fire behavior of zinc borate, phosphinic acid and zinc borate/phosphinic acid combination doped poly(butylene terephthalate was investigated. Firstly, the mean particle size of zinc borate (2ZnO.3B2O3.3.5H2O powders were reduced by attrition milling. Samples were produced by twin screw micro compounder. The fire properties of the ZnB, DPA and ZnB/DPA doped PBT were investigated and compared to each other by LOI and thermal analysis. LOI values of ZnB/PBT samples were found very low even with higher filling content. At higher loading of ZnB, the dripping of the sample strongly decreased and char residue increased. It was seen that organic diethyl phosphinic acid based additives DPA is particularly effective with PBT. It was found that the combination of DPA and ZnB can be used to increase the char residue, decrease spread of flame and the melt dripping of PBT.

  5. Neutron-irradiation + helium hardening and embrittlement modeling of 9% Cr-steels in an engineering perspective (HELENA)

    International Nuclear Information System (INIS)

    Chaouadi, Rachid

    2008-01-01

    This report provides a physically-based engineering model to estimate the radiation hardening of 9%Cr-steels under both displacement damage (dpa) and helium. The model is essentially based on the dispersed barrier hardening theory and the dynamic re-solution of helium under displacement cascades. However, a number of assumptions and simplifications were considered to obtain a simple description of irradiation hardening and embrittlement primarily relying on the available experimental data. As a result, two components were basically identified, the dpa component that can be associated with black dots and small loops and the He-component accounting for helium bubbles. The dpa component is strongly dependent on the irradiation temperature and its dependence law was based on a first-order annealing kinetics. The damage accumulation law was also modified to take saturation into account. Finally, the global kinetics of the damage accumulation kept defined, its amplitude is fitted to one experimental condition. The model was rationalized on an experimental database that mainly consists of ∝9%Cr-steels irradiated in the technologically important temperature range of 50 to 600 C up do 50 dpa and with a He-content up to ∝5000 appm, including neutron and proton irradiation as well as implantation. The test temperature effect is taken into account through a normalization procedure based on the change of the Young's modulus and the anelastic deformation that occurs at high temperature. Finally, the hardening-to-embrittlement correlation is obtained using the load diagram approach. Despite the large experimental scatter, inherent to the variety of the materials and irradiation as well as testing conditions, the obtained results are very promising. Improvement of the model performance is still possible by including He-hardening saturation and high temperature softening but unfortunately, at this stage, a number of conflicting experimental data reported in literature should

  6. Dietary supplement enriched in antioxidants and omega-3 protects from progressive light-induced retinal degeneration.

    Science.gov (United States)

    Ramchani-Ben Othman, Khaoula; Cercy, Christine; Amri, Mohamed; Doly, Michel; Ranchon-Cole, Isabelle

    2015-01-01

    In the present study, we have evaluated one of the dietary supplements enriched with antioxidants and fish oil used in clinical care for patient with age-related macular degeneration. Rats were orally fed by a gastric canula daily with 0.2 ml of water or dietary supplement until they were sacrificed. After one week of treatment, animals were either sacrificed for lipid analysis in plasma and retina, or used for evaluation of rod-response recovery by electroretinography (ERG) followed by their sacrifice to measure rhodopsin content, or used for progressive light-induced retinal degeneration (PLIRD). For PLIRD, animals were transferred to bright cyclic light for one week. Retinal damage was quantified by ERG, histology and detection of apoptotic nuclei. Animals kept in dim-cyclic-light were processed in parallel. PLIRD induced a thinning of the outer nuclear layer and a reduction of the b-wave amplitude of the ERG in the water group. Retinal structure and function were preserved in supplemented animals. Supplement induced a significant increase in omega-3 fatty acids in plasma by 168% for eicosapentaenoic acid (EPA), 142% for docosapentaenoic acid (DPA) and 19% for docosahexaenoic acid (DHA) and a decrease in the omega-6 fatty acids, DPA by 28%. In the retina, supplement induced significant reduction of linolenic acid by 67% and an increase in EPA and DPA by 80% and 72%, respectively, associated with significant decrease in omega-6 DPA by 42%. Supplement did not affect rhodopsin content or rod-response recovery. The present data indicate that supplement rapidly modified the fatty acid content and induced an accumulation of EPA in the retina without affecting rhodopsin content or recovery. In addition, it protected the retina from oxidative stress induced by light. Therefore, this supplement might be beneficial to slow down progression of certain retinal degeneration.

  7. Capillary-wave dynamics and interface structure modulation in binary Bose-Einstein condensate mixtures

    Science.gov (United States)

    Indekeu, Joseph O.; Van Thu, Nguyen; Lin, Chang-You; Phat, Tran Huu

    2018-04-01

    The localized low-energy interfacial excitations, or interfacial Nambu-Goldstone modes, of phase-segregated binary mixtures of Bose-Einstein condensates are investigated analytically. To this end a double-parabola approximation (DPA) is performed on the Lagrangian density in Gross-Pitaevskii theory for a system in a uniform potential. This DPA entails a model in which analytic expressions are obtained for the excitations underlying capillary waves or ripplons for arbitrary strength K (>1 ) of the phase segregation. The dispersion relation ω (k ) ∝k3 /2 is derived directly from the Bogoliubov-de Gennes equations in the limit that the wavelength 2 π /k is much larger than the interface width. The proportionality constant in the dispersion relation provides the static interfacial tension. A correction term in ω (k ) of order k5 /2 is calculated analytically within the DPA model. The combined result is tested against numerical diagonalization of the exact Bogoliubov-de Gennes equations. Satisfactory agreement is obtained in the range of physically relevant wavelengths. The ripplon dispersion relation is relevant to state-of-the-art experiments using (quasi)uniform optical-box traps. Furthermore, within the DPA model explicit expressions are obtained for the structural deformation of the interface due to the passing of the capillary wave. It is found that the amplitude of the wave is enhanced by an amount that is quadratic in the ratio of the phase velocity ω /k to the sound velocity c . For generic mixtures consisting of condensates with unequal healing lengths, an additional modulation is predicted of the common value of the condensate densities at the interface.

  8. Peer Victimization and Social Alienation: Predicting Deviant Peer Affiliation in Middle School

    Science.gov (United States)

    Rudolph, Karen D.; Lansford, Jennifer E.; Agoston, Anna M.; Sugimura, Niwako; Schwartz, David; Dodge, Kenneth A.; Pettit, Gregory S.; Bates, John E.

    2014-01-01

    Two prospective studies examined a theoretical model wherein exposure to victimization, resulting from early behavioral risk, heightens children's social alienation and subsequent deviant peer affiliation (DPA). Across Study 1 (298 girls, 287 boys; K-7th grade; 5-12 years) and Study 2 (338 girls, 298 boys; 2nd-6th grade; 8-12 years),…

  9. Carvacrol suppresses high pressure high temperature inactivation of Bacillus cereus spores.

    Science.gov (United States)

    Luu-Thi, Hue; Corthouts, Jorinde; Passaris, Ioannis; Grauwet, Tara; Aertsen, Abram; Hendrickx, Marc; Michiels, Chris W

    2015-03-16

    The inactivation of bacterial spores generally proceeds faster and at lower temperatures when heat treatments are conducted under high pressure, and high pressure high temperature (HPHT) processing is, therefore, receiving an increased interest from food processors. However, the mechanisms of spore inactivation by HPHT treatment are poorly understood, particularly at moderately elevated temperature. In the current work, we studied inactivation of the spores of Bacillus cereus F4430/73 by HPHT treatment for 5 min at 600MPa in the temperature range of 50-100°C, using temperature increments of 5°C. Additionally, we investigated the effect of the natural antimicrobial carvacrol on spore germination and inactivation under these conditions. Spore inactivation by HPHT was less than about 1 log unit at 50 to 70°C, but gradually increased at higher temperatures up to about 5 log units at 100°C. DPA release and loss of spore refractility in the spore population were higher at moderate (≤65°C) than at high (≥70°C) treatment temperatures, and we propose that moderate conditions induced the normal physiological pathway of spore germination resulting in fully hydrated spores, while at higher temperatures this pathway was suppressed and replaced by another mechanism of pressure-induced dipicolinic acid (DPA) release that results only in partial spore rehydration, probably because spore cortex hydrolysis is inhibited. Carvacrol strongly suppressed DPA release and spore rehydration during HPHT treatment at ≤65°C and also partly inhibited DPA release at ≥65°C. Concomitantly, HPHT spore inactivation was reduced by carvacrol at 65-90°C but unaffected at 95-100°C. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Saturation behavior of irradiation hardening in F82H irradiated in the HFIR

    Energy Technology Data Exchange (ETDEWEB)

    Hirose, T. [Blanket Engineering Group, Japan Atomic Energy Agency, Naka, Ibaraki (Japan); Shiba, K.; Tanigawa, H.; Ando, M. [Japan Atomic Energy Agency, Tokai-mura, Naga-gun, Ibaraki-ken (Japan); Klueh, R.L. [Oak Ridge National Laboratory, TN (United States); Stoller, R. [ORNL - Oak Ridge National Laboratory, Materials Science and Technology Div., Oak Ridge, AK TN (United States)

    2007-07-01

    Full text of publication follows: Post irradiation tensile tests on reduced activation ferritic/martensitic steel, F82H have been conducted over the past two decades using Japan Materials Testing Reactor (JMTR) of JAEA, and Fast Flux Testing Facility (FFTF) of PNNL and High Flux Isotope Reactor (HFIR) of ORNL, USA, under Japan/US collaboration programs. According to these results, F82H does not demonstrate irradiation hardening above 673 K up to 60 dpa. The current study has been concentrated on hardening behavior at temperature around 573 K. A series of low temperature irradiation experiment has been conducted at the HFIR under the international collaborative research between JAEA/US-DOE. In this collaboration, the irradiation condition is precisely controlled by the well matured capsule designing and instrumentation. This paper summarizes recent results of the irradiation experiments focused on F82H and its modified steels compared with the irradiation properties database on F82H. Post irradiation tensile tests have been conducted on the F82H and its modified steels irradiated at 573 K and the dose level was up to 25 dpa. According to these results, irradiation hardening of F82H is saturated by 9 dpa and the as-irradiated 0.2 % proof stress is less than 1 GPa at ambient temperature. The deterioration of total elongation was also saturated by 9 dpa irradiation. The ductility of some modified steels which showed larger total elongation than that of F82H before irradiation become the same level as that of standard F82H steel after irradiation, even though its magnitude of irradiation hardening is smaller than that of F82H. This suggests that the more ductile steel demonstrates the more ductility loss at this temperature, regardless to the hardening level. The difference in ductility loss behavior between various tensile specimens will be discussed as the ductility could depend on the specimen dimension. (authors)

  11. Evaluation of fatigue properties of HFIR-irradiated nimonic PE-16 at 4300C

    International Nuclear Information System (INIS)

    Grossbeck, M.L.; Liu, K.C.

    1984-01-01

    Nimonic PE-16 was irradiated in the HFIR to 6 to 9 dpa and 560 to 1000 at. ppM He at 430 0 C. Postirradiation fatigue tests revealed a reduction in fatigue life by about a factor of 10 at 430 0 C. In contrast with AISI type 316 stainless steel, no endurance limit was observed. All irradiated specimens exhibited some intergranular fracture with an increasing tendency toward cleavage like intragranular fracture for low strain ranges

  12. Fatigue performance of HFIR-irradiated Nimonic PE-16 at 4300C

    International Nuclear Information System (INIS)

    Grossbeck, M.L.; Liu, K.C.

    1983-01-01

    Nimonic PE-16 was irradiated in the HFIR to 6 to 9 dpa and 560 to 1000 at. ppM He at 430 0 C. Postirradiation fatigue tests revealed a reduction in fatigue life by about a factor of 10 at 430 0 C. In contrast to AISI type 316 stainless steel, no endurance limit was observed. All irradiated specimens exhibited some intergranular fracture with an increasing tendency toward cleavage-like intragranular fracture for low strain ranges

  13. Dietary supplement enriched in antioxidants and omega-3 protects from progressive light-induced retinal degeneration.

    Directory of Open Access Journals (Sweden)

    Khaoula Ramchani-Ben Othman

    Full Text Available In the present study, we have evaluated one of the dietary supplements enriched with antioxidants and fish oil used in clinical care for patient with age-related macular degeneration. Rats were orally fed by a gastric canula daily with 0.2 ml of water or dietary supplement until they were sacrificed. After one week of treatment, animals were either sacrificed for lipid analysis in plasma and retina, or used for evaluation of rod-response recovery by electroretinography (ERG followed by their sacrifice to measure rhodopsin content, or used for progressive light-induced retinal degeneration (PLIRD. For PLIRD, animals were transferred to bright cyclic light for one week. Retinal damage was quantified by ERG, histology and detection of apoptotic nuclei. Animals kept in dim-cyclic-light were processed in parallel. PLIRD induced a thinning of the outer nuclear layer and a reduction of the b-wave amplitude of the ERG in the water group. Retinal structure and function were preserved in supplemented animals. Supplement induced a significant increase in omega-3 fatty acids in plasma by 168% for eicosapentaenoic acid (EPA, 142% for docosapentaenoic acid (DPA and 19% for docosahexaenoic acid (DHA and a decrease in the omega-6 fatty acids, DPA by 28%. In the retina, supplement induced significant reduction of linolenic acid by 67% and an increase in EPA and DPA by 80% and 72%, respectively, associated with significant decrease in omega-6 DPA by 42%. Supplement did not affect rhodopsin content or rod-response recovery. The present data indicate that supplement rapidly modified the fatty acid content and induced an accumulation of EPA in the retina without affecting rhodopsin content or recovery. In addition, it protected the retina from oxidative stress induced by light. Therefore, this supplement might be beneficial to slow down progression of certain retinal degeneration.

  14. Dependence of irradiation creep on temperature and atom displacements in 20% cold worked type 316 stainless steel

    International Nuclear Information System (INIS)

    Gilbert, E.R.

    1976-04-01

    Irradiation creep studies with pressurized tubes of 20 percent cold worked Type 316 stainless steel were conducted in EBR-2. Results showed that as atom displacements are extended above 5 dpa and temperatures are increased above 375 0 C, the irradiation induced creep rate increases with both increasing atom displacements and increasing temperature. The stress exponent for irradiation induced creep remained near unity. Irradiation-induced effective creep strains up to 1.8 percent were observed without specimen failure. 13 figures

  15. Detection of radiation-induced changes in electrochemical properties of austenitic stainless steels using miniaturized specimens and the single-loop electrochemical potentiokinetic reactivation method

    International Nuclear Information System (INIS)

    Inazumi, T.; Bell, G.E.C.; Kenik, E.A.; Kiuchi, K.

    1993-01-01

    Single-loop electrochemical potentiokinetic reactivation testing of miniaturized (TEM) specimens can provide reliable data comparable to data obtained with larger specimens. Significant changes in electrochemical properties (increased reactivation current and Flade potential) were detected for PCA and type 316 stainless steels irradiated at 200--420 degrees C up to 7--9 dpa. Irradiations in the FFTF Materials Open Test Assembly and in the Oak Ridge Research Reactor are reported on. 45 figs., 5 tabs., 52 refs

  16. Swelling behavior of titanium-modified AISI 316 alloys

    International Nuclear Information System (INIS)

    Garner, F.A.; Brager, H.R.; Puigh, R.J.

    1984-01-01

    It appears that titanium additions to stainless steels covering a wide compositional range around the specifications of AISI 316 result only in an increased delay period before neutron-induced void swelling proceeds. Once swelling is initiated the post transient behavior of both annealed and cold-worked titanium-modified steels is quite consistent with that of AISI 316, approaching a relatively temperature-independent swelling rate of approx. 1% per dpa

  17. A study of the effect of helium concentration and displacement damage on the microstructure of helium ion irradiated tungsten

    Science.gov (United States)

    Harrison, R. W.; Greaves, G.; Hinks, J. A.; Donnelly, S. E.

    2017-11-01

    Transmission electron microscopy (TEM) with in-situ He ion irradiation has been used to examine the damage microstructure of W when varying the helium concentration to displacement damage ratio, irradiation temperature and total dose. Irradiations employed 15, 60 or 85 keV He ions, at temperatures between 500 and 1000 °C up to doses of ∼3.0 DPA. Once nucleated and grown to an observable size in the TEM, bubble diameter as a function of irradiation dose did not measurably increase at irradiation temperatures of 500 °C between 1.0 and 3.0 DPA; this is attributed to the low mobility of vacancies and He/vacancy complexes at these temperatures. Bubble diameter increased slightly for irradiation temperatures of 750 °C and rapidly increased when irradiated at 1000 °C. Dislocation loops were observed at irradiation temperatures of 500 and 750 °C and no loops were observed at 1000 °C. Burgers vectors of the dislocations were determined to be b = ±½ type only and both vacancy and interstitial loops were observed. The proportion of interstitial loops increased with He-appm/DPA ratio and this is attributed to the concomitant increase in bubble areal density, which reduces the vacancy flux for both the growth of vacancy-type loops and the annihilation of interstitial clusters.

  18. Radiation-induced segregation at grain boundaries in AL-6XN stainless steels irradiated by hydrogen ions

    Science.gov (United States)

    Long, Yunxiang; Zheng, Zhongcheng; Guo, Liping; Zhang, Weiping; Shen, Zhenyu; Tang, Rui

    2018-04-01

    The effect of high concentration of hydrogen on the segregation of radiation-induced segregation (RIS) in AL-6XN stainless steels has been investigated by transmission electron microscopy (TEM) with energy-dispersive X-ray spectroscopy. Specimens were irradiated with 100 keV H2+ ions from 1 dpa to 5 dpa at 380 °C to investigated the dose dependence of grain boundary RIS. A specimen was irradiated to 5 dpa at 290 °C to study the effect of irradiation temperature. The trends of Cr depletion and Ni enrichment with irradiation dose is similar to that of other austenitic steels reported in the literatures, but the higher concentration of hydrogen made the RIS profile wider. An abnormal phenomenon that the degree of RIS increased with decreasing irradiation temperature was found, indicating that with the retention of hydrogen in the steels, temperature dependence of RIS is dominated by the quantity of retained hydrogen, rather than by thermal segregation processes.

  19. Enhanced dipicolinic acid production during the stationary phase in Bacillus subtilis by blocking acetoin synthesis.

    Science.gov (United States)

    Toya, Yoshihiro; Hirasawa, Takashi; Ishikawa, Shu; Chumsakul, Onuma; Morimoto, Takuya; Liu, Shenghao; Masuda, Kenta; Kageyama, Yasushi; Ozaki, Katsuya; Ogasawara, Naotake; Shimizu, Hiroshi

    2015-01-01

    Bacterial bio-production during the stationary phase is expected to lead to a high target yield because the cells do not consume the substrate for growth. Bacillus subtilis is widely used for bio-production, but little is known about the metabolism during the stationary phase. In this study, we focused on the dipicolinic acid (DPA) production by B. subtilis and investigated the metabolism. We found that DPA production competes with acetoin synthesis and that acetoin synthesis genes (alsSD) deletion increases DPA productivity by 1.4-fold. The mutant showed interesting features where the glucose uptake was inhibited, whereas the cell density increased by approximately 50%, resulting in similar volumetric glucose consumption to that of the parental strain. The metabolic profiles revealed accumulation of pyruvate, acetyl-CoA, and the TCA cycle intermediates in the alsSD mutant. Our results indicate that alsSD-deleted B. subtilis has potential as an effective host for stationary-phase production of compounds synthesized from these intermediates.

  20. Behavior of ferritic/martensitic steels after n-irradiation at 200 and 300 deg. C

    International Nuclear Information System (INIS)

    Matijasevic, M.; Lucon, E.; Almazouzi, A.

    2008-01-01

    High chromium ferritic/martensitic (F/M) steels are considered as the most promising structural materials for accelerator driven systems (ADS). One drawback that needs to be quantified is the significant hardening and embrittlement caused by neutron irradiation at low temperatures with production of spallation elements. In this paper irradiation effects on the mechanical properties of F/M steels have been studied and comparisons are provided between two ferritic/martensitic steels, namely T91 and EUROFER97. Both materials have been irradiated in the BR2 reactor of SCK-CEN/Mol at 300 deg. C up to doses ranging from 0.06 to 1.5 dpa. Tensile tests results obtained between -160 deg. C and 300 deg. C clearly show irradiation hardening (increase of yield and ultimate tensile strengths), as well as reduction of uniform and total elongation. Irradiation effects for EUROFER97 starting from 0.6 dpa are more pronounced compared to T91, showing a significant decrease in work hardening. The results are compared to our latest data that were obtained within a previous program (SPIRE), where T91 had also been irradiated in BR2 at 200 deg. C (up to 2.6 dpa), and tested between -170 deg. C and 300 deg. C. Irradiation effects at lower irradiation temperatures are more significant

  1. Behavior of ferritic/martensitic steels after n-irradiation at 200 and 300 °C

    Science.gov (United States)

    Matijasevic, M.; Lucon, E.; Almazouzi, A.

    2008-06-01

    High chromium ferritic/martensitic (F/M) steels are considered as the most promising structural materials for accelerator driven systems (ADS). One drawback that needs to be quantified is the significant hardening and embrittlement caused by neutron irradiation at low temperatures with production of spallation elements. In this paper irradiation effects on the mechanical properties of F/M steels have been studied and comparisons are provided between two ferritic/martensitic steels, namely T91 and EUROFER97. Both materials have been irradiated in the BR2 reactor of SCK-CEN/Mol at 300 °C up to doses ranging from 0.06 to 1.5 dpa. Tensile tests results obtained between -160 °C and 300 °C clearly show irradiation hardening (increase of yield and ultimate tensile strengths), as well as reduction of uniform and total elongation. Irradiation effects for EUROFER97 starting from 0.6 dpa are more pronounced compared to T91, showing a significant decrease in work hardening. The results are compared to our latest data that were obtained within a previous program (SPIRE), where T91 had also been irradiated in BR2 at 200 °C (up to 2.6 dpa), and tested between -170 °C and 300 °C. Irradiation effects at lower irradiation temperatures are more significant.

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

    International Nuclear Information System (INIS)

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

    2005-01-01

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

  3. Microstructural evolution in low alloy steels under high dose ion irradiation

    International Nuclear Information System (INIS)

    Fujii, Katsuhiko; Fukuya, Koji; Ohkubo, Tadakatsu; Hono, Kazuhiro

    2006-01-01

    Radiation hardening and microstructural evolution in low Cu A533B steels (0.03 wt% Cu) irradiated by 3 MeV Ni 2+ ions at 290degC to 1 dpa were investigated by ultra-micro hardness measurement and leaser type three dimensional atom probe analysis. Mn-Ni-Si enriched precipitates were detected in the samples irradiated to 1 dpa by 3DAP analysis. The well-defined precipitates had a size of less than 4 nm, and the number density increased with dose. The formation of the precipitates under high dose rate irradiation suggested that Mn-Ni-Si enriched precipitates were formed by a process such as radiation induced precipitation rather than by thermal equilibrium process. The increase of yield stress calculated by size and number density of the precipitates in 1 dpa irradiated sample using the similar value of hardening efficiency to that of Cu rich precipitates was consistent with that estimated by data of increases of hardness measured by nano-indentation. The result indicates that effects of Mn-Ni-Si enriched precipitates on radiation embrittlement are similar to those of Cu rich precipitates. (author)

  4. Modulation of in vivo distribution through chelator: Synthesis and evaluation of a 2-nitroimidazole-dipicolylamine-(99m)Tc(CO)3 complex for detecting tumor hypoxia.

    Science.gov (United States)

    Mallia, Madhava B; Mittal, Sweety; Sarma, Haladhar D; Banerjee, Sharmila

    2016-01-01

    Previous studies have clearly demonstrated strong correlation between in vivo distribution and blood clearance of radiopharmaceuticals for the detection of hypoxia. Present study describes an attempt to improve the in vivo distribution of a previously reported 2-nitroimidazole-(99m)Tc(CO)3 complex by tuning its blood clearance pattern through structural modification of the ligand. Herein, a 2-nitroimidazole-dipicolylamine ligand (2-nitroimidazole-DPA) was synthesized in a two-step procedure and radiolabeled with (99m)Tc(CO)3 core. Subsequently, the complex was evaluated in Swiss mice bearing fibrosarcoma tumor. As intended by its design, 2-nitroimidazole-DPA-(99m)Tc(CO)3 complex was more lipophilic than previously reported 2-nitroimidazole-DETA-(99m)Tc(CO)3 complex (DETA-diethylenetriamine) and showed slower blood clearance. Consequently it showed higher tumor uptake than 2-nitroimidazole-DETA-(99m)Tc(CO)3 complex. Significantly, despite structural modifications, other parameters such as the tumor to blood ratio and tumor to muscle ratio of the 2-nitroimidazole-DPA-(99m)Tc(CO)3 complex remained comparable to that of 2-nitroimidazole-DETA-(99m)Tc(CO)3 complex. Present study demonstrates the feasibility of structural modifications for improving in vivo tumor uptake of hypoxia detecting radiopharmaceuticals. This might encourage researchers to improve suboptimal properties of a potential radiopharmaceuticals rather than ignoring it altogether. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Effect of irradiation damage and helium on the swelling and structure of vanadium-base alloys

    International Nuclear Information System (INIS)

    Chung, H.M.; Loomis, B.A.; Smith, D.L.

    1993-12-01

    Swelling behavior and microstructural evolution of V-Ti, V-Cr-Ti, and V-Ti-Si alloys were investigated after irradiation at 420--600C up to 114 dpa. The alloys exhibited swelling maxima between 30 and 80 dpa and swelling decreased on irradiation to higher dpa. This is in contrast to the monotonically increasing swelling of binary alloys that contain Fe, Ni, Cr, Mo, W, and Si. Precipitation of dense Ti 5 Si 3 promotes good resistance to swelling of the Ti-containing alloys and it was concluded that Ti of >3 wt.% and 400--1000 wppm Si are necessary to effectively suppress swelling. Swelling was minimal in V-4Cr-4Ti, identified as the most promising alloy based on good mechanical properties and superior resistance to irradiation embrittlement. V-20Ti doped with B exhibited somewhat higher swelling because of He generation. Lithium atoms, generated from transmutation of 10 B, formed γ-LiV 2 O 5 precipitates and did not seem to produce undesirable effects on mechanical properties

  6. Efecto del calcio en aplicaciones precosecha y poscosecha sobre la severidad de antracnosis (Colletotrichum gloeosporioides y la calidad de frutos de papaya (Carica papaya

    Directory of Open Access Journals (Sweden)

    Daniel Saborío

    2000-01-01

    Full Text Available Se evalu6 el efecto de aplicaciones pre- cosecha y poscosecha de calcio en papaya va- riedad "criolla" sabre la severidad de antracno- sis (CoUetotrichum gloeosporioides y varia- hIes de calidad del fruto. Los tratamientos pre- cosecha fueron 4: aspersi6n de CaCl2 al 1% Y 4% (2 aplicaciones: <40 dfas posantesis (dpa y entre 100-140 dpa con el penetrante alquilaril- polimero (NP- 7 Bayer (0.4 mIlL, CaCO3 al suelo (1 ton/ha, 70 dpa y testigo (0% Ca. El diseno experimental fue un BCA (4 repeticio- nes de 20 frutos. Los tratamientos poscosecha fueron 3: inmersiones par 5 min con 0%, 1 % Y 4% de CaCI2, con el mismo penetrante. El dise- no experimental fue un BCA (3 repeticiones de 15 frutas. Se evalu6 severidad, % calcio en cascara, brix, pH, % acidez, firmeza (cascara y pulpa y % de madurez. En la aplicaci6n de cal- cia precosecha la severidad fue: 1 % CaC12 con 6%, testigo 7%, CaCO3 9% y 4% CaC12 con 11 %, no se encontr6 que el Ca tuviera un efec-

  7. Transcriptome analysis reveals key differentially expressed genes involved in wheat grain development

    Directory of Open Access Journals (Sweden)

    Yonglong Yu

    2016-04-01

    Full Text Available Wheat seed development is an important physiological process of seed maturation and directly affects wheat yield and quality. In this study, we performed dynamic transcriptome microarray analysis of an elite Chinese bread wheat cultivar (Jimai 20 during grain development using the GeneChip Wheat Genome Array. Grain morphology and scanning electron microscope observations showed that the period of 11–15 days post-anthesis (DPA was a key stage for the synthesis and accumulation of seed starch. Genome-wide transcriptional profiling and significance analysis of microarrays revealed that the period from 11 to 15 DPA was more important than the 15–20 DPA stage for the synthesis and accumulation of nutritive reserves. Series test of cluster analysis of differential genes revealed five statistically significant gene expression profiles. Gene ontology annotation and enrichment analysis gave further information about differentially expressed genes, and MapMan analysis revealed expression changes within functional groups during seed development. Metabolic pathway network analysis showed that major and minor metabolic pathways regulate one another to ensure regular seed development and nutritive reserve accumulation. We performed gene co-expression network analysis to identify genes that play vital roles in seed development and identified several key genes involved in important metabolic pathways. The transcriptional expression of eight key genes involved in starch and protein synthesis and stress defense was further validated by qRT-PCR. Our results provide new insight into the molecular mechanisms of wheat seed development and the determinants of yield and quality.

  8. Discriminative ability of total body bone-mineral measured by dual photon absorptiometry

    International Nuclear Information System (INIS)

    Gotfredsen, A.; Poedenphant, J.; Nilas, L.; Christiansen, C.

    1989-01-01

    We investigated the descriminative ability of total body bone-mineral expressed as the total body bone-density (TBBD) measured by dual photon absorptiometry (DPA) in 79 healthy premenopausal women, 27 healthy postmenopausal women, and 120 female osteoporotic fracture patients presenting with either Colles' fracture, vertebral fracture or femoral neck-fracture. TBBD was compared to the bone-mineral density of the lumbar spine (BMD spine ) also measured by DPA, and to the bone-mineral content of the forearms (BMC forearm ) measured by single photon absorptiometry (SPA). TBBD, BMD spine and BMC forearm showed that all the fracture patient groups had significantly reduced bone-mass. Using receiver operating characteristic (ROC) analysis, we found that TBBD had a tendency towards better discriminative ability than BMD spine or BMC forearm with regard to the discrimination between healthy premenopausal women and the three types of osteoporotic fractures. BMC forearm had an intermediate position, whereas BMD spine had the smallest discriminative ability. TBBD also discriminated better between healthy postmenopausal women and hip-fracture patients than BMD spine or BMC forearm , whereas there was no significant difference between the three methods regarding the discrimination between the healthy postmenopausal women and the Colles' and spinal fracture patients. We conclude that the TBBD measurement by DPA has a discriminative potential which is better than the local spine or forearm measurements. (author)

  9. Influence of displacement gradients on the interpretation of charged particle simulation experiments

    International Nuclear Information System (INIS)

    Garner, F.A.; Guthrie, G.L.

    1975-08-01

    Neutron flux and spectrum gradients are negligible within a single grain of structural materials in fusion reactors. In charged particle simulation, however, substantial gradients exist in the flux of displaced atoms (dpa) along the ion path, which is typically several microns or less in length. In interpretation of such experiments, one must account for the influence of variables that are atypical of the simulated environment. Experimental and modeling studies show that dpa gradients lead to gradients in microstructure, which in turn modify the effect of diffusion on the effective growth environment of voids and other defects. For some ions, these effects are overwhelmed by a phenomenon designated the ''internal temperature shift.'' Although the physical temperature is relatively invariant along the ion path, the temperature regime of swelling shifts as the displacement rate changes. The swelling vs. depth profile is altered substantially from that expected from the dpa profile, and the type of modification is dependent on the relation of the irradiation temperature to the peak swelling temperature at the mean displacement flux. Swelling profiles for a variety of simulations were analyzed and found to include the influence of surface denuded zones, incubation effects, diffusion, swelling-generated stresses and internal temperature shifts. The impact of the latter imposes restrictions on the interpretation of step height measurements and full range intercorrelations for high energy ions

  10. Influence of displacement gradients on the interpretation of charged particle simulation experiments

    International Nuclear Information System (INIS)

    Garner, F.A.; Guthrie, G.L.

    1976-01-01

    Neutron flux and spectrum gradients are negligible within a single grain of structural materials in fusion reactors. In charged particle simulation, however, substantial gradients exist in the flux of displaced atoms (dpa) along the ion path, which is typically several microns or less in length. In interpretation of such experiments, one must account for the influence of variables that are atypical of the simulated environment. Experimental and modeling studies show that dpa gradients lead to gradients in microstructure, which in turn modify the effect of diffusion on the effective growth environment of voids and other defects. For some ions, these effects are overwhelmed by a phenomenon designated the ''internal temperature shift.'' Although the physical temperature is relatively invariant along the ion path, the temperature regime of swelling shifts as the displacement rate changes. The swelling vs. depth profile is altered substantially from that expected from the dpa profile, and the type of modification is dependent on the relation of the irradiation temperature to the peak swelling temperature at the mean displacement flux. Swelling profiles for a variety of simulations were analyzed and found to include the influence of surface denuded zones, incubation effects, diffusion, swelling-generated stresses and internal temperature shifts. The impact of the latter imposes restrictions on the interpretation of step height measurements and full range intercorrelations for high energy ions

  11. Tb3+ and Eu3+ luminescence in imidazolium ionic liquids

    International Nuclear Information System (INIS)

    Hopkins, Todd; Goldey, Matt

    2009-01-01

    The luminescence properties of Tb 3+ and Eu 3+ dissolved in ionic liquids are studied. Solutes in this study include simple lanthanide compounds (e.g., EuBr 3 , TbCl 3 ) and lanthanide complexes (e.g., Eu(dpa) 3 3- where dpa = 2,6 pyridine dicarboxylate dianion) dissolved in a 1-butyl-3-methylimidazolium bromide(BMIBr)/water mixture. Emission, excitation, and time-resolved emission measurements are utilized to characterize the spectroscopic properties. It is well established in the literature that the solubility and spectroscopic properties of lanthanides in ionic liquids are highly dependent upon environmental factors including purity, and water content [K. Binnemans, Chemical Reviews (2007); I. Billard, S. Mekki, C. Gaillard, P. Hesemann, C. Mariet, G. Moutiers, A. Labet, J.-C.G. Buenzli, European Journal of Inorganic Chemistry 6 (2004) 1190-1197; S. Samikkanu, K. Mellem, M. Berry, P.S. May, Inorganic Chemistry 46 (2007) 7121-7128]. The water in this ionic liquid system acts as a co-solvent to facilitate solubility of Tb 3+ and Eu 3+ compounds. The observed spectroscopic properties of Eu 3+ and Tb 3+ salts are expectedly impacted by the high water content, but unexpectedly impacted by the BMIBr ionic liquid. However, the spectroscopy of Eu(dpa) 3 3- is unaffected by the presence of BMIBr.

  12. Helium sequestration at nanoparticle-matrix interfaces in helium + heavy ion irradiated nanostructured ferritic alloys

    Energy Technology Data Exchange (ETDEWEB)

    Parish, C.M., E-mail: parishcm@ornl.gov [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Unocic, K.A.; Tan, L. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Zinkle, S.J. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); University of Tennessee, Knoxville, TN 37996 (United States); Kondo, S. [Institute of Advanced Energy, Kyoto University, Uji, Kyoto, 611-0011 (Japan); Snead, L.L. [Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Hoelzer, D.T.; Katoh, Y. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2017-01-15

    We irradiated four ferritic alloys with energetic Fe and He ions: one castable nanostructured alloy (CNA) containing Ti-W-Ta-carbides, and three nanostructured ferritic alloys (NFAs). The NFAs were: 9Cr containing Y-Ti-O nanoclusters, and two Fe-12Cr-5Al NFAs containing Y-Zr-O or Y-Hf-O clusters. All four were subjected to simultaneous dual-beam Fe + He ion implantation (650 °C, ∼50 dpa, ∼15 appm He/dpa), simulating fusion-reactor conditions. Examination using scanning/transmission electron microscopy (STEM) revealed high-number-density helium bubbles of ∼8 nm, ∼10{sup 21} m{sup −3} (CNA), and of ∼3 nm, 10{sup 23} m{sup −3} (NFAs). STEM combined with multivariate statistical analysis data mining suggests that the precipitate-matrix interfaces in all alloys survived ∼50 dpa at 650 °C and serve as effective helium trapping sites. All alloys appear viable structural material candidates for fusion or advanced fission energy systems. Among these developmental alloys the NFAs appear to sequester the helium into smaller bubbles and away from the grain boundaries more effectively than the early-generation CNA.

  13. Removal of phosphate using copper-loaded polymeric ligand exchanger prepared by radiation grafting of polypropylene/polyethylene (PP/PE) nonwoven fabric

    Science.gov (United States)

    Barsbay, Murat; Kavaklı, Pınar Akkaş; Güven, Olgun

    2010-03-01

    A novel polymeric ligand exchanger (PLE) was prepared for the removal of phosphate ions from water. 2,2'-dipyridylamine (DPA), a bidentate ligand forming compound with high coordination capacity with a variety of metal ions was bound to glycidyl methacrylate (GMA) grafted polypropylene/polyethylene (PP/PE) nonwoven fabric synthesized by radiation-induced grafting technique. DPA attachment on epoxy ring of GMA units was tested in different solvents, i.e. methanol, ethanol, dioxane and dimethylsulfoxide (DMSO). The highest amount of modification was achieved in dioxane. In order to prepare the corresponding PLE for the removal of phosphate, DPA-immobilized fabric was loaded with Cu(II) ions. Phosphate adsorption experiments were performed in batch mode at different pH (5-9) and phosphate concentrations. The fabric was found to be effective for the removal of phosphate ions. At every stage of preparation and use, the nonwoven fabric was characterized by thermal (i.e. DSC and TGA) and spectroscopic (FTIR) methods. Competitive adsorption experiments were also carried out using two solutions with different concentration levels at pH 7 to see the effect of competing ions. Phosphate adsorption was found to be effective and selective from solutions having trace amounts of competitive anions. It is expected that the novel PLE synthesized can be used for the removal of phosphate ions in low concentrations over a large range of pH.

  14. The Primary Origin of Dose Rate Effects on Microstructural Evolution of Austenitic Alloys During Neutron Irradiation

    International Nuclear Information System (INIS)

    Okita, Taira; Sato, Toshihiko; Sekimura, Naoto; Garner, Francis A.; Greenwood, Lawrence R.

    2002-01-01

    The effect of dose rate on neutron-induced microstructural evolution was experimentally estimated. Solution-annealed austenitic model alloys were irradiated at approximately 400 degrees C with fast neutrons at seven different dose rates that vary more than two orders difference in magnitude, and two different doses were achieved at each dose rate. Both cavity nucleation and growth were found to be enhanced at lower dose rate. The net vacancy flux is calculated from the growth rate of cavities that had already nucleated during the first cycle of irradiation and grown during the second cycle. The net vacancy flux was found to be proportional to (dpa/sec) exp (1/2) up to 28.8 dpa and 8.4 x 10 exp (-7) dpa/sec. This implies that mutual recombination dominates point defect annihilation, in this experiment even though point defect sinks such as cavities and dislocations were well developed. Thus, mutual recombination is thought to be the primary origin of the effect of dose rate on microstructural evolution

  15. Modeling precipitation thermodynamics and kinetics in type 316 austenitic stainless steels with varying composition as an initial step toward predicting phase stability during irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Shim, Jae-Hyeok, E-mail: jhshim@kist.re.kr [Department of Nuclear Engineering, University of Tennessee, Knoxville, TN 37996 (United States); High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Povoden-Karadeniz, Erwin [Christian Doppler Laboratory for Early Stages of Precipitation, Vienna University of Technology, A-1040 Vienna (Austria); Kozeschnik, Ernst [Institute of Materials Science and Technology, Vienna University of Technology, A-1040 Vienna (Austria); Wirth, Brian D. [Department of Nuclear Engineering, University of Tennessee, Knoxville, TN 37996 (United States)

    2015-07-15

    Highlights: • We model the precipitation kinetics in irradiated 316 austenitic stainless steels. • Radiation-induced phases are predicted to form at over 10 dpa segregation conditions. • The Si content is the most critical for the formation of radiation-induced phases. - Abstract: The long-term evolution of precipitates in type 316 austenitic stainless steels at 400 °C has been simulated using a numerical model based on classical nucleation theory and the thermodynamic extremum principle. Particular attention has been paid to the precipitation of radiation-induced phases such as γ′ and G phases. In addition to the original compositions, the compositions for radiation-induced segregation at a dose level of 5, 10 or 20 dpa have been used in the simulation. In a 316 austenitic stainless steel, γ′ appears as the main precipitate with a small amount of G phase forming at 10 and 20 dpa. On the other hand, G phase becomes relatively dominant over γ′ at the same dose levels in a Ti-stabilized 316 austenitic stainless steel, which tends to suppress the formation of γ′. Among the segregated alloying elements, the concentration of Si seems to be the most critical for the formation of radiation-induced phases. An increase in dislocation density as well as increased diffusivity of Mn and Si significantly enhances the precipitation kinetics of the radiation-induced phases within this model.

  16. Microstructural defect evolution in neutron – Irradiated 12Cr18Ni9Ti stainless steel during subsequent isochronous annealing

    Energy Technology Data Exchange (ETDEWEB)

    Tsay, K.V.; Maksimkin, O.P.; Turubarova, L.G.; Rofman, O.V. [Institute of Nuclear Physics NNC RK, Almaty (Kazakhstan); Garner, F.A., E-mail: frank.garner@dslextreme.com [Radiation Effects Consulting, Richland, WA (United States)

    2013-08-15

    Transmission electron microscopy and microhardness measurements were used to examine changes in microstructure and associated strengthening induced in austenitic stainless steel 12Cr18Ni9Ti irradiated to ∼0.001 and ∼5 dpa in the WWR-K reactor before and after being subjected to post-irradiation isochronal annealing. The relatively low values of irradiation temperature and dpa rate (∼80 °C and ∼1.2 × 10{sup −8} dpa/s) experienced by this steel allowed characterization of defect microstructures over a wide range of defect ensembles, all at constant composition, produced first by irradiation and then by annealing at temperatures between 450 and 1050 °C. It was shown that the dispersed barrier hardening model with commonly accepted physical properties successfully predicted the observed hardening. It was also observed that when TiC precipitates form at higher annealing temperatures, the alloy does not change in hardness, reflecting a balance between precipitate-hardening and matrix-softening due to removal of solute-strengthening elements titanium and carbon. Such matrix-softening is not often considered in other studies, especially where the contribution of precipitates to hardening is a second-order effect.

  17. Fracture mechanics behaviour of neutron irradiated Alloy A-286

    International Nuclear Information System (INIS)

    Mills, W.J.; James, L.A.

    The effect of fast-neutron irradiation on the fatigue-crack propagation and fracture toughness behaviour of Alloy A-286 was characterized using fracture mechanics techniques. The fracture toughness was found to decrease continuously with increasing irradiation damage at both 24 deg. C and 427 deg. C. In the unirradiated and low fluence conditions, specimens displayed appreciable plasticity prior to fracture, and equivalent Ksub(Ic) values were determined from Jsub(Ic) fracture toughness results. At high irradiation exposure levels, specimens exhibited a brittle Ksub(Ic) fracture mode. The 427 deg. C fracture toughness fell from 129 MPa√m in the unirradiated condition to 35 MPa√m at an exposure of 16.2 dpa (total fluence of 5.2x10 22 n/cm 2 ). Room temperature fracture toughness values were consistently 40 to 60 percent higher than the 427 deg. C values. Electron fractography revealed that the reduction in fracture resistance was attributed to a fracture mechanism transition from ductile microvoid coalescence to channel fracture. Fatigue-crack propagation tests were conducted at 427 deg. C on specimens irradiated at 2.4 dpa and 16.2 dpa. Crack growth rates at the lower exposure level were comparable to those in unirradiated material, while those at the higher exposure were slightly higher than in unirradiated material. (author)

  18. Comparison of deuterium retention for ion-irradiated and neutron-irradiated tungsten

    International Nuclear Information System (INIS)

    Oya, Yasuhisa; Kobayashi, Makoto; Okuno, Kenji; Shimada, Masashi; Calderoni, Pattrick; Oda, Takuji; Hara, Masanori; Hatano, Yuji; Watanabe, Hideo

    2014-01-01

    The behavior of D retentions for Fe 2+ irradiated tungsten with the damage of 0.025-3 dpa was compared with that for neutron irradiated tungsten with 0.025 dpa. The D 2 TDS spectra for Fe 2+ irradiated tungsten consisted of two desorption stages at 450 K and 550 K although that for neutron irradiated tungsten was composed of three stages and addition desorption stage was found around 750 K. The desorption rate of major desorption stage at 550 K increased as the number of dpa by Fe 2+ irradiation increased. In addition, the first desorption stage at 450 K was only found for the damaged samples, indicating that the second stage would be based on intrinsic defects or vacancy produced by Fe 2+ irradiation and the first stage should be the accumulation of D in mono vacancy leading to the lower activation energy, where the dislocation loop and vacancy was produced. The third one was only found for the neutron irradiation, showing the D trapping by void or vacancy cluster and the diffusion effect is also contributed due to high FWHM of TDS spectrum. It can be said that the D 2 TDS spectra for Fe 2+ -irradiated tungsten could not represent that for neutron-irradiated one, showing that the deuterium trapping and desorption mechanism for neutron-irradiated tungsten has a difference from that for ion-irradiated one. (author)

  19. Irradiation-induced amorphization process in graphite

    Energy Technology Data Exchange (ETDEWEB)

    Abe, Hiroaki [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    1996-04-01

    Effects of the element process of irradiation damage on irradiation-induced amorphization processes of graphite was studied. High orientation thermal decomposed graphite was cut about 100 nm width and used as samples. The irradiation experiments are carried out under the conditions of electronic energy of 100-400 KeV, ion energy of 200-600 KeV, ionic species Xe, Ar, Ne, C and He and the irradiation temperature at from room temperature to 900 K. The critical dose ({phi}a) increases exponentially with increasing irradiation temperature. The displacement threshold energy of graphite on c-axis direction was 27 eV and {phi}a{sup e} = 0.5 dpa. dpa is the average number of displacement to atom. The critical dose of ion irradiation ({phi}a{sup i}) was 0.2 dpa at room temperature, and amorphous graphite was produced by less than half of dose of electronic irradiation. Amorphization of graphite depending upon temperature is discussed. (S.Y.)

  20. Threshold irradiation dose for amorphization of silicon carbide

    International Nuclear Information System (INIS)

    Snead, L.L.; Zinkle, S.J.

    1997-01-01

    The amorphization of silicon carbide due to ion and electron irradiation is reviewed with emphasis on the temperature-dependent critical dose for amorphization. The effect of ion mass and energy on the threshold dose for amorphization is summarized, showing only a weak dependence near room temperature. Results are presented for 0.56 MeV silicon ions implanted into single crystal 6H-SiC as a function of temperature and ion dose. From this, the critical dose for amorphization is found as a function of temperature at depths well separated from the implanted ion region. Results are compared with published data generated using electrons and xenon ions as the irradiating species. High resolution TEM analysis is presented for the Si ion series showing the evolution of elongated amorphous islands oriented such that their major axis is parallel to the free surface. This suggests that surface or strain effects may be influencing the apparent amorphization threshold. Finally, a model for the temperature threshold for amorphization is described using the Si ion irradiation flux and the fitted interstitial migration energy which was found to be ∼0.56eV. This model successfully explains the difference in the temperature dependent amorphization behavior of SiC irradiated with 0.56 MeV Si + at 1 x 10 -3 dpa/s and with fission neutrons irradiated at 1 x 10 -6 dpa/s irradiated to 15 dpa in the temperature range of ∼340±10K