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Sample records for post irradiation effect

  1. Post-irradiation effects in polyethylenes irradiated under various atmospheres

    NASA Astrophysics Data System (ADS)

    Suljovrujic, E.

    2013-08-01

    If a large amount of polymer free radicals remain trapped after irradiation of polymers, the post-irradiation effects may result in a significant alteration of physical properties during long-term shelf storage and use. In the case of polyethylenes (PEs) some failures are attributed to the post-irradiation oxidative degradation initiated by the reaction of residual free radicals (mainly trapped in crystal phase) with oxygen. Oxidation products such as carbonyl groups act as deep traps and introduce changes in carrier mobility and significant deterioration in the PEs electrical insulating properties. The post-irradiation behaviour of three different PEs, low density polyethylene (LDPE), linear low density polyethylene (LLDPE) and high density polyethylene (HDPE) was studied; previously, the post-irradiation behaviour of the PEs was investigated after the irradiation in air (Suljovrujic, 2010). In this paper, in order to investigate the influence of different irradiation media on the post-irradiation behaviour, the samples were irradiated in air and nitrogen gas, to an absorbed dose of 300 kGy. The annealing treatment of irradiated PEs, which can substantially reduce the concentration of free radicals, is used in this study, too. Dielectric relaxation behaviour is related to the difference in the initial structure of PEs (such as branching, crystallinity etc.), to the changes induced by irradiation in different media and to the post-irradiation changes induced by storage of the samples in air. Electron spin resonance (ESR), differential scanning calorimetry (DSC), infra-red (IR) spectroscopy and gel measurements were used to determine the changes in the free radical concentration, crystal fraction, oxidation and degree of network formation, respectively.

  2. Post irradiation effects (PIE) in integrated circuits

    NASA Technical Reports Server (NTRS)

    Shaw, D. C.; Lowry, L.; Barnes, C.; Zakharia, M.; Agarwal, S.; Rax, B.

    1991-01-01

    Post-irradiation effects (PIE) ranging from normal recovery to catastrophic failure have been observed in integrated circuits during the PIE period. Data presented show failure due to rebound after a 10 krad(Si) dose. In particular, five device types are investigated with varying PIE response. Special attention has been given to the HI1-507A analog multiplexer because its PIE response is extreme. X-ray diffraction has been uniquely employed to measure physical stress in the HI1-507A metallization. An attempt has been made to show a relationship between stress relaxation and radiation effects. All data presented support the current MIL-STD Method 1019.4 but demonstrate the importance of performing PIE measurements, even when mission doses are as low as 10 krad(Si).

  3. Effect of boron on post irradiation tensile properties of reduced activation ferritic steel (F-82H) irradiated in HFIR

    SciTech Connect

    Shiba, Kiyoyuki; Suzuki, Masahide; Hishinuma, Akimichi; Pawel, J.E.

    1994-12-31

    Reduced activation ferritic/martensitic steel, F-82H (Fe-8Cr-2W-V-Ta), was irradiated in the High Flux Isotope Reactor (HFIR) to doses between 11 and 34 dpa at 400 and 500 C. Post irradiation tensile tests were performed at the nominal irradiation temperature in vacuum. Some specimens included {sup 10}B or natural boron (nB) to estimate the helium effect on tensile properties. Tensile properties including the 0.2% offset yield stress, the ultimate tensile strength, the uniform elongation and the total elongation were measured. The tensile properties were not dependent on helium content in specimens irradiated to 34 dpa, however {sup 10}B-doped specimens with the highest levels of helium showed slightly higher yield strength and less ductility than boron-free specimens. Strength appears to go through a peak, and ductility through a trough at about 11 dpa. The irradiation to more than 21 dpa reduced the strength and increased the elongation to the unirradiated levels. Ferritic steels are one of the candidate alloys for nuclear fusion reactors because of their good thermophysical properties, their superior swelling resistance, and the low corrosion rate in contact with potential breeder and coolant materials.

  4. Molecular structure effects on the post irradiation diffusion in polymer gel dosimeters.

    PubMed

    Mattea, Facundo; Romero, Marcelo R; Vedelago, José; Quiroga, Andrés; Valente, Mauro; Strumia, Miriam C

    2015-06-01

    Polymer gel dosimeters have specific advantages for recording 3D radiation dose distribution in diagnostic and therapeutic medical applications. But, even in systems where the 3D structure is usually maintained for long periods of time after irradiation, it is still not possible to eliminate the diffusion of the different species in the regions of dose gradients within the gel. As a consequence, information of the dose loses quality over time. In the pursuit of a solution and to improve the understanding of this phenomenon a novel system based on itaconic acid and N-N'-methylene-bisacrylamide (BIS) is hereby proposed. Effects of changes in the chemical structure of the monomers over the dosimetric sensitivity and over the post-irradiation diffusion of species was studied. In this study, one of the carboxylic groups of the itaconic acid molecule was modified with aniline to obtain molecules with similar reactivity but different molecular sizes. Then, dosimeters based on these modified species and on the original ITA molecules were irradiated in an X-ray tomography apparatus at different doses up to 173Gy. Afterwards, the resulting dosimeters were characterized by Raman spectroscopy and optical absorbance in order to study their feasibility and capabilities as dosimetric systems, and by optical-CT to analyze the post irradiation diffusion. PMID:25773266

  5. Effect of ultraviolet light irradiation on bond strength of fiber post: Evaluation of surface characteristic and bonded area of fiber post with resin cement

    PubMed Central

    Reza, Fazal; Ibrahim, Nur Sukainah

    2015-01-01

    Objective: Fiber post is cemented to a root canal to restore coronal tooth structure. This research aims to evaluate the effect of ultraviolet (UV) irradiation on bond strength of fiber post with resin cement. Materials and Methods: A total of 40 of the two types of fiber posts, namely, FRC Prostec (FRC) and Fiber KOR (KOR), were used for the experiment. UV irradiation was applied on top of the fiber post surface for 0, 15, 20, and 30 min. The irradiated surface of the fiber posts (n = 5) were immediately bonded with resin cement (Rely X U200) after UV irradiation. Shear bond strength (SBS) MPa was measured, and the dislodged area of post surfaces was examined with scanning electron microscopes. Changes in surface roughness (Ra) of the FRC group after UV irradiation were observed (n = 3) using atomic force microscopy. Data of SBS were statistically analyzed using one-way analysis of variance, followed by multiple comparisons (P < 0.05). Results: SBS was significantly higher for 20 min of UV irradiation of the FRC group while significantly higher SBS was observed with 15 min of UV irradiation of the KOR group. Resin cement was more evident (cohesive failure) on the dislodged post surface of the UV treated groups compared with the control. The surface roughness of the FRC post was Ra = 175.1 nm and Ra = 929.2 nm for the control and the 20 min group, respectively. Conclusions: Higher surface roughness of the UV irradiated group indicated formation of mechanical retention on the fiber post surface. Evidence of cohesive failure was observed which indicated higher SBS of fiber post with the UV irradiated group. PMID:25713488

  6. Neutron, gamma ray and post-irradiation thermal annealing effects on power semiconductor switches

    SciTech Connect

    Schwarze, G.E.; Frasca, A.J.

    1994-09-01

    The effects of neutrons and gamma rays on the electrical and switching characteristics of power semiconductor switches must be known and understood by the designer of the power conditioning, control, and transmission subsystem of space nuclear power systems. The SP-100 radiation requirements at 25 m from the nuclear source are a neutron fluence of 10{sup 13} n/cm {sup 2} and a gamma dose of 0.5 Mrads. Experimental data showing the effects of neutrons and gamma rays on the performance characteristics of power-type NPN Bipolar Junction Transistors (BJTs), Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs), and Static Induction Transistors (SITs) are given in this paper. These three types of devices were tested at radiation levels which met or exceeded the SP-100 requirements. For the SP-100 radiation requirements, the BJTs were found to be most sensitive to neutrons, the MOSFETs were most sensitive to gamma rays, and the SITs were only slightly sensitive to neutrons. Post-irradiation thermal anneals at 300 K and up to 425 K were done on these devices and the effectiveness of these anneals are also discussed.

  7. Neutron, gamma ray and post-irradiation thermal annealing effects on power semiconductor switches

    NASA Technical Reports Server (NTRS)

    Schwarze, G. E.; Frasca, A. J.

    1991-01-01

    The effects of neutron and gamma rays on the electrical and switching characteristics of power semiconductor switches must be known and understood by the designer of the power conditioning, control, and transmission subsystem of space nuclear power systems. The SP-100 radiation requirements at 25 m from the nuclear source are a neutron fluence of 10(exp 13) n/sq cm and a gamma dose of 0.5 Mrads. Experimental data showing the effects of neutrons and gamma rays on the performance characteristics of power-type NPN Bipolar Junction Transistors (BJTs), Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs), and Static Induction Transistors (SITs) are presented. These three types of devices were tested at radiation levels which met or exceeded the SP-100 requirements. For the SP-100 radiation requirements, the BJTs were found to be most sensitive to neutrons, the MOSFETs were most sensitive to gamma rays, and the SITs were only slightly sensitive to neutrons. Post-irradiation thermal anneals at 300 K and up to 425 K were done on these devices and the effectiveness of these anneals are also discussed.

  8. AGR-1 Post Irradiation Examination Final Report

    SciTech Connect

    Demkowicz, Paul Andrew

    2015-08-01

    The post-irradiation examination (PIE) of the Advanced Gas Reactor (AGR)-1 experiment was a multi-year, collaborative effort between Idaho National Laboratory (INL) and Oak Ridge National Laboratory (ORNL) to study the performance of UCO (uranium carbide, uranium oxide) tristructural isotropic (TRISO) coated particle fuel fabricated in the U.S. and irradiated at the Advanced Test Reactor at INL to a peak burnup of 19.6% fissions per initial metal atom. This work involved a broad array of experiments and analyses to evaluate the level of fission product retention by the fuel particles and compacts (both during irradiation and during post-irradiation heating tests to simulate reactor accident conditions), investigate the kernel and coating layer morphology evolution and the causes of coating failure, and explore the migration of fission products through the coating layers. The results have generally confirmed the excellent performance of the AGR-1 fuel, first indicated during the irradiation by the observation of zero TRISO coated particle failures out of 298,000 particles in the experiment. Overall release of fission products was determined by PIE to have been relatively low during the irradiation. A significant finding was the extremely low levels of cesium released through intact coatings. This was true both during the irradiation and during post-irradiation heating tests to temperatures as high as 1800°C. Post-irradiation safety test fuel performance was generally excellent. Silver release from the particles and compacts during irradiation was often very high. Extensive microanalysis of fuel particles was performed after irradiation and after high-temperature safety testing. The results of particle microanalysis indicate that the UCO fuel is effective at controlling the oxygen partial pressure within the particle and limiting kernel migration. Post-irradiation examination has provided the final body of data that speaks to the quality of the AGR-1 fuel, building

  9. Enhanced killing effects of caffein post-treatment in ultraviolet-light irradiated mouse lymphoma cells: is cAMP a mediator of the effects?

    PubMed

    Kuwashima, Y; Miyachi, Y; Okada, S; Iio, M; Nakamura, N

    1983-01-01

    Effects of post-treatment with caffein, cyclic adenosine 3':5'-monophosphate (cAMP) and N6, O2-dibutyryl cAMP (dbcAMP) were investigated in ultraviolet light (UV)-irradiated mouse lymphoma L5178Y cells. Under conditions where UV or each chemical alone caused only slight cytotoxic effects, caffein post-treatment showed clear synergistic effects in cell killing but not for cAMP or dbcAMP. Subsequently, a mutant clone resistant to cAMP was isolated. This mutant was supposed to be deficient in cAMP-mediated cellular functions. Using the mutant cells, it was found that these cells were also sensitive to caffein post-treatment as wild cells after UV-irradiation. The results imply that the enhanced killing effects by caffein post-treatment in UV irradiated cells is not mediated by cAMP. PMID:6093199

  10. Effects of gamma irradiation on onion sprouting. I.--Influence of dose rate and post-harvest period of treatment.

    PubMed

    Farooqi, W A; Donini, B

    1976-01-01

    Onions of "Dorata di Parma" variety were exposed to 10 Krads of Co60 gamma irradiation in 5, 10, 20, 40, and 80 minutes in December, 1975 and then stored in the cold storage (10 +/- 1 degree C; R.H. 65-70%) and at the room temperature (15-20 degrees C; R.H. 40-70%) for 3 months, to study the influence of dose-rate and post-harvest period of treatment. Average number of buds sprouted in each onion bulb under cold storage condition ranged from 2-3, while this number was found to increase to 3-4 under ambient storage conditions. Although no effect of either irradiation or dose rate was observed when onions were irradiated after the break of their dormancy, however, a significant slowing down effect of irradiation could be observed as far as the rate of growth of sprouts was concerned. Weight loss was also reduced significantly in the irradiated onions as compared with controls. PMID:1037423

  11. Effects of Irradiation and Post-Irradiation Annealing on the Thermal Conductivity/ Diffusivity of Monolithic SIC and SIC/SIC Composites

    SciTech Connect

    Youngblood, Gerald E.; Senor, David J.; Jones, Russell H.

    2004-08-01

    Laser flash thermal diffusivity measurements were made on high-purity monolithic CVD-SiC (impurity concentration <5 wppm) and 2D f-SiC/PyC/ICVI-SiC composite samples (plain weave Hi-Nicalon (Trademark) fabric layers with 0-90 layup made by the isothermal chemical vapor infiltration process and with either a “thick” 1.0 µm or a “thin” 0.11 µm PyC fiber coating) before and after irradiation in the HFIR reactor (250 to 800°C, 4-8 dpa-SiC) and after post-irradiation annealing composite samples to 1200°C. Thermal conductivity in SiC is controlled by phonon transport. Point defects introduced into SiC during neutron irradiation are effective scattering centers for phonons, and as a consequence the thermal conductivity is sharply reduced. For irradiation temperatures below ~800°C, the accumulation of point defects (in SiC mostly single or small clusters of interstitials and isolated vacancies) saturates when the interstitial-vacancy recombination rate equals the defect production rate. For saturation conditions, the relative reduction in the SiC thermal conductivity decreases in a manner similar to its swelling reduction with increasing irradiation temperature. Examination of SiC swelling data at various irradiation temperatures and doses indicates that saturation occurs for ~2 dpa-SiC at 200°C and decreases continuously to ~0.4 dpa-SiC at 800°C. Based on a model that assumes a uniform distribution of the phonon scattering defects, the calculated defect concentration for unirradiated CVD-SiC was less than 1 appm, which is consistent with the manufacturer’s value of <5 wppm impurities. The defect concentrations estimated for the irradiated CVD-SiC samples decreased continuously from ~25,000 to 940 appm as the irradiation temperature increased from 252 to 800°C. The small intrinsic defect concentration in comparison to the rather large extrinsic irradiation-induced defect concentrations illustrates why CVD-SiC makes an ideal irradiation damage monitor.

  12. Effect of Irradiation on Incidence of Post-Transplant Lymphoproliferative Disorder after Hematopoietic Cell Transplantation in Miniature Swine.

    PubMed

    Matar, Abraham J; Patil, Aarti R; Al-Musa, Ahmad; Hanekamp, Isabel; Sachs, David H; Huang, Christene A; Duran-Struuck, Raimon

    2015-10-01

    Post-transplant lymphoproliferative disease (PTLD) is a major complication of clinical organ and cell transplantation. Conditioning and immunosuppressive regimens that significantly impair T cell immunity, including depleting antibodies and calcineurin inhibitors, increase the risk of PTLD after transplantation. Swine PTLD has been shown to closely resemble human PTLD in morphology, histology, and viral-driven reactivation of B cells. Previously, we reported high incidences of PTLD after hematopoietic cell transplantation (HCT) in miniature swine recipients conditioned with thymic irradiation (TI) in addition to T cell depletion and cyclosporine A monotherapy after transplantation. Replacement of TI with 100 cGy of total body irradiation resulted in similar numbers of B cells early post-transplantation, greater numbers of T cells at day 0, and markedly decreased incidence of PTLD, suggesting that a threshold number of T cells may be necessary to prevent subsequent B cell proliferation and development of overt PTLD. Results from this large cohort of animals provide insight into the important effect of irradiation and T cell immunity on the incidence of PTLD after HCT and reinforce the pig model as a valuable tool for the study of PTLD and HCT. PMID:26210443

  13. Role of isolated and clustered DNA damage and the post-irradiating repair process in the effects of heavy ion beam irradiation.

    PubMed

    Tokuyama, Yuka; Furusawa, Yoshiya; Ide, Hiroshi; Yasui, Akira; Terato, Hiroaki

    2015-05-01

    Clustered DNA damage is a specific type of DNA damage induced by ionizing radiation. Any type of ionizing radiation traverses the target DNA molecule as a beam, inducing damage along its track. Our previous study showed that clustered DNA damage yields decreased with increased linear energy transfer (LET), leading us to investigate the importance of clustered DNA damage in the biological effects of heavy ion beam radiation. In this study, we analyzed the yield of clustered base damage (comprising multiple base lesions) in cultured cells irradiated with various heavy ion beams, and investigated isolated base damage and the repair process in post-irradiation cultured cells. Chinese hamster ovary (CHO) cells were irradiated by carbon, silicon, argon and iron ion beams with LETs of 13, 55, 90 and 200 keV µm(-1), respectively. Agarose gel electrophoresis of the cells with enzymatic treatments indicated that clustered base damage yields decreased as the LET increased. The aldehyde reactive probe procedure showed that isolated base damage yields in the irradiated cells followed the same pattern. To analyze the cellular base damage process, clustered DNA damage repair was investigated using DNA repair mutant cells. DNA double-strand breaks accumulated in CHO mutant cells lacking Xrcc1 after irradiation, and the cell viability decreased. On the other hand, mouse embryonic fibroblast (Mef) cells lacking both Nth1 and Ogg1 became more resistant than the wild type Mef. Thus, clustered base damage seems to be involved in the expression of heavy ion beam biological effects via the repair process. PMID:25717060

  14. THE EFFECT OF POST-IRRADATION ANNEALING ON STACKING FAULT TETRAHEDRA IN NEUTRON-IRRADIATED OFHC COPPER

    SciTech Connect

    Edwards, Danny J.; Singh, Bachu N.; Eldrup, M.

    2003-09-03

    Two irradiation experiments have been completed wherein two sets of tensile specimens of OFHC copper were irradiated with fission neutrons, one set at 200 degrees C and the other at 250 degrees C. Post-irradiation annealing in vacuum was then used to evaluate the change in the defect microstructure, including vacancy-type SFT, voids, and dislocation loops. Individual samples within each set were given one annealing exposure at 300, 350, 400, 450, 500, or 550 degrees C for 2 hours. The fine-scale defect microstructure was characterized by transmission electron microscopy (TEM) to compare the defect size and spatial distribution at each annealing temperature and reference the results to that measured in the as-irradiated condition. Based on the change in the SFT size distributions, post-irradiation annealing led to a preferential removal of the smaller sized SFT, but did not lead to a general coarsening as might be expected from an Oswald ripening scenario. The issue of whether the SFT produced during irradiation are all structurally perfect is still being investigated at the time of this report, however, the images of the SFT appeared more perfect after annealing at 300 degrees C and higher. Further analysis is being performed to determine whether intermediate stages of SFT formation exist in the as-irradiated condition.

  15. Effects of irradiation and post-irradiation annealing on the thermal conductivity/diffusivity of monolithic SiC and f-SiC/SiC composites

    SciTech Connect

    Youngblood, Gerald E.; Senor, David J.; Jones, Russell H.

    2004-08-01

    Laser flash thermal diffusivity measurements were made on high-purity monolithic CVD-SiC and 2D f-SiC(Hi-Nicalon)/ICVI-SiC composite samples before and after irradiation (250 to 800C, 4-8 dpa-SiC) and after post-irradiation annealing composite samples to 1200C. For irradiated CVD-SiC, the defect concentrations at saturation were estimated to range from 25,300 appm (250C) down to 940 appm (800C). The transverse thermal conductivity ratios after-to-before irradiation (Kir/Ko) determined at the irradiation temperatures were: 0.044 up to 0.12 (250 up to 800C) for irradiated CVD-SiC and 0.18 up to 0.29 (330 up to 800C) for the irradiated Hi-Nicalon composite. Analysis of thermal diffusivity values for the Hi-Nicalon composite measured in air, argon, helium and vacuum indicated that thermal conductivity degradation occurred primarily due to point defect accumulation in the matrix component. After annealing to 1200C and cooling to the irradiation temperature, fiber/matrix debonding occurred due to net shrinkage in the fiber and PyC interface components.

  16. Effects of irradiation and post-irradiation annealing on the thermal conductivity/diffusivity of monolithic SiC and f-SiC/SiC composites

    NASA Astrophysics Data System (ADS)

    Youngblood, G. E.; Senor, D. J.; Jones, R. H.

    2004-08-01

    Laser flash thermal diffusivity measurements were made on high-purity monolithic CVD-SiC and 2D f-SiC(Hi-Nicalon™)/ICVI-SiC composite samples before and after irradiation (250-800 °C, 4-8 dpa-SiC) and after post-irradiation annealing composite samples to 1200 °C. For irradiated CVD-SiC, the defect concentrations at saturation were estimated to range from 25 300 appm (250 °C) down to 940 appm (800 °C). The transverse thermal conductivity ratios after-to-before irradiation ( Kir/ Ko) determined at the irradiation temperatures ranged from: 0.044 (250 °C) up to 0.12 (800 °C) for irradiated CVD-SiC and 0.18 (330 °C) up to 0.29 (800 °C) for the irradiated Hi-Nicalon™ composite. Analysis of thermal diffusivity values for the Hi-Nicalon composite measured in air, argon, helium and vacuum indicated that thermal conductivity degradation occurred primarily due to point defect accumulation in the matrix component. After annealing to 1200 °C and cooling to ambient, fiber/matrix debonding occurred due to net shrinkage in the fiber and PyC interface components.

  17. Effect of the hydrolytic state of dietary protein on post-irradiation morbidity and mucosal cell regeneration

    SciTech Connect

    Beitler, M.K.; Mahler, P.A.; Yamanaka, W.K.; Guy, D.G.; Hutchinson, M.L.

    1987-03-01

    Diets containing hydrolyzed casein have been observed to enhance post-irradiation intestinal mucosal recovery. The intake and the composition of such diets were not carefully controlled. This study attempted to do so. Male specific pathogen-free Sprague-Dawley rats were randomized to receive either an enzymatically hydrolyzed casein semi-purified diet (EHC), a whole casein semi-purified diet (WC), or powdered lab chow (C). All diets were isonitrogenous, and the WC and C rats were pair-fed to the ad libitum fed EHC rats. Seven days after initiation of feeding, the rats were abdominally irradiated with a single 9.0 Gy dose of 137Cs gamma rays. The rats were continued on the diets for another 5 days. Intestinal mucosa from transverse segments at the duodenum, jejunum, proximal ileum, and distal ileum were measured for incorporation of (/sup 3/H methyl) thymidine 1 hour after intraperitoneal injection. Incorporation reached a maximum by day 4 post-irradiation regardless of diet or segment. Incorporation in the duodenum was enhanced by the EHC diet compared to the C diet, while the incorporation in the jejunum was initially suppressed by the EHC diet compared to the WC diet. In the jejunum, the number of mitoses per crypt of 25 anti-mesenteric crypts post-irradiation was increased by the EHC diet. Prior to irradiation, all groups gained similar amounts of weight. After irradiation, the C rats lost weight, while the EHC and WC rats remained the same or gained weight. Guaiac tests for occult blood were negative prior to irradiation, but positive for all rats on days 1-5 postirradiation. When calorie and protein intakes were controlled, different areas of the small intestine responded differently to EHC.

  18. Post-irradiation annealing effect on helium diffusivity in austenitic stainless steels

    NASA Astrophysics Data System (ADS)

    Katsura, R.; Morisawa, J.; Kawano, S.; Oliver, B. M.

    2004-08-01

    As an experimental basis for helium induced weld cracking of neutron irradiated austenitic stainless steels, helium diffusivity has been evaluated by measuring helium release at high temperature. Isochronal and isothermal experiments were performed at temperatures between 700 and 1300 °C for 304 and 316L stainless steels. In 1 h isochronal experiments, helium was released beginning at ˜900 °C and reaching almost 100% at 1300 °C. No apparent differences in helium release were observed between the two stainless steel types. At temperatures between 900 and 1300 °C, the diffusion rate was calculated from the time dependence of the helium release rate to be: D0=4.91 cm 2/s, E=289 kJ/mol. The observed activation energy suggests that the release of helium from the steels is associated with the removal of helium from helium bubbles and/or from vacancy diffusion.

  19. Post-Irradiation Annealing Effect on Helium Diffusivity in Austenitic Stainless Steels

    SciTech Connect

    Katsura, Ryoei; Morisawa, J; Kawano, S; Oliver, Brian M.

    2004-08-01

    As an experimental basis for helium induced weld cracking of neutron irradiated austenitic stainless steels, helium diffusivity has been evaluated by measuring helium release rates at high temperature. Isochronal and isothermal experiment were performed at temperatures between 700 and 1300 for Type 304 and 316L stainless steels. In 1 hour isochronal experiments, helium was released beginning at {approx}900 and reaching near 100% at 1300. No apparent differences in helium release rate were observed between Type 304 and 316L stainless steels. At temperatures between 1100 and 1300, the diffusion rate was calculated from the time dependence of the helium release rate to be:?D0=3.42?104 cm2/s, E=173.2 kJ/mol. The observed activation energy suggests that the release of helium from the steels is associated with the removal of helium from helium bubbles.

  20. Neutron, gamma ray and post-irradiation thermal annealing effects on power semiconductor switches

    NASA Technical Reports Server (NTRS)

    Schwarze, G. E.; Frasca, A. J.

    1991-01-01

    Experimental data showing the effects of neutrons and gamma rays on the performance characteristics of power-type NPN bipolar junction transistors (BJTs), metal-oxide-semiconductor field effect transistors (MOSFETs), and static induction transistors (SITs) are given. These three types of devices were tested at radiation levels which met or exceeded the SP-100 requirements. For the SP-100 radiation requirements, the BJTs were found to be most sensitive to neutrons, the MOSFETs were most sensitive to gamma rays, and the SITs were only slightly sensitive to neutrons. Postirradiation thermal anneals at 300 K and up to 425 K were done on these devices and the effectiveness of these anneals are also discussed.

  1. New facility for post irradiation examination of neutron irradiated beryllium

    SciTech Connect

    Ishitsuka, Etsuo; Kawamura, Hiroshi

    1995-09-01

    Beryllium is expected as a neutron multiplier and plasma facing materials in the fusion reactor, and the neutron irradiation data on properties of beryllium up to 800{degrees}C need for the engineering design. The acquisition of data on the tritium behavior, swelling, thermal and mechanical properties are first priority in ITER design. Facility for the post irradiation examination of neutron irradiated beryllium was constructed in the hot laboratory of Japan Materials Testing Reactor to get the engineering design data mentioned above. This facility consist of the four glove boxes, dry air supplier, tritium monitoring and removal system, storage box of neutron irradiated samples. Beryllium handling are restricted by the amount of tritium;7.4 GBq/day and {sup 60}Co;7.4 MBq/day.

  2. AGC-2 Specimen Post Irradiation Data Package Report

    SciTech Connect

    Windes, William Enoch; Swank, W. David; Rohrbaugh, David T.; Cottle, David L.

    2015-08-01

    This report documents results of the post-irradiation examination material property testing of the creep, control, and piggyback specimens from the irradiation creep capsule Advanced Graphite Creep (AGC)-2 are reported. This is the second of a series of six irradiation test trains planned as part of the AGC experiment to fully characterize the neutron irradiation effects and radiation creep behavior of current nuclear graphite grades. The AGC-2 capsule was irradiated in the Idaho National Laboratory Advanced Test Reactor at a nominal temperature of 600°C and to a peak dose of 5 dpa (displacements per atom). One-half of the creep specimens were subjected to mechanical stresses (an applied stress of either 13.8, 17.2, or 20.7 MPa) to induce irradiation creep. All post-irradiation testing and measurement results are reported with the exception of the irradiation mechanical strength testing, which is the last destructive testing stage of the irradiation testing program. Material property tests were conducted on specimens from 15 nuclear graphite grades using a similar loading configuration as the first AGC capsule (AGC-1) to provide easy comparison between the two capsules. However, AGC-2 contained an increased number of specimens (i.e., 487 total specimens irradiated) and replaced specimens of the minor grade 2020 with the newer grade 2114. The data reported include specimen dimensions for both stressed and unstressed specimens to establish the irradiation creep rates, mass and volume data necessary to derive density, elastic constants (Young’s modulus, shear modulus, and Poisson’s ratio) from ultrasonic time-of-flight velocity measurements, Young’s modulus from the fundamental frequency of vibration, electrical resistivity, and thermal diffusivity and thermal expansion data from 100–500°C. No data outliers were determined after all measurements were completed. A brief statistical analysis was performed on the irradiated data and a limited comparison between

  3. AGC-1 Post Irradiation Examination Status

    SciTech Connect

    David Swank

    2011-09-01

    The Next Generation Nuclear Plant (NGNP) Graphite R&D program is currently measuring irradiated material property changes in several grades of nuclear graphite for predicting their behavior and operating performance within the core of new Very High Temperature Reactor (VHTR) designs. The Advanced Graphite Creep (AGC) experiment consisting of six irradiation capsules will generate this irradiated graphite performance data for NGNP reactor operating conditions. All six AGC capsules in the experiment will be irradiated in the Advanced Test Reactor (ATR), disassembled in the Hot Fuel Examination Facility (HFEF), and examined at the INL Research Center (IRC) or Oak Ridge National Laboratory (ORNL). This is the first in a series of status reports on the progress of the AGC experiment. As the first capsule, AGC1 was irradiated from September 2009 to January 2011 to a maximum dose level of 6-7 dpa. The capsule was removed from ATR and transferred to the HFEF in April 2011 where the capsule was disassembled and test specimens extracted from the capsules. The first irradiated samples from AGC1 were shipped to the IRC in July 2011and initial post irradiation examination (PIE) activities were begun on the first 37 samples received. PIE activities continue for the remainder of the AGC1 specimen as they are received at the IRC.

  4. High dose neutron irradiation of MgAl2O4 spinel: effects of post-irradiation thermal annealing on EPR and optical absorption

    SciTech Connect

    Ibarra, A.; Bravo, D.; Lopez, F J.; Garner, Francis A.

    2005-01-01

    Electron paramagnetic resonance (EPR) and optical absorption spectra were measured during thermal annealing for stoichiometric MgAl2O4 spinel that was previously irradiated in FFTF-MOTA at {approx}405 C to {approx}50 dpa. Both F and F+ centres are to persist up to very high temperatures (over 700C), suggesting the operation of an annealing mechanism based on evaporation from extended defects Using x-ray irradiation following the different annealing steps it was shown that the optical absorption band is related to a sharp EPR band at g=2.0005 and that the defect causing these effects is the F+ centre.

  5. Gamma irradiation of Tetrapleura tetraptera fruit as a post-harvest technique and its subsequent effect on some phytochemicals, free scavenging activity and physicochemical properties

    NASA Astrophysics Data System (ADS)

    Darfour, B.; Agbenyegah, S.; Ofosu, D. O.; Okyere, A. A.; Asare, I. K.

    2014-09-01

    Herbs, spices and medicinal plants have been cherished by many ancient cultures for their use in curing common ailments and promoting good health. The dry fruit of Tetrapleura tetraptera has a pleasant aroma and hence used as a spice for seasoning in many parts of Ghana. Contamination of the fruit can occur at any stage during harvesting, drying, processing, transportation and storage. T. tetraptera is prone to microbial contamination and insect infestation resulting in quality deterioration and economic loss. The study aimed at establishing the effect of gamma irradiation as a post-harvest processing technique on T. tetraptera fruit and the subsequent effect of the gamma irradiation on some phytochemicals, free radical scavenging activity and physicochemical properties. The T. tetraptera powder was packed in polythene bags and gamma irradiated with Cobalt 60 source at 5 kGy and 10 kGy at room temperature at a dose rate of 2 kGy/h. The total phenolic content, total flavonoid and DPPH free radical scavenging activity, pH, lactic acid, vitamin C, moisture, carbohydrate, protein and trace element content of the samples were analysed. The antioxidant potential of the T. tetraptera extract was observed to be enhanced in the solvent used for the extraction after the irradiation but not the radiation dose used. Irradiation only had substantial impacts on carbohydrate and protein, Cu, Mg, and Mn. The T. tetraptera studied was safe for human consumption as far as trace metal levels are concerned. This study therefore suggest that gamma irradiation up to 10 kGy could be used as a post-harvest technique in T. tetraptera as a spice or herb.

  6. High-dose neutron irradiation of MgAl 2O 4 spinel: effects of post-irradiation thermal annealing on EPR and optical absorption

    NASA Astrophysics Data System (ADS)

    Ibarra, A.; Bravo, D.; Lopez, F. J.; Garner, F. A.

    2005-02-01

    Electron paramagnetic resonance (EPR) and optical absorption spectra were measured during thermal annealing of stoichiometric MgAl 2O 4 spinel that was previously irradiated in the Materials Open Test Assembly in the Fast Flux Test Facility (FFTF/MOTA) at ≈680 K to ≈50 dpa. Both F and F + centres are to persist up to very high temperatures (over 1000 K) suggesting the operation of an annealing mechanism controlled by the thermal stability of extended defects. Using X-ray irradiation following the different annealing steps it was shown that an optical absorption band at 37 000 cm -1 is related to a sharp EPR band at g = 2.0005 and that the defect causing these effects is the F + centre.

  7. Computational Modeling of Cellular Effects Post-Irradiation with Low- and High-Let Particles and Different Absorbed Doses

    PubMed Central

    Tavares, Adriana Alexandre S.; Tavares, João Manuel R. S.

    2013-01-01

    The use of computational methods to improve the understanding of biological responses to various types of radiation is an approach where multiple parameters can be modelled and a variety of data is generated. This study compares cellular effects modelled for low absorbed doses against high absorbed doses. The authors hypothesized that low and high absorbed doses would contribute to cell killing via different mechanisms, potentially impacting on targeted tumour radiotherapy outcomes. Cellular kinetics following irradiation with selective low- and high-linear energy transfer (LET) particles were investigated using the Virtual Cell (VC) radiobiology algorithm. Two different cell types were assessed using the VC radiobiology algorithm: human fibroblasts and human crypt cells. The results showed that at lower doses (0.01 to 0.2 Gy), all radiation sources used were equally able to induce cell death (p>0.05, ANOVA). On the other hand, at higher doses (1.0 to 8.0 Gy), the radiation response was LET and dose dependent (p<0.05, ANOVA). The data obtained suggests that the computational methods used might provide some insight into the cellular effects following irradiation. The results also suggest that it may be necessary to re-evaluate cellular radiation-induced effects, particularly at low doses that could affect therapeutic effectiveness. PMID:23930101

  8. Effects of bonding bakeout thermal cycles on pre- and post irradiation microstructures, physical, and mechanical properties of copper alloys

    SciTech Connect

    Singh, B.N.; Eldrup, M.; Toft, P.; Edwards, D.J.

    1996-10-01

    At present, dispersion strengthened (DS) copper is being considered as the primary candidate material for the ITER first wall and divertor components. Recently, it was agreed among the ITER parties that a backup alloy should be selected from the two well known precipitation hardened copper alloys, CuCrZr and CuNiBe. It was therefore decided to carry out screening experiments to simulate the effect of bonding and bakeout thermal cycles on microstructure, mechanical properties, and electrical resistivity of CuCrZr and CuNiBe alloys. On the basis of the results of these experiments, one of the two alloys will be selected as a backup material. Tensile specimens of CuCrZr and CuNiBe alloys were given various heat treatments corresponding to solution anneal, prime ageing, and bonding thermal cycle followed by reageing and the reactor bakeout treatment at 623K for 100 hours. Tensile specimens of the DS copper were also given the heat treatment corresponding to the bonding thermal cycle. A number of these heat treated specimens of CuCrZr, CuNiBe, and DS copper were neutron irradiated at 523K to a dose level of {approx}0.3 dpa (NRT) in the DR-3 reactor at Riso. Both unirradiated and irradiated specimens with the various heat treatments were tensile tested at 532K. The dislocation, precipitate and void microstructures and electrical resistivity of these specimens were also determined. Results of these investigations will be reported and discussed in terms of thermal and irradiation stability of precipitates and irradiation-induced precipitation and recovery of dislocation microstructure. Results show that the bonding and bakeout thermal cycles are not likely to have any serious deleterious effects on the performance of these alloys. The CuNiBe alloys were found to be susceptible to radiation-induced embrittlement, however, the exact mechanism is not yet known. It is thought that radiation-induced precipitation and segregation of the beryllium may be responsible.

  9. Effect of low-energy laser irradiation and antioxidant supplementation on cell apoptosis during skeletal muscle post-injury regeneration in pigs.

    PubMed

    Otrocka-Domagała, I; Mikołajczyk, A; Paździor-Czapula, K; Gesek, M; Rotkiewicz, T; Mikiewicz, M

    2015-01-01

    The aim of this study was to evaluate the effect of low-energy laser irradiation, coenzyme Q10 and vitamin E supplementation on the apoptosis of macrophages and muscle precursor cells during skeletal muscle regeneration after bupivacaine-induced injury. The experiment was conducted on 75 gilts, divided into 5 experimental groups: I--control, II--low-energy laser irradiation, III--coenzyme Q10, IV--coenzyme Q10 and vitamin E, V--vitamin E. Muscle necrosis was induced by injection of 0.5% bupivacaine hydrochloride. The animals were euthanized on subsequent days after injury. Samples were formalin fixed and processed routinely for histopathology. Apoptosis was detected using the TUNEL method. The obtained results indicate that low-energy laser irradiation has a beneficial effect on macrophages and muscle precursor cell activity during muscle post-injury regeneration and protects these cells against apoptosis. Vitamin E has a slightly lower protective effect, limited mainly to the macrophages. Coenzyme Q10 co-supplemented with vitamin E increases the activity of macrophages and muscle precursor cells, myotube and young muscle formation. Importantly, muscle precursor cells seem to be more sensitive to apoptosis than macrophages in the environment of regenerating damaged muscle. PMID:26618584

  10. Effect of Processing, Post-Harvest Irradiation, and Production System on the Cytotoxicity and Mutagenicity of Vitis labrusca L. Juices in HTC Cells

    PubMed Central

    Düsman, Elisângela; de Almeida, Igor Vivian; Lucchetta, Luciano; Vicentini, Veronica Elisa Pimenta

    2014-01-01

    The juices of grapes (Vitis labrusca L.) are similar to the fruit itself because the main constituents of the fruit are present in the juice. However, their quality characteristics may be modified by the harsh technological processes used for the production of integral food, such as production systems of raw materials and post-harvest treatment of grapes with ultraviolet (UV) irradiation. Therefore, the present study analyzed juices produced naturally (by liquefying the fruit) or by the technological process of extraction by steam distillation (90°C) of grapes from organic and conventional production systems that were untreated or treated with UV type C (65.6 J/m2 for 10 minutes). Using cultures of Rattus norvegicus hepatoma cells (HTC) in vitro, cytotoxic effects were assayed by the MTT test and by calculating the cytokinesis blocked proliferation index (CBPI), and mutagenic effects were measured by the cytokinesis block micronucleus assay. The results of the MTT assay and the CBPIs indicated that none of the juices were cytotoxic, including those that induced cell proliferation. The results of the micronucleus assay showed that none of the juices were mutagenic. However, the average number of micronuclei was lower in the juices produced from organic grapes, and cell proliferation, soluble acids and phenolic compounds were significantly higher. Compared with the natural juices, the integral juices of conventional grapes showed a higher average number of micronuclei as well as lower stimulation of cell proliferation and lower levels of bioactive compounds. The results demonstrate a beneficial effect of UV-C irradiation of post-harvest grapes in stimulating the synthesis of nutraceutical compounds without generating cytotoxic or mutagenic substances. Taken together, our findings support the consumption of grape juice and the application of food production techniques that enhance its nutritional value and promote its production, marketing and consumption. PMID

  11. Theoretical and practical implications of the effects of temperature during irradiation and during pre- and post-irradiation storage on the response of thermoluminescence dosimeters

    SciTech Connect

    Gail de Planque, E.

    1984-01-01

    Experiments have been conducted to determine the applicability of the Randall-Wilkins theory for describing the behavior of CaF/sub 2/:Mn thermoluminescence dosimeters (Harshaw TLD-400 chips). Results were obtained for four different conditions: irradiation followed by storage, irradiation after storage, irradiation both preceded and followed by storage, and continuous simultaneous irradiation and storage. The experiments were performed for storage intervals of approximately 1, 2, 3, 5, 6 and 7 days at five different storage temperatures: -25, +20, +65, +150 and +175/sup 0/C. The results indicate fading that is described not by the Randall-Wilkins theory but rather as a linear function of the logarithm of the storage time. While the results suggest that the trapping efficiency is independent of temperature, they do demonstrate a small decrease in TL response with storage time prior to irradiation which is independent of temperature and time (>17 hours) and hence probably not dosimetric in origin but perhaps optically related. Glow curve analyses support the concept of a band of traps rather than a single trap. The overall results are compared to other data available in the literature most of which is for room-temperature storage. These data, for storage periods ranging from minutes to one year, can also be described as a linear function of the logarithm of the storage time and are remarkably consistent when uniformly normalized. Although peripheral experiments revealed problems associated with self-irradiation as well as a decline in sensitivity with use, the stability experiment results verify the highly favorable stability properties of CaF/sub 2/:Mn for widespread application.

  12. Pre- and post-irradiation fading effect for LiF:Mg,Ti and LiF:Mg,Cu,P materials used in routine monitoring.

    PubMed

    Carinou, E; Askounis, P; Dimitropoulou, F; Kiranos, G; Kyrgiakou, H; Nirgianaki, E; Papadomarkaki, E; Kamenopoulou, V

    2011-03-01

    LiF is a well-known thermoluminescent (TL) material used in individual monitoring, and its fading characteristics have been studied for years. In the present study, the fading characteristics (for a period of 150 d) of various commercial LiF materials with different dopants have been evaluated. The materials used in the study are those used in routine procedures by the Personal Dosimetry Department of Greek Atomic Energy Commission and in particular, LiF:Mg,Ti (MTS-N, TL Poland), LiF:Mg,Cu,P (MCP-N, TL Poland), LiF:Mg,Cu,P (MCP-Ns, thin active layer detector, TL Poland) and LiF:Mg,Cu,P (TLD100H, Harshaw). The study showed that there is a sensitivity loss in signal of up to 20 % for the MTS-N material for a 150-d period in the pre-irradiation fading phase. The MCP-N has a stable behaviour in the pre-irradiation fading phase, but this also depends on the readout system. As far as the post-irradiation fading effect is concerned, a decrease of up to 20 % for the MTS-N material is observed for the same time period. On the other hand, the LiF:Mg,Cu,P material presents a stable behaviour within ± 5 %. These results show that the fading effect is different for each material and should be taken into account when estimating doses from dosemeters that are in use for >2 months. PMID:21199822

  13. Post Irradiation Capabilities at the Idaho National Laboratory

    SciTech Connect

    Schulthess, J.L.; Robert D. Mariani; Rory Kennedy; Doug Toomer

    2011-08-01

    The U.S. Department of Energy (DOE) Office of Nuclear Energy (NE) oversees the research, development, and demonstration activities that ensure nuclear energy remains a viable energy option for the United States. Fuel and material development through fabrication, irradiation, and characterization play a significant role in accomplishing the research needed to support nuclear energy. All fuel and material development requires the understanding of irradiation effects on the fuel performance and relies on irradiation experiments ranging from tests aimed at targeted scientific questions to integral effects under representative and prototypic conditions. The DOE recently emphasized a solution-driven, goal-oriented, science-based approach to nuclear energy development. Nuclear power systems and materials were initially developed during the latter half of the 20th century and greatly facilitated by the United States’ ability and willingness to conduct large-scale experiments. Fifty-two research and test reactors with associated facilities for performing fabrication and pre and post irradiation examinations were constructed at what is now Idaho National Laboratory (INL), another 14 at Oak Ridge National Laboratory (ORNL), and a few more at other national laboratory sites. Building on the scientific advances of the last several decades, our understanding of fundamental nuclear science, improvements in computational platforms, and other tools now enable technological advancements with less reliance on large-scale experimentation.

  14. Post Irradiation Capabilities at the Idaho National Laboratory

    SciTech Connect

    Schulthess, J.L.

    2011-08-01

    The U.S. Department of Energy (DOE) Office of Nuclear Energy (NE) oversees the research, development, and demonstration activities that ensure nuclear energy remains a viable energy option for the United States. Fuel and material development through fabrication, irradiation, and characterization play a significant role in accomplishing the research needed to support nuclear energy. All fuel and material development requires the understanding of irradiation effects on the fuel performance and relies on irradiation experiments ranging from tests aimed at targeted scientific questions to integral effects under representative and prototypic conditions. The DOE recently emphasized a solution-driven, goal-oriented, science-based approach to nuclear energy development. Nuclear power systems and materials were initially developed during the latter half of the 20th century and greatly facilitated by the United States ability and willingness to conduct large-scale experiments. Fifty-two research and test reactors with associated facilities for performing fabrication and pre and post irradiation examinations were constructed at what is now Idaho National Laboratory (INL), another 14 at Oak Ridge National Laboratory (ORNL), and a few more at other national laboratory sites. Building on the scientific advances of the last several decades, our understanding of fundamental nuclear science, improvements in computational platforms, and other tools now enable technological advancements with less reliance on large-scale experimentation.

  15. Post-irradiation effect of Broncho-Vaxom, OM-85 BV, and its relationship to anti-oxidant activities.

    PubMed

    Saada, H N; Azab, K S; Zahran, A M

    2001-08-01

    This study was conducted to test the efficacy of Broncho-Vaxom (OM-85 BV) in rats after exposure to radiation-induced oxidative stress. Daily administration of Broncho-Vaxom (2.5 mg/kg/day) to rats for a period of 28 days produced a progressive significant increase in the activities of superoxide dismutase (SOD) and catalase in lungs and erythrocytes. No changes were recorded in reduced glutathione (GSH) content in lungs, while an increase was recorded in erythrocytes. Significant increase was also observed in serum gamma-globulin content. Intraperitoneal administration of Broncho-Vaxom to rats for 11 days before gamma-irradiation and daily during the period of irradiation, delivered as 1 Gy every other day to reach 9 Gy, significantly reduced radiation-induced lipid peroxidation (LPO) measured as thiobarbituric acid-reactive substances (TBARS) in the lungs and erythrocytes. Treatment with Broncho-Vaxom modified the radiation-induced decrease of serum gamma-globulins contents. It is postulated that Broncho-Vaxom, by enhancing the antioxidant system and increasing serum gamma-globulin content, could play an important role in modifying radiation-induced oxidative stress. PMID:11534345

  16. Investigation of the effect of some irradiation parameters on the response of various types of dosimeters to electron irradiation

    NASA Astrophysics Data System (ADS)

    Farah, K.; Kuntz, F.; Kadri, O.; Ghedira, L.

    2004-09-01

    Several undyed and dyed polymer films are commercially available for dosimetry in intense radiation fields, especially for radiation processing of food and sterilisation of medical devices. The effects of temperature during irradiation and post-irradiation stability, on the response of these dosimeters are of importance to operators of irradiation facilities. The present study investigates the effects of temperature during irradiation by 2.2 MeV electrons beam accelerator and post irradiation storage on the response of several types of dosimeter films. All dosimeters showed a significant effect of temperature during irradiation and post-irradiation storage.

  17. Post irradiation analysis of RERTR-7A, 7B and RERTR-8 tests

    SciTech Connect

    Hofman, G.L.; Kim, Yeon Soo; Shevlyakov, G.V.; Robinson, A.B.

    2008-07-15

    Addition of 2 wt% or more of silicon in the Al matrix for U-Mo/Al dispersion fuel has proved to be effective in reducing interaction layer growth from the RERTR-7A test to a burnup of {approx}100 at% U-235 (LEU equivalent). The recent RERTR-8 test also showed the consistent results. In this paper, we present the post irradiation analysis results of these tests. A considerable number of monolithic fuel plates were irradiated in the RERTR-7A and RERTR-8 tests. The post irradiation results of these plates are also included. The RERTR-7B test was a lower burnup test with similar power to the RERTR-7A. In this test, dispersion fuel plates with U-7Mo-1Ti and U- 7Mo-2Zr in Al-5Si were irradiated. The post irradiation results of these plates are also covered. (author)

  18. US RERTR FUEL DEVELOPMENT POST IRRADIATION EXAMINATION RESULTS

    SciTech Connect

    A. B. Robinson; D. M. Wachs; D. E. Burkes; D. D. Keiser

    2008-10-01

    Post irradiation examinations of irradiated RERTR plate type fuel at the Idaho National Laboratory have led to in depth characterization of fuel behavior and performance. Both destructive and non-destructive examination capabilities at the Hot Fuels Examination Facility (HFEF) as well as recent results obtained are discussed herein. New equipment as well as more advanced techniques are also being developed to further advance the investigation into the performance of the high density U-Mo fuel.

  19. Post-irradiation mechanical properties of an AlMgSi alloy

    NASA Astrophysics Data System (ADS)

    Ismail, Z. H.; Birt, B.

    1995-03-01

    The effect of fast-neutron irradiation on the tensile properties and hardness of the age-hardenable alloy AlMgSi is investigated. Post-irradiation tensile tests are carried out in the temperature range 298 to 628 K. The results show that the degree of irradiation-produced hardening is dependent upon the initial condition of the alloy. The alloy in its soft condition exhibits a higher degree of irradiation hardening compared with that in the hard condition. The implication of the results is discussed in terms of the variation in the microstructures involved and compared with previosly published data.

  20. Effect of post-harvest calcium chloride dip treatment and gamma irradiation on storage quality and shelf-life extension of Red delicious apple.

    PubMed

    Hussain, P R; Meena, R S; Dar, M A; Wani, A M

    2012-08-01

    Freshly harvested Red delicious apples were dipped in calcium chloride solution of varying concentrations (0.5-2.0% w/v) for 1 h prior to irradiation at dose level of 0.4 kGy. Fruits after radiation treatment were stored at 2 ± 1°C, RH 90% and evaluated at intervals of 30 days for various quality parameters. Results revealed significant (p ≤ 0.05) retention in firmness, juice yield and ascorbic acid content in samples treated with combination of calcium chloride at 2.0% w/v and gamma irradiation (0.4 kGy) during storage. Water soluble pectin was inversely correlated with firmness (r = 0.88) and was significantly (p ≤ 0.05) lower in samples subjected to combination treatment of 2.0% w/v CaCl2 and 0.4 kGy irradiation throughout the storage. The combination treatment of 2.0% CaCl2 and 0.4 kGy irradiation gave about 4.3 log reduction in yeast and mold count of apple samples. Results of the post refrigeration weight loss, firmness and overall acceptability revealed that combination treatment was helpful in extending the shelf-life of Red Delicious apples by around 20-25 days at 17 ± 2°C, RH 75% following 90 days of refrigeration. PMID:23904650

  1. Final Report on MEGAPIE Target Irradiation and Post-Irradiation Examination

    SciTech Connect

    Yong, Dai

    2015-06-30

    Megawatt pilot experiment (MEGAPIE) was successfully performed in 2006. One of the important goals of MEGAPIE is to understand the behaviour of structural materials of the target components exposed to high fluxes of high-energy protons and spallation neutrons in flowing LBE (liquid lead-bismuth eutectic) environment by conducting post-irradiation examination (PIE). The PIE includes four major parts: non-destructive test, radiochemical analysis of production and distribution of radionuclides produced by spallation reaction in LBE, analysis of LBE corrosion effects on structural materials, T91 and SS 316L steels, and mechanical testing of the T91 and SS 316L steels irradiated in the lower part of the target. The non-destructive test (NDT) including visual inspection and ultrasonic measurement was performed in the proton beam window area of the T91 calotte of the LBE container, the most intensively irradiated part of the MEGAPIE target. The visual inspection showed no visible failure and the ultrasonic measurement demonstrated no detectable change in thickness in the beam window area. Gamma mapping was also performed in the proton beam window area of the AlMg3 safety-container. The gamma mapping results were used to evaluate the accumulated proton fluence distribution profile, the input data for determining irradiation parameters. Radiochemical analysis of radionuclides produced by spallation reaction in LBE is to improve the understanding of the production and distribution of radionuclides in the target. The results demonstrate that the radionuclides of noble metals, 207Bi, 194Hg/Au are rather homogeneously distributed within the target, while radionuclides of electropositive elements are found to be deposited on the steel-LBE interface. The corrosion effect of LBE on the structural components under intensive irradiation was investigated by metallography. The results show that no evident corrosion damages. However, unexpected deep

  2. Nondestructive post-irradiation examination of Loop-1, S1 and B1 rods

    SciTech Connect

    Bratton, R.L.

    1997-05-01

    As a part of the Pacific Northwest National Laboratory`s Tritium Target Development Program, eleven tritium target rods were irradiated in the Advanced Test Reactor located at the Idaho National Engineering and Environmental Laboratory during 1991. Both nondestructive and destructive post-irradiation examination on all eleven rods was planned under the Tritium Target Development Program. Funding for the program was reduced in 1991 resulting in the early removal of the program experiments before reaching their irradiation goals. Post-irradiation examination was only performed on one of the irradiated rods at the Pacific Northwest National Laboratory before the program was terminated in 1992. On December 6, 1995, the Secretary of Energy announced the pursuit of the Commercial Light-Water Reactor option for producing tritium establishing the Tritium Target Qualification Program at the Pacific Northwest National Laboratory. This program decided to pursue nondestructive and destructive post-irradiation examination of the ten remaining rods from the previous program. The ten rods comprise three experiments. The Loop-1 experiment irradiated eight target rods in a loop configuration for 217 irradiation days. The other two rods were irradiated in two separate irradiation experiments, designated as S1 and B1 for 143 effective full-power days, but at different power levels. After the ten rods were transferred from the ATR Canal to the Hot Fuels Examination Facility, the following examinations were performed: (1) visual examination and photography; (2) neutron radiography; (3) axial gamma scanning; (4) contact profilometry measurement; (5) bow and length measurements; (6) rod puncture and plenum gas analysis/measurement of plenum gas quantity; (7) void volume determination; and (8) internal pressure determination. This report presents the data collected during these examinations.

  3. Combined therapy for post-irradiation infection

    SciTech Connect

    Elliott, T.B.; Madonna, G.S.; Ledney, G.D.; Brook, I.

    1989-01-01

    Increased susceptibility to bacterial infection, probably by translocation from the intestinal flora, can be a lethal complication for 2-3 weeks after exposure to ionizing radiation. Antibiotics alone do not provide adequate therapy for induced infections in neutropenic mice. Because some substances that are derived from bacterial cell walls activate macrophages and stimulate nonspecific resistance to infection, such agents might be used to prevent or treat postirradiation infections. In this study, a cell-wall glycolipid, trehalose dimycolate (TDM), was evaluated together with a third-generation cephalosporin, ceftriaxone, for their separate and combined effects on survival of B6D2F1 female mice that were exposed to the sublethal dose of 7.0 Gy Co radiation and challenged s.c. with lethal doses of Klebsiella pneumoniae. A single injection of TDM inoculated i.p. 1 hr postirradiation increased 30-day survival to 80% after a lethal challenge by K. pneumoniae 4 days later. When the challenge dose of K. pneumoniae was increased to 5000 Ld 50/30 on Day 4, all mice died.

  4. Advanced Post-Irradiation Examination Capabilities Alternatives Analysis Report

    SciTech Connect

    Jeff Bryan; Bill Landman; Porter Hill

    2012-12-01

    An alternatives analysis was performed for the Advanced Post-Irradiation Capabilities (APIEC) project in accordance with the U.S. Department of Energy (DOE) Order DOE O 413.3B, “Program and Project Management for the Acquisition of Capital Assets”. The Alternatives Analysis considered six major alternatives: ? No Action ? Modify Existing DOE Facilities – capabilities distributed among multiple locations ? Modify Existing DOE Facilities – capabilities consolidated at a few locations ? Construct New Facility ? Commercial Partnership ? International Partnerships Based on the alternatives analysis documented herein, it is recommended to DOE that the advanced post-irradiation examination capabilities be provided by a new facility constructed at the Materials and Fuels Complex at the Idaho National Laboratory.

  5. High post-irradiation ductility thermomechanical treatment for precipitation strengthened austenitic alloys

    DOEpatents

    Laidler, James J.; Borisch, Ronald R.; Korenko, Michael K.

    1982-01-01

    A method for improving the post-irradiation ductility is described which prises a solution heat treatment following which the materials are cold worked. They are included to demonstrate the beneficial effect of this treatment on the swelling resistance and the ductility of these austenitic precipitation hardenable alloys.

  6. Post irradiation examination of the Spallation Neutron Source target vessels

    SciTech Connect

    McClintock, David A; Ferguson, Phillip D; Mansur, Louis K

    2010-01-01

    The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory is an accelerator-based pulsed neutron source that produces high-energy spallation neutrons by bombarding liquid mercury flowing through a stainless steel target vessel. During operation the proton beam and spallation neutrons produce radiation damage in the AISI 316L austenitic stainless steel target vessel and water-cooled shroud. The beam pulses also cause rapid heating of the liquid mercury, which may produce cavitation erosion damage on the inner surface of the target vessel. The cavitation erosion rate is thought to be highly sensitive to beam power and predicted to be the primary life-limiting factor of target vessel. Though mitigation of cavitation erosion and radiation damage to the target vessel will be a critical for successful high-power operation of the SNS facility, the effects of radiation damage and cavitation erosion to target vessels in liquid metal spallation systems are not well known. Therefore preparations are being undertaken to perform post irradiation examination (PIE) of the liquid mercury target vessel and water-cooled shroud after end-of-life occurs. An overview of the planned PIE for the SNS target vessel is presented here, including proposed techniques for specimen acquisition and subsequent material properties characterization.

  7. Modification of the radiosensitivity of barley seed by post-treatment with caffein. IV. Effect of the moisture content of seed and storage temperature after irradiation.

    PubMed

    Kesavan, P C; Nadkarni, S

    1977-02-01

    The oxygen-dependent damage which develops in barley seeds with approximately 7-8 per cent moisture content disappears after post-irradiation storage in vacuo for 48 hours at 40 degrees C and for 24 hours at 50 degrees C. When the diration of storage at 40 degrees C is extended to 384 hours, oxygen-independent damage becomes potentiated. There is oxygen-dependent damage in seeds of approximately 13.3 per cent moisture content and after the seeds have been stored in vacuo at 50 degrees C, the oxygen-dependent damage begins to increase by 168 hours, and it is very significantly potentiated by 192 hours. Under these circumstances, caffeine acts as a radioprotector only as long as the precursors of oxic damage are present in the seeds. Once these sites are lost, caffeine acts only as a radiosensitizer. The oxygen-independent damage which increases with storage at high temperature is further potentiated by caffeine. PMID:300722

  8. Post-/γ-irradiation reactions in vitamin E stabilised and unstabilised HDPE

    NASA Astrophysics Data System (ADS)

    Mallégol, J.; Carlsson, D. J.; Deschênes, L.

    2001-12-01

    The oxidation of high density polyethylene (HDPE), both unstabilised and vitamin E stabilised, has been studied by infrared (IR) and electron paramagnetic resonance (EPR) spectroscopies in the period following γ-irradiation at doses from 1 to 60 kGy (range of food sterilisation). Derivatisation by reaction with sulphur tetrafluoride was used to identify macro-ketone and carboxylic acid components of the overlapped IR carbonyl region. Oxidation continued for several hundred hours after the cessation of irradiation as shown by the increase in hydroxyl, ketone and acid groups. Carboxylic acid groups are particularly important as a direct indication of backbone scission. Vitamin E, although an effective antioxidant during γ-irradiation, was less effective in reducing the post-irradiation changes, which are probably driven by migration of radical sites along the polymer backbone from within the crystalline phase to the amorphous/crystalline inter-phase, where they become oxygen accessible.

  9. Post Irradiation Capabilities at the Idaho National Laboratory

    SciTech Connect

    J. L. Schulthess; K. E. Rosenberg

    2011-05-01

    The U.S. Department of Energy (DOE), Office of Nuclear Energy (NE) oversees the efforts to ensure nuclear energy remains a viable option for the United States. A significant portion of these efforts are related to post-irradiation examinations (PIE) of highly activated fuel and materials that are subject to the extreme environment inside a nuclear reactor. As the lead national laboratory, Idaho National Laboratory (INL) has a rich history, experience, workforce and capabilities for performing PIE. However, new advances in tools and techniques for performing PIE now enable understanding the performance of fuels and materials at the nano-scale and smaller level. Examination at this level is critical since this is the scale at which irradiation damage occurs. The INL is on course to adopt these advanced tools and techniques to develop a comprehensive nuclear fuels and materials characterization capability that is unique in the world. Because INL has extensive PIE capabilities currently in place, a strong foundation exist to build upon as new capabilities are implemented and work load increases. In the recent past, INL has adopted significant capability to perform advanced PIE characterization. Looking forward, INL is planning for the addition of two facilities that will be built to meet the stringent demands of advanced tools and techniques for highly activated fuels and materials characterization. Dubbed the Irradiated Materials Characterization Laboratory (IMCL) and Advanced Post Irradiation Examination Capability , these facilities are next generation PIE laboratories designed to perform the work of PIE that cannot be performed in current DOE facilities. In addition to physical capabilities, INL has recently added two significant contributors to the Advanced Test Reactor-National Scientific User Facility (ATR-NSUF), Oak Ridge National Laboratory and University of California, Berkeley.

  10. Post-training gamma irradiation-enhanced contextual fear memory associated with reduced neuronal activation of the infralimbic cortex.

    PubMed

    Kugelman, Tara; Zuloaga, Damian G; Weber, Sydney; Raber, Jacob

    2016-02-01

    The brain might be exposed to irradiation under a variety of situations, including clinical treatments, nuclear accidents, dirty bomb scenarios, and military and space missions. Correctly recalling tasks learned prior to irradiation is important but little is known about post-learning effects of irradiation. It is not clear whether exposure to X-ray irradiation during memory consolidation, a few hours following training, is associated with altered contextual fear conditioning 24h after irradiation and which brain region(s) might be involved in these effects. Brain immunoreactivity patterns of the immediately early gene c-Fos, a marker of cellular activity was used to determine which brain areas might be altered in post-training irradiation memory retention tasks. In this study, we show that post-training gamma irradiation exposure (1 Gy) enhanced contextual fear memory 24h later and is associated with reduced cellular activation in the infralimbic cortex. Reduced GABA-ergic neurotransmission in parvalbumin-positive cells in the infralimbic cortex might play a role in this post-training radiation-enhanced contextual fear memory. PMID:26522840

  11. Post irradiation examination of irradiated americium oxide and uranium dioxide in magnesium aluminate spinel

    NASA Astrophysics Data System (ADS)

    Klaassen, F. C.; Bakker, K.; Schram, R. P. C.; Klein Meulekamp, R.; Conrad, R.; Somers, J.; Konings, R. J. M.

    2003-06-01

    To study MgAl 2O 4 spinel as inert matrix material for the transmutation of minor actinides, two capsules were irradiated at the high flux reactor in Petten, containing 12.5 wt% micro-dispersed 241AmO x in spinel and 25 wt% micro-dispersed enriched UO 2 in spinel. During irradiation, the initially present 241Am was converted for 99.8% to fission products (50%), plutonium (30%), curium (16%) and 243Am (4%). The UO 2 spinel target experienced a burn-up of 32% fission per initial metal atom. The post irradiation examination of the AmO x inert matrix target showed swelling of 27 vol.%, and a gas release of 48% for He and 16% for Xe and Kr. The UO 2 inert matrix target also showed a large volumetric swelling of 11%, directed mainly radially. Ceramography on the UO 2 inert matrix target revealed a complete restructuring of the spinel grains upon irradiation and the absence of porosity, suggesting that amorphisation is the main cause of the swelling.

  12. Effects of growth irradiance, nitrogen nutrition and watering regime on photosynthesis, leaf conductance and isoprene emission in leaves of Post Oak, Quercus stellata

    SciTech Connect

    Harley, P.; Archer, S.; Guenther, A. Texas A M Univ., College Station )

    1994-06-01

    Seedlings of Post Oak (Quercus stellata), the dominant woody species of oak savannas of east-central Texas, were grown outside in College Station, TX from April to November 1993. Plants were randomly placed in one cell of a 3 [times] 2 [times] 2 factorial experiment, employing 3 nitrogen fertilization (25, 100 and 225 ppm NH[sub 4]NO[sub 23]), 2 light levels (70% and 20% of full sun) and 2 watering regimes (to maintain 80-100% or 30-50% of field capacity). In November, net photosynthesis, leaf conductance and leaf isoprene emission rates at 30[degrees]C and PPFD=1000 [mu]mol m[sup [minus]2]s[sup [minus]1] were determined for two mature leaves on each of four plants from eight growth treatments and data were analyzed stastically. For plants grown under the lower watering regime, photosynthesis and isoprene emission increased with both increasing PPFD and nitrogen (effects significant at p<0.01). For plants grown at 70% full sun, effects of nitrogen treatment on photosynthesis, conductance and isoprene emission were significant (p<0.0001) while effects of watering treatment were not significant (p<0.2). Although watering treatment did not lead to significant differences between treatments, in a short-term drying experiment conducted on four plants, isoprene emissions increased through the drying period in previously well-watered plants, but decreased in previously droughted plants. Measurements were also made on two leaves to determine the effects of varying PPFD and temperature on rates of isoprene emission.

  13. Post-irradiation Examination of the AGR-1 Experiment: Plans and Preliminary Results

    SciTech Connect

    Paul Demkowicz

    2001-10-01

    Abstract – The AGR-1 irradiation experiment contains seventy-two individual cylindrical fuel compacts (25 mm long x 12.5 mm diameter) each containing approximately 4100 TRISO-coated uranium oxycarbide fuel particles. The experiment accumulated 620 effective full power days in the Advanced Test Reactor at the Idaho National Laboratory with peak burnups exceeding 19% FIMA. An extensive post-irradiation examination campaign will be performed on the AGR-1 fuel in order to characterize the irradiated fuel properties, assess the in-pile fuel performance in terms of coating integrity and fission metals release, and determine the fission product retention behavior during high temperature accident testing. PIE experiments will include dimensional measurements of fuel and irradiated graphite, burnup measurements, assessment of fission metals release during irradiation, evaluation of coating integrity using the leach-burn-leach technique, microscopic examination of kernel and coating microstructures, and accident testing of the fuel in helium at temperatures up to 1800°C. Activities completed to date include opening of the irradiated capsules, measurement of fuel dimensions, and gamma spectrometry of selected fuel compacts.

  14. Effect of 4-hydroxypyrazolo (3,4-D) pyrimidine (allopurinol) on post-irradiation cerebral blood flow: implications of free-radical involvement

    SciTech Connect

    Cockerham, L.G.; Arroyo, C.M.; Hampton, J.D.

    1988-01-01

    Early transient incapacitation (ETI) is the complete cessation of motor performance, occurring transiently and within the first 30 min following exposure to supralethal doses of ionizing irradiation. Studies have reported severe decreases in regional cerebral blood flow (rCBF) in primates at the same postirradiation time after receiving supralethal doses of gamma irradiation. One study demonstrated a dramatic fall of total cerebral blood flow following a single, 25-Gy, Co exposure. Free radical interactions have been implicated in a large number of pathological conditions including irradiation injury, ischemia, microvascular injury, and cell membrane damage. The triphasic cerebral ischemic response seen after irradiation may be even more damaging than complete ischemia since reperfusion may lead to the formation of additional free radicals. A possible mode of pharmacologic intervention may be the introduction of superoxide dismutase or allopurinol since both were used to attenuate the biochemical and functional damage usually associated with free-radical production. This study was designed to determine whether the inhibition of free radical formation via the preirradiation administration of allopurinol would be successful in altering the postirradiation hypotension and reduced rCBF. The hippocampus and the hypothalamus, were selected for the determination of blood flow in this study since a dramatic, postirradiation decrease in blood flow has been reported in these areas.

  15. Irradiation and post-irradiation examination of uranium-free nitride fuel

    NASA Astrophysics Data System (ADS)

    Hania, P. R.; Klaassen, F. C.; Wernli, B.; Streit, M.; Restani, R.; Ingold, F.; Fedorov, A. V.; Wallenius, J.

    2015-11-01

    Two identical Phénix-type 15-15Ti steel pinlets each containing a 70 mm Pu0.3Zr0.7N fuel stack in a 1-bar helium atmosphere have been irradiated in the HFR Petten at medium high linear power (46-47 kW/m at BOL) and an average cladding temperature of 505 °C. The pins were irradiated to a plutonium burn-up of 9.7% (88 MWd/kgHM) in 170 full power days. Both pins remained fully intact. Post-irradiation examination performed at NRG and PSI showed that the overall swelling rate of the fuel was 0.92 vol-%/%FIHMA. Fission gas release was 5-6%, while helium release was larger than 50%. No fuel restructuring was observed, and only mild cracking. EPMA measurements show a burn-up increase toward the pellet edge of up to 4 times. All investigated fission products except to some extent the noble metals were found to be evenly distributed over the matrix, indicating good solubility. Local formation of a secondary phase with high Pu content and hardly any Zr was observed. A general conclusion of this investigation is that ZrN is a suitable inert matrix for burning plutonium at high destruction rates.

  16. RERTR-12 Post-irradiation Examination Summary Report

    SciTech Connect

    Rice, Francine; Williams, Walter; Robinson, Adam; Harp, Jason; Meyer, Mitch; Rabin, Barry

    2015-02-01

    The following report contains the results and conclusions for the post irradiation examinations performed on RERTR-12 Insertion 2 experiment plates. These exams include eddy-current testing to measure oxide growth; neutron radiography for evaluating the condition of the fuel prior to sectioning and determination of fuel relocation and geometry changes; gamma scanning to provide relative measurements for burnup and indication of fuel- and fission-product relocation; profilometry to measure dimensional changes of the fuel plate; analytical chemistry to benchmark the physics burnup calculations; metallography to examine the microstructural changes in the fuel, interlayer and cladding; and microhardness testing to determine the material-property changes of the fuel and cladding. These characterization activities are tailored specifically to define: • The mechanical response of fuel meat, cladding, and interlayers, including diffusion barrier integrity • Whether geometry is stable and predictable; that changes in channel gap do not compromise ability to cool fuel • That fuel performance is known and predictable • A limited set of physical properties that are important for the analysis of fuel burnup limits • Whether swelling is stable and predictable.

  17. Endovascular Management of Post-Irradiated Carotid Blowout Syndrome

    PubMed Central

    Chang, Feng-Chi; Luo, Chao-Bao; Lirng, Jiing-Feng; Lin, Chung-Jung; Lee, Han-Jui; Wu, Chih-Chun; Hung, Sheng-Che; Guo, Wan-Yuo

    2015-01-01

    Purpose To retrospectively evaluate the clinical and technical factors related to the outcomes of endovascular management in patients with head-and-neck cancers associated with post-irradiated carotid blowout syndrome (PCBS). Materials and Methods Between 2000 and 2013, 96 patients with PCBS underwent endovascular management. The 40 patients with the pathological lesions located in the external carotid artery were classified as group 1 and were treated with embolization. The other 56 patients with the pathological lesions located in the trunk of the carotid artery were divided into 2 groups as follows: group 2A comprised the 38 patients treated with embolization, and group 2B comprised the 18 patients treated with stent-graft placement. Fisher’s exact test was used to examine endovascular methods, clinical severities, and postprocedural clinical diseases as predictors of outcomes. Results Technical success and immediate hemostasis were achieved in all patients. The results according to endovascular methods (group 1 vs 2A vs 2B) were as follows: technical complication (1/40[2.5%] vs 9/38[23.7%] vs 9/18[50.0%], P = 0.0001); rebleeding (14/40[35.0%] vs 5/38[13.2%] vs 7/18[38.9%]), P = 0.0435). The results according to clinical severity (acute vs ongoing PCBS) were as follows: technical complication (15/47[31.9%] vs 4/49[8.2%], P = 0.0035); rebleeding (18/47[38.3%] vs 8/49[16.3%], P = 0.0155). The results according to post-procedural clinical disease (regressive vs progressive change) were as follows: alive (14/21[66.7%] vs 8/75[10.7%], P<0.0001); survival time (34.1±30.6[0.3–110] vs 3.6±4.0[0.07–22] months, P<0.0001). Conclusion The outcomes of endovascular management of PCBS can be improved by taking embolization as a prior way of treatment, performing endovascular intervention in slight clinical severity and aggressive management of the post-procedural clinical disease. PMID:26439632

  18. Post-irradiation Examination and Fission Product Inventory Analysis of AGR-1 Irradiation Capsules

    SciTech Connect

    J M Harp; P D Demkowicz; S A Ploger

    2012-10-01

    The AGR-1 experiment was the first in a series of Advanced Gas Reactor (AGR) experiments designed to test TRISO fuel under High Temperature Gas Reactor irradiation conditions. This experiment was irradiated in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL) and is currently undergoing post-irradiation examination (PIE) at INL’s Materials and Fuels Complex (MFC). The inventory and distribution of fission products, especially Ag-110m, was assessed and analyzed for all the components of the AGR-1 capsules. This data should help inform the study of fission product migration in coated particle fuel. Gamma spectrometry was used to measure the activity of various different fission products in the different components of the AGR-1 test train. Each capsule contained: 12 fuel compacts, a graphite holder that kept the fuel compacts in place, graphite spacers that were above and below the graphite holders and fuel compacts, gas lines through which a helium neon gas mixture flowed in and out of each capsule, and the stainless steel shell that contained the experiment. Gamma spectrometry results and the experimental techniques used to capture these results will be presented for all the capsule components. The components were assayed to determine the total activity of different fission products present in or on them. These totals are compared to the total expected activity of a particular fission product in the capsule based on predictions from physics simulation. Based on this metric, a significant fraction of the Ag-110m was detected outside the fuel compacts, but the amount varied highly between the 6 capsules. Very small fractions of Cs-137 (<2E-5), Cs-134 (<1e-5), and Eu-154 (<4e-4) were detected outside of the fuel compacts. Additionally, the distribution of select fission products in some of the components including the fuel compacts and the graphite holders were measured and will be discussed.

  19. Recovery from hematopoietic injury by modulating prostaglandin E(2) signaling post-irradiation.

    PubMed

    Hoggatt, Jonathan; Singh, Pratibha; Stilger, Kayla N; Plett, P Artur; Sampson, Carol H; Chua, Hui Lin; Orschell, Christie M; Pelus, Louis M

    2013-03-01

    While high dose total body irradiation (TBI) is used therapeutically, the proliferation of nuclear weapons, increasing use of nuclear power, and worldwide radical terrorism underscore the need to develop countermeasures to a radiological mass casualty event. The hematopoietic syndrome of the acute radiation syndrome (HS-ARS) results from severe compromise to the hematopoietic system, including lymphocytopenia, neutropenia, thrombocytopenia, and possible death from infection and/or hemorrhage. Given adequate time to recover, expand, and appropriately differentiate, bone marrow hematopoietic stem cells (HSC) and progenitor cells (HPC) may overcome HS-ARS and restore homeostasis of the hematopoietic system. Prostaglandin E(2) (PGE(2)) has been shown to have pleiotropic effects on hematopoiesis, acting to inhibit apoptosis and promote self-renewal of HSC, while inhibiting HPC proliferation. We assessed the radio-mitigating potential of modulating PGE(2) signaling in a mouse model of HS-ARS. Treatment with the PGE(2) analog 16,16 dimethyl PGE(2) (dmPGE(2)) 6h post-irradiation or inhibition of PGE(2) synthesis via delayed administration of the non-steroidal anti-inflammatory drug (NSAID) Meloxicam resulted in increased survival of lethally irradiated mice. Both early dmPGE(2) and delayed Meloxicam treatment were associated with increased HPC activity 35days following irradiation, demonstrating enhanced recovery of hematopoiesis. Our results define two different treatment modalities that are highly effective and safe to administer, and can be readily available. PMID:23206586

  20. Accumulation efficiency of cancer stem-like cells post γ-ray and proton irradiation

    NASA Astrophysics Data System (ADS)

    Quan, Yi; Wang, Weikang; Fu, Qibin; Mei, Tao; Wu, Jingwen; Li, Jia; Yang, Gen; Wang, Yugang

    2012-09-01

    Ionizing radiation (IR) has been proven to be a powerful medical treatment in cancer therapy. Rational and effective use of its killing power depends on understanding IR-mediated responses at the molecular, cellular and tissue levels. Increasing evidence supports that cancer stem-like cells (CSCs) play an important role in tumor regrowth and spread post radiotherapy, for they are resistant to various therapy methods including radiation. Presently, SW620 colon carcinoma monolayer culture cells were irradiated with γ-rays and protons of 2 Gy. Then apoptosis, clonogenic survival and the expression of CD133+ protein were examined. The results showed that there was no significantly difference either on long-term clonogenic survival or on short-term apoptosis ratio. However, compared with γ-rays, irradiation with protons was less efficient to accumulate CSCs at the same dose, although both protons and γ-rays can significantly accumulate the CD133+ CSCs subpopulation. In addition, the results of sphere formation assay also confirmed that proton irradiation is less efficient in CSCs accumulation, suggesting proton irradiation might have higher efficiency in CSCs elimination for cancer radiotherapy.

  1. Caspase 3 in dying tumor cells mediates post-irradiation angiogenesis

    PubMed Central

    Zhang, Zhengxiang; Yu, Yang; Cheng, Jin; Gong, Yanping; Li, Chuan-Yuan; Huang, Qian

    2015-01-01

    Cytotoxic radiotherapy unfavorably induces tumor cells to generate various proangiogenic substances, promoting post-irradiation angiogenesis (PIA), which is one of major causes of radiotherapy failure. Though several studies have reported some mechanisms behind PIA, they have not yet described the beginning proangiogenic motivator buried in the irradiated microenvironment. In this work, we revealed that dying tumor cells induced by irradiation prompted PIA via a caspase 3 dependent mechanism. Proteolytic inactivation of caspase 3 in dying tumor cells by transducing a dominant-negative version weakened proangiogenic effects in vitro and in vivo. In addition, inhibition of caspase 3 activity suppressed tumor angiogenesis and tumorigenesis in xenograft mouse model. Importantly, we identified vascular endothelial growth factor (VEGF)-A as a downstream proangiogenic factor regulated by caspase 3 possibly through Akt signaling. Collectively, these findings indicated that besides acting as a key executioner in apoptosis, caspase 3 in dying tumor cells may play a central role in driving proangiogenic response after irradiation. Thus, radiotherapy in combination with caspase 3 inhibitors may be a novel promising therapeutic strategy to reduce tumor recurrence due to restrained PIA. PMID:26431328

  2. Transient and Post-irradiation Response of Optoelectronic Devices to Ionizing Radiation

    NASA Astrophysics Data System (ADS)

    Haider, F. A. A.; Chee, F. P.

    2015-01-01

    Space and ground level electronic equipment with semiconductor devices are subjected to the deleterious effects by radiation. This paper is attempted to present the transient and post-irradiation response of optoelectronic devices to gamma (γ) rays utilizing cobalt-60. In situ measurements were made on the devices under test (DUTs) up to a total dose of 60 krad followed by a post-irradiation not in-flux test for eight hours. Current transfer ratio (CTR) with is the vital merit of the optoelectronic system is found to decrease remarkably with the absorbed dose. This degradation is induced by the interaction of the energetic photons from gamma rays via two main mechanisms. The dominant effect is the mechanism by ionization while the secondary is by displacement. This radiation effect is found to arouse either a permanent or temporarily damage in the DUTs depending on their current drives and also the Total Ionizing Dose (TID) absorbed. The TID effects by gamma rays are cumulative and gradually take place throughout the lifecycle of the devices exposed to radiation. The full damage cascade phenomenon in the DUTs is calculated via the simulation.

  3. Validation of a Monte Carlo Based Depletion Methodology Using HFIR Post-Irradiation Measurements

    SciTech Connect

    Chandler, David; Maldonado, G Ivan; Primm, Trent

    2009-11-01

    Post-irradiation uranium isotopic atomic densities within the core of the High Flux Isotope Reactor (HFIR) were calculated and compared to uranium mass spectrographic data measured in the late 1960s and early 70s [1]. This study was performed in order to validate a Monte Carlo based depletion methodology for calculating the burn-up dependent nuclide inventory, specifically the post-irradiation uranium

  4. Pre- and post-irradiation characterization and properties measurements of ZrC coated surrogate TRISO particles

    SciTech Connect

    Vasudevamurthy, Gokul; Katoh, Yutai; Hunn, John D; Snead, Lance Lewis

    2010-09-01

    Zirconium carbide is a candidate to either replace or supplement silicon carbide as a coating material in TRISO fuel particles for high temperature gas-cooled reactor fuels. Six sets of ZrC coated surrogate microsphere samples, fabricated by the Japan Atomic Energy Agency using the fluidized bed chemical vapor deposition method, were irradiated in the High Flux Isotope Reactor at the Oak Ridge National Laboratory. These developmental samples available for the irradiation experiment were in conditions of either as-fabricated coated particles or particles that had been heat-treated to simulate the fuel compacting process. Five sets of samples were composed of nominally stoichiometric compositions, with the sixth being richer in carbon (C/Zr = 1.4). The samples were irradiated at 800 and 1250 C with fast neutron fluences of 2 and 6 dpa. Post-irradiation, the samples were retrieved from the irradiation capsules followed by microstructural examination performed at the Oak Ridge National Laboratory's Low Activation Materials Development and Analysis Laboratory. This work was supported by the US Department of Energy Office of Nuclear Energy's Advanced Gas Reactor program as part of International Nuclear Energy Research Initiative collaboration with Japan. This report includes progress from that INERI collaboration, as well as results of some follow-up examination of the irradiated specimens. Post-irradiation examination items included microstructural characterization, and nanoindentation hardness/modulus measurements. The examinations revealed grain size enhancement and softening as the primary effects of both heat-treatment and irradiation in stoichiometric ZrC with a non-layered, homogeneous grain structure, raising serious concerns on the mechanical suitability of these particular developmental coatings as a replacement for SiC in TRISO fuel. Samples with either free carbon or carbon-rich layers dispersed in the ZrC coatings experienced negligible grain size

  5. Irradiation effects in ferritic steels

    NASA Astrophysics Data System (ADS)

    Lechtenberg, Thomas

    1985-08-01

    Since 1979 the Alloy Development for Irradiation Performance (ADIP) task funded by the US Department of Energy has been studying the 2-12Cr class of ferritic steels to establish the feasibility of using them in fusion reactor first wall/breeding blanket (FW/B) applications. The advantages of ferritic steels include superior swelling resistance, low thermal stresses compared to austenitic stainless steels, attractive mechanical properties up to 600°C. and service histories exceeding 100 000 h. These steels are commonly used in a range of microstructural conditions which include ferritic, martensitic. tempered martensitic, bainitic etc. Throughout this paper where the term "ferritic" is used it should be taken to mean any of these microstructures. The ADIP task is studying several candidate alloy systems including 12Cr-1MoWV (HT-9), modified 9Cr-1MoVNb, and dual-phased steels such as EM-12 and 2 {1}/{4}Cr-Mo. These materials are ferromagnetic (FM), body centered cubic (bcc), and contain chromium additions between 2 and 12 wt% and molybdenum additions usually below 2%. The perceived issues associated with the application of this class of steel to fusion reactors are the increase in the ductile-brittle transition temperature (DBTT) with neutron damage, the compatibility of these steels with liquid metals and solid breeding materials, and their weldability. The ferromagnetic character of these steels can also be important in reactor design. It is the purpose of this paper to review the current understanding of these bcc steels and the effects of irradiation. The major points of discussion will be irradiation-induced or -enhanced dimensional changes such as swelling and creep, mechanical properties such as tensile strength and various measurements of toughness, and activation by neutron interactions with structural materials.

  6. A comparative TEM study of in-reactor and post-irradiation tensile tested copper

    NASA Astrophysics Data System (ADS)

    Pakarinen, J.; Tähtinen, S.; Singh, B. N.

    2013-11-01

    The deformation microstructures of oxygen-free high-conductivity (OFHC) copper were examined by transmission electron microscopy (TEM) following in-reactor and post-irradiation slow strain rate tensile tests. The TEM results suggest that the main modes of deformation differ between all examined cases. Plastic deformation appeared predominantly localized in the defect-free cleared channels following post-irradiation testing and hardly any dislocations were seen outside the channels. The microstructures following in-reactor tests were characterized by a small amount of cleared channels and a distinct dislocation density within the matrix. However, the dislocations observed following in-reactor testing did not seem to interact with each other, whereas that was the main mode of deformation in the non-irradiated reference sample. The possible mechanisms of plastic deformation are discussed based on the experimental results. Dislocation-dislocation interactions played the major role if irradiation or irradiation damage is not present. As a result of the interactions, the microstructure of non-irradiated reference copper was characterized by a well-defined cellularized dislocation microstructure. Dynamic dislocation-displacement cascade interactions dominated the deformation process at the in-reactor tensile tests. As a result, the formation of defect-free cleared channels was delayed, dislocations were found from the matrix between the channels, and a clear strain hardening was observed after the yield point. No clear difference between accumulated irradiation damage at in-reactor and post-irradiation samples was found, which may be due to localized nature of SFT evolution in displacement cascades at copper. In the post-irradiation experiments, dislocations were confined to slip planes and annihilate irradiation defects, while moving on the planes and creating defect-free cleared channels. The plastic deformation is localized into these channels, causing a decrease in

  7. Post-Irradiation Examination of Array Targets - Part I

    SciTech Connect

    Icenhour, A.S.

    2004-01-23

    During FY 2001, two arrays, each containing seven neptunium-loaded targets, were irradiated at the Advanced Test Reactor in Idaho to examine the influence of multi-target self-shielding on {sup 236}Pu content and to evaluate fission product release data. One array consisted of seven targets that contained 10 vol% NpO{sub 2} pellets, while the other array consisted of seven targets that contained 20 vol % NpO{sub 2} pellets. The arrays were located in the same irradiation facility but were axially separated to minimize the influence of one array on the other. Each target also contained a dosimeter package, which consisted of a small NpO{sub 2} wire that was inside a vanadium container. After completion of irradiation and shipment back to the Oak Ridge National Laboratory, nine of the targets (four from the 10 vol% array and five from the 20 vol% array) were punctured for pressure measurement and measurement of {sup 85}Kr. These nine targets and the associated dosimeters were then chemically processed to measure the residual neptunium, total plutonium production, {sup 238}Pu production, and {sup 236}Pu concentration at discharge. The amount and isotopic composition of fission products were also measured. This report provides the results of the processing and analysis of the nine targets.

  8. Carcinoma of the prostate: results of post-irradiation biopsy

    SciTech Connect

    Freiha, F.S.; Bagshaw, M.A.

    1984-01-01

    One hundred and forty-six patients with clinically localized carcinoma of the prostate were surgically staged and treated with external beam irradiation to the prostate and to the lymph node-bearing areas. Sixty-four (44%) of these patients had needle biopsy of the prostate 18 months or more following completion of therapy. Thirty-nine (61%) of the biopsies were interpreted as positive and 25 (39%) as negative. Twenty-eight (72%) of the 39 patients with a positive biopsy have subsequently developed metastases as compared to only 6 of 25 (24%) of the patients with a negative biopsy. It is concluded that an apparently positive postirradiation biopsy is likely to indicate active disease and identifies patients at a higher risk for development of metastases. Other details of staging, grading, and outcomes that compare these two groups are discussed.

  9. Post-irradiation-examination of irradiated fuel outside the hot cell

    SciTech Connect

    Dawn E. Janney; Adam B. Robinson; Thomas P. O'Holleran; R. Paul Lind; Marc Babcock; Laurence C. Brower; Julie Jacobs; Pamela K. Hoggan

    2007-09-01

    Because of their high radioactivity, irradiated fuels are commonly examined in a hot cell. However, the Idaho National Laboratory (INL) has recently investigated irradiated U-Mo-Al metallic fuel from the Reduced Enrichment for Research and Test Reactors (RERTR) project using a conventional unshielded scanning electron microscope outside a hot cell. This examination was possible because of a two-step sample-preparation approach in which a small volume of fuel was isolated in a hot cell and shielding was introduced during later stages of sample preparation. The resulting sample contained numerous sample-preparation artifacts but allowed analysis of microstructures from selected areas.

  10. Post-irradiation examination of capsule P13T

    SciTech Connect

    Scheffel, W.J.

    1981-08-01

    Postirradiation examination revealed excellent performance of the H-451 and TS-1240 graphite bodies and fuel rods irraidated to a peak fluence of 8.0 x 10/sup 25/ n/m/sup 2/ (E > 29 fJ)/sub HTGR/ and to a peak volume-average fuel rod temperature of 1215/sup 0/C. A range of fuel rod variables was tested matrix filler graphite, shim particles, compositions; no variable was detrimental to the rod integrity. Particle batches with coating designs representative of the LHTGR (Large HTGR) design requirements exhibited fair irradiation performance to full fast neutron exposure ((8.0 x 10/sup 25/ n/m/sup 2/) (E > 29 fJ)/sub HTGR/) and burnups of 75%. True in-service particle failures were concluded to be <0.3% for all P13T particles. The observed failure was attributed to the outer pyrolytic carbons (OPyC) layer. The failure fraction for 32 P13T fuel rods are greater than predicted, but the mean observed value is less than predicted up to fast fluences of approx. 6.0 x 10/sup 25/ n/m/sup 2/ (E > 29 fJ)/sub HTGT/ at 50% confidence. Incipient degradation of the SiC coating due to palladium attack was observed in the HEU UC/sub 2/-TRISO and the UCO (oxygen/uranium ratio (O/U) = 0.64) fuel rods.

  11. [Effect of infrared laser irradiation on the arterial blood pressure in liquidators of the accident at the Chernobyl power plant].

    PubMed

    Korkushko, O O

    2003-01-01

    Liquidators of Tchernobyl accident with discirculatory post-irradiation encephalopathy were treated with infra-red lazer irradiation together with a half doze of pharmacological agents usually used. Infra-red lazer irradiation has been shown to result in a significant reduce in the arterial pressure level, so it can be effective in correcting the disturbances in haemodynamics. PMID:12669529

  12. Effects of irradiation on mandibular scintigraphy

    SciTech Connect

    Aitasalo, K.; Ruotsalainen, P.

    1985-11-01

    Technetium-99m methylene diphosphonate (Sn) scintigraphy with computer analysis was used to investigate alterations in the pathophysiology of the normal mandible and the pathologic mandible during and after irradiation. Slight but significant elevations of uptake levels were recorded as an early effect of irradiation. The elevations correlated with the duration of treatment and normalized over a follow-up period of 6 to 12 mo. Increased mandibular metabolism was found during irradiation and in osteomyelitis and osteoradionecrosis of the mandible. Scintigraphy with computer analysis proved a simple and valid method in the evaluation of early irradiation damage and pathophysiologic conditions of the mandible. The method can also be used to predict whether the irradiation damage will become irreversible.

  13. Post-irradiation examination of the Spallation Neutron Source target module

    NASA Astrophysics Data System (ADS)

    McClintock, D. A.; Ferguson, P. D.; Mansur, L. K.

    2010-03-01

    The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory is an accelerator-based pulsed neutron source that produces high-energy spallation neutrons by bombarding liquid mercury flowing through a stainless steel target vessel. During operation the proton beam and spallation neutrons produce radiation damage in the AISI 316L austenitic stainless steel target vessel and water-cooled shroud. The beam pulses also cause rapid heating of the liquid mercury, which may produce cavitation erosion damage on the inner surface of the target vessel. The cavitation erosion rate is thought to be highly sensitive to beam power and predicted to be the primary life-limiting factor of the target module. Though cavitation erosion and radiation damage to the target vessel are expected to dictate its lifetime, the effects of radiation damage and cavitation erosion to target vessels in liquid metal spallation systems are not well known. Therefore preparations are being undertaken to perform post-irradiation examination (PIE) of the liquid mercury target vessel and water-cooled shroud after end-of-life occurs. An overview of the planned PIE for the SNS target vessel is presented here, including proposed techniques for specimen acquisition and subsequent material properties characterization.

  14. Evaluation of irradiation effects on concrete structure

    SciTech Connect

    Kontani, O.; Ishizawa, A.; Maruyama, I.; Takizawa, M.; Sato, O.

    2012-07-01

    In assessing the soundness of irradiated concrete of nuclear power plants operated for more than 30 years, reference levels are employed: 1x10{sup 20} n/cm{sup 2} for fast neutrons and 2x10{sup 10} rad (2x10{sup 5} kGy) for gamma rays. Concrete structures are regarded as sound when the estimated irradiance levels after 60 years of operation are less than the reference levels. The reference levels were obtained from a paper by Hilsdorf. It was found, however, that the test conditions in which data were obtained by the researchers referred in that paper are very different from the irradiation and heat conditions usually found in a Light Water Reactor (LWR), and therefore aren't appropriate for assessing the soundness of irradiated concrete of an LWR. This paper investigates the interactions between radiation and concrete and presents the results of gamma ray irradiation tests on cement paste samples in order to provide a better understanding of the irradiation effects on concrete. (authors)

  15. The effects of irradiation on blood components

    SciTech Connect

    Button, L.N.; DeWolf, W.C.; Newburger, P.E.; Jacobson, M.S.; Kevy, S.V.

    1981-01-01

    The functional properties of formed elements of whole blood were studied following irradiation doses of 500 to 20,000 rads. Irradiated lymphocytes retained only 1.5 per cent of their 3H thymidine uptake after a 5,000-rad exposure and none after 7,500 rads. Red blood cells stored for 21 days and then irradiated with 5,000 rads had the same survival as nonirradiated controls. In contrast, 5,000 rads reduced platelet yields. However, transfused irradiated platelets produced the expected increases in platelet counts and controlled hemostasis in thrombocytopenic patients. After 5,000 rads, granulocytes had normal bacterial killing capacity, chemotactic mobility, and normal superoxide production after high-dose stimulation. Nitroblue tetrazolium reduction and ingestion stimulated by complement opsonized oil droplets were not diminished by 5,000- and 10,000-rad irradiation. The functional qualities of cellular blood components other than lymphocytes are not compromised by 5,000 rads. This irradiation dose may be an effective means of controlling incidence of graft-vs-host disease in immunosuppressed patients.

  16. Improving Thermal Model Prediction Through Statistical Analysis of Irradiation and Post-Irradiation Data from AGR Experiments

    SciTech Connect

    Dr. Binh T. Pham; Grant L. Hawkes; Jeffrey J. Einerson

    2012-10-01

    As part of the Research and Development program for Next Generation High Temperature Reactors (HTR), a series of irradiation tests, designated as Advanced Gas-cooled Reactor (AGR), have been defined to support development and qualification of fuel design, fabrication process, and fuel performance under normal operation and accident conditions. The AGR tests employ fuel compacts placed in a graphite cylinder shrouded by a steel capsule and instrumented with thermocouples (TC) embedded in graphite blocks enabling temperature control. The data representing the crucial test fuel conditions (e.g., temperature, neutron fast fluence, and burnup) while impossible to obtain from direct measurements are calculated by physics and thermal models. The irradiation and post-irradiation examination (PIE) experimental data are used in model calibration effort to reduce the inherent uncertainty of simulation results. This paper is focused on fuel temperature predicted by the ABAQUS code’s finite element-based thermal models. The work follows up on a previous study, in which several statistical analysis methods were adapted, implemented in the NGNP Data Management and Analysis System (NDMAS), and applied for improving qualification of AGR-1 thermocouple data. The present work exercises the idea that the abnormal trends of measured data observed from statistical analysis may be caused by either measuring instrument deterioration or physical mechanisms in capsules that may have shifted the system thermal response. As an example, the uneven reduction of the control gas gap in Capsule 5 revealed by the capsule metrology measurements in PIE helps justify the reduction in TC readings instead of TC drift. This in turn prompts modification of thermal model to better fit with experimental data, thus help increase confidence, and in other word reduce model uncertainties in thermal simulation results of the AGR-1 test.

  17. Improving Thermal Model Prediction Through Statistical Analysis of Irradiation and Post-Irradiation Data from AGR Experiments

    SciTech Connect

    Binh T. Pham; Grant L. Hawkes; Jeffrey J. Einerson

    2014-05-01

    As part of the High Temperature Reactors (HTR) R&D program, a series of irradiation tests, designated as Advanced Gas-cooled Reactor (AGR), have been defined to support development and qualification of fuel design, fabrication process, and fuel performance under normal operation and accident conditions. The AGR tests employ fuel compacts placed in a graphite cylinder shrouded by a steel capsule and instrumented with thermocouples (TC) embedded in graphite blocks enabling temperature control. While not possible to obtain by direct measurements in the tests, crucial fuel conditions (e.g., temperature, neutron fast fluence, and burnup) are calculated using core physics and thermal modeling codes. This paper is focused on AGR test fuel temperature predicted by the ABAQUS code's finite element-based thermal models. The work follows up on a previous study, in which several statistical analysis methods were adapted, implemented in the NGNP Data Management and Analysis System (NDMAS), and applied for qualification of AGR-1 thermocouple data. Abnormal trends in measured data revealed by the statistical analysis are traced to either measuring instrument deterioration or physical mechanisms in capsules that may have shifted the system thermal response. The main thrust of this work is to exploit the variety of data obtained in irradiation and post-irradiation examination (PIE) for assessment of modeling assumptions. As an example, the uneven reduction of the control gas gap in Capsule 5 found in the capsule metrology measurements in PIE helps identify mechanisms other than TC drift causing the decrease in TC readings. This suggests a more physics-based modification of the thermal model that leads to a better fit with experimental data, thus reducing model uncertainty and increasing confidence in the calculated fuel temperatures of the AGR-1 test.

  18. Post Irradiation Evaluation of Thermal Control Coatings and Solid Lubricants to Support Fission Surface Power Systems

    NASA Astrophysics Data System (ADS)

    Bowman, Cheryl L.; Jaworske, Donald A.; Stanford, Malcolm K.; Persinger, Justin A.; Khorsandi, Behrooz; Blue, Thomas E.

    2007-01-01

    The development of a nuclear power system for space missions, such as the Jupiter Icy Moons Orbiter or a lunar outpost, requires substantially more compact reactor design than conventional terrestrial systems. In order to minimize shielding requirements and hence system weight, the radiation tolerance of component materials within the power conversion and heat rejection systems must be defined. Two classes of coatings, thermal control paints and solid lubricants, were identified as material systems for which limited radiation hardness information was available. Screening studies were designed to explore candidate coatings under a predominately fast neutron spectrum. The Ohio State Research Reactor Facility staff performed irradiation in a well characterized, mixed energy spectrum and performed post irradiation analysis of representative coatings for thermal control and solid lubricant applications. Thermal control paints were evaluated for 1 MeV equivalent fluences from 1013 to 1015 n/cm2. No optical degradation was noted although some adhesive degradation was found at higher fluence levels. Solid lubricant coatings were evaluated for 1 MeV equivalent fluences from 1015 to 1016 n/cm2 with coating adhesion and flexibility used for post irradiation evaluation screening. The exposures studied did not lead to obvious property degradation indicating the coatings would have survived the radiation environment for the previously proposed Jupiter mission. The results are also applicable to space power development programs such as fission surface power for future lunar and Mars missions.

  19. Post Irradiation Evaluation of Thermal Control Coatings and Solid Lubricants to Support Fission Surface Power Systems

    NASA Technical Reports Server (NTRS)

    Bowman, Cheryl L.; Jaworske, Donald A.; Stanford, Malcolm K.; Persinger, Justin A.; Khorsandi, Behrooz; Blue, Thomas E.

    2007-01-01

    The development of a nuclear power system for space missions, such as the Jupiter Icy Moons Orbiter or a lunar outpost, requires substantially more compact reactor design than conventional terrestrial systems. In order to minimize shielding requirements and hence system weight, the radiation tolerance of component materials within the power conversion and heat rejection systems must be defined. Two classes of coatings, thermal control paints and solid lubricants, were identified as material systems for which limited radiation hardness information was available. Screening studies were designed to explore candidate coatings under a predominately fast neutron spectrum. The Ohio State Research Reactor Facility staff performed irradiation in a well characterized, mixed energy spectrum and performed post irradiation analysis of representative coatings for thermal control and solid lubricant applications. Thermal control paints were evaluated for 1 MeV equivalent fluences from 10(exp 13) to 10(exp 15) n per square centimeters. No optical degradation was noted although some adhesive degradation was found at higher fluence levels. Solid lubricant coatings were evaluated for 1 MeV equivalent fluences from 10(exp 15) to 10(exp 16) n per square centimeters with coating adhesion and flexibility used for post irradiation evaluation screening. The exposures studied did not lead to obvious property degradation indicating the coatings would have survived the radiation environment for the previously proposed Jupiter mission. The results are also applicable to space power development programs such as fission surface power for future lunar and Mars missions.

  20. Post Irradiation Evaluation of Thermal Control Coatings and Solid Lubricants to Support Fission Surface Power Systems

    SciTech Connect

    Bowman, Cheryl L.; Jaworske, Donald A.; Stanford, Malcolm K.; Persinger, Justin A.; Khorsandi, Behrooz; Blue, Thomas E.

    2007-01-30

    The development of a nuclear power system for space missions, such as the Jupiter Icy Moons Orbiter or a lunar outpost, requires substantially more compact reactor design than conventional terrestrial systems. In order to minimize shielding requirements and hence system weight, the radiation tolerance of component materials within the power conversion and heat rejection systems must be defined. Two classes of coatings, thermal control paints and solid lubricants, were identified as material systems for which limited radiation hardness information was available. Screening studies were designed to explore candidate coatings under a predominately fast neutron spectrum. The Ohio State Research Reactor Facility staff performed irradiation in a well characterized, mixed energy spectrum and performed post irradiation analysis of representative coatings for thermal control and solid lubricant applications. Thermal control paints were evaluated for 1 MeV equivalent fluences from 1013 to 1015 n/cm2. No optical degradation was noted although some adhesive degradation was found at higher fluence levels. Solid lubricant coatings were evaluated for 1 MeV equivalent fluences from 1015 to 1016 n/cm2 with coating adhesion and flexibility used for post irradiation evaluation screening. The exposures studied did not lead to obvious property degradation indicating the coatings would have survived the radiation environment for the previously proposed Jupiter mission. The results are also applicable to space power development programs such as fission surface power for future lunar and Mars missions.

  1. Fuel Accident Condition Simulator (FACS) Furnace for Post-Irradiation Heating Tests of VHTR Fuel Compacts

    SciTech Connect

    Paul A Demkowicz; Paul Demkowicz; David V Laug

    2010-10-01

    Abstract –Fuel irradiation testing and post-irradiation examination are currently in progress as part of the Next Generation Nuclear Plant Fuels Development and Qualification Program. The PIE campaign will include extensive accident testing of irradiated very high temperature reactor fuel compacts to verify fission product retention characteristics at high temperatures. This work will be carried out at both the Idaho National Laboratory (INL) and the Oak Ridge National Laboratory, beginning with accident tests on irradiated fuel from the AGR-1 experiment in 2010. A new furnace system has been designed, built, and tested at INL to perform high temperature accident tests. The Fuel Accident Condition Simulator furnace system is designed to heat fuel specimens at temperatures up to 2000°C in helium while monitoring the release of volatile fission metals (e.g. Cs, Ag, Sr, Eu, and I) and fission gases (Kr, Xe). Fission gases released from the fuel to the sweep gas are monitored in real time using dual cryogenic traps fitted with high purity germanium detectors. Condensable fission products are collected on a plate attached to a water-cooled cold finger that can be exchanged periodically without interrupting the test. Analysis of fission products on the condensation plates involves dry gamma counting followed by chemical analysis of selected isotopes. This paper will describe design and operational details of the Fuel Accident Condition Simulator (FACS) furnace system, as well as preliminary system calibration results.

  2. Summary of Post Irradiation Examination Results of the AFIP-6 Failure

    SciTech Connect

    Adam Robinson; Daniel M. Wachs; Francine Rice; Danielle Perez

    2011-10-01

    The AFIP-6 test assembly was irradiated for one cycle in the Advanced Test Reactor at Idaho National Laboratory. The experiment was designed to test two monolithic fuel plates at power and burn-ups which bounded the operating conditions of both ATR and HFIR driver fuel. Both plates contain a solid U-Mo fuel foil with a zirconium diffusion barrier between 6061-aluminum cladding plates bonded by hot isostatic pressing. The experiment was designed with an orifice to restrict the coolant flow in order to obtain prototypic coolant temperature conditions. While these coolant temperatures were obtained, flow restriction resulted in low heat transfer coefficients and the failure of the fuel plates. The results from the post irradiation examinations and some observations of the failure mechanisms are outlined herein.

  3. Enhancement effect of irradiation by methotrexate

    SciTech Connect

    Shehata, W.M.; Meyer, R.L.

    1980-09-15

    Three cases are described in which complications developed which were believed to be due to the enhancement effect of irradiation by methotrexate during the course of therapy for lung, kidney, and bladder cancer. These included esophageal and large bowel complications. In two of these cases, the patients improved with conservative therapy.

  4. Impairment in Extinction of Contextual and Cued Fear Following Post-Training Whole-Body Irradiation

    PubMed Central

    Olsen, Reid H. J.; Marzulla, Tessa; Raber, Jacob

    2014-01-01

    Because of the use of radiation in cancer therapy, the risk of nuclear contamination from power plants, military conflicts, and terrorism, there is a compelling scientific and public health interest in the effects of environmental radiation exposure on brain function, in particular hippocampal function and learning and memory. Previous studies have emphasized changes in learning and memory following radiation exposure. These approaches have ignored the question of how radiation exposure might impact recently acquired memories, which might be acquired under traumatic circumstances (cancer treatment, nuclear disaster, etc.). To address the question of how radiation exposure might affect the processing and recall of recently acquired memories, we employed a fear conditioning paradigm wherein animals were trained, and subsequently irradiated (whole-body X-ray irradiation) 24 h later. Animals were given 2 weeks to recover, and were tested for retention and extinction of hippocampus-dependent contextual fear conditioning or hippocampus-independent cued fear conditioning. Exposure to irradiation following training was associated with reduced daily increases in body weights over the 22-days of the study and resulted in greater freezing levels and aberrant extinction 2 weeks later. This was also observed when the intensity of the training protocol was increased. Cued freezing levels and measures of anxiety 2 weeks after training were also higher in irradiated than sham-irradiated mice. In contrast to contextual freezing levels, cued freezing levels were even higher in irradiated mice receiving 5 shocks during training than sham-irradiated mice receiving 10 shocks during training. In addition, the effects of radiation on extinction of contextual fear were more profound than those on the extinction of cued fear. Thus, whole-body irradiation elevates contextual and cued fear memory recall. PMID:25071488

  5. Ion irradiation effects on metallic nanocrystals

    NASA Astrophysics Data System (ADS)

    Kluth, P.; Johannessen, B.; Giulian, R.; Schnohr, C. S.; Foran, G. J.; Cookson, D. J.; Byrne, A. P.; Ridgway, M. C.

    We have investigated structural and morphological properties of metallic nanocrystals (NCs) exposed to ion irradiation. NCs were characterized by transmission electron microscopy in combination with advanced synchrotron-based analytical techniques, in particular X-ray absorption spectroscopy and small-angle X-ray scattering. A number of different effects were observed depending on the irradiation conditions. At energies where nuclear stopping is predominant, structural disorder/amorphization followed by inverse Ostwald ripening/dissolution due to ion beam mixing was observed for Au and Cu NCs embedded in SiO2. The ion-irradiation-induced crystalline to amorphous transition in the NCs, which cannot be achieved in the corresponding bulk metals, was attributed to their initially higher structural energy as compared to bulk material and possibly preferential nucleation of the amorphous phase at the NC/SiO2 interface. At very high irradiation energies (swift heavy ion irradiation), where the energy loss is nearly entirely due to electronic stopping, a size-dependent shape transformation of the NCs from spheres to rod like shapes was apparent in Au NCs. Our preliminary results are in good agreement with considerations on melting of the NCs in the ion track as one mechanism involved in the shape transformation.

  6. Ion irradiation effects on metallic nanocrystals

    SciTech Connect

    Kluth, P.; Johannessen, B.; Giulian, R.; Schnohr, C.S.; Foran, G.J.; Cookson, D.J.; Byrne, A.P.; Ridgway, M.C.

    2008-04-02

    We have investigated structural and morphological properties of metallic nanocrystals (NCs) exposed to ion irradiation. NCs were characterized by transmission electron microscopy in combination with advanced synchrotron-based analytical techniques, in particular X-ray absorption spectroscopy and small-angle X-ray scattering. A number of different effects were observed depending on the irradiation conditions. At energies where nuclear stopping is predominant, structural disorder/amorphization followed by inverse Ostwald ripening/dissolution due to ion beam mixing was observed for Au and Cu NCs embedded in SiO{sub 2}. The ion-irradiation-induced crystalline to amorphous transition in the NCs, which cannot be achieved in the corresponding bulk metals, was attributed to their initially higher structural energy as compared to bulk material and possibly preferential nucleation of the amorphous phase at the NC/SiO{sub 2} interface. At very high irradiation energies (swift heavy ion irradiation), where the energy loss is nearly entirely due to electronic stopping, a size-dependent shape transformation of the NCs from spheres to rod like shapes was apparent in Au NCs. Our preliminary results are in good agreement with considerations on melting of the NCs in the ion track as one mechanism involved in the shape transformation.

  7. Effects of irradiation on platelet function

    SciTech Connect

    Rock, G.; Adams, G.A.; Labow, R.S.

    1988-09-01

    Current medical practice involves the irradiation of blood components, including platelet concentrates, before their administration to patients with severe immunosuppression. The authors studied the effect of irradiation on in vitro platelet function and the leaching of plasticizers from the bag, both immediately and after 5 days of storage. The platelet count, white cell count, pH, glucose, lactate, platelet aggregation and release reaction, and serotonin uptake were not altered by the irradiation of random-donor or apheresis units with 2000 rads carried out at 0 and 24 hours and 5 days after collection. The leaching of di(2-ethylhexyl)phthalate from the plastic bags followed by the conversion to mono(2-ethylhexyl)phthalate was not increased by irradiation. Therefore, it is possible to irradiate platelet concentrates on the day of collection and subsequently store them for at least 5 days while maintaining in vitro function. This procedure could have considerable benefit for blood banks involved in the provision of many platelet products.

  8. Effects of Laser Irradiation on Peripheral Nerve

    NASA Astrophysics Data System (ADS)

    Baxter, G. D.; Chow, R.; Armati, P.; Bjordal, J. M.; Laakso, L.

    2009-06-01

    A literature review was undertaken to determine the electrophysiological effects of Laser Irradiation (LI) on peripheral mammalian nerves, as a means of elucidating the potential mechanisms underlying pain relief associated with laser therapy. Relevant computerized databases and reference lists were searched, and experts consulted for further articles. A total of 38 studies, comprising 82 separate experiments were identified. In human studies, all types of LI (red and infrared, pulsed and cw) slowed nerve conduction velocity, and reduced compound action potential of irradiated nerves. In animal studies, infrared LI suppressed conduction velocity, as well as noxious stimulation evoked potential. This review thus indicates the potential of laser irradiation to inhibit activity in peripheral nerves, and highlights one potential mechanism of action for laser-mediated pain relief.

  9. Effects of gamma irradiation on deteriorated paper

    NASA Astrophysics Data System (ADS)

    Bicchieri, Marina; Monti, Michela; Piantanida, Giovanna; Sodo, Armida

    2016-08-01

    Even though gamma radiation application, also at the minimum dosage required for disinfection, causes depolymerization and degradation of the paper substrate, recently published papers seemed, instead, to suggest that γ-rays application could be envisaged in some conditions for Cultural Heritage original documents and books. In some of the published papers, the possible application of γ-rays was evaluated mainly by using mechanical tests that scarcely reflect the chemical modifications induced in the cellulosic support. In the present article the effect of low dosage γ-irradiation on cellulosic substrates was studied and monitored applying different techniques: colorimetry, spectroscopic measurements, carbonyl content and average viscometric degree of polymerization. Two different papers were investigated, a non-sized, non-filled cotton paper, and a commercial permanent paper. To simulate a real deteriorated document, which could need γ-rays irradiation, some samples were submitted to a hydrolysis treatment. We developed a treatment based on the exposition of paper to hydrochloric acid vapors, avoiding any contact of the samples with water. This method induces a degradation similar to that observed on original documents. The samples were then irradiated with 3 kGy γ-rays at a 5258 Gy/h rate. The aforementioned analyses were performed on the samples just irradiated and after artificial ageing. All tests showed negative effects of gamma irradiation on paper. Non-irradiated paper preserves better its appearance and chemical properties both in the short term and after ageing, while the irradiated samples show appreciable color change and higher oxidation extent. Since the Istituto centrale restauro e conservazione patrimonio archivistico e librario is responsible for the choice of all restoration treatments that could be applied on library and archival materials under the protection of the Italian State (http://www.icpal.beniculturali.it/allegati/DM-7

  10. Simple SE Methods Deployed in Revitalizing the Nuclear Post- Irradiation Examination Capability for the Idaho National Laboratory

    SciTech Connect

    Larry R. Zirker; R. Douglas Hamelin; Lori Braase

    2010-07-01

    The “crown jewels” of nuclear energy research facilities (i.e., hot cells, analysis systems, and scientists) have been centered at the Idaho National Laboratory for over 40 years, but in recent years, emphasis and funding for nuclear fuel research and development have declined to adversely affect the readiness and effectiveness of research facilities and equipment. Conversely, the current national nuclear renaissance forces the need for immediate enhancements in facilities, equipment, capabilities, and staff for the post-irradiation examination (PIE) of nuclear fuel. PIE characterizes the “burn-up” and structural integrity of fuel elements and defines the effectiveness of new fuels/alloys in search for optimum fuel burn-up and alloys for current and next generation nuclear reactors. This paper details how a team of system engineers adapted simple system engineering tools and techniques for a customer unfamiliar with the power and effectiveness of system engineering, to achieve project success.

  11. Helium irradiation effects on retention behavior of deuterium implanted into boron coating film by PCVD

    NASA Astrophysics Data System (ADS)

    Kodama, H.; Oyaidzu, M.; Yoshikawa, A.; Kimura, H.; Oya, Y.; Matsuyama, M.; Sagara, A.; Noda, N.; Okuno, K.

    2005-03-01

    Helium irradiation effects on the retention of energetic deuterium implanted into the boron coating film were investigated by means of X-ray photoelectron spectroscopy (XPS) and thermal desorption spectroscopy (TDS). It was found, by XPS, that the B 1s peak was shifted to lower binding energy side by He + ion irradiation and the FWHM was extended. These facts show that the some defects were introduced into the boron coating film by He + ion irradiation. From TDS experiment, the deuterium retention, especially the amount of B-D terminal bond, increased by the pre-He + ion irradiation. However, it decreased by the post-He + ion irradiation. These experimental results indicate that the B-D terminal bond was mainly influenced by the He + ion irradiation because the two neighbor B-D bonds have to dissociate simultaneously for the B-D-B bridge bond.

  12. SU-E-T-222: Investigation of Pre and Post Irradiation Fading of the TLD100 Thermoluminescence Dosimetry for Photon Beams

    SciTech Connect

    Sina, S; Sadeghi, M; Faghihi, R

    2014-06-01

    Purpose: The pre-irradiation and post-irradiation fading of the Thermoluminescense dosimeter signals were investigated in this study. Methods: Two groups of TLD chips with pre-determined ECC values were used in this study. The two groups were divided into 6 series, each composing of 5 TLD chips.The first group was used for pre-irradiation fading. 5 TLDs were exposed to a known amount of radiation from Cs-137 source, and were read out the next day. After seven days, the other 5 TLDs were exposed to the same amount of radiation and were read out after a day. The other series of 5 TLDs were also exposed after 7,19,28, 59, and 90 days, and were read out a day after irradiation. The loss in TLD signal were obtained for all the above cases. The second group, was used for postirradiation fading. All the TLDs of this group were exposed to a known amount of radiation from Cs-137 source. The 6 series composed of 5 TLDs were read out after 1,7,19,28,59, and 90 days. The above-mentioned procedures for obtaining pre-irradiation, and post-irradiation fading were performed for three storage temperatures (25°C, 4°C, and −18°C). Results: According to the results obtained in this study, in case of pre-irradiation fading study, the signal losses after 90 days are 12%, 24%, and 17% for 25°C, 4°C, and −18°C respectively. In case of post-irradiation fading study, the sensitivity losses after 90 days are 25%, 216%, and 20% for 25°C, 4°C, and −18°C respectively. Conclusion: The results indicate that the optimized time between exposing and reading out, and also the optimized time between annealing and exposing is 1 day.The reduction of Storage temperature will reduce the post-irradiation fading, While temperature reduction does not have any effect on pre-irradiation fading.

  13. An SEM Approach for the Evaluation of Intervention Effects Using Pre-Post-Post Designs

    ERIC Educational Resources Information Center

    Mun, Eun Young; von Eye, Alexander; White, Helene R.

    2009-01-01

    This study analyzes latent change scores using latent curve models (LCMs) for evaluation research with pre-post-post designs. The article extends a recent article by Willoughby, Vandergrift, Blair, and Granger (2007) on the use of LCMs for studies with pre-post-post designs, and demonstrates that intervention effects can be better tested using…

  14. The Effect of Neutron Irradiation on the Fracture Toughness of Graphite

    SciTech Connect

    Burchell, Timothy D; Strizak, Joe P

    2012-01-01

    As part of our irradiated graphite recycle program a small quantity of PCEA grade graphite was irradiated in the High Flux Isotope Reactor (HFIR) at ORNL. The graphite will provide the raw material for future recycle experiments. The geometry of the irradiated graphite allowed us to study the effects of neutron irradiation on the Critical Stress Intensity Factor, KIc, of graphite. The specimens where irradiated in two groups of 6 at an irradiation temperature of 900 C in rabbit capsules to doses of 6.6 and 10.2 DPA, respectively. Following a full suite of pre-and post-irradiation examination, which included dimensions, mass, electrical resistivity, elastic constants, and thermal expansion (to 800 C) the samples were notched and tested to determine their KIc using the newly approved ATSM test method for SENB fracture toughness of graphite. Here we report the irradiation induced changes in the dimensions, elastic constants, resistivity, and coefficient of thermal expansion of PCEA graphite. Moreover, irradiation induced changes in the Critical Stress Intensity Factor, KIc, or fracture toughness, are reported and discussed. Very little work on the effect of neutron irradiation on the fracture toughness of graphite has previously be performed or reported.

  15. An animal model of prophylactic cranial irradiation: Histologic effects at acute, early and delayed stages

    SciTech Connect

    Mildenberger, M.; Beach, T.G.; McGeer, E.G.; Ludgate, C.M. )

    1990-05-01

    Wistar rats (body wt. 200 g) were subjected to a fractionated course of radiation similar to that used in prophylactic brain irradiation for small cell carcinoma of the lung (2000 cGy in 5 fractions over 5 days with {sup 60}Co). Effects of this regimen were assessed by histologic examination of brain sections at 1 week, 1 month and 6 months post-irradiation. With conventional stains there were no apparent differences between control and irradiated brains at any of the post-irradiation intervals. Immunohistochemistry for neurotransmitter synthetic enzymes tyrosine hydroxylase and glutamate decarboxylase, as well as histochemistry for acetylcholinesterase, failed to uncover any changes in the irradiated animals. Immunohistochemistry for glial fibrillary acidic protein, an astrocyte marker, also showed no differences in the irradiated groups. However, an antibody against a major histocompatibility complex, class II antigen (OX-6) revealed a microglial response in grey and white matter beginning at 1 month and increasing up to the 6 month post-irradiation interval. The neuroanatomical basis for this microglial response was suggested by the results of silver stains for nerve axons, which revealed axonal loss in striatal white matter bundles in a pattern implicating vascular insufficiency.

  16. Effects and consequences of prenatal irradiation.

    PubMed

    Vos, O

    1989-06-01

    After a brief introduction about the historic development of risk estimates and maximum permissible doses of ionizing radiation, the risks of prenatal irradiation are discussed. Experimental data mainly obtained with mice indicate that the most important risk exists during the period of organogenesis and concerns the induction of malformations. Although in man this period lies between about 10 and 80 days after fertilization for most organs, the main development of the brain occurs later, namely between the 8th and 15th week after conception. Data from Japanese victims of the atomic bomb explosions above Hiroshima and Nagasaki indicate that during development the brain is the most sensitive organ to irradiation and maximal sensitivity is found between the 8th and 15th week after fertilization. A dose of one Gray received during this period induces a severe mental retardation in about 45% of the newborns. The dose response relationship is not significantly different from a linear one without a threshold dose. Studies of intelligence and school performance have shown that 1 Gray received during the 8th-15th week causes a shift of the average intelligence of about 30 points. Irradiation before the 8th week and after the 25th week had no effect on intelligence or mental retardation. During the 16th and 25th week sensitivity was about one fourth of that during the 8th-15th week. Although the irradiation of the embryo and fetus should be avoided as much as possible, the new data have led to an abandonment of the so-called 10-day rule. Generally an accidental irradiation of the embryo or fetus of less than 5 cGy is not considered as a medical indication for abortion. Retrospective studies showed that mothers from children who died from leukemia or other childhood tumors, had been subjected to a diagnostic irradiation of the pelvis or lower abdomen more frequently than mothers from children that did not develop a tumor. It has been estimated that prenatal sensitivity for

  17. Calibrated photostimulated luminescence is an effective approach to identify irradiated orange during storage

    NASA Astrophysics Data System (ADS)

    Jo, Yunhee; Sanyal, Bhaskar; Chung, Namhyeok; Lee, Hyun-Gyu; Park, Yunji; Park, Hae-Jun; Kwon, Joong-Ho

    2015-06-01

    Photostimulated luminescence (PSL) has been employed as a fast screening method for various irradiated foods. In this study the potential use of PSL was evaluated to identify oranges irradiated with gamma ray, electron beam and X-ray (0-2 kGy) and stored under different conditions for 6 weeks. The effects of light conditions (natural light, artificial light, and dark) and storage temperatures (4 and 20 °C) on PSL photon counts (PCs) during post-irradiation periods were studied. Non-irradiated samples always showed negative values of PCs, while irradiated oranges exhibited intermediate results after first PSL measurements. However, the irradiated samples had much higher PCs. The PCs of all the samples declined as the storage time increased. Calibrated second PSL measurements showed PSL ratio <10 for the irradiated samples after 3 weeks of irradiation confirming their irradiation status in all the storage conditions. Calibrated PSL and sample storage in dark at 4 °C were found out to be most suitable approaches to identify irradiated oranges during storage.

  18. Post-Irradiation Fracture Toughness of Unalloyed Molybdenum, ODS molybdenum, and TZM molybdenum following irradiation at 244C to 507C

    SciTech Connect

    Cockeram, Brian V; Byun, Thak Sang; Leonard, Keith J; Snead, Lance Lewis

    2013-01-01

    Commercially available unalloyed molybdenum (Low Carbon Arc Cast (LCAC)), Oxide Dispersion Strengthened (ODS) molybdenum, and TZM molybdenum were neutron irradiated at temperatures of nominally 244 C, 407 C, and 509 C to neutron fluences between 1.0 to 4.6x1025 n/m2 (E>0.1 MeV). Post-irradiation fracture toughness testing was performed. All alloys exhibited a Ductile to Brittle Transition Temperature that was defined to occur at 30 4 MPa-m1/2. The highest post-irradiated fracture toughness values (26-107 MPa-m1/2) and lowest DBTT (100-150 C) was observed for ODS molybdenum in the L-T orientation. The finer grain size for ODS molybdenum results in fine laminates that improve the ductile laminate toughening. The results for ODS molybdenum are anisotropic with lower post-irradiated toughness values (20-30 MPa-m1/2) and higher DBTT (450-600 C) in the T-L orientation. The results for T-L ODS molybdenum are consistent or slightly better than those for LCAC molybdenum (21-71 MPa-m1/2 and 450-800 C DBTT). The fracture toughness values measured for LCAC and T-L ODS molybdenum at temperatures below the DBTT were determined to be 8-18 MPa-m1/2. Lower non-irradiated fracture toughness values were measured for TZM molybdenum that are attributed to the large carbide precipitates serving as preferential fracture initiation sites. The role of microstructure and grain size on post-irradiated fracture toughness was evaluated by comparing the results for LCAC molybdenum and ODS molybdenum.

  19. Performance of AGR-1 High-Temperature Reactor Fuel During Post-Irradiation Heating Tests

    SciTech Connect

    Morris, Robert Noel; Baldwin, Charles A; Hunn, John D; Demkowicz, Paul; Reber, Edward

    2014-01-01

    The fission product retention of irradiated low-enriched uranium oxide/uranium carbide TRISO fuel compacts from the AGR-1 experiment has been evaluated at temperatures of 1600 1800 C during post-irradiation safety tests. Fourteen compacts (a total of ~58,000 particles) with a burnup ranging from 13.4 to 19.1% FIMA have been tested using dedicated furnace systems at Idaho National Laboratory and Oak Ridge National Laboratory. The release of fission products 110mAg, 134Cs, 137Cs, 154Eu, 155Eu, 90Sr, and 85Kr was monitored while heating the fuel specimens in flowing helium. The behavior of silver, europium, and strontium appears to be dominated by inventory that was originally released through intact SiC coating layers during irradiation, but was retained in the compact at the end of irradiation and subsequently released during the safety tests. However, at a test temperature of 1800 C, the data suggest that release of these elements through intact coatings may become significant after ~100 h. Cesium was very well retained by intact SiC layers, with a fractional release <5 10-6 after 300 h at 1600 C or 100 h at 1800 C. However, it was rapidly released from individual particles if the SiC layer failed, and therefore the overall cesium release fraction was dominated by the SiC defect and failure fractions in the fuel compacts. No complete TRISO coating layer failures were observed after 300 h at 1600 or 1700 C, and 85Kr release was very low during the tests (particles with breached SiC, but intact outer pyrocarbon, retained most of their krypton). Krypton release from TRISO failures was only observed after ~210 h at 1800 C in one compact. Post-safety-test examination of fuel compacts and particles has focused on identifying specific particles from each compact with notable fission product release and detailed analysis of the coating layers to understand particle behavior.

  20. The reduction of radiation damage to the spinal cord by post-irradiation administration of vasoactive drugs

    SciTech Connect

    Hornsey, S.; Myers, R.; Jenkinson, T. )

    1990-06-01

    Radiation induced white matter necrosis in the rat spinal cord is preceded by changes in permeability of the blood brain-barrier, reduced blood flow, and infarction so that the necrosis is an ischemic necrosis. Attempts have been made to modify this developing pathology by the administration of drugs post-irradiation but just prior to the changes in vascular permeability. Verapamyl, a calcium channel blocker, had no effect on the development of ataxia. Dipyridamole, a drug which increases blood flow and reduces thrombosis, delayed and reduced the onset of ataxia. A low iron diet and desferrioxamine which reduces reperfusion injury also delayed and reduced ataxia. These results support the thesis that vascular changes are an important pathway in the development of radiation necrosis and that reperfusion injury is an important factor in the development and exacerbation of radiation damage to the spinal cord.

  1. The effects of tungsten's pre-irradiation surface condition on helium-irradiated morphology

    DOE PAGESBeta

    Garrison, Lauren M.; Kulcinski, Gerald L.

    2015-07-17

    Erosion is a concern associated with the use of tungsten as a plasma-facing component in fusion reactors. To compare the damage progression, polycrystalline tungsten (PCW) and (110) single crystal tungsten (SCW) samples were prepared with (1) a mechanical polish (MP) with roughness values in the range of 0.018–0.020 μm and (2) an MP and electropolish (MPEP) resulting in roughness values of 0.010–0.020 μm for PCW and 0.003–0.005 μm for SCW samples. Samples were irradiated with 30 keV He+ at 1173 K to fluences between 3 × 1021 and 6 × 1022 He/m2. The morphologies that developed after low-fluence bombardment weremore » different for each type of sample—MP SCW, MPEP SCW, MP PCW, and MPEP PCW. At the highest fluence, the SCW MPEP sample lost significantly more mass and developed a different morphology than the MP SCW sample. The PCW samples developed a similar morphology and had similar mass loss at the highest fluence. Surface preparation can have a significant effect on post-irradiation morphology that should be considered for the design of future fusion reactors such as ITER and DEMO.« less

  2. The effects of tungsten's pre-irradiation surface condition on helium-irradiated morphology

    SciTech Connect

    Garrison, Lauren M.; Kulcinski, Gerald L.

    2015-07-17

    Erosion is a concern associated with the use of tungsten as a plasma-facing component in fusion reactors. To compare the damage progression, polycrystalline tungsten (PCW) and (110) single crystal tungsten (SCW) samples were prepared with (1) a mechanical polish (MP) with roughness values in the range of 0.018–0.020 μm and (2) an MP and electropolish (MPEP) resulting in roughness values of 0.010–0.020 μm for PCW and 0.003–0.005 μm for SCW samples. Samples were irradiated with 30 keV He+ at 1173 K to fluences between 3 × 1021 and 6 × 1022 He/m2. The morphologies that developed after low-fluence bombardment were different for each type of sample—MP SCW, MPEP SCW, MP PCW, and MPEP PCW. At the highest fluence, the SCW MPEP sample lost significantly more mass and developed a different morphology than the MP SCW sample. The PCW samples developed a similar morphology and had similar mass loss at the highest fluence. Surface preparation can have a significant effect on post-irradiation morphology that should be considered for the design of future fusion reactors such as ITER and DEMO.

  3. IRRADIATION EFFECTS ON THE PHYSICAL CHARACTERISTICS OF SEWAGE SLUDGE

    SciTech Connect

    Lee, M-J.; Lee, J-K.; Yoo, D-H.; Ho, K.

    2004-10-05

    The radiation effects on the physical characteristic of the sewage sludge were studied in order to obtain information which will be used for study on the enhancement of the sludge's dewaterability. Water contents, capillary suction time, zeta potential, irradiation dose, sludge acidity, total solid concentration, sludge particle size and microbiology before and after irradiation were investigated. Irradiation gave an effect on physical characteristics sludge. Water content in sludge cake could be reduced by irradiation at the dose of 10kGy.

  4. Irradiation effects on polymer-model compounds

    NASA Astrophysics Data System (ADS)

    Seguchi, Tadao; Katsumura, Yosuke; Hayashi, Nariyuki; Hayakawa, Naohiro; Tamura, Naoyuki; Tabata, Yoneho

    Irradiation effects on n-paraffins and squalane, used as models of polymers, were investigated by product analysis. Four n-paraffins, C 20H 42, C 21H 44, C 23H 48 and C 24H 50, and squalane (C 30H 62) were γ-irradiated under vacuum in liquid, crystalline and glassy states. The evolved gases were analyzed by gas chromatography and changes in molecular weight were analyzed by liquid chromatography and mass spectroscopy. G-values for crosslinking of n-paraffins were 1.2 for crystalline states (at 25°C) and 1.7 for liquid states (at 55°C), and showed no difference between odd and even carbon numbers. The G-value of liquid squalane was 1.7; it was 1.3 for the glassy state at low temperature (-77°C). Double bonds were common in the crosslinked products, especially after liquid-phase irradiation. The probability of chain scission was estimated as being negligible, though a small number of chain-scission products (which were products of scission at chain-ends or side chains) were observed by gas analysis.

  5. Irradiation effects on base metal and welds of 9Cr-1Mo (EM10) martensitic steel

    SciTech Connect

    Alamo, A.; Seran, J.L.; Rabouille, O.; Brachet, J.C.; Maillard, A.; Touron, H.; Royer, J.

    1996-12-31

    9Cr martensitic steels are being developed for core components (wrapper tubes) of fast breeder reactors as well as for fusion reactor structures. Here, the effects of fast neutron irradiation on the mechanical behavior of base metal and welds of 9Cr-1Mo (EM10) martensitic steel have been studied. Two types of weldments have been produced by TIG and electron beam techniques. Half of samples have been post-weld heat treated to produce a stress-relieved structure. The irradiation has been conducted in the Phenix reactor to doses of 63--65 dpa in the temperature range 450--459 C. The characterization of the welds, before and after irradiation, includes metallographic observations, hardness measurements, tensile and Charpy tests. It is shown that the mechanical properties of the welds after irradiation are in general similar to the characteristics obtained on the base metal, which is little affected by neutron irradiation.

  6. Silicon/HfO{sub 2} interface: Effects of proton irradiation

    SciTech Connect

    Maurya, Savita; Radhakrishna, M.

    2015-06-24

    Substrate oxide interfaces are of paramount importance in deciding the quality of the semiconductor devices. In this work we have studied how 200 keV proton irradiation affects the interface of a 13 nm thick, atomic layer deposited hafnium dioxide on silicon substrate. Pre- and post-irradiation electrical measurements are used to quantify the effect of proton irradiation for varying electrode geometries. Proton irradiation introduces positive charge in the oxide and at the interface of Si/HfO{sub 2} interface. The gate current is not very much affected under positive injection since the induced positive charge is compensated by the injected electrons. Current voltage characteristics under negative bias get affected by the proton irradiation.

  7. The effect of post surface treatments on the bond strength of fiber posts to root surfaces.

    PubMed

    Tuncdemir, Ali Riza; Yildirim, Cihan; Güller, Fatma; Ozcan, Erhan; Usumez, Aslihan

    2013-01-01

    The aim of the present study was to evaluate the influence of post surface treatment methods on the push-out bond strength of adhesively luted quartz fiber posts. Thirty freshly extracted and endodontically treated human incisor teeth were prepared for quartz fiber posts. The posts were submitted to three different surface treatments (n = 10), including no treatment, 50-µm aluminum-oxide (Al(2)O(3)) airborne-particle abrasion and Er:YAG laser (10 Hz, 150 mJ) irradiation. The posts were luted with resin cement. Each root was sectioned perpendicularly to its long axis to create specimens of 1-mm thickness. After the specimens were stored in distilled water at 37°C for 24 h, their push-out bond strength was tested using a universal testing machine at a crosshead speed of 1 mm/min. The data were analyzed by two-way ANOVA (α = .05). The two-way ANOVA indicated that push-out test values did not vary significantly according to surface treatments applied (control, airborne particle abrasion, Er:YAG laser irradiation) (p > 0.05), however, values varied according to the root segments (cervical, middle, and apical) (p < 0.01). The push-out bond strength values of the coronal root sections were the highest (p < 0.05) and there were no significant differences between the middle and apical root sections in push-out bond strength of fiber posts (p > 0.05). Air-borne particle abrasion or Er:YAG laser irradiation applied on the quartz fiber posts did not affect the push-out bond strengths relative to the root surfaces. The highest bond strength was observed in the cervical third of the roots in all groups. PMID:22274875

  8. The effect of gamma irradiation on injectable human amnion collagen

    SciTech Connect

    Liu, B.C.; Harrell, R.; Davis, R.H.; Dresden, M.H.; Spira, M. )

    1989-08-01

    The effect of gamma irradiation on the physicochemical properties of injectable human amnion collagen was investigated. Pepsin-extracted human amnion collagen was purified, reconstituted, and irradiated with varying doses of gamma irradiation (0.25 Mrads to 2.5 Mrads). Gamma irradiation had a significant impact on the physical characteristics of the collagen. The neutral solubility of collagen in PBS at 45{degrees}C was decreased from 100% for the nonirradiated control sample to 16% for the 2.5 Mrads irradiated sample. SDS polyacrylamide gel electrophoresis also demonstrated the dose-dependent effect of gamma irradiation on collagen cross-links. Electron microscopic observation revealed that even at low irradiation dose (0.25 Mrads), collagen fibril diameter increased. The average diameter was 50 nm for nonirradiated control fibrils, while 4.4% of the irradiated collagen fibrils had a diameter greater than 100 nm. Irradiated collagen showed little evidence of damage. Well-preserved cross-striations were found in collagen fibrils at all doses of irradiation. Native amnion collagen irradiated with gamma rays demonstrated a slight increase in resistance to collagenase degradation compared with nonirradiated native collagen samples. Increased resistance to collagenase did not correlate with increasing irradiation dose. After 30 min of incubation at 37{degrees}C, both irradiated and nonirradiated collagen was completely digested by collagenase. However, gamma-irradiated collagen did become more sensitive to hydrolysis by trypsin. The higher the irradiation doses used, the greater sensitivity to trypsin was observed. At 0.25 Mrads irradiation only a slight increase was found. No marked differences in amino acid composition were noted among the high dose irradiated, low dose irradiated and control amnion collagen.

  9. Review of Research on Post Irradiation Fruit Quality of Blueberries and Peaches

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The commercial use of irradiation is accelerating with the approval of low dose generic treatments for insect disinfestations and the availability of irradiation facilities. Commercial adoption of irradiation treatment requires an understanding of the radiotolerance limits for individual commodities...

  10. EFFECTS OF GAMMA IRRADIATION ON EPDM ELASTOMERS

    SciTech Connect

    Clark, E.

    2011-09-22

    Two formulations of EPDM elastomer, one substituting a UV stabilizer for the normal antioxidant in this polymer, and the other the normal formulation, were synthesized and samples of each were exposed to gamma irradiation in initially pure deuterium gas to compare their radiation stability. Stainless steel containers having rupture disks were designed for this task. After 130 MRad dose of cobalt-60 radiation in the SRNL Gamma Irradiation Facility, a significant amount of gas was created by radiolysis; however the composition indicated by mass spectroscopy indicated an unexpected increase in the total amount deuterium in both formulations. The irradiated samples retained their ductility in a bend test. No change of sample weight, dimensions, or density was observed. No change of the glass transition temperature as measured by dynamic mechanical analysis was observed, and most of the other dynamic mechanical properties remained unchanged. There appeared to be an increase in the storage modulus of the irradiated samples containing the UV stabilizer above the glass transition, which may indicate hardening of the material by radiation damage. Polymeric materials become damaged by exposure over time to ionizing radiation. Despite the limited lifetime, polymers have unique engineering material properties and polymers continue to be used in tritium handling systems. In tritium handling systems, polymers are employed mainly in joining applications such as valve sealing surfaces (eg. Stem tips, valve packing, and O-rings). Because of the continued need to employ polymers in tritium systems, over the past several years, programs at the Savannah River National Laboratory have been studying the effect of tritium on various polymers of interest. In these studies, samples of materials of interest to the SRS Tritium Facilities (ultra-high molecular weight polyethylene (UHMW-PE), polytetrafluoroethylene (PTFE, Teflon{reg_sign}), Vespel{reg_sign} polyimide, and the elastomer

  11. Effects of carbon ion irradiation and X-ray irradiation on the ubiquitylated protein accumulation.

    PubMed

    Isozaki, Tetsuro; Fujita, Mayumi; Yamada, Shigeru; Imadome, Kaori; Shoji, Yoshimi; Yasuda, Takeshi; Nakayama, Fumiaki; Imai, Takashi; Matsubara, Hisahiro

    2016-07-01

    C-ion radiotherapy is associated with improved local control and survival in several types of tumors. Although C-ion irradiation is widely reported to effectively induce DNA damage in tumor cells, the effects of irradiation on proteins, such as protein stability or degradation in response to radiation stress, remain unknown. We aimed to compare the effects of C-ion and X-ray irradiation focusing on the cellular accumulation of ubiquitylated proteins. Cells from two human colorectal cancer cell lines, SW620 and SW480, were subjected to C-ion or X-ray irradiation and determination of ubiquitylated protein levels. High levels of ubiquitylated protein accumulation were observed in the C-ion-irradiated SW620 with a peak at 3 Gy; the accumulation was significantly lower in the X-ray-irradiated SW620 at all doses. Enhanced levels of ubiquitylated proteins were also detected in C-ion or X-ray-irradiated SW480, however, those levels were significantly lower than the peak detected in the C-ion-irradiated SW620. The levels of irradiation-induced ubiquitylated proteins decreased in a time-dependent manner, suggesting that the proteins were eliminated after irradiation. The treatment of C-ion-irradiated SW620 with a proteasome inhibitor (epoxomicin) enhanced the cell killing activity. The accumulated ubiquitylated proteins were co-localized with γ-H2AX, and with TP53BP1, in C-ion-irradiated SW620, indicating C-ion-induced ubiquitylated proteins may have some functions in the DNA repair system. Overall, we showed C-ion irradiation strongly induces the accumulation of ubiquitylated proteins in SW620. These characteristics may play a role in improving the therapeutic ratio of C-ion beams; blocking the clearance of ubiquitylated proteins may enhance sensitivity to C-ion radiation. PMID:27175736

  12. Effects of carbon ion irradiation and X-ray irradiation on the ubiquitylated protein accumulation

    PubMed Central

    ISOZAKI, TETSURO; FUJITA, MAYUMI; YAMADA, SHIGERU; IMADOME, KAORI; SHOJI, YOSHIMI; YASUDA, TAKESHI; NAKAYAMA, FUMIAKI; IMAI, TAKASHI; MATSUBARA, HISAHIRO

    2016-01-01

    C-ion radiotherapy is associated with improved local control and survival in several types of tumors. Although C-ion irradiation is widely reported to effectively induce DNA damage in tumor cells, the effects of irradiation on proteins, such as protein stability or degradation in response to radiation stress, remain unknown. We aimed to compare the effects of C-ion and X-ray irradiation focusing on the cellular accumulation of ubiquitylated proteins. Cells from two human colorectal cancer cell lines, SW620 and SW480, were subjected to C-ion or X-ray irradiation and determination of ubiquitylated protein levels. High levels of ubiquitylated protein accumulation were observed in the C-ion-irradiated SW620 with a peak at 3 Gy; the accumulation was significantly lower in the X-ray-irradiated SW620 at all doses. Enhanced levels of ubiquitylated proteins were also detected in C-ion or X-ray-irradiated SW480, however, those levels were significantly lower than the peak detected in the C-ion-irradiated SW620. The levels of irradiation-induced ubiquitylated proteins decreased in a time-dependent manner, suggesting that the proteins were eliminated after irradiation. The treatment of C-ion-irradiated SW620 with a proteasome inhibitor (epoxomicin) enhanced the cell killing activity. The accumulated ubiquitylated proteins were co-localized with γ-H2AX, and with TP53BP1, in C-ion-irradiated SW620, indicating C-ion-induced ubiquitylated proteins may have some functions in the DNA repair system. Overall, we showed C-ion irradiation strongly induces the accumulation of ubiquitylated proteins in SW620. These characteristics may play a role in improving the therapeutic ratio of C-ion beams; blocking the clearance of ubiquitylated proteins may enhance sensitivity to C-ion radiation. PMID:27175736

  13. AGR-1 Fuel Compact 6-3-2 Post-Irradiation Examination Results

    SciTech Connect

    Paul demkowicz; jason Harp; Scott Ploger

    2012-12-01

    Destructive post-irradiation examination was performed on fuel Compact 6-3-2, which was irradiated in the AGR-1 experiment to a final compact average burnup of 11.3% FIMA and a time-average, volume-average temperature of 1070°C. The analysis of this compact was focused on characterizing the extent of fission product release from the particles and examining particles to determine the condition of the kernels and coating layers. The work included deconsolidation of the compact and leach-burn-leach analysis, visual inspection and gamma counting of individual particles, measurement of fuel burnup by several methods, metallurgical preparation of selected particles, and examination of particle cross-sections with optical microscopy. A single particle with a defective SiC layer was identified during deconsolidation-leach-burn-leach analysis, which is in agreement with previous measurements showing elevated cesium in the Capsule 6 graphite fuel holder associated with this fuel compact. The fraction of the compact europium inventory released from the particles and retained in the matrix was relatively high (approximately 6E-3), indicating release from intact particle coatings. The Ag-110m inventory in individual particles exhibited a very broad distribution, with some particles retaining =80% of the predicted inventory and others retaining less than 25%. The average degree of Ag-110m retention in 60 gamma counted particles was approximately 50%. This elevated silver release is in agreement with analysis of silver on the Capsule 6 components, which indicated an average release of 38% of the Capsule 6 inventory from the fuel compacts. In spite of the relatively high degree of silver release from the particles, virtually none of the Ag-110m released was found in the compact matrix, and presumably migrated out of the compact and was deposited on the irradiation capsule components. Release of all other fission products from the particles appears to be less than a single

  14. Biological effects of ultraviolet irradiation on bees

    SciTech Connect

    Es`kov, E.K.

    1995-09-01

    The influence of natural solar and artificial ultraviolet irradiation on developing bees was studied. Lethal exposures to irradiation at different stages of development were determined. The influence of irradiation on the variability of the morphometric features of bees was revealed. 5 refs., 1 fig.

  15. The post-thaw irradiation of avian spermatozoa with He-Ne laser differently affects chicken, pheasant and turkey sperm quality.

    PubMed

    Iaffaldano, N; Paventi, G; Pizzuto, R; Passarella, S; Cerolini, S; Zaniboni, L; Marzoni, M; Castillo, A; Rosato, M P

    2013-11-30

    The effects of post-thaw Helium-Neon (He-Ne) laser irradiation on mobility and functional integrity of frozen/thawed chicken, pheasant and turkey spermatozoa were investigated. Cytochrome C oxidase (COX) activity was also determined as a measure of the effect of irradiation on mitochondrial bioenergetics. Semen samples from each species were collected, processed and frozen according to the pellet procedure. After thawing, each semen sample was divided into two subsamples: the first one was the control; the second one was irradiated with a single mode continuous He-Ne laser wave (wavelength 632.8 nm; 6 mW; 3.96 J/cm(2)). Then the samples were assessed for sperm mobility (Accudenz(®) swim-down test), viability (SYBR-14/PI staining), osmotic-resistance (HOS test) and COX activity. The irradiation was effective P<0.05 increasing sperm motility in the turkey semen (0.228 ± 0.01 compared with 0.294 ± 0.02). The irradiation also caused an increase (P<0.05) of the COX activity in pheasant (+135 ± 4%) and turkey (+116 ± 4%) sperm, without affecting viability and osmotic-resistance. The COX was positively correlated (P<0.05) with the viability of chicken sperm, however no significant interactions were found between mobility and COX activity in the three avian species. Due to the difference in energetic metabolism among avian species used in this study, the He-Ne laser irradiation has a differential action on bio-stimulation of turkey, chicken and pheasant spermatozoa. The present results are the first to elucidate the possibility for restoration of motility of cryopreserved avian spermatozoa by bio-stimulation provided via He-Ne laser irradiation. PMID:24125852

  16. Effects of HZE irradiation on chemical neurotransmission in rodent hippocampus

    NASA Astrophysics Data System (ADS)

    Machida, Mayumi

    Space radiation represents a significant risk to the CNS (central nervous system) during space missions. Most harmful are the HZE (high mass, highly charged (Z), high energy) particles, e.g. 56Fe, which possess high ionizing ability, dense energy deposition pattern, and high penetrance. Accumulating evidence suggests that radiation has significant impact on cognitive functions. In ground-base experiments, HZE radiation induces pronounced deficits in hippocampus dependent learning and memory in rodents. However, the mechanisms underlying these impairments are mostly unknown. Exposure to HZE radiation elevates the level of oxidation, resulting in cell loss, tissue damage and functional deficits through direct ionization and generation of reactive oxygen species (ROS). When hippocampal slices were exposed to ROS, neuronal excitability was reduced. My preliminary results showed enhanced radio-vulnerability of the hippocampus and reduction in basal and depolarization-evoked [3H]-norepinephrine release after HZE exposure. These results raised the possibility that HZE radiation deteriorates cognitive function through radiation-induced impairments in hippocampal chemical neurotransmission, the hypothesis of this dissertation. In Aim 1 I have focused on the effects of HZE radiation on release of major neurotransmitter systems in the hippocampus. I have further extended my research on the levels of receptors of these systems in Aim 2. In Aim 3, I have studied the level of oxidation in membranes of my samples. My research reveals that HZE radiation significantly reduces hyperosmotic sucrose evoked [3H]-glutamate and [14C]-GABA release both three and six months post irradiation. The same radiation regimen also significantly enhances oxidative stress as indicated by increased levels of lipid peroxidation in the hippocampus, suggesting that increased levels of lipid peroxidation may play a role in reduction of neurotransmitter release. HZE radiation also significantly reduces

  17. Influence of atomic oxygen irradiation during deposition on crystallization of post-annealed barium zirconate thin films

    NASA Astrophysics Data System (ADS)

    Iguchi, Fumitada; Shibata, Yoshikazu; Miyazaki, Takamichi; Sata, Noriko; Yugami, Hiroo

    2014-11-01

    The role of atomic oxygen irradiation in the epitaxial crystallization of yttrium-doped barium zirconate thin films fabricated by pulsed laser deposition (PLD) was investigated. X-ray diffraction and transmission electron microscopy revealed that, for films deposited without irradiation, random nucleation and growth occurred below the onset temperature for continuous crystallization at the film-interlayer interface. In contrast, for films deposited with oxygen irradiation, random nucleation and growth was not detected at the temperature of continuous crystallization, which facilitates epitaxial crystallization in these films. This study suggests the combined low temperature deposition with atomic oxygen irradiation and post-annealing could control microstructure of solid-state electrochemical devices such as solid oxide fuel cells and solid-state lithium secondary batteries.

  18. Effects of X irradiation on angiogenesis

    SciTech Connect

    Prionas, S.D.; Kowalski, J.; Fajardo, L.F.; Kaplan, I.; Kwan, H.H.; Allison, A.C. )

    1990-10-01

    We have evaluated the effect of X irradiation on the mesenchymal tissue growth (blood capillaries and stromal cells) in an angiogenesis system in the mouse. This was accomplished by implanting a polyvinyl alcohol sponge disc in the subcutis of the thorax, and quantifying the extent of growth reduction of capillaries and stromal cells following graded doses of X rays. The sponge disc contained a centrally located pellet impregnated with 20 micrograms of epidermal growth factor and coated with a thin film of slow-releasing compound. Total growth of vessels and fibroblasts was determined by morphometric analysis of histologic sections. The incorporation of ({sup 3}H)TdR was measured during a 24-h period. A dose-response relationship was observed when X irradiation was given on Day 11 after implantation, with the disc removed on Day 20. A single dose of 15 Gy reduced both the rate of incorporation of ({sup 3}H)TdR and the total growth area. These and previous observations point to endothelial cells as important targets of ionizing radiation in the stroma, especially during the period of active proliferation of these cells, induced by growth factors.

  19. Irradiation effects on hydrases for biomedical applications

    NASA Astrophysics Data System (ADS)

    Furuta, Masakazu; Ohashi, Isao; Oka, Masahito; Hayashi, Toshio

    2000-03-01

    To apply an irradiation technique to sterilize "Hybrid" biomedical materials including enzymes, we selected papain, a well-characterized plant endopeptidase as a model to examine durability of enzyme activity under the practical irradiation condition in which limited data were available for irradiation inactivation of enzymes. Dry powder and frozen aqueous solution of papain showed significant durability against 60Co-gamma irradiation suggesting that, the commercial irradiation sterilizing method is applicable without modification. Although irradiation of unfrozen aqueous papain solution showed an unusual change of the enzymatic activity with the increasing doses, and was totally inactivated at 15 kGy, we managed to keep the residual activity more than 50% of initial activity after 30-kGy irradiation, taking such optimum conditions as increasing enzyme concentration from 10 to 100 mg/ml and purging with N 2 gas to suppress the formation of free radicals.

  20. Silicon/HfO2 interface: Effects of gamma irradiation

    NASA Astrophysics Data System (ADS)

    Maurya, Savita

    2016-05-01

    Quality of MOS devices is a strong function of substrate and oxide interface. In this work we have studied how gamma photon irradiation affects the interface of a 13 nm thick, atomic layer deposited hafnium dioxide deposited on silicon wafer. CV and GV measurements have been done for pristine and irradiated samples to quantify the effect of gamma photon irradiation. Gamma photon irradiation not only introduces positive charge in the oxide and at the interface of Si/HfO2 interface but also induce phase change of oxide layer. Maximum oxide capacitances are affected by gamma photon irradiation.

  1. Retention of Root Canal Posts: Effect of Cement Film Thickness, Luting Cement, and Post Pretreatment.

    PubMed

    Sahafi, A; Benetti, A R; Flury, S; Peutzfeldt, A

    2015-01-01

    The aim of this study was to investigate the effect of the cement film thickness of a zinc phosphate or a resin cement on retention of untreated and pretreated root canal posts. Prefabricated zirconia posts (CosmoPost: 1.4 mm) and two types of luting cements (a zinc phosphate cement [DeTrey Zinc] and a self-etch adhesive resin cement [Panavia F2.0]) were used. After removal of the crowns of 360 extracted premolars, canines, or incisors, the root canals were prepared with a parallel-sided drill system to three different final diameters. Half the posts did not receive any pretreatment. The other half received tribochemical silicate coating according to the manufacturer's instructions. Posts were then luted in the prepared root canals (n=30 per group). Following water storage at 37°C for seven days, retention of the posts was determined by the pull-out method. Irrespective of the luting cement, pretreatment with tribochemical silicate coating significantly increased retention of the posts. Increased cement film thickness resulted in decreased retention of untreated posts and of pretreated posts luted with zinc phosphate cement. Increased cement film thickness had no influence on retention of pretreated posts luted with resin cement. Thus, retention of the posts was influenced by the type of luting cement, by the cement film thickness, and by the post pretreatment. PMID:25764045

  2. Effect of low-level laser irradiating point on immunity

    NASA Astrophysics Data System (ADS)

    Cai, ChangSong; Qi, Qiong-fang; Xin, Jiang

    1993-03-01

    This paper reports that cellular immune function was observed when He-Ne laser was used to irradiate `zusanli' point in rats using various power, time, and periods. The indicator was a lymphocyte transformation test (LTT) by MTT colorimetric analysis. The best irradiating condition was determined, the effect and both virtues and defects of the laser were compared with those of electropuncture. The results show (1) LTT was enhanced in the group of laser irradiating point, but LTT was not enhanced in non-point (t' test, P < 0.01). (2) Lower power -- 2 mW or 5 mW of irradiating for 15 - 20 min, was better; 10 mW or 20 mW of irradiating for 10 - 15 min was suitable. Prolonged irradiating time did not enhance the immune function of the rats. On the contrary, immune function was inhibited. (3) A 7-day period of irradiating was best (once a day, 10 mW for 10 min). Enhanced LTT was not seen when irradiation days were added (SNK, P > 0.05). (4) Laser irradiation point and electropuncture were compared with vehicle control, LTT in the former two groups was enhanced significantly (ANOVA, P < 0.01), and laser irradiating point and electropuncture had the same effect (SNK, P > 0.05). The data suggest that laser irradiating point was able to enhance cell immunity and the enhancement of LTT had a point specific characteristic. The best condition of laser irradiating point was 2 mW for 15 - 20 min, and 10 mW or 20 mW for 10 - 15 min. The best period was 7-day irradiation. The results show laser irradiating the point may activate the main and collateral channels system, then modify the immune function of the body. Our observations provide experimental evidence for proper clinical application of laser irradiating points. The paper theoretically discusses and analyzes the experiment results in detail.

  3. The Change in the hardness of LCAC. TZM, and ODS molybdenum in the post-irradiated and annealed conditions

    SciTech Connect

    Cockeram, Brian V; Smith, Richard W; Byun, Thak Sang; Snead, Lance Lewis

    2009-01-01

    Hardness measurements were performed on wrought Low Carbon Arc Cast (LCAC), TZM, and Oxide Dispersion Strengthened (ODS) molybdenum in the post-irradiated and post-irradiated + annealed condition to determine the recovery kinetics. Irradiations performed in the High Flux Isotope Reactor (HFIR) at nominally 300 C and 600 C to neutron fluence levels that range from 10.5 to 246 x 10{sup 24} n/m{sup 2} (E > 0.1 MeV) resulted in relatively large increases in hardness (77-109%), while small increases in hardness (<18%) were observed for irradiations at 870-1100 C. The hardness recovery for ODS and LCAC irradiated at 300 C and 600 C were shown to be complete at 980 C and {approx} 1100-1250 C, respectively. Isothermal annealing at 700 C was used to determine the activation energy for recovery of LCAC and ODS (3.70-4.88 eV {+-} 0.28-0.77 eV), which is comparable to values reported in the literature for molybdenum vacancy self-diffusion. This suggests that recovery of LCAC and ODS is controlled by the solid-state diffusion of vacancies in the bulk, and that the finer grain size and particle size ODS does not affect this mechanism. TZM exhibited slower recovery kinetics, which can be explained by the solute atoms (titanium and zirconium) inhibiting vacancy diffusion.

  4. Charge transfer inefficiency in the pre- and post-irradiated Swept Charge Device CCD236

    NASA Astrophysics Data System (ADS)

    Smith, P. H.; Gow, J. P. D.; Pool, P.; Holland, A. D.

    2015-03-01

    This paper describes the mapping of spectral response of an e2v technologies Swept Charge Device (SCD) CCD236 pre and post irradiation with a 10 MeV equivalent proton fluence of 5.0 × 108 protons cm-2. The CCD236 is a large area (4.4 cm2) X-ray detector which will be used in India's Chandrayaan-2 Large Soft X-ray Spectrometer (CLASS) and China's Hard X-ray Modulation Telescope (HXMT). To enable the suppression of surface dark current, clocking is performed continuously resulting in a linear readout. As such the flat field illumination used to measure any change in spectral response over a conventional Charge-Coupled Devices (CCDs) is not possible. An alternative masking technique has been used to expose pinpoint regions of the device to Mn-Kα and Mn-Kβ X-rays, enabling a local map of spectral response to be built up over the device. This novel approach allows for an estimation of the Charge Transfer Inefficiency (CTI) of the device to be made by allowing the creation of a CTI scatter plot similar to that typically observed in conventional CCDs.

  5. The pre- and post-accretion irradiation history of cometary ices

    NASA Technical Reports Server (NTRS)

    Chyba, Christopher; Sagan, Carl

    1989-01-01

    Comets Halley and Wilson exhibited similar 3.4 micron emission features at approx. 1 AU from the Sun. A simple model of thermal emission from organic grains fits the feature, provides optical depths in good agreement with spacecraft measurements, and explains the absence of longer-wavelength organic features as due to spectral heliocentric evolution (Chyba and Sagan, 1987). The model utilizes transmission spectra of organics synthesized in the laboratory by irradiation of candidate cometary ices; the authors have long noted that related gas-phase syntheses yield polycyclic aromatic hydrocarbons, among other organic residues (Sagan et al., 1967). The authors previously concluded (Chyba and Sagan, 1987) that Halley's loss of several meters' depth with each perihelion passage, combined with the good fit of the Halley 3.4 micron feature to that of comet Wilson (Allen and Wickramasinghe, 1987), argues for the primordial - but not necessarily interstellar - origin of cometary organics. The authors examine the relative importance to the formation of organics of the variety of radiation environments experienced by comets. They conclude that there is at present no compelling reason to choose any of three contributing mechanisms (pre-accretion UV, pre-accretion cosmic ray, and post-accretion radionuclide processing) as the most important.

  6. Post irradiation analysis and performance modeling of dispersion and monolithic U-Mo fuels

    SciTech Connect

    Kim, Yeon Soo; Hofman, G.L.; Medvedev, P.G.; Robinson, A.B.; Shevlyakov, G.V.; Ryu, H.J.

    2008-07-15

    We analyzed fission product swelling of post-irradiation U-Mo fuels from the early RERTR tests to the recent RERTR-8 test. We found that the gas bubble swelling of the fuel-swelling model was overestimated. From the recent tests, RERTR-7A and 8, we could also collect a considerable amount of fuel swelling data from monolithic U-Mo fuel plates. The fuel swelling data from the monolithic fuel plates are considered more reliable because the interaction layer growth between the fuel and matrix in dispersion fuel, which obscures fuel swelling, does not exist. The swelling correlation comparison to the Si-added dispersion fuel data and monolithic fuel data suggested that a modification of the existing model was necessary. We also developed an interaction layer growth model for U-Mo/Al dispersion fuel plates with a Si-added matrix. PLATE code calculations with the new PIE data analysis results were performed. The updated versions predict with better accuracies for both monolithic fuel plates and dispersion fuel plates. In this paper, we present the results of fission product swelling characterization. In addition, the interaction layer growth model for U-Mo/Al with a Si-added matrix is presented. (author)

  7. Iterative ct reconstruction from few projections for the nondestructive post irradiation examination of nuclear fuel assemblies

    NASA Astrophysics Data System (ADS)

    Abir, Muhammad Imran Khan

    The core components (e.g. fuel assemblies, spacer grids, control rods) of the nuclear reactors encounter harsh environment due to high temperature, physical stress, and a tremendous level of radiation. The integrity of these elements is crucial for safe operation of the nuclear power plants. The Post Irradiation Examination (PIE) can reveal information about the integrity of the elements during normal operations and off?normal events. Computed tomography (CT) is a tool for evaluating the structural integrity of elements non-destructively. CT requires many projections to be acquired from different view angles after which a mathematical algorithm is adopted for reconstruction. Obtaining many projections is laborious and expensive in nuclear industries. Reconstructions from a small number of projections are explored to achieve faster and cost-efficient PIE. Classical reconstruction algorithms (e.g. filtered back projection) cannot offer stable reconstructions from few projections and create severe streaking artifacts. In this thesis, conventional algorithms are reviewed, and new algorithms are developed for reconstructions of the nuclear fuel assemblies using few projections. CT reconstruction from few projections falls into two categories: the sparse-view CT and the limited-angle CT or tomosynthesis. Iterative reconstruction algorithms are developed for both cases in the field of compressed sensing (CS). The performance of the algorithms is assessed using simulated projections and validated through real projections. The thesis also describes the systematic strategy towards establishing the conditions of reconstructions and finds the optimal imaging parameters for reconstructions of the fuel assemblies from few projections.

  8. Remotely Operated Equipment for Post Irradiation Examination of the SNS Target Vessel

    SciTech Connect

    Carroll, Adam J; Graves, Van B; Dayton, Michael J; Riemer, Bernie

    2011-01-01

    The Spallation Neutron Source produces neutrons by accelerating protons into flowing mercury contained inside a stainless steel target vessel. During facility operation the target vessel is degraded by a combination of high-energy neutrons, the proton beam, and cavitation-induced corrosion. The degradation is primarily concentrated at the nose of the target vessel, where the proton beam passes through. Currently, the Spallation Neutron Source has replaced three target vessels and is operating the fourth. To minimize the operational costs of manufacturing and disposing of target vessels, efforts are underway to increase the operational lifetimes of the target vessels by conducting post irradiation examinations of spent vessels. This examination involves remotely removing multiple coupons from the nose of the target vessel using a single piece of equipment, called the Nose Sampling Cutter, installed inside the Spallation Neutron Source s hot cell. The Cutter produces circular coupons approximately 2 inches in diameter using a carbide-tipped hole saw. The nose of the target vessel consists of four layers of material, and the Nose Sampling Cutter is capable of cutting through the layers in a single stroke. This remote operation has been successfully completed twice. In addition to the Nose Sampling Cutter, a large reciprocation saw capable of removing a sizable section of the nose of the target vessel has been constructed and tested, but never implemented. To support this large reciprocation saw other equipment has also been designed. The details of the Nose Sampling Cutter, reciprocation saw, and associated equipment are discussed.

  9. Current understanding of the effects of enviromental and irradiation variables on RPV embrittlement

    SciTech Connect

    Odette, G.R.; Lucas, G.E.; Wirth, B.; Liu, C.L.

    1997-02-01

    Radiation enhanced diffusion at RPV operating temperatures around 290{degrees}C leads to the formation of various ultrafine scale hardening phases, including copper-rich and copper-catalyzed manganese-nickel rich precipitates. In addition, defect cluster or cluster-solute complexes, manifesting a range of thermal stability, develop under irradiation. These features contribute directly to hardening which in turn is related to embrittlement, manifested as shifts in Charpy V-notch transition temperature. Models based on the thermodynamics, kinetics and micromechanics of the embrittlement processes have been developed; these are broadly consistent with experiment and rationalize the highly synergistic effects of most important irradiation (temperature, flux, fluence) and metallurgical (copper, nickel, manganese, phosphorous and heat treatment) variables on both irradiation hardening and recovery during post-irradiation annealing. A number of open questions remain which can be addressed with a hierarchy of new theoretical and experimental tools.

  10. Post-Irradiation Properties of Candidate Materials for High-Power Targets

    SciTech Connect

    Kirk, H.G.; Ludewig, H.; Mausner, L.F.; Simos, N.; Thieberger, P.; Hayato, Y.; Yoshimura, K.; McDonald, K.T.; Sheppard, J.; Trung, L.P.; /SUNY, Stony Brook

    2006-03-15

    The desire of the high-energy-physics community for more intense secondary particle beams motivates the development of multi-megawatt, pulsed proton sources. The targets needed to produce these secondary particle beams must be sufficiently robust to withstand the intense pressure waves arising from the high peak-energy deposition which an intense pulsed beam will deliver. In addition, the materials used for the targets must continue to perform in a severe radiation environment. The effect of the beam induced pressure waves can be mitigated by use of target materials with high-yield strength and/or low coefficient of thermal expansion (CTE). We report here first results of an expanded study of the effects of irradiation on several additional candidate materials with high strength (AlBeMet, beryllium, Ti-V6-Al4) or low CTE (a carbon-carbon composite, a new Toyota ''gum'' metal alloy, Super-Invar).

  11. Post mastectomy linac IMRT irradiation of chest wall and regional nodes: dosimetry data and acute toxicities

    PubMed Central

    2013-01-01

    Background Conventional post-mastectomy radiation therapy is delivered with tangential fields for chest wall and separate fields for regional nodes. Although chest wall and regional nodes delineation has been discussed with RTOG contouring atlas, CT-based planning to treat chest wall and regional nodes as a whole target has not been widely accepted. We herein discuss the dosimetric characteristics of a linac IMRT technique for treating chest wall and regional nodes as a whole PTV after modified radical mastectomy, and observe acute toxicities following irradiation. Methods Patients indicated for PMRT were eligible. Chest wall and supra/infraclavicular region +/−internal mammary nodes were contoured as a whole PTV on planning CT. A simplified linac IMRT plan was designed using either integrated full beams or two segments of half beams split at caudal edge of clavicle head. DVHs were used to evaluate plans. The acute toxicities were followed up regularly. Results Totally, 85 patients were enrolled. Of these, 45 had left-sided lesions, and 35 received IMN irradiation. Planning designs yielded 55 integrated and 30 segmented plans, with median number of beams of 8 (6–12). The integrated and segmented plans had similar conformity (1.41±0.14 vs. 1.47±0.15, p=0.053) and homogeneity indexes (0.13±0.01 vs. 0.14±0.02, p=0.069). The percent volume of PTV receiving >110% prescription dose was <5%. As compared to segmented plans, integrated plans typically increased V5 of ipsilateral lung (p=0.005), and heart (p=0.001) in patients with left-sided lesions. Similarly, integrated plans had higher spinal cord Dmax (p=0.009), ipsilateral humeral head (p<0.001), and contralateral lung Dmean (p=0.019). During follow-up, 36 (42%) were identified to have ≥ grade 2 radiation dermatitis (RD). Of these, 35 developed moist desquamation. The median time to onset of moist desquamation was 6 (4–7) weeks from start of RT. The sites of moist desquamation were most frequently occurred

  12. Persistent Conductivity in Post-Growth Doped ZnO Films Following Pulsed UV Laser Irradiation

    SciTech Connect

    Wang, Lisa J.; Exarhos, Gregory J.

    2010-12-30

    Solution and rf sputter deposited doped ZnO films were subjected to cumulative 4-nsec pulses of 355 nm light from a pulsed Nd:YAG laser at fluences between 5 and 150 mJ/cm2. Film densification, change in refractive index, and an increase in conductivity were observed following room temperature irradiation in air, a carbon monoxide reducing environment, or under vacuum. At fluences between 20 and 80 mJ/cm2, the films did not damage catastrophically under irradiation and high visible transparency persisted. The increase in conductivity is attributed to creation of oxygen vacancies and subsequent promotion of free carriers into the conduction band. Effects were most pronounced in films treated in vacuum. All treated films became insulating again upon equilibration in air at room temperature after several days. Films were characterized by means of UV-VIS-NIR transmission spectroscopy, Raman spectroscopy and Hall measurements. Analysis of interference fringes in measured transmission spectra allowed evaluation of optical properties. Raman measurements showed an increase of LO mode intensity with respect to TO mode intensity as the films became more conducting in accord with previous work. Results of this study are not only important for continued development of transparent conducting oxides, but also provide compelling evidence for the role of free carriers as initiators of the laser damage process in these wide bandgap metal oxide films.

  13. A Multi-stage Carcinogenesis Model to Investigate Caloric Restriction as a Potential Tool for Post-irradiation Mitigation of Cancer Risk

    PubMed Central

    Tani, Shusuke; Blyth, Benjamin John; Shang, Yi; Morioka, Takamitsu; Kakinuma, Shizuko; Shimada, Yoshiya

    2016-01-01

    The risk of radiation-induced cancer adds to anxiety in low-dose exposed populations. Safe and effective lifestyle changes which can help mitigate excess cancer risk might provide exposed individuals the opportunity to pro-actively reduce their cancer risk, and improve mental health and well-being. Here, we applied a mathematical multi-stage carcinogenesis model to the mouse lifespan data using adult-onset caloric restriction following irradiation in early life. We re-evaluated autopsy records with a veterinary pathologist to determine which tumors were the probable causes of death in order to calculate age-specific mortality. The model revealed that in both irradiated and unirradiated mice, caloric restriction reduced the age-specific mortality of all solid tumors and hepatocellular carcinomas across most of the lifespan, with the mortality rate dependent more on age owing to an increase in the number of predicted rate-limiting steps. Conversely, irradiation did not significantly alter the number of steps, but did increase the overall transition rate between the steps. We show that the extent of the protective effect of caloric restriction is independent of the induction of cancer from radiation exposure, and discuss future avenues of research to explore the utility of caloric restriction as an example of a potential post-irradiation mitigation strategy. PMID:27390741

  14. Proliferation effect of He-Ne laser intermittent irradiation on mouse bone-marrow cells

    NASA Astrophysics Data System (ADS)

    Chen, Ji; Zhang, Jianjun

    1993-03-01

    The effect of He-Ne laser intermittent irradiation on the bone marrow cell suspension of donor mice is presented in this paper. The recipient mice, irradiated with 8.5 GY CO60-(gamma) ray, were then infused, and they were killed different days (1, 3, 5, 7, 9, and 11 days post injection). Spleens were removed and fixed in Bouin's solution for 24 hours, and then the numbers of protruding splenic nodules visible on the surface of the spleens were counted. According to statistics, the number of the splenic nodules increased with laser exposure over the control group.

  15. Development of Commercial-Length Nuclear Fuel Post-Irradiation Examination Capabilities at the Oak Ridge National Laboratory

    SciTech Connect

    Ott, Larry J; Spellman, Donald J; Bevard, Bruce Balkcom; Chesser, Joel B; Morris, Robert Noel

    2009-01-01

    The U.S. Department of Energy Fissile Materials Disposition Program is pursuing disposal of surplus weapons-usable plutonium by reactor irradiation as the fissile constituent of mixed oxide (MOX) fuel. Lead test assemblies (LTAs) have been irradiated for approximately 36 months in Duke Energy s Catawba-1 nuclear power plant. Per the MOX fuel qualification plan, destructive post-irradiation examinations (PIEs) are to be performed on second-cycle rods (irradiated to an average burnup of approximately 42 GWd/MTHM). These LTA bundles are planned to be returned to the reactor and further irradiated to approximately 52 GWd/MTHM. Nondestructive and destructive PIEs of these commercially irradiated weapons-derived MOX fuel rods will be conducted at the Oak Ridge National Laboratory (ORNL) in the Irradiated Fuels Examination Laboratory (IFEL). PIE began in early 2009. In order to support the examination of the irradiated full-length (~3.66 m) MOX fuel rods, ORNL in 2004 began to develop the necessary infrastructure and equipment for the needed full-scope PIE capabilities. The preparations included modifying the IFEL building to handle a commercial spent-fuel shipping cask; procurement of cask-handling equipment and a skid to move the cask inside the building; development of in-cell handling equipment for cask unloading; and design, fabrication, and testing of the automated, state-of-the-art PIE examination equipment. This paper describes these activities and the full-scope PIE capabilities available at ORNL for commercial full-length fuel rods.

  16. Effect of gamma irradiation on Korean traditional multicolored paintwork

    NASA Astrophysics Data System (ADS)

    Yoon, Minchul; Kim, Dae-Woon; Choi, Jong-il; Chung, Yong-Jae; Kang, Dai-Ill; Hoon Kim, Gwang; Son, Kwang-Tae; Park, Hae-Jun; Lee, Ju-Woon

    2015-10-01

    Gamma irradiation can destroy fungi and insects involved in the bio-deterioration of organic cultural heritages. However, this irradiation procedure can alter optical and structural properties of historical pigments used in wooden cultural heritage paintings. The crystal structure and color centers of these paintings must be maintained after application of the irradiation procedure. In this study, we investigated the effects of gamma irradiation on Korean traditional multicolored paintwork (Dancheong) for the preservation of wooden cultural heritages. The main pigments in Korean traditional wooden cultural heritages, Sukganju (Hematite; Fe2O3), Jangdan (Minium; Pb3O4), Whangyun (Crocoite; PbCrO4), and Jidang (Rutile; TiO2), were irradiated by gamma radiation at doses of 1, 5, and 20 kGy. After irradiation, changes in Commision Internationale d'Eclairage (CIE) color values (L*, a*, b*) were measured using the color difference meter, and their structural changes were analyzed using X-ray diffraction (XRD) analysis. The slightly change in less than 1 dE* unit by gamma irradiation was observed, and structural changes in the Dancheong were stable after exposure to 20 kGy gamma irradiation. In addition, gamma irradiation could be applied to painted wooden cultural properties from the Korean Temple. Based on the color values, gamma irradiation of 20 kGy did not affect the Dancheong and stability was maintained for five months. In addition, the fungicidal and insecticidal effect by less than 5 kGy gamma irradiation was conformed. Therefore, the optical and structural properties of Dancheong were maintained after gamma irradiation, which suggested that gamma irradiation can be used for the preservation of wooden cultural heritages painted with Dancheong.

  17. Post-Irradiated Human Submandibular Glands Display High Collagen Deposition, Disorganized Cell Junctions, and an Increased Number of Adipocytes.

    PubMed

    Nam, Kihoon; Maruyama, Christina L; Trump, Bryan G; Buchmann, Luke; Hunt, Jason P; Monroe, Marcus M; Baker, Olga J

    2016-06-01

    Salivary glands are vital for maintaining oral health. Head and neck radiation therapy is one of the most common causes of salivary gland hypofunction. Little is known about the structural changes that occur in salivary glands after radiation therapy. The aim of this study is to understand the structural changes that occur in post-irradiated human (submandibular gland [SMG]) as compared with untreated ones. We determined changes in epithelial polarity, presence of collagen deposition, and alteration in adipose tissue. We used formalin-fixed paraffin-embedded human SMG from two female subjects exposed to head and neck irradiation. We utilized hematoxylin and eosin staining and Masson's Trichrome staining. The immunostained tissue sections were examined using confocal microscopy. The number and size of adipocytes per tissue section were calculated using ImageJ, Prism, and SPSS software. Post-irradiated human SMG displayed high collagen deposition, disorganized cell junctions, and an increased number of adipocytes as compared with non-irradiated controls. These findings are important to improve our understanding of the individual risk and variation in radiation-related salivary gland dysfunction. PMID:27126825

  18. Effect of electron- and neutron-irradiation on Fe-Cu model alloys studied by positron annihilation spectroscopy

    NASA Astrophysics Data System (ADS)

    Nagai, Y.; Takadate, K.; Tang, Z.; Ohkubo, H.; Sunaga, H.; Takizawa, H.; Hasegawa, M.

    2011-01-01

    Electron- and neutron-irradiation effects on dilute Fe-Cu model alloys of nuclear reactor pressure vessel steels are studied by positron annihilation spectroscopy. We have found that, not only by high-dose neutron-irradiation but also by low-dose electron-irradiation, the aggregation of Cu atoms and vacancies takes place and the ultrafine Cu precipitates are formed after post-irradiation annealing at 400°C. In spite of large difference in the irradiation doses between the electron- and the neutron-irradiated samples, no significant difference is observed in the isochronal annealing behaviour above 400°C of positron annihilation and micro-hardness, indicating that small amount of extra vacancies enhance the aggregation of Cu atoms in Fe during the annealing-out process of the vacancies.

  19. An Assessment of ORNL PIE Capabilities for the AGR Program Capsule Post Irradiation Examination

    SciTech Connect

    Morris, Robert Noel

    2006-09-01

    ORNL has facilities and experienced staff that can execute +the Advanced Gas Reactor (AGR) Post Irradiation Examination (PIE) task. While the specific PIE breakdown needs to be more formally defined, the basic outline is clear and the existing capabilities can be assessed within the needs of the tasks defined in the program plan. A one-to-one correspondence between the program plan tasks and the current ORNL PIE status was conducted and while some shortcomings were identified, the general capability is available. Specific upgrade needs were identified and reviewed. A path forward was formulated. Building 3525 is available for this work and this building is currently receiving renewed attention from management so that it will be in good working order prior to the expected PIE start date. This building is equipped with the tools necessary for PIEs of this nature, but the long hiatus in coated particle fuel work has left it with aging analysis tools. This report identified several of these tools and rough estimates of what would be required to update and replace them. In addition, other ORNL buildings are available to support Building 3525 in specialized tasks along with the normal laboratory infrastructure. Before the AGR management embarks on any equipment development effort, the PIE tasks should be updated against current program (modeling and data) needs and better defined so that the items to be measured, their measurement uncertainties, and thru-put needs can be reviewed. A Data Task Matrix (DTM) should be prepared so that the program data needs can be compared against the identified PIE tasks and what is practical in the hot cell environment to make sure nothing is overlooked. Finally, thought should be given to the development of standardized equipment designs between sites to avoid redundant design efforts and different measurement techniques. This is a potentially cost saving effort that can also avoid data inconsistencies.

  20. Effects of residual stress on irradiation hardening in stainless steels

    NASA Astrophysics Data System (ADS)

    Okubo, N.; Miwa, Y.; Kondo, K.; Kaji, Y.

    2009-04-01

    Effects of residual stress on irradiation hardening were studied in advance for predicting irradiation assisted stress corrosion cracking. The specimens of SUS316 and SUS316L with several % plastic strains, which correspond to weld residual stress, were prepared by bending and keeping deformation under irradiation. Ion irradiations of 12 MeV Ni 3+ were performed at 330, 400 and 550 oC to 45 dpa. No bended specimen was simultaneously irradiated with the bended specimen. The residual stress was estimated by X-ray residual stress measurements before and after the irradiation. The micro-hardness was measured by using nanoindenter. The residual stress did not relax even for the case of the higher temperature aging at 500 oC for the same time of irradiation. The residual stress after ion irradiation up to high dpa, however, relaxed at these experimental temperatures. The irradiation hardening of stressed specimen was obviously lower than that of un-stressed one in case of SUS316L irradiated at 300 oC to 12 dpa.

  1. The combined effects of irradiation and herpes simplex virus type 1 infection on an immortal gingival cell line

    PubMed Central

    2014-01-01

    Background Oral mucosa is frequently exposed to Herpes simplex virus type 1 (HSV-1) infection and irradiation due to dental radiography. During radiotherapy for oral cancer, the surrounding clinically normal tissues are also irradiated. This prompted us to study the effects of HSV-1 infection and irradiation on viability and apoptosis of oral epithelial cells. Methods Immortal gingival keratinocyte (HMK) cells were infected with HSV-1 at a low multiplicity of infection (MOI) and irradiated with 2 Gy 24 hours post infection. The cells were then harvested at 24, 72 and 144 hours post irradiation for viability assays and qRT-PCR analyses for the apoptosis-related genes caspases 3, 8, and 9, bcl-2, NFκB1, and viral gene VP16. Mann–Whitney U-test was used for statistical calculations. Results Irradiation improved the cell viability at 144 hours post irradiation (P = 0.05), which was further improved by HSV-1 infection at MOI of 0.00001 (P = 0.05). Simultaneously, the combined effects of infection at MOI of 0.0001 and irradiation resulted in upregulation in NFκB1 (P = 0.05). The combined effects of irradiation and HSV infection also significantly downregulated the expression of caspases 3, 8, and 9 at 144 hours (P = 0.05) whereas caspase 3 and 8 significantly upregulated in non-irradiated, HSV-infected cells as compared to uninfected controls (P = 0.05). Infection with 0.0001 MOI downregulated bcl-2 in non-irradiated cells but was upregulated by 27% after irradiation when compared to non-irradiated infected cells (P = 0.05). Irradiation had no effect on HSV-1 shedding or HSV gene expression at 144 hours. Conclusions HSV-1 infection may improve the viability of immortal cells after irradiation. The effect might be related to inhibition of apoptosis. PMID:25005804

  2. Post-irradiation Examination Plan for ORNL and University of California Santa Barbara Assessment of UCSB ATR-2 Irradiation Experiment

    SciTech Connect

    Nanstad, R. K.; Yamamoto, T.; Sokolov, M. A.

    2014-01-25

    New and existing databases will be combined to support development of physically based models of transition temperature shifts (TTS) for high fluence-low flux (φ < 10{sup 11}n/cm{sup 2}-s) conditions, beyond the existing surveillance database, to neutron fluences of at least 1×10{sup 20} n/cm{sup 2} (>1 MeV). All references to neutron flux and fluence in this report are for fast neutrons (>1 MeV). The reactor pressure vessel (RPV) task of the Light Water Reactor Sustainability (LWRS) Program is working with various organizations to obtain archival surveillance materials from commercial nuclear power plants to allow for comparisons of the irradiation-induced microstructural features from reactor surveillance materials with those from similar materials irradiated under high flux conditions in test reactors

  3. Post-irradiation plastic deformation in bcc Fe grains investigated by means of 3D dislocation dynamics simulations

    NASA Astrophysics Data System (ADS)

    Gururaj, K.; Robertson, C.; Fivel, M.

    2015-04-01

    Post-irradiation tensile straining is investigated by means of three-dimensional dislocation dynamics simulations adapted to body centred cubic Fe. Namely, 1 μm Fe grains are strained at various temperatures in the 100-300 K range, in absence and in presence of radiation-induced defect dispersions. The defect-induced hardening is consistent with the disperse barrier effect up to 5 ×1021m-3 loops and is weakly dependent on the straining temperature. The dislocation-loops interaction rate augments with the accumulated plastic strain, loop density and strength; while it is mainly independent of the number of active slip systems and thermally activated screw dislocation mobility. An additional, radiation-induced hardening mechanism known as dislocation "decoration" is also implemented and tested for comparison. Those results show that the plastic flow localisation transition depends on the total yield point rise rather than on the lone, dispersed loop density. The simulation results are then rationalized through an original micro-mechanical model relating the grain-scale stress-strain behaviour to dislocation sub-structure formation and spreading. That model combines strain dependent and strain independent hardening mechanisms, which both contribute to the associated stress-strain response and plastic flow spreading.

  4. Effect of preoperative irradiation on healing of low colorectal anastomoses

    SciTech Connect

    Morgenstern, L.; Sanders, G.; Wahlstrom, E.; Yadegar, J.; Amodeo, P.

    1984-02-01

    The effect of preoperative irradiation on the healing of low colorectal anastomoses was studied experimentally. In 12 dogs in whom preoperative irradiation of 4,000 rads was given before low colorectal stapled anastomosis was performed, anastomotic leakage occurred in 66 percent. More than half of the anastomotic leaks were associated with either severe sepsis or death. In a matched group of control animals that underwent stapled anastomoses without irradiation, no anastomotic complications occurred. The clinical implications of this study are that stapled anastomoses in irradiated colon are at serious risk of anastomotic dehiscence and, therefore, should be protected with a proximal colostomy.

  5. Gamma irradiation effects in W films

    SciTech Connect

    Claro, Luiz H.; Santos, Ingrid A.; Silva, Cassia F.

    2013-05-06

    Using the van Der Pauw methodology, the surface resistivity of irradiated tungsten films deposited on Silicon substrate was measured. The films were exposed to {gamma} radiation using a isotopic {sup 60}Co source in three irradiation stages attaining 40.35 kGy in total dose. The obtained results for superficial resistivity display a time annealing features and their values are proportional to the total dose.

  6. Post-harvest UV-B irradiation induces changes of phenol contents and corresponding biosynthetic gene expression in peaches and nectarines.

    PubMed

    Scattino, Claudia; Castagna, Antonella; Neugart, Susanne; Chan, Helen M; Schreiner, Monika; Crisosto, Carlos H; Tonutti, Pietro; Ranieri, Annamaria

    2014-11-15

    In the present study the possibility of enhancing phenolic compound contents in peaches and nectarines by post-harvest irradiation with UV-B was assessed. Fruits of 'Suncrest' and 'Babygold 7' peach and 'Big Top' nectarine cultivars were irradiated with UV-B for 12 h, 24 h and 36 h. Control fruits underwent the same conditions but UV-B lamps were screened by benzophenone-treated polyethylene film. The effectiveness of the UV-B treatment in modulating the concentration of phenolic compounds and the expression of the phenylpropanoid biosynthetic genes, was genotype-dependent. 'Big Top' and 'Suncrest' fruits were affected by increasing health-promoting phenolics whereas in 'Babygold 7' phenolics decreased after UV-B irradiation. A corresponding trend was exhibited by most of tested phenylpropanoid biosynthesis genes. Based on these results UV-B irradiation can be considered a promising technique to increase the health-promoting potential of peach fruits and indirectly to ameliorate the aesthetic value due to the higher anthocyanin content. PMID:24912695

  7. A study of the effect of sequential injection of 5-androstenediol on irradiation-induced myelosuppression in mice.

    PubMed

    Kim, Joong Sun; Jang, Won Suk; Lee, Sunjoo; Son, Yeonghoon; Park, Sunhoo; Lee, Seung Sook

    2015-06-01

    Herein, we aimed at examining the therapeutic effects of 5-androstenediol (5-AED), a natural hormone produced in the adrenal cortex, on radiation-induced myelosuppression in C3H/HeN mice. The mice were subjected to whole-body irradiation with a sublethal dose of 5 Gy gamma-irradiation to induce severe myelosuppression, and 5-AED (50 mg/kg) was administered subcutaneously. 5-AED was administrated 1 day before irradiation (pre-treatment) or twice weekly for 3 weeks starting from 1 h after irradiation (post-treatment). Treatment with 5-AED significantly ameliorated the decrease in the peripheral blood neutrophil and platelet populations in irradiated myelosuppressive mice, but had no effect on the lymphocyte population. It also ameliorated hypocellularity and disruption of bone marrow induced by irradiation and led to rapid recovery of myeloid cells. Further, it attenuated the decrease in spleen weight and megakaryocyte and myeloid cell populations in the spleen and promoted multilineage hematopoietic recovery. We found that a single injection of 5-AED produced only a temporary therapeutic effect, while sequential injection of 5-AED after irradiation had a more pronounced and prolonged therapeutic effect and reduced myelosuppression by irradiation. Thus, sequential injection of 5-AED after irradiation has therapeutic potential for radiation-induced myelosuppression when administered continuously and can be a significant therapeutic candidate for the management of acute radiation syndrome, particularly in a mass casualty scenario where rapid and economic intervention is important. PMID:25234002

  8. Effect of. gamma. -ray irradiation on alcohol production from corn

    SciTech Connect

    Han, Y.W.; Cho, Y.K.; Ciegler, A.

    1983-11-01

    Cracked corn was irradiated with ..gamma.. rays at 0-100 Mrad and the effects of the irradiation on sugar yield, susceptibility to enzymatic hydrolysis of starch, yeast growth, and alcohol production were studied. Gamma irradiation at 50 Mrad or greater produced a considerable amount of reducing sugar but little glucose. At lower dosages, ..gamma.. irradiation significantly increased the susceptibility of corn starch to enzymatic hydrolysis, but dosages of 50 Mrad or greater decomposed the starch molecules as indicated by the reduction in iodine uptake. About 12.5% reducing sugar was produced by amylase treatment of uncooked, irradiated corn. This amount exceeded the level of sugar produced from cooked (gelatinized) corn by the same enzyme treatment. The yeast numbers in submerged cultivation were lower on a corn substrate that was irradiated at 50 Mrad or greater compared to that on an unirradiated control. About the same level of alcohol was produced on uncooked, irradiated (10/sup 5/ - 10/sup 6/ rad) corn as from cooked (121 degrees C for 30 min) corn. Therefore, the conventional cooking process for gelatinization of starch prior to its saccharification can be eliminated by irradiation. Irradiation also eliminated the necessity of sterilization of the medium and reduced the viscosity of high levels of substrate in the fermentation broth. (Refs. 10).

  9. Efficacy of post-storage irradiation to reduce Salmonella on sliced tomatoes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Contamination of tomatoes with Salmonella is a recurring food safety concern. Irradiation is a nonthermal intervention that can inactivate pathogens on fresh produce. The best practices for implementing irradiation for fresh produce have yet to be determined. Roma tomatoes were sliced and inoculated...

  10. Effect of neutron irradiation on vanadium alloys

    SciTech Connect

    Braski, D.N.

    1986-01-01

    Neutron-irradiated vanadium alloys were evaluated for their susceptibility to irradiation hardening, helium embrittlement, swelling, and residual radioactivity, and the results were compared with those for the austenitic and ferritic stainless steels. The VANSTAR-7 and V-15Cr-5Ti alloys showed the greatest hardening between 400 and 600/sup 0/C while V-3Ti-1Si and V-20Ti had lower values that were comparable to those of ferritic steels. The V-15Cr-5Ti and VANSTAR-7 alloys were susceptible to helium embrittlement caused by the combination of weakened grain boundaries and irradiation-hardened grain matrices. Specimen fractures were entirely intergranular in the most severe instances of embrittlement. The V-3Ti-1Si and V-20Ti alloys were more resistant to helium embrittlement. Except for VANSTAR-7 irradiated to 40 dpa at 520/sup 0/C, all of the vanadium alloys exhibited low swelling that was similar to the ferritic steels. Swelling was greater in specimens that were preimplanted with helium using the tritium trick. The vanadium alloys clearly exhibit lower residual radioactivity after irradiation than the ferrous alloys.

  11. Effects of UV-B irradiation on a marine microecosystem.

    PubMed

    Marangoni, Roberto; Messina, Nicola; Gioffré, Domenico; Colombetti, Giuliano

    2004-01-01

    Purpose of this work was to study the effect of UV irradiation on a microecosystem consisting of several interacting species. The system chosen was of a hypersaline type, where all the species present live at high salt concentration; it comprises different bacteria; a producer, the photosynthetic green alga Dunaliella salina; and a consumer, the ciliated protozoan Fabrea salina, which form a complete food chain. We were able to establish the initial conditions that give rise to a self-sustaining microecosystem, stable for at least 3 weeks. We then determined the effect of UV irradiation on this microecosystem under laboratory-controlled conditions, in particular by measuring the critical UV exposure for the two main components of the microecosystem (algae and protozoa) under UV-B irradiances comparable to those of solar irradiation. In our experiments, we varied irradiance, total dose and spectral composition of the actinic light. The critical doses at irradiances of the order of 56 kJ/m(2) (typical average daily irradiance in a sunny summer day in Pisa), measured for each main component of the microecosystem (algae and ciliates), turned out to be around 70 kJ/m(2) for ciliates and 50 kJ/m(2) for D. salina. By exposing microecosystems to daily UV-B irradiances of the order of 8 kJ/m(2) (typical average daily irradiance in a sunny winter day in Pisa), we found no effect at total doses of the order of the critical doses at high irradiances, showing that the reciprocity law does not hold. We have also measured a preliminary spectral-sensitive curve of the UV effects, which shows an exponential decay with wavelength. PMID:15339218

  12. Neutron irradiation effects in GaAs

    SciTech Connect

    Patel, J.U.

    1992-01-01

    Changes in electrical properties of n-GaAs as a result of irradiations with fast neutron have been studied, after epitaxial layers doped with Si at concentrations in the range 1.35 x 10[sup 15] to 1.60 x 10[sup 16] cm[sup [minus]3] were irradiated with reactor neutron fluences up to 1.31 x 10[sup 15] cm [sup [minus]2]. When the changes in carrier concentration, Hall mobility and resistivity were more than 25% of their initial values, nonlinear dependence on neutron fluence was apparent. New theory is proposed which explains the changes in electrical properties in terms of rates of trapping and release of charges. A theoretical relationship is derived for the change in carrier concentration as a function of neutron fluence and Fermi level shift was found to be consistent with the observed changes in carrier concentration. A correlation has been found between the changes in carrier concentration and mobility with neutron fluence using newly defined physically meaningful parameters in the case of two pairs of samples. The correlation has been explained in terms of the increased scattering of charge carriers from the defects created by neutrons that trap the free carriers. Mobility changes were measured at temperatures from 15 K to 305 K in n-GaAs van-der Pauw samples irradiated by fast reactor neutrons. The inverse mobility values obtain versus temperature, from the variable temperature Hall measurements, in the case of irradiated and in-irradiated samples were fitted using the relation [mu][sup [minus]1] = T[sup [minus]3/2] + B T[sup 3/2]. The inverse mobility increased as a result of neutron irradiations over the whole range of temperature, the increase being attributed to the increased scattering from neutron induced charged defects.

  13. The effects of sunspots on solar irradiance

    NASA Technical Reports Server (NTRS)

    Hudson, H. S.; Silva, S.; Woodard, M.; Willson, R. C.

    1982-01-01

    It is pointed out that the darkness of a sunspot on the visible hemisphere of the sun will reduce the solar irradiance on the earth. Approaches are discussed for obtaining a crude estimate of the irradiance deficit produced by sunspots and of the total luminosity reduction for the whole global population of sunspots. Attention is given to a photometric sunspot index, a global measure of spot flux deficit, and models for the compensating flux excess. A model is shown for extrapolating visible-hemisphere spot areas to the invisible hemisphere. As an illustration, this extrapolation is used to calculate a very simple model for the reradiation necessary to balance the flux deficit.

  14. gamma-Irradiation of PEGd,lPLA and PEG-PLGA multiblock copolymers. I. Effect of irradiation doses.

    PubMed

    Dorati, R; Colonna, C; Serra, M; Genta, I; Modena, T; Pavanetto, F; Perugini, P; Conti, B

    2008-01-01

    To evaluate the effects of different gamma irradiation doses on PEGd,lPLA and PEG-PLGA multiblock copolymers. The behaviour of the multiblock copolymers to irradiation was compared to that of PLA, PLGA polymers. PEGd,lPLA, PEG-PLGA, PLA and PLGA polymers were irradiated by using a (60)Co irradiation source at 5, 15, 25 and 50 kGy total dose. Characterization was performed on all samples before and after irradiation, by nuclear magnetic resonance (NMR), infrared absorption spectrophotometry (FTIR) and gel permeation chromatography (GPC). The effect of gamma irradiation on polymer stability was also evaluated. Results of NMR and FTIR suggest an increase in -OH and -COOH groups, attributed to scission reactions induced by irradiation treatment. Data of GPC analysis showed that the weight average molecular weight (Mw) of polymer samples decreased with increasing irradiation dose. The extent of Mw degradation expressed as percentage of Mw reduction was more prominent for polymers with high molecular weight as PEGd,lPLA and PLA. The dominant effect of gamma-irradiation on both polymer samples was chain scission. The multiblock copolymer PEGd,lPLA presented higher sensitivity to irradiation treatment with respect to PLA, likely due to the presence of PEG in the matrix. The effect of gamma irradiation continues over a much longer period of time after gamma irradiation has been performed. It is suggested that the material reacts with oxygen to form peroxyl free radicals, which may further undergo degradation reactions during storage after irradiation. PMID:18528761

  15. Effects of temperature during the irradiation of calcium carbonate.

    PubMed

    Negrón-Mendoza, Alicia; Camargo-Raya, Claudia; Gómez-Vidales, Virginia; Uribe, Roberto M; Ramos-Bernal, Sergio

    2016-05-01

    Calcium carbonate received gamma irradiation at different doses (0-309kGy) and temperature regimes (77-298K) to study the effects of irradiation temperature. The changes were followed by EPR spectroscopy. We observed the formation of a composite EPR spectrum, even at low radiation doses and temperature. There was a strong effect on the evaluation of the radicals formed as a function of irradiation temperature, probably due to the diffusion in the frozen powder and the recombination of some radicals at room temperature. PMID:26901240

  16. Effect of green laser irradiation on hydrogen production

    NASA Astrophysics Data System (ADS)

    Bidin, Noriah; Razak, Siti Noraiza A.; Radiana Azni, Siti; Nguroho, Waskito; Mohsin, Ali Kamel; Abdullah, Mundzir; Krishnan, Ganesan; Bakhtiar, Hazri

    2014-06-01

    The effect of green laser irradiation on hydrogen production via water electrolysis was investigated. Diode pumped solid-state laser operating in second harmonic generation was employed as a source of irradiation. The hydrogen production system was also irradiated by a conventional light, a halogen source, for comparison. The best catalyst was identified by mixing distilled water with two types of salt: NaCl and Na2SO4. Optimization of hydrogen production from water electrolysis was realized by using NaCl and green laser irradiation. The power of green laser irradiation and the concentration of NaCl in water contribute to hydrogen production. The hydrogen yield also depends on the distance and direction of the green beam to the electrode.

  17. Effects of chlorhexidine and fluoride on irradiated enamel and dentin.

    PubMed

    Soares, C J; Neiva, N A; Soares, P B F; Dechichi, P; Novais, V R; Naves, L Z; Marques, M R

    2011-05-01

    The effectiveness of mouthwash protocols in preventing gamma irradiation therapy damage to the ultimate tensile strength (UTS) of enamel and dentin is unknown. It was hypothesized that the use of chlorhexidine and fluoride mouthwash would maintain the UTS of dental structures. One hundred and twenty teeth were divided into 2 groups: irradiated (subjected to 60 Gy of gamma irradiation in daily increments of 2 Gy) and non-irradiated. They were then subdivided into 2 mouthwash protocols used 3 times per day: 0.12% chlorhexidine, 0.05% sodium fluoride, and control group (n = 10). The specimens were evaluated by microtensile testing. The results of the Tukey test (p < 0.05) indicated that the gamma irradiation therapy significantly reduced the UTS of the enamel, crown, and root dentin. Macromolecular alterations were suggested by optical retardation data in dentin. Structural alterations, in both substrates, were detected by scanning electron microscopy analysis. Mouthwash with 0.12% chlorhexidine partially prevented the damage to the mechanical properties of the irradiated crown dentin, whereas the 0.05% sodium-fluoride-irradiated enamel showed UTS similar to that of non-irradiated enamel. PMID:21335538

  18. Post-irradiation mechanical tests on F82H EB and TIG welds

    NASA Astrophysics Data System (ADS)

    Rensman, J.; van Osch, E. V.; Horsten, M. G.; d'Hulst, D. S.

    2000-12-01

    The irradiation behaviour of electron beam (EB) and tungsten inert gas (TIG) welded joints of the reduced-activation martensitic steel IEA heat F82H-mod. was investigated by neutron irradiation experiments in the high flux reactor (HFR) in Petten. Mechanical test specimens, such as tensile specimens and KLST-type Charpy impact specimens, were neutron irradiated up to a dose level of 2-3 dpa at a temperature of 300°C in the HFR reactor in Petten. The tensile results for TIG and EB welds are as expected with practically no strain hardening capacity left. Considering impact properties, there is a large variation in impact properties for the TIG weld. The irradiation tends to shift the DBTT of particularly the EB welds to very high values, some cases even above +250°C. PWHT of EB-welded material gives a significant improvement of the DBTT and USE compared to the as-welded condition.

  19. High temperature post-irradiation performance of spent pressurized-water-reactor fuel rods under dry-storage conditions

    SciTech Connect

    Einziger, R.E.; Atkin, S.D.; Stellrecht, D.E.; Pasupathi, V.

    1981-06-01

    Post-irradiation studies on failure mechanisms of well characterized PWR rods were conducted for up to a year at 482, 510 and 571/sup 0/C in unlimited air and inert gas atmospheres. No cladding breaches occurred even though the tests operated many orders of magnitude longer in time than the lifetime predicted by Blackburn's analyses. The extended lifetime is due to significant creep strain of the Zircaloy cladding which decreases the internal rod pressures. The cladding creep also contributes to radial cracks, through the external oxide and internal FCCI layers, which propagated into and arrested in an oxygen stabilized ..cap alpha..-Zircaloy layer. There were no signs of either additional cladding hydriding, stress-corrosion cracking or fuel pellet degradation. Using the Larson-Miller formulization, a conservative maximum storage temperature of 400/sup 0/C is recommended to ensure a 1000-year cladding lifetime. This accounts for crack propagation and assumes annealing of the irradiation-hardened cladding.

  20. Interim report on the post irradiation examination of capsules 2 and 3 of the HFR-B1 experiment

    SciTech Connect

    Myers, B.F.; Pott, G.; Schenk, W.; Schroeder, R.; Kuehlein, W.; Buecker, H.J.; Dahmen, H.; Landsgesell, K.; Nieveler, F.

    1994-09-01

    This is an interim report on the post irradiation examination (PIE) of capsules 2 and 3 of the HFR-B1 experiment The PIE has been conducted by the Forschungszentrum Juelich and is nearing completion. After disassembly of the capsules, the examination focused on capsule components including fuel compacts, inert compacts fired in different media, graphite cylinders of different grades, unbonded coated fuel particles and unfueled graphite; in addition, heating experiments with intermittent injections of water vapor were conducted using fuel compacts and the kernels of uranium oxycarbide. Measurement involved gamma scanning and counting, photography, metallography, dimensional and weight changes, burnup determination and fission product release.

  1. [Indralin--a novel effective radioprotector during irradiation by high-energy protons].

    PubMed

    Shashkov, V S; Efimov, V I; Vasin, M V; Antipov, V V; Iliukhin, A V; Vlasov, P A; Karsanova, S K; Grigor'ev, Iu G; Ushakov, I B

    2010-01-01

    Experiments with 120 mongrel dogs were aimed at the assessment of radio protective strength of indralin and local shielding of the pelvic marrow from 2.5 Gy, and also their concurrent use for the dogs irradiated by protons (240 MeV) at absolutely lethal and over-lethal 4 Gy and 5 Gy. Clinical observations, hematological investigations and ECG analysis of survived animals were conducted 4.5 years post the irradiation. Dogs that remained healthy following 3.5 to 4.5 years since the irradiation were sacrificed for pathomorphological investigations. The radioprotective effect of local shielding against 4 Gy was weak while this effect of intramuscular indralin (10, 20, 40 mg/kg of body) was significant reaching 50 to 67.7%. The concurrent use of two methods had, apparently, potentiated the 100% radioprotection of the animals irradiated by overlethal 5 Gy. Blood investigations of the survived dogs every 2-4 months evidenced that complete recovery of the total leukocyte count had taken 9 to 13 months. Also, dogs' pregnancy in 9-10 months since the beginning of irradiation pointed to maintenance of fertility and the ability to parturiate 2 or 3 times yielding 5-6 live cubs. Necropsy of the dogs did not reveal gross macroscopic structural changes of visceral organs or tissues. Seven out of 27 sacrificed dogs had benign tumors infrequent in intact dogs at this age. PMID:20803992

  2. Effect of gamma irradiation and cooking on cowpea bean grains ( Vigna unguiculata L. Walp)

    NASA Astrophysics Data System (ADS)

    Lima, Keila dos Santos Cople; Souza, Luciana Boher e.; Godoy, Ronoel Luiz de Oliveira; França, Tanos Celmar Costa; Lima, Antônio Luís dos Santos

    2011-09-01

    Leguminous plants are important sources of proteins, vitamins, carbohydrates, fibers and minerals. However, some of their non-nutritive elements can present undesirable side effects like flatulence provoked by the anaerobic fermentation of oligosaccharides, such as raffinose and stachyose, in the gut. A way to avoid this inconvenience, without any change in the nutritional value and post-harvesting losses, is an irradiation process. Here, we evaluated the effects of gamma irradiation on the amino acids, thiamine and oligosaccharide contents and on the fungi and their toxin percentages in cowpea bean ( Vigna unguiculata L. Walp) samples. For irradiation doses of 0.0, 0.5, 1.0, 2.5, 5.0 and 10.0 kGy the results showed no significant differences in content for the uncooked samples. However, the combination of irradiation and cooking processes reduced the non-nutritive factors responsible for flatulence. Irradiation also significantly reduced the presence of Aspergillus, Penicilium, Rhizopus and Fusarium fungi and was shown to be efficient in grain conservation for a storage time of 6 months.

  3. Microbial community in the soil determines the forest recovery post-exposure to gamma irradiation.

    PubMed

    Shah, Vishal; Shah, Shreya; Mackey, Herman; Kambhampati, Murty; Collins, Daniel; Dowd, Scot E; Colichio, Robert; McDonnell, Kevin T; Green, Timothy

    2013-10-15

    Exposure of an ecosystem to ionizing radiation remains a possibility either due to accidents involving nuclear fuel rods or contamination with high-level radioactive wastes. While the short and long-term effect of ionizing radiation on higher eukaryotes has been well documented, we do not have an understanding on the recovery of the microbial community post radiation. Here we report that at a site within Brookhaven National Laboratory that was radiated from 1961 to 1978 with γ rays (Gamma Forest), the ecosystem has not yet fully recovered from the effects of radiation. The current vegetation type in the Gamma Forest varies as one goes away from the source of ionizing radiation, with the region closest to the source having no vegetation. The microbial tag-encoded FLX amplicon pyrosequencing analysis of the soil from different regions suggests that the current microbial community structure is identical in all the Zones. When soil samples from each vegetation zone of the Gamma Forest were radiated with 1.8 kGy γ radiation and survival microbial community analyzed, clear difference in the microbial communities were observed. It is evident based on the experimental data that the colonization of soil with Nitrosomonadaceae is critical for the higher plants in pine barrens to reestablish and grow after the area had been exposed to ionizing radiation. PMID:24063597

  4. Construction of a Post-Irradiated Fuel Examination Shielded Enclosure Facility

    SciTech Connect

    Michael A. Lehto, Ph.D.; Boyd D. Christensen

    2008-05-01

    The U.S. Department of Energy (DOE) has committed to provide funding to the Idaho National Laboratory (INL) for new post-irradiation examination (PIE) equipment in support of advanced fuels development. This equipment will allow researchers at the INL to accurately characterize the behavior of experimental test fuels after they are removed from an experimental reactor also located at the INL. The accurate and detailed characterization of the fuel from the reactor, when used in conjunction with computer modeling, will allow DOE to more quickly understand the behavior of the fuel and to guide further development activities consistent with the missions of the INL and DOE. Due to the highly radioactive nature of the specimen samples that will be prepared and analyzed by the PIE equipment, shielded enclosures are required. The shielded cells will be located in the existing Analytical Laboratory (AL) basement (Rooms B-50 and B-51) at the INL Material and Fuels Complex (MFC). AL Rooms B-50 and B-51 will be modified to establish an area where sample containment and shielding will be provided for the analysis of radioactive fuels and materials while providing adequate protection for personnel and the environment. The area is comprised of three separate shielded cells for PIE instrumentation. Each cell contains an atmosphere interface enclosure (AIE) for contamination containment. The shielding will provide a work area consistent with the as-low-as-reasonably-achievable (ALARA) concept, assuming a source term of 10 samples in each of the three shielded areas. Source strength is assumed to be a maximum of 3 Ci at 0.75 MeV gamma for each sample. Each instrument listed below will be installed in an individual shielded enclosure: Shielded electron probe micro-analyzer (EPMA) Focused ion beam instrument (FIB) Micro-scale x-ray diffractometer (MXRD). The project is designed and expected to be built incrementally as funds are allocated. The initial phase will be to fund the

  5. Effect of ion beam parameters on engineering of nanoscale voids and their stability under post-growth annealing

    NASA Astrophysics Data System (ADS)

    Hooda, Sonu; Khan, S. A.; Satpati, B.; Stange, D.; Buca, D.; Bala, M.; Pannu, C.; Kanjilal, D.; Kabiraj, Debdulal

    2016-03-01

    Swift heavy ion (SHI) irradiation of damaged germanium (d-Ge) layer results in porous structure with voids aligned along ion trajectory due to local melting and resolidification during high electronic energy deposition. The present study focuses on the irradiation temperature- and incident angle-dependent growth dynamics and shape evolution of these voids due to 100 MeV Ag ions irradiation. The d-Ge layers were prepared by multiple low-energy Ar ion implantations in single crystalline Ge with damage formation of ~7 displacements per atom. Further, these d-Ge layers were irradiated using 100 MeV Ag ions at two different temperatures (77 and 300 K) and three different angles (7°, 30° and 45°). After SHI irradiation, substantial volume expansion of d-Ge layer is detected which is due to formation of nanoscale voids. The volume expansion is observed to be more in the samples irradiated at 77 K as compared to 300 K at a given irradiation fluence. It is observed that the voids are of spherical shape at low ion irradiation fluence. The voids grow in size and change their shape from spherical to prolate spheroid with increasing ion fluence. The major axis of spheroid is observed to be aligned approximately along the ion beam direction which has been confirmed by irradiation at three different angles. The change in shape is a consequence of combination of compressive strain and plastic flow developed due to thermal spike generated along ion track. Post-SHI irradiation annealing shows increase in size of voids and reversal of shape from prolate spheroid towards spherical through strain relaxation. The stability of voids was studied with the effect of post-growth annealing.

  6. Micro-CT evaluation of the radioprotective effect of resveratrol on the mandibular incisors of irradiated rats.

    PubMed

    Barbosa, Gabriella Lopes de Rezende; Pimenta, Luiz André; Almeida, Solange Maria de

    2016-01-01

    The purpose of this study was to perform a microcomputed tomographic evaluation of the radioprotective effect of resveratrol on the volume of mandibular incisors of irradiated rats. A second aim was to make a quantitative assessment of the effect of x-ray exposure on these dental tissues. Twenty adult male rats were divided into four groups: control, irradiated control, resveratrol, and irradiated resveratrol. The resveratrol groups received 100 mg/kg of resveratrol, whereas the irradiated groups were exposed to 15 Gy of irradiation. The animals were sacrificed 30 days after the irradiation procedure, and their mandibles were removed and scanned in a microcomputed tomography unit. The images were loaded into Mimics software to allow segmentation of the mandibular incisor and assessment of its volume. The results were compared by One-way ANOVA and Tukey's post hoc test, considering a 5% significance level. The irradiated groups showed significantly diminished volumes of the evaluated teeth, as compared with the control group (p < 0.05). The resveratrol group presented higher values than those of the irradiated groups, and volumes similar to those of the control group. High radiation doses significantly affected tooth formation, resulting in alterations in the dental structure, and thus lower volumes. Moreover, resveratrol showed no effective radioprotective impact on dental tissues. Future studies are needed to evaluate different concentrations of this substance, in an endeavor to verify its potential as a radioprotector for these dental tissues. PMID:26981750

  7. The effect of bonding and bakeout thermal cycles on the properties of copper alloys irradiated at 100 C

    SciTech Connect

    Edwards, D.J.; Singh, B.N.; Toft, P.; Eldrup, M.

    1998-03-01

    This report describes the final irradiation experiment in a series of screening experiments aimed at investigating the effects of bonding and bakeout thermal cycles on irradiated copper alloys. Tensile specimens of CuCrZr and CuNiBe alloys were given various heat treatments corresponding to solution anneal, prime-ageing and bonding thermal treatment. The post-irradiation tests at 100 C revealed the greatest loss of ductility occurred in the CuCrZr alloys, irrespective of the pre-irradiation heat treatment, with the uniform elongation dropping to levels of less than 1.5%. The yield and ultimate strengths for all of the individual heat treated samples increased substantially after irradiation. The same trend was observed for the CuNiBe alloys, which overall exhibited a factor of 3 higher uniform elongation after irradiation with almost double the strength. In both alloys irradiation-induced precipitation lead to a large increase in the strength of the solution annealed specimens with a noticeable decrease in uniform elongation. The Al25 alloy also experienced an increase in the overall strength of the alloy after irradiation, accompanied by approximately a 50% decrease in the uniform and total elongation. The additional bakeout treatments given to the CuCrZr and CuNiBe before irradiation served to increase the strength, but in terms of the ductility no improvement or degradation resulted from the additional thermal exposure. The results of this experiment confirm that the al25 possesses the most resistant microstructure to thermal and irradiation-induced changes, while the competing effects of ballistic dissolution and reprecipitation lead to important changes in the two precipitation strengthened alloys. This study and others have repeatedly shown that these materials can only be used if the very low uniform elongation (1% or less) can be accounted for in the design since pre-irradiation thermal processing cannot mitigate the irradiation embrittlement.

  8. Effects of gamma irradiation on solid and lyophilised phospholipids

    NASA Astrophysics Data System (ADS)

    Stensrud, G.; Redford, K.; Smistad, G.; Karlsen, J.

    1999-11-01

    The effects of gamma irradiation (25 kGy) as a sterilisation method for phospholipids (distearoylphosphatidylcholine and distearoylphosphatidylglycerol) were investigated. 31P-NMR revealed minor chemical degradation of the phospholipids but lower dynamic viscosity and pseudoplasticity, lower turbidity, higher diffusion constant, smaller size, more negative zeta potential and changes in the phase transition behaviour of the subsequently produced liposomes were observed. The observed changes could to some extent be explained by the irradiation-induced degradation products (distearoylphosphatidic acid, fatty acids, lysophospholipids).

  9. Effect of different post-space pretreatments on fiber post bonding to root dentine

    PubMed Central

    Alaghemand, Homayon; Mirzae, Mansoreh; Ahmadi, Elham; Saidi, Akam

    2013-01-01

    Background: Before the resin bond endodontic post-cementation, various solutions are used to improve bond strength of these posts to root dentine. The purpose of this study was to evaluate the effect of the different pre-treatments (ethanol, ethylene de amine tetra acetic acid [EDTA] and EDTA + ethanol) on the bond strength of adhesively lutted tooth colored fiber post. Materials and Methods: Forty-eight human anterior teeth (incisor and canine) were selected in this experimental study. The species were endodontically treated, and the post-space was prepared. The species were randomly divided into four groups of 12 teeth in each and were treated as follows: (i) 0.1 M EDTA, (ii) 99.6% ethanol, (iii) 0.1 M EDTA followed by 99.6% ethanol and (iv) without any treatment (control). A push-out test was carried out after 24 h. Each tooth was cut into three 1 mm-thick sections. Fracture type was assessed using stereomicroscope. The data were analyzed by one way-ANOVA followed by Scheffe post-hoc test at P = 0.05. Results: Almost, in EDTA and (EDTA + ethanol) every sample failed at the interface between post and lutting cement. Predominant failure mode in ethanol and control group was mixed failure. The surface treatment methods did not have any significant effect (P > 0.05) on any group but EDTA group had the highest bond strength. Conclusion: Surface treatment with (ethanol, EDTA, and EDTA + ethanol) does not significantly appear to be effective in improving the bond strength of fiber posts into root dentine. The highest bond strength was observed in EDTA group and the lowest in the control group. PMID:24130594

  10. Low Doses of Gamma-Irradiation Induce an Early Bystander Effect in Zebrafish Cells Which Is Sufficient to Radioprotect Cells

    PubMed Central

    Pereira, Sandrine; Malard, Véronique; Ravanat, Jean-Luc; Davin, Anne-Hélène; Armengaud, Jean; Foray, Nicolas; Adam-Guillermin, Christelle

    2014-01-01

    The term “bystander effect” is used to describe an effect in which cells that have not been exposed to radiation are affected by irradiated cells though various intracellular signaling mechanisms. In this study we analyzed the kinetics and mechanisms of bystander effect and radioadaptation in embryonic zebrafish cells (ZF4) exposed to chronic low dose of gamma rays. ZF4 cells were irradiated for 4 hours with total doses of gamma irradiation ranging from 0.01–0.1 Gy. In two experimental conditions, the transfer of irradiated cells or culture medium from irradiated cells results in the occurrence of DNA double strand breaks in non-irradiated cells (assessed by the number of γ-H2AX foci) that are repaired at 24 hours post-irradiation whatever the dose. At low total irradiation doses the bystander effect observed does not affect DNA repair mechanisms in targeted and bystander cells. An increase in global methylation of ZF4 cells was observed in irradiated cells and bystander cells compared to control cells. We observed that pre-irradiated cells which are then irradiated for a second time with the same doses contained significantly less γ-H2AX foci than in 24 h gamma-irradiated control cells. We also showed that bystander cells that have been in contact with the pre-irradiated cells and then irradiated alone present less γ-H2AX foci compared to the control cells. This radioadaptation effect is significantly more pronounced at the highest doses. To determine the factors involved in the early events of the bystander effect, we performed an extensive comparative proteomic study of the ZF4 secretomes upon irradiation. In the experimental conditions assayed here, we showed that the early events of bystander effect are probably not due to the secretion of specific proteins neither the oxidation of these secreted proteins. These results suggest that early bystander effect may be due probably to a combination of multiple factors. PMID:24667817

  11. ECRIX-H experiment: Synthesis of post-irradiation examinations and simulations

    NASA Astrophysics Data System (ADS)

    Béjaoui, S.; Lamontagne, J.; Esbelin, E.; Bonnerot, J. M.; Brunon, E.; Bourdot, P.

    2011-08-01

    The purpose of the ECRIX-H experiment is to study the behaviour of a composite ceramic target made of AmO 1.62 microdispersed in an MgO matrix irradiated for 318 EFPD in the Phenix sodium-cooled fast reactor (SFR), in a specific carrier sub-assembly equipped with annular blocks of CaH x acting as a neutron moderator. Results indicate that magnesia-based inert matrix targets display satisfactory behaviour and moderate swelling under irradiation, even for significant quantities of helium produced and a high burn-up. On this basis, the design of transmutation fuel pins for recycling of minor actinides (MA) in accelerator-driven systems (ADS) or in fast neutron reactors (FR) could be optimised so as to increase their performance level (initial MA content, burn-up, etc.). The measured Am fission rate (25 at.%) was found to be lower than that predicted by neutronic simulations probably due to the inaccuracies linked to the complexity of neutron modelling and the uncertainties on nuclear data related to moderated neutron spectrum. In addition, as most of the initial Am transmuted into Pu under irradiation, a PuO x-type phase was created within the initial AmO 1.62 particles, leading to the incomplete dissolution of the irradiated targets under standard reprocessing conditions. This issue will have to be considered and investigated in greater detail for all transmutation fuels and targets devoted to the multi-recycling of MA.

  12. Proton and neutron irradiation effect of Ti: Sapphires

    SciTech Connect

    Wang, G.; Zhang, J.; Yang, J.

    1999-07-01

    Various effects of proton and neutron irradiated Ti: sapphires were studied. Proton irradiation induced F, F{sup +} and V center in Ti: sapphires and 3310 cm{sup -1} infrared absorption, and made ultraviolet absorption edge shift to short wave. Neutron irradiation produced a number of F, F{sup +} and F{sub 2} centers and larger defects in Ti: sapphires, and changed Ti{sup 4+}into Ti{sup 3+} ions. Such valence state variation enhanced characteristic luminescence of Ti: sapphires, and no singular variances of intrinsic fluorescence spectra of Ti: sapphires took place with neutron flux of 1 x 10{sup 17}n/cm{sup 2}, but the fluorescence vanished with neutron flux of 1 x 10{sup 18}n/cm{sup 2} which means the threshold for the concentration of improving Ti{sup 3+} ions by neutron irradiation.

  13. Effects of Electron Beam Irradiation on the Electrospinning of Polyacrylonitrile.

    PubMed

    Jeun, Joon-Pyo; Kim, Hyun-Bin; Oh, Seung-Hwan; Park, Jung-Ki; Kang, Phil-Hyun

    2015-08-01

    Electron beam (e-beam) irradiation of polyacrylonitrile (PAN) was performed to investigate the effects of radiation on the electrospinning process. For this study, polyacrylonitrile powder was subjected to e-beam irradiation with different doses of up to 100 kGy under an N2 atmosphere. Polymer solutions were prepared by dissolving PAN in N,N-dimethyl-formamide (DMF) at a 1:9 ratio by weight. The prepared PAN/DMF solutions showed different colors with different e-beam doses. The resulting structures in solutions contained conjugated C=N bonds, which caused the observed color formation. In addition, the conductivity of the PAN/DMF solution increased with an increase in e-beam irradiation dose. In the DSC spectra of electrospun PAN fibers, the peak temperature of the exothermic reactions was observed to decrease with an increase in the e-beam irradiation strength. PMID:26369176

  14. Effect of irradiation on Brazilian honeys' consistency and their acceptability

    NASA Astrophysics Data System (ADS)

    Matsuda, A. H.; Sabato, S. F.

    2004-09-01

    Contamination of bee products may occur during packing or even during the process of collection. Gamma irradiation was found to decrease the number of bacteria and fungi. However, little information is available on the effects of gamma irradiation on viscosity which is an important property of honey. In this work the viscosity of two varieties of Brazilian honey was measured when they were irradiated at 5 and 10 kGy. The viscosity was measured at four temperatures (25°C, 30°C, 35°C and 40°C) for both samples and compared with control and within the doses. The sensory evaluation was carried on for the parameters color, odor, taste and consistency, using a 9-point hedonic scale. All the data were treated with a statistical tool (Statistica 5.1, StatSoft, 1998). The viscosity was not impaired significantly by gamma irradiation in doses 5 and 10 kGy ( p<0.05). The effect of gamma irradiation on sensorial characteristics (odor, color, taste and consistency) is presented. The taste for Parana type indicated a significant difference among irradiation doses ( p<0.05) but the higher value was for 5 kGy dose, demonstrating the acceptability for this case. The Organic honey presented the taste parameter for 10 kGy, significantly lower than the control mean but it did not differ significantly from the 5 kGy value.

  15. High Temperature Irradiation Effects in Selected Generation IV Structural Alloys

    SciTech Connect

    Nanstad, Randy K; McClintock, David A; Hoelzer, David T; Tan, Lizhen; Allen, Todd R.

    2009-01-01

    In the Generation IV Materials Program cross-cutting task, irradiation and testing were carried out to address the issue of high temperature irradiation effects with selected current and potential candidate metallic alloys. The materials tested were (1) a high-nickel iron-base alloy (Alloy 800H); (2) a nickel-base alloy (Alloy 617); (3) two advanced nano-structured ferritic alloys (designated 14YWT and 14WT); and (4) a commercial ferritic-martensitic steel (annealed 9Cr-1MoV). Small tensile specimens were irradiated in rabbit capsules in the High-Flux Isotope Reactor at temperatures from about 550 to 700 C and to irradiation doses in the range 1.2 to 1.6 dpa. The Alloy 800H and Alloy 617 exhibited significant hardening after irradiation at 580 C; some hardening occurred at 660 C as well, but the 800H showed extremely low tensile elongations when tested at 700 C. Notably, the grain boundary engineered 800H exhibited even greater hardening at 580 C and retained a high amount of ductility. Irradiation effects on the two nano-structured ferritic alloys and the annealed 9Cr-1MoV were relatively slight at this low dose.

  16. Post-Irradiation Examination of 237Np Targets for 238Pu Production

    SciTech Connect

    Morris, Robert Noel; Baldwin, Charles A; Hobbs, Randy W; Schmidlin, Joshua E

    2015-01-01

    Oak Ridge National Laboratory is recovering the US 238Pu production capability and the first step in the process has been to evaluate the performance of a 237Np target cermet pellet encased in an aluminum clad. The process proceeded in 3 steps; the first step was to irradiate capsules of single pellets composed of NpO2 and aluminum power to examine their shrinkage and gas release. These pellets were formed by compressing sintered NpO2 and aluminum powder in a die at high pressure followed by sintering in a vacuum furnace. Three temperatures were chosen for sintering the solution precipitated NpO2 power used for pellet fabrication. The second step was to irradiate partial targets composed of 8 pellets in a semi-prototypical arrangement at the two best performing sintering temperatures to determine which temperature gave a pellet that performed the best under the actual planned irradiation conditions. The third step was to irradiate ~50 pellets in an actual target configuration at design irradiation conditions to assess pellet shrinkage and gas release, target heat transfer, and dimensional stability. The higher sintering temperature appeared to offer the best performance after one cycle of irradiation by having the least shrinkage, thus keeping the heat transfer gap between the pellets and clad small minimizing the pellet operating temperature. The final result of the testing was a target that can meet the initial production goals, satisfy the reactor safety requirements, and can be fabricated in production quantities. The current focus of the program is to verify that the target can be remotely dissembled, the pellets dissolved, and the 238Pu recovered. Tests are being conducted to examine these concerns and to compare results to code predictions. Once the performance of the full length targets has been quantified, the pellet 237Np loading will be revisited to determine if it can be

  17. Irradiation spectrum and ionization-induced diffusion effects in ceramics

    SciTech Connect

    Zinkle, S.J.

    1997-08-01

    There are two main components to the irradiation spectrum which need to be considered in radiation effects studies on nonmetals, namely the primary knock-on atom energy spectrum and ionizing radiation. The published low-temperature studies on Al{sub 2}O{sub 3} and MgO suggest that the defect production is nearly independent of the average primary knock-on atom energy, in sharp contrast to the situation for metals. On the other hand, ionizing radiation has been shown to exert a pronounced influence on the microstructural evolution of both semiconductors and insulators under certain conditions. Recent work on the microstructure of ion-irradiated ceramics is summarized, which provides evidence for significant ionization-induced diffusion. Polycrystalline samples of MgO, Al{sub 2}O{sub 3}, and MgAl{sub 2}O{sub 4} were irradiated with various ions ranging from 1 MeV H{sup +} to 4 MeV Zr{sup +} ions at temperatures between 25 and 650{degrees}C. Cross-section transmission electron microscopy was used to investigate the depth-dependent microstructural of the irradiated specimens. Dislocation loop nucleation was effectively suppressed in specimens irradiated with light ions, whereas the growth rate of dislocation loops was enhanced. The sensitivity to irradiation spectrum is attributed to ionization-induced diffusion. The interstitial migration energies in MgAl{sub 2}O{sub 4} and Al{sub 2}O{sub 3} are estimated to be {le}0.4 eV and {le}0.8 eV, respectively for irradiation conditions where ionization-induced diffusion effects are expected to be negligible.

  18. Behavior of nitrogen in Si crystal during irradiation and post-annealing

    SciTech Connect

    Inoue, Naohisa; Oyama, Hidenori; Watanabe, Kaori; Seki, Hirofumi; Kawamura, Yuichi

    2014-02-21

    Radiation induced complexes in nitrogen (N) -doped silicon crystal was investigated by highly sensitive infrared absorption spectroscopy. The absorption by N{sub 2} pair was reduced by the electron irradiation in FZ crystals. The absorptions appeared on both sides of N{sub 2} line at 766 cm{sup −1}, at about 725 and 778 cm{sup −1}. By the annealing, N{sub 2} lines recovered a little at 600 °C and mostly at 800 °C. The above new absorption lines reduced by the annealing at lower temperatures and other absorption appeared. In CZ silicon, N{sub 2} lines did not change by the irradiation. Dominant absorption in low carbon FZ silicon was that of C-rich type complexes, VO and I{sub n}C{sub i}O{sub im}(n=0–3, m=0,1). Dominant absorption in the irradiated low carbon CZ silicon was that of C-lean type complexes I{sub n}O{sub 2+mi}(n=1, 2, m=0, 1), and the decrease of C-lean type O{sub 2i} and TDD was observed. By the annealing of CZ Si, VO{sub n} (n=2–4) formation and annihilation was observed.

  19. Irradiation-induced effects of proton irradiation on zirconium carbides with different stoichiometries

    SciTech Connect

    Y. Huang; B.R. Maier; T.R. Allen

    2014-10-01

    Zirconium carbide (ZrC) is being considered for utilization in deep burn TRISO fuel particles for hightemperature, gas-cooled reactors. Zirconium carbide has a cubic B1 type crystal structure along with a very high melting point (3420 ?C), exceptional hardness and good thermal and electrical conductivities. Understanding the ZrC irradiation response is crucial for establishing ZrC as an alternative component in TRISO fuel. Until now, very few studies on irradiation effects on ZrC have been released and fundamental aspects of defect evolution and kinetics are not well understood although some atomistic simulations and phenomenological studies have been performed. This work was carried out to understand the damage evolution in float-zone refined ZrC with different stoichiometries. Proton irradiations at 800 ?C up to doses of 3 dpa were performed on ZrCx (where x ranges from 0.9 to 1.2) to investigate the damage evolution. The irradiation-induced defects, such as density of dislocation loops, at different stoichiometries and doses which were characterized by transmission electron microscopy (TEM) is presented and discussed.

  20. Effect of gamma ray irradiation on sodium borate single crystals

    NASA Astrophysics Data System (ADS)

    Kalidasan, M.; Asokan, K.; Baskar, K.; Dhanasekaran, R.

    2015-12-01

    In this work, the effects of 5 kGy, 10 kGy and 20 kGy doses of gamma ray irradiation on sodium borate, Na2[B4O5(OH)4]·(H2O)8 single crystals have been studied. Initially these crystals were grown by solution growth technique and identified as monoclinic using X-ray diffraction analysis. X-ray rocking curves confirm the formation of crystalline defects due to gamma rays in sodium borate single crystals. The electron paramagnetic resonance spectra have been recorded to identify the radicals created due to gamma ray irradiation in sodium borate single crystals. The thermoluminescence glow curves due to the defects created by gamma rays in this crystal have been observed and their kinetic parameters were calculated using Chen's peak shape method. The optical absorption increases and photoluminescence spectral intensity decreases for 5 kGy and 20 kGy doses gamma ray irradiated crystals compared to pristine and 10 kGy dose irradiated one. The effect of various doses of gamma rays on vibrational modes of the sodium borate single crystals was studied using FT-Raman and ATR-FTIR spectral analysis. The dielectric permittivity, conductance and dielectric loss versus frequency graphs of these crystals have been analyzed to know the effect of gamma ray irradiation on these parameters.

  1. Rescue effects: irradiated cells helped by unirradiated bystander cells.

    PubMed

    Lam, R K K; Fung, Y K; Han, W; Yu, K N

    2015-01-01

    The rescue effect describes the phenomenon where irradiated cells or organisms derive benefits from the feedback signals sent from the bystander unirradiated cells or organisms. An example of the benefit is the mitigation of radiation-induced DNA damages in the irradiated cells. The rescue effect can compromise the efficacy of radioimmunotherapy (RIT) (and actually all radiotherapy). In this paper, the discovery and subsequent confirmation studies on the rescue effect were reviewed. The mechanisms and the chemical messengers responsible for the rescue effect studied to date were summarized. The rescue effect between irradiated and bystander unirradiated zebrafish embryos in vivo sharing the same medium was also described. In the discussion section, the mechanism proposed for the rescue effect involving activation of the nuclear factor κB (NF-κB) pathway was scrutinized. This mechanism could explain the promotion of cellular survival and correct repair of DNA damage, dependence on cyclic adenosine monophosphate (cAMP) and modulation of intracellular reactive oxygen species (ROS) level in irradiated cells. Exploitation of the NF-κB pathway to improve the effectiveness of RIT was proposed. Finally, the possibility of using zebrafish embryos as the model to study the efficacy of RIT in treating solid tumors was also discussed. PMID:25625514

  2. Rescue Effects: Irradiated Cells Helped by Unirradiated Bystander Cells

    PubMed Central

    Lam, R. K. K.; Fung, Y. K.; Han, W.; Yu, K. N.

    2015-01-01

    The rescue effect describes the phenomenon where irradiated cells or organisms derive benefits from the feedback signals sent from the bystander unirradiated cells or organisms. An example of the benefit is the mitigation of radiation-induced DNA damages in the irradiated cells. The rescue effect can compromise the efficacy of radioimmunotherapy (RIT) (and actually all radiotherapy). In this paper, the discovery and subsequent confirmation studies on the rescue effect were reviewed. The mechanisms and the chemical messengers responsible for the rescue effect studied to date were summarized. The rescue effect between irradiated and bystander unirradiated zebrafish embryos in vivo sharing the same medium was also described. In the discussion section, the mechanism proposed for the rescue effect involving activation of the nuclear factor κB (NF-κB) pathway was scrutinized. This mechanism could explain the promotion of cellular survival and correct repair of DNA damage, dependence on cyclic adenosine monophosphate (cAMP) and modulation of intracellular reactive oxygen species (ROS) level in irradiated cells. Exploitation of the NF-κB pathway to improve the effectiveness of RIT was proposed. Finally, the possibility of using zebrafish embryos as the model to study the efficacy of RIT in treating solid tumors was also discussed. PMID:25625514

  3. X-ray versus gamma irradiation effects on polymers

    NASA Astrophysics Data System (ADS)

    Croonenborghs, B.; Smith, M. A.; Strain, P.

    2007-11-01

    Today, the most common methods used for medical device sterilisation are by gaseous ethylene oxide and by electron beam or gamma irradiation. With X-ray sterilisation about to enter the market, its material compatibility needs to be assessed at doses typically encountered during a sterilisation process. This paper reports on a study that compares the effects of exposing different types of plastics that are commonly used in medical devices to 60Co or to 5 MeV X-rays. The dose rate for both irradiation modalities was of the same order of magnitude. Under these conditions, both types of radiation are found to have similar effects on polymer properties.

  4. Effect of gamma irradiation on rice and its food products

    NASA Astrophysics Data System (ADS)

    Sung, Wen-Chieh

    2005-07-01

    Two milled indica rice varieties were exposed to gamma radiation with doses ranging from 0 to 1.0 kGy. The effects of gamma irradiation on rice flour pasting properties and the qualities of its food product, rice curd, were compared to the effects of storage. A dose of 1 kGy can decrease the flour paste viscosity and tenderize the texture of the rice curd to similar levels as those obtained after 12 months of storage. It was thus shown that gamma irradiation could shorten the indica rice aging time and improve the processing stability and quality of rice products.

  5. Effects of aeration on gamma irradiation of sewage sludge

    NASA Astrophysics Data System (ADS)

    Chu, Libing; Wang, Jianlong; Wang, Bo

    2010-08-01

    In this paper the effect of aeration on gamma irradiation of sewage sludge was investigated to examine the potential solubilization of solids in sewage sludge to ultimately reduce the solids volume for disposal. Results showed that aeration increased the effectiveness of gamma radiation. The efficiency of sludge solubilization with aeration was increased by around 25% compared to that without aeration at an irradiation dose of 2.5-9 kGy. The soluble protein, polysaccharide and humic (like) substance concentrations were higher under aerated conditions. With aeration the overall reaction appears to be oxidative as evidenced by the higher nitrate and nitrite ion concentrations in solution.

  6. The effect of Argon ion irradiation on the thickness and structure of ultrathin amorphous carbon films

    NASA Astrophysics Data System (ADS)

    Xie, J.; Komvopoulos, K.

    2016-03-01

    Carbon films synthesized by plasma-enhanced chemical vapor deposition (PECVD) and filtered cathodic vacuum arc (FCVA) exhibit a layered structure consisting of a bottom (interface) and a top (surface) layer rich in sp2 atomic carbon bonding and a middle (bulk) layer of much higher sp3 content. Because of significant differences in the composition, structure, and thickness of these layers, decreasing the film thickness may negatively affect its properties. In this study, transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS) were used to examine the effect of Ar+ ion irradiation on the structure and thickness of ultrathin films of hydrogenated amorphous carbon (a-C:H) and hydrogen-free amorphous carbon (a-C) deposited by PECVD and FCVA, respectively. The TEM and EELS results show that 2-min ion irradiation decreases the film thickness without markedly changing the film structure and composition, whereas 4-min ion irradiation results in significant film thinning and a moderate decrease of the sp3 content of the bulk layer. This study demonstrates that Ar+ ion irradiation is an effective post-deposition process for reducing the thickness and tuning the structure of ultrathin carbon films. This capability has direct implications in the synthesis of ultrathin protective carbon overcoats for extremely high-density magnetic recording applications.

  7. DNA microarray analyses reveal a post-irradiation differential time-dependent gene expression profile in yeast cells exposed to X-rays and {gamma}-rays

    SciTech Connect

    Kimura, Shinzo; Ishidou, Emi; Kurita, Sakiko; Suzuki, Yoshiteru; Shibato, Junko; Rakwal, Randeep . E-mail: rakwal-68@aist.go.jp; Iwahashi, Hitoshi

    2006-07-21

    Ionizing radiation (IR) is the most enigmatic of genotoxic stress inducers in our environment that has been around from the eons of time. IR is generally considered harmful, and has been the subject of numerous studies, mostly looking at the DNA damaging effects in cells and the repair mechanisms therein. Moreover, few studies have focused on large-scale identification of cellular responses to IR, and to this end, we describe here an initial study on the transcriptional responses of the unicellular genome model, yeast (Saccharomyces cerevisiae strain S288C), by cDNA microarray. The effect of two different IR, X-rays, and gamma ({gamma})-rays, was investigated by irradiating the yeast cells cultured in YPD medium with 50 Gy doses of X- and {gamma}-rays, followed by resuspension of the cells in YPD for time-course experiments. The samples were collected for microarray analysis at 20, 40, and 80 min after irradiation. Microarray analysis revealed a time-course transcriptional profile of changed gene expressions. Up-regulated genes belonged to the functional categories mainly related to cell cycle and DNA processing, cell rescue defense and virulence, protein and cell fate, and metabolism (X- and {gamma}-rays). Similarly, for X- and {gamma}-rays, the down-regulated genes belonged to mostly transcription and protein synthesis, cell cycle and DNA processing, control of cellular organization, cell fate, and C-compound and carbohydrate metabolism categories, respectively. This study provides for the first time a snapshot of the genome-wide mRNA expression profiles in X- and {gamma}-ray post-irradiated yeast cells and comparatively interprets/discusses the changed gene functional categories as effects of these two radiations vis-a-vis their energy levels.

  8. Survival after total body irradiation: Effects of irradiation of exteriorized small intestine. (Reannouncement with new availability information)

    SciTech Connect

    Vriesendorp, H.M.; Vigneulle, R.M.; Kitto, G.; Pelky, T.; Taylor, P.

    1993-12-31

    Rats receiving lethal irradiation to their exteriorized small intestine with pulsed 18 MVp bremsstrahlung radiation live about 4 days longer than rats receiving a dose of total-body irradiation (TBI) causing intestinal death. The LD50 for intestinal irradiation is approximately 6 Gy higher than the LD50 for intestinal death after TBI. Survival time after exteriorized intestinal irradiation can be decreased, by adding abdominal irradiation. Adding thoracic or pelvic irradiation does not alter survival time. Shielding of large intestine improves survival after irradiation of the rest of the abdomen while the small intestine is also shielded. The kinetics of histological changes in small intestinal tissues implicate the release of humoral factors after irradiation of the abdomen. Radiation injury develops faster in the first (proximal) 40 cm of the small intestine and is expressed predominantly as shortening in villus height. In the last (distal) 40 cm of the small intestine, the most pronounced radiation effect is a decrease in the number of crypts per millimeter. Irradiation (20 Gy) of the proximal small intestine causes 92 % mortality (median survival 10 days). Irradiation (20 Gy) of the distal small intestine causes 27% mortality (median survival > 30 days). In addition to depletion of crypt stem cells in the small intestine, other issues (humoral factors, irradiated subsection of the small intestine and shielding of the large intestine) appear to influence radiation-induced intestinal mortality.

  9. Effect of extracorporeal ultraviolet blood irradiation on blood cholesterol level

    NASA Astrophysics Data System (ADS)

    Zalesskaya, G. A.; Laskina, O. V.; Mitkovskaya, N. P.; Kirkovsky, V. V.

    2012-07-01

    We have studied the effect of extracorporeal ultraviolet blood irradiation on cholesterol metabolism in patients with cardiovascular diseases. We have carried out a comprehensive analysis of the spectral characteristics of blood and plasma, gas-exchange and oximetry parameters, and the results of a complete blood count and chemistry panel before and after UV blood irradiation. We have assessed the changes in concentrations of cholesterols (total cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides) in the blood of the patients in response to a five-day course of UV blood irradiation. The changes in the spectral characteristics of blood and plasma, the chemistry panel, the gas composition, and the fractional hemoglobin composition initiated by absorption of UV radiation are used to discuss the molecular mechanisms for the effect of therapeutic doses of UV radiation on blood cholesterols.

  10. Neutron and gamma irradiation effects on power semiconductor switches

    SciTech Connect

    Schwarze, G.E.; Frasca, A.J.

    1994-09-01

    The performance characteristics of high power semiconductor switches subjected to high levels of neutron fluence and gamma dose must be known by the designer of the power conditioning, control and transmission subsystem of space nuclear power systems. Location and the allowable shielding mass budget will determine the level of radiation tolerance required by the switches to meet performance and reliability requirements. Neutron and gamma ray interactions with semiconductor materials and how these interactions affect the electrical and switching characteristics of solid state power switches is discussed. The experimental measurement system and radiation facilities are described. Experimental data showing the effects of neutron and gamma irradiation on the performance characteristics are given for power-type NPN Bipolar Junction Transistors (BJTs), and Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs). BJTs show a rapid decrease in gain, blocking voltage, and storage time for neutron irradiation, and MOSFETs show a rapid decrease in the gate threshold voltage for gamma irradiation.

  11. Gastroprotective effect of kefir on ulcer induced in irradiated rats.

    PubMed

    Fahmy, Hanan A; Ismail, Amel F M

    2015-03-01

    The current study was designed to investigate the protective effect of kefir milk on ethanol-induced gastric ulcers in γ-irradiated rats. The results of the present study revealed that treatment with γ-irradiation and/or ethanol showed a significant increase in ulcers number, total acidity, peptic, H(+)K(+)ATPase, MMP-2 and MMP-9 activities and MDA level, which were accompanied by a significant decrease in the mucus content, the stomach GSH level, the GSH-Px activity and DNA damage. Pre-treatment with kefir milk exert significant improvement in all the tested parameters. Kefir milk exerts comparable effect to that of the antiulcer drug ranitidine. In conclusion, the present study revealed that oral administration of kefir milk prevents ethanol-induced gastric ulcer in γ-irradiated rats that could attribute to its antioxidant, anti-apoptotic and radio-protective activities. PMID:25728227

  12. Precompaction irradiation effects: Particles from an early active sun?

    NASA Technical Reports Server (NTRS)

    Caffee, M. W.; Goswami, J. N.; Hohenberg, C. M.; Swindle, T. D.

    1986-01-01

    Two recent studies have shown that solar flare irradiated grains from Murchison and Kapoeta have excess spallogenic Ne-21 compared to unirradiated grains, indicating large precompaction particle irradiation effects. The quantity of cosmogenic neon in these grains presents serious difficulties for either galactic cosmic ray or normal solar flare sources. In the first study it was suggested that the effect might be the result of exposure to an early active sun. The more recent experiment both confirms the earlier results and provides constraints on the characteristic energy spectrum on the irradiation. The first results were obtained from Murchison olivines and Kapoeta pyroxenes by mass spectrometric analysis of sets of grains selected on the basis of the presence or absence of solar flare particle tracks. In the second work plagioclase feldspar grains from Kapoeta were studied.

  13. Neutron and gamma irradiation effects on power semiconductor switches

    NASA Technical Reports Server (NTRS)

    Schwarze, G. E.; Frasca, A. J.

    1990-01-01

    The performance characteristics of high power semiconductor switches subjected to high levels of neutron fluence and gamma dose must be known by the designer of the power conditioning, control and transmission subsystem of space nuclear power systems. Location and the allowable shielding mass budget will determine the level of radiation tolerance required by the switches to meet performance and reliability requirements. Neutron and gamma ray interactions with semiconductor materials and how these interactions affect the electrical and switching characteristics of solid state power switches is discussed. The experimental measurement system and radiation facilities are described. Experimental data showing the effects of neutron and gamma irradiation on the performance characteristics are given for power-type NPN Bipolar Junction Transistors (BJTs), and Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs). BJTs show a rapid decrease in gain, blocking voltage, and storage time for neutron irradiation, and MOSFETs show a rapid decrease in the gate threshold voltage for gamma irradiation.

  14. Neutron and gamma irradiation effects on power semiconductor switches

    NASA Technical Reports Server (NTRS)

    Schwarze, G. E.; Frasca, A. J.

    1990-01-01

    The performance characteristics of high-power semiconductor switches subjected to high levels of neutron fluence and gamma dose must be known by the designer of the power conditioning, control and transmission subsystem of space nuclear power systems. Location and the allowable shielding mass budget will determine the level of radiation tolerance required by the switches to meet performance and reliability requirements. Neutron and gamma ray interactions with semiconductor materials and how these interactions affect the electrical and switching characteristics of solid state power switches is discussed. The experimental measurement system and radiation facilities are described. Experimental data showing the effects of neutron and gamma irradiation on the performance characteristics are given for power-type NPN Bipolar Junction Transistors (BJTs), and Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs). BJTs show a rapid decrease in gain, blocking voltage, and storage time for neutron irradiation, and MOSFETs show a rapid decrease in the gate threshold voltage for gamma irradiation.

  15. Phase-field simulations of intragranular fission gas bubble evolution in UO2 under post-irradiation thermal annealing

    SciTech Connect

    Li, Yulan; Hu, Shenyang Y.; Montgomery, Robert O.; Gao, Fei; Sun, Xin

    2013-05-15

    Fission gas bubble is one of evolving microstructures, which affect thermal mechanical properties such as thermo-conductivity, gas release, volume swelling, and cracking, in operating nuclear fuels. Therefore, fundamental understanding of gas bubble evolution kinetics is essential to predict the thermodynamic property and performance changes of fuels. In this work, a generic phasefield model was developed to describe the evolution kinetics of intra-granular fission gas bubbles in UO2 fuels under post-irradiation thermal annealing conditions. Free energy functional and model parameters are evaluated from atomistic simulations and experiments. Critical nuclei size of the gas bubble and gas bubble evolution were simulated. A linear relationship between logarithmic bubble number density and logarithmic mean bubble diameter is predicted which is in a good agreement with experimental data.

  16. Effects of irradiation in combination with waxing on the essential oils in orange peel

    NASA Astrophysics Data System (ADS)

    Moussaid, M.; Lacroix, M.; Nketsia-Tabiri, J.; Boubekri, C.

    2000-03-01

    The study evaluated the effects of waxing and irradiation dose on the essential oils in orange peel. Mature oranges ( Maroc late) waxed or unwaxed were treated with 0-2 kGy radiation. Volatiles in the peel were extracted and analyzed by G.C. D-limonene was significantly lower ( P⩽0.05) in waxed oranges; levels in samples treated with 2 kGy were higher than those treated with 0 or 1 kGy. Linalool, methyl anthranilate and 3.7-dimethyl-2.6-octadienal decreased as the dose increased. The analysis of variance indicates that only linalool was influenced by post-irradiation storage time. The level of this compound increased with storage time.

  17. Micromechanisms of Twin Nucleation in TiAl: Effects of Neutron Irradiation

    SciTech Connect

    Hishinuma, A.; Yoo, M.H.

    1999-01-28

    The so-called radiation-induced ductility (RID) reported in neutron-irradiated 47at%Al alloys is attributed to the formation of effective twin embryos in the presence of interstitial-type Frank loops in {gamma}-TiAl and the subsequent nucleation and growth of microtwins during post-irradiation tensile deformation. The stability of large faulted Frank loops is explained in terms of the repulsive interaction between Shockley and Frank partials. Interaction of only six ordinary slip dislocations with a Frank loop can facilitate a pole mechanism for twin formation to work. The relative ease of heterogeneous twin nucleation is the reason for the RID and the lack of changes in yield strength and work hardening.

  18. Results of Uranium Dioxide-Tungsten Irradiation Test and Post-Test Examination

    NASA Technical Reports Server (NTRS)

    Collins, J. F.; Debogdan, C. E.; Diianni, D. C.

    1973-01-01

    A uranium dioxide (UO2) fueled capsule was fabricated and irradiated in the NASA Plum Brook Reactor Facility. The capsule consisted of two bulk UO2 specimens clad with chemically vapor deposited tungsten (CVD W) 0.762 and 0.1016 cm (0.030-and 0.040-in.) thick, respectively. The second specimen with 0.1016-cm (0.040-in.) thick cladding was irradiated at temperature for 2607 hours, corresponding to an average burnup of 1.516 x 10 to the 20th power fissions/cu cm. Postirradiation examination showed distortion in the bottom end cap, failure of the weld joint, and fracture of the central vent tube. Diametral growth was 1.3 percent. No evidence of gross interaction between CVD tungsten or arc-cast tungsten cladding and the UO2 fuel was observed. Some of the fission gases passed from the fuel cavity to the gas surrounding the fuel specimen via the vent tube and possibly the end-cap weld failure. Whether the UO2 loss rates through the vent tube were within acceptable limits could not be determined in view of the end-cap weld failure.

  19. Post-operative epidural analgesia: effects on lung volumes.

    PubMed

    Wahba, W M; Don, H F; Craig, D B

    1975-07-01

    A study was undertaken to assess the role of post-operative pain in reducing Functional Residual Capacity (FRC) and Vital Capacity (VC). The efficacy of post-operative epidural analgesia in reversing these changes was measured in eight subjects after upper abdominal operations. With pain, FRC and VC were 78 per cent and 37 per cent of control respectively. Following epidural analgesia, the values were 84 per cent and 55 per cent. These figures indicate the pain component in the post-operative reduction of these two lung capacities. This partial restoration may be of value in the prevention of post-operative pulmonary complications by avoiding closure of small airways during tidal breathing and by increasing the effectiveness of deep breathing and coughing in the removal of secretions and the reversal of atelectasis. PMID:1095163

  20. An algorithm for pre- and post-irradiation fade in the thermo 8802 LiF:Mg,Ti thermoluminescent dosimeter.

    SciTech Connect

    Hill, Carolyn D.

    2004-08-01

    The diminished response of thermoluminescent phosphors over time is a well-documented challenge to thermoluminescent dosimetry. Wide ranges in fading rates for various phosphor types have been reported, making it necessary for many external dosimetry programs to perform individual studies on thermoluminescent fade. Sandia National Laboratories currently uses the Thermo 8802 LiF:Mg,Ti thermoluminescent dosimeter (TLD) in its personnel external dosimetry program. Doses received in the field are calculated by applying a fade algorithm published by the manufacturer to TLD readings. Since the algorithm was established by characterizing the diminished response of a TLD similar to the 8802, Sandia chose to model its fade study after the analysis done by Thermo. As a result, the parameters of each experiment were comparable, and data from the two studies were compared to determine whether or not the current algorithm should be modified specifically for use at Sandia. Cards were irradiated using an internal Sr/Y source, and pre- and post-irradiation fading rates were monitored over a period of 18 wk. While significant fading was demonstrated, results closely matched those found in the original Thermo study.

  1. An algorithm for pre- and post-irradiation fade in the Thermo 8802 LiF:Mg,Ti thermoluminescent dosimeter.

    PubMed

    Hill, Carolyn D

    2005-05-01

    The diminished response of thermoluminescent phosphors over time is a well-documented challenge to thermoluminescent dosimetry. Wide ranges in fading rates for various phosphor types have been reported, making it necessary for many external dosimetry programs to perform individual studies on thermoluminescent fade. Sandia National Laboratories currently uses the Thermo 8802 LiF:Mg,Ti thermoluminescent dosimeter (TLD) in its personnel external dosimetry program. Doses received in the field are calculated by applying a fade algorithm published by the manufacturer to TLD readings. Since the algorithm was established by characterizing the diminished response of a TLD similar to the 8802, Sandia chose to model its fade study after the analysis done by Thermo. As a result, the parameters of each experiment were comparable, and data from the two studies were compared to determine whether or not the current algorithm should be modified specifically for use at Sandia. Cards were irradiated using an internal Sr/Y source, and pre- and post-irradiation fading rates were monitored over a period of 18 wk. While significant fading was demonstrated, results closely matched those found in the original Thermo study. PMID:15824586

  2. Effect of UV-C Irradiation on Nutraceuticals in Blueberries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    UV-C treatment has been shown to reduce decay of fruits after harvest. However, little information is available on the influence of UV-C illumination on changes of nutraceutical content in fruits. This study was initiated to investigate the effect of UV-C irradiation on total phenolics, total anth...

  3. Effects of light exposure on irradiated barium fluoride crystals

    SciTech Connect

    Wuest, C.R.; Mauger, G.J.

    1993-04-20

    Small barium fluoride crystals have been irradiated using cobalt-60 gamma rays under various illumination conditions to establish the effect of photo-bleaching of the radiation-induced color centers. This paper describes results of a few different experiments conducted at LLNL over the past few weeks.

  4. Electron irradiation effects in epitaxial InP solar cells

    NASA Technical Reports Server (NTRS)

    Pearsall, N. M.; Robson, N.; Sambell, A. J.; Anspaugh, B.; Cross, T. A.

    1991-01-01

    Performance data for InP-based solar cells after irradiation with 1-MeV electrons up to a fluence of 1 x 1016 e/cm2 are presented. Three InP cell structures are considered. Two of these have epitaxially grown active regions, these being a homojunction design and in ITO/InP structure. These are compared with ITO/InP cells without the epitaxial base region. The cell parameter variations, the influence of illumination during irradiation, and the effect on cell spectral response and capacitance measurements are discussed. Substantial performance recovery after thermal annealing at 90 C is reported.

  5. Effects of self-irradiation in plutonium alloys

    DOE PAGESBeta

    Chung, B. W.; Lema, K. E.; Allen, P. G.

    2015-09-16

    In this paper, we present updated results of self-irradiation effects on 238Pu-enriched 239Pu alloys measured by immersion density, dilatometry, and tensile tests. We obtained the self-irradiation equivalent time of nearly 200 years, nearly 100 years longer than in our previous papers. At this extended aging, we find the rate of decrease in density has slowed significantly, stabilizing around 15.73 g/cc, without signs of void swelling. The volume expansion measured at 35°C also shows apparent saturation at less than 0.25%. Quasi-static tensile measurement still show gradual increase in the strength of plutonium alloys with age.

  6. Low energy argon ion irradiation surface effects on triglycine sulfate

    NASA Astrophysics Data System (ADS)

    Aragó, Carmen; Plaza, José L.; Marqués, Manuel I.; Gonzalo, Julio A.

    2013-09-01

    An experimental study of the effects of low energy (1-2 keV) argon ion (Ar+) irradiation on Triglycine Sulfate (TGS) has been performed. Ferroelectric parameters, such as the Curie temperature TC determined from the dielectric constant peaks ɛ(T), or the remnant polarization Pr, and coercive field Ec, obtained from the hysteresis loops, show interesting differences between samples irradiated in ferroelectric and paraelectric phases, respectively. The radiation damage seems to be superficial, as observed by AFM microscope, and the surface alteration in both phases becomes eventually notorious when the radiation dosage increases.

  7. Effect of solar irradiation on extracellular enzymes of Aeromonas proteolytica

    NASA Technical Reports Server (NTRS)

    Foster, B. G.

    1973-01-01

    The bacterium Aeromonas proteolytica was selected for studying the effects of solar irradiation on extracellular enzymes because it produces an endopeptidase that is capable of degrading proteins and a hemolysin that is active in lysing human erythrocytes. Possible alterations in the rate of enzyme production in response to the test conditions are currently underway and are not available for this preliminary report. Completed viability studies are indicative that little difference exists among the survival curves derived for cells exposed to various components of ultraviolet irradiation in space.

  8. Helium effects on irradiation dmage in V alloys

    SciTech Connect

    Doraiswamy, N.; Alexander, D.

    1996-10-01

    Preliminary investigations were performed on V-4Cr-4Ti samples to observe the effects of He on the irradiation induced microstructural changes by subjecting 3 mm electropolished V-4Cr-4Ti TEM disks, with and without prior He implantation, to 200 keV He irradiation at room temperature and monitoring, in-situ, the microstructural evolution as a function of total dose with an intermediate voltage electron microscope directly connected to an ion implanter. A high density of black dot defects were formed at very low doses in both He pre-implanted and unimplanted samples.

  9. Neutron irradiation effects in magnesium-aluminate spinel doped with transition metals

    NASA Astrophysics Data System (ADS)

    Gritsyna, V. T.; Afanasyev-Charkin, I. V.; Kobyakov, V. A.; Sickafus, K. E.

    2000-12-01

    We present data on optical properties for stoichiometric (MgO · Al 2O 3) and non-stoichiometric (MgO · 2Al 2O 3) spinel crystals: (1) nominally pure; (2) doped with transition metals Mn, Cr, and Fe to a concentration of 0.01 wt%; (3) irradiated with neutrons to a fluence of 1.8×10 21 m -2; (4) post-annealed at 650 K. The temperature during neutron irradiation was 350 K. Optical absorption and thermoluminescence measurements were performed on irradiated and annealed samples at room temperature. Results of absorption measurements show spectra with the following features: (1) a prominent band at 2.33 eV (for stoichiometric spinel); (2) overlapping bands attributed to hole centers (3.17 eV); (3) optical centers on antisite defects (3.78 and 4.14 eV); (4) F +- and F-centers (4.75 and 5.3 eV); (5) bands related to defect complexes. For nominally pure samples, the efficiency of optical center formation in stoichiometric spinel is half that in non-stoichiometric spinel. Doped crystals exhibit high efficiencies for defect creation, independent of spinel composition. All dopants enhance the efficiency of defect creation in spinel. Doping with Mn has the least effect on increasing the number of radiation-induced stable defects. Apparently, impurities in spinel serve as centers for stabilization of irradiation-induced interstitials or vacancies.

  10. Radioprotective effect of Ganoderma lucidum (Leyss. ex. Fr. ) Karst after X-ray irradiation in mice

    SciTech Connect

    Hsu, H.Y.; Lian, S.L.; Lin, C.C. )

    1990-01-01

    Six to seven week old male mice of ICR strain were exposed to 500 or 650 cGy of X-ray during experiments to determine if Ganoderma lucidum could be a factor in modification of radiation damage. Continuous intraperitoneal injection of the extract from Ganoderma lucidum before or after irradiation of 500 and 650 cGy of X-ray was found to improve the 30-day survival fractions of ICR mice, but wasn't significant by statistical analysis. The administration also enhanced the recoveries of the body weights and increased the recovery of hemograms of irradiated mice from radiation damage by injecting before or after radiation exposure, especially for the treatment of 500 cGy irradiation. The 10-day CFUs was significantly higher for Ganoderma lucidum treated groups than for untreated groups. However, the differences of radioprotective effect between the X-ray irradiated groups with Ganoderma lucidum pretreated and post-treated were not significant (p greater than 0.05).

  11. Effects of laser irradiation on the morphology of Cu(110)

    SciTech Connect

    Brandstetter, T.; Draxler, M.; Hohage, M.; Zeppenfeld, P.; Stehrer, T.; Heitz, J.; Georgiev, N.; Martinotti, D.; Ernst, H.-J.

    2008-07-15

    The effects of pulsed laser irradiation on the morphology of the Cu(110) surface were investigated by means of reflectance difference spectroscopy (RDS) and spot profile analysis low-energy electron diffraction (SPA-LEED). The laser light induces surface defects (adatoms and islands) as well as subsurface dislocation lines. The high surface mobility leads to efficient annealing of the surface defects even at room temperature, whereas the subsurface dislocation lines persist up to temperatures T>800 K. SPA-LEED profiles of the (00) diffraction spot from the laser irradiated surface suggest an anisotropic distribution of the subsurface line defects related to the geometry of the fcc easy glide system, which is corroborated by STM measurements. Comparative experiments using conventional Ar ion bombardment point out the distinctiveness of the morphological changes induced by laser irradiation.

  12. Effects of irradiation on alaryngeal voice of totally laryngectomized patients

    SciTech Connect

    Izdebski, K.; Fontanesi, J.; Ross, J.C.; Hetzler, D.

    1988-06-01

    The effects of radiation therapy on the ability of totally laryngectomized patients to produce voice and speech were examined using objective non-invasive methods. Moderate to severe losses were noted in patients producing voice with all types of alaryngeal modalities: tracheoesophageal, esophageal, and electrolaryngeal. Voice and speech losses were related to the impaired motility and vibratory capability of the esophageal wall and mucosa, to fibrosis of the submandibular region and to trismus. Tracheoesophageal and esophageal voice was recovered some weeks after completion of irradiation. No voice losses were observed in alaryngeal speakers who did not undergo voice restoration until after irradiation. All irradiated patients also showed various degrees of dysphagia during the treatment.

  13. Effects of antioxidants on lipid peroxide formation in irradiated synthetic diets.

    PubMed

    Wills, E D

    1980-04-01

    The effect of the antoxidants, vitamin E, propyl gallate (PG), 2-t-butyl-4-methoxy phenol (BHA), 2,6-di-t-butyl-4-methoxy phenol (BHT), nordihydroguaiaretic acid (NDGA) and diphenyl-p-phenylene diamine (DPPD) in concentrations ranging between 0.001 per cent and 0.1 per cent have been tested on lipid peroxide formation in synthetic diet mixtures containing herring oil (10 per cent) mixed with starch (90 per cent) irradiated with gamma-ray doses of 100-2000 krad. On a weight basis NDGA, DPPD, BHA and BHT were most effective and vitamin E and propyl were least effective. An antioxidant concentration of 0.01 per cent normally protected against peroxide formation after a dose of 500 krad but if the dose was increased to 1000 or 2000 krad, much higher doses of antoxidant, up to 0.1 per cent, were required to give protection. Antioxidants prevented peroxide developing during post-irradiation storage even when added after irradiation. Antioxidants were partially or completely destroyed by irradiation with doses of 100 krad or more. The percentage of total antioxidant destroyed depended on the concentration; much greater destruction occurred in dilute solutions than in concentrated solutions. Vitamin E and propyl gallate were most sensitive whereas NDGA was relatively resistant. Antioxidant destruction was much enhanced if irradiation was carried out in presence of herring oil. Free radicals formed in unsaturated fatty acids of the herring oil are believed to be responsible. Lecithin and citric acid, which have been described as antioxidant synergists when added with vitamin E, caused a limited enhancement of its antioxidant action against radiation-induced peroxidation. PMID:6968724

  14. Progress Report on Disassembly and Post-Irradiation Experiments for UCSB ATR-2 Experiment

    SciTech Connect

    Nanstad, Randy K; Odette, G. R.; Robertson, Janet Pawel; Yamamoto, T

    2015-09-01

    The reactor pressure vessel (RPV) in a light-water reactor (LWR) represents the first line of defense against a release of radiation in case of an accident. Thus, regulations that govern the operation of commercial nuclear power plants require conservative margins of fracture toughness, both during normal operation and under accident scenarios. In the unirradiated condition, the RPV has sufficient fracture toughness such that failure is implausible under any postulated condition, including pressurized thermal shock (PTS) in pressurized water reactors (PWR). In the irradiated condition, however, the fracture toughness of the RPV may be severely degraded, with the degree of toughness loss dependent on the radiation sensitivity of the materials. As stated in previous progress reports, the available embrittlement predictive models, e.g. [1], and our present understanding of radiation damage are not fully quantitative, and do not treat all potentially significant variables and issues, particularly considering extension of operation to 80y.

  15. INL Initial Input to the Mission Need for Advanced Post-Irradiation Examination Capability A Non-Major System Acquisition Project

    SciTech Connect

    Vince Tonc

    2010-04-01

    Consolidated and comprehensive post-irradiation examination (PIE) capabilities will enable the science and engineering understanding needed to develop the innovative nuclear fuels and materials that are critical to the success of the U.S. Department of Energy’s (DOE) Office of Nuclear Energy (NE) programs. Existing PIE capabilities at DOE Laboratories, universities, and in the private sector are widely distributed, largely antiquated, and insufficient to support the long-range mission needs. In addition, DOE’s aging nuclear infrastructure was not designed to accommodate modern, state-of-the-art equipment and instrumentation. Currently, the U.S. does not have the capability to make use of state-of-the-art technology in a remote, hot cell environment to characterize irradiated fuels and materials on the micro, nano, and atomic scale. This “advanced PIE capability” to make use of state-of-the-art scientific instruments in a consolidated nuclear operating environment will enable comprehensive characterization and investigation that is essential for effectively implementing the nuclear fuels and materials development programs in support of achieving the U.S. DOE-NE Mission.

  16. IUD most effective post-coital contraception.

    PubMed

    1995-06-01

    In some cases, placement of a copper IUD after unprotected intercourse may be more effective than emergency contraceptive pills (ECPs) in preventing an unplanned pregnancy. The IUD can be inserted 7 days after unprotected sex, compared with 72 hours for ECPs. A study of 8300 postcoital IUD insertions indicated a failure rate of only 0.1%, compared with 1.5% for ECPs. Moreover, most women who use an IUD postcoitally leave the device in place, providing continuing protection from pregnancy. On the other hand, using an IUD after 6 days may not be an option for women who consider disrupting a fertilized egg that has already implanted in the uterine lining to constitute abortion. In addition, in cases where insurance carriers do not provide coverage for IUD insertion, this option may be too expensive. ParaGard, the manufacturer of the only copper IUD available in the US, is concerned about any association of their product with abortion and has stated that postcoital IUD use is "very much discouraged." PMID:12292271

  17. Effect of low power laser irradiation on macrophage phagocytic capacity

    NASA Astrophysics Data System (ADS)

    Lu, Cuixia; Song, Sheng; Tang, Yu; Zhou, Feifan

    2011-03-01

    Phagocytosis and subsequent degradation of pathogens by macrophages play a pivotal role in host innate immunity in mammals. Laser irradiation has been found to produce photobiological effects with evidence of interference with immunological functions. However, the effects of laser on the immune response have not been extensively characterized. In this study, we focused our attention on the effects of He-Ne laser on the phagocytic activity of macrophages by using flow cytometry (FCM). After irradiating at fluence of 0, 1, 2 J/cm2 with He-Ne laser (632.8 nm, 3mw), the cells were incubated with microsphere and then subjected to FACS analysis. The results showed that Low-power laser irradiation (LPLI) leads to an increase in phagocytosis on both mouse peritoneal macrophages and the murine macrophage-like cell line RAW264.7. In addition, we demonstrated that LPLI increased phagocytosis of microsphere in a dose-dependent manner, reaching a maximum at fluence of 2 J/cm2. Taken together, our results indicated that Low-power laser irradiation with appropriate dosage can enhance the phagocytosis of macrophage, and provided a theoretical base for the clinical use of the He-Ne laser.

  18. Irradiation effect on deuterium behaviour in low-dose HFIR neutron-irradiated tungsten

    NASA Astrophysics Data System (ADS)

    Shimada, Masashi; Cao, G.; Otsuka, T.; Hara, M.; Kobayashi, M.; Oya, Y.; Hatano, Y.

    2015-01-01

    Tungsten samples were irradiated by neutrons in the High Flux Isotope Reactor (HFIR), Oak Ridge National Laboratory at reactor coolant temperatures of 50-70 °C to low displacement damage of 0.025 and 0.3 dpa. After cooling down, the HFIR neutron-irradiated tungsten samples were exposed to deuterium plasmas in the Tritium Plasma Experiment, Idaho National Laboratory at 100, 200 and 500 °C twice at the ion fluence of 5 × 1025 m-2 to reach the total ion fluence of 1 × 1026 m-2 in order to investigate the near-surface deuterium retention and saturation via nuclear reaction analysis. Final thermal desorption spectroscopy was performed to elucidate the irradiation effect on total deuterium retention. Nuclear reaction analysis results showed that the maximum near-surface (<5 µm depth) deuterium concentration increased from 0.5 at% D/W in 0.025 dpa samples to 0.8 at% D/W in 0.3 dpa samples. The large discrepancy between the total retention via thermal desorption spectroscopy and the near-surface retention via nuclear reaction analysis indicated the deuterium was trapped in bulk (at least 50 µm depth for 0.025 dpa and 35 µm depth for 0.3 dpa) at 500 °C cases even in the relatively low ion fluence of 1026 m-2.

  19. Low-dose γ-irradiation induces dual radio-adaptive responses depending on the post-irradiation time by altering microRNA expression profiles in normal human dermal fibroblasts.

    PubMed

    Bae, Seunghee; Kim, Karam; Cha, Hwa Jun; Choi, Yeongmin; Shin, Shang Hun; An, In-Sook; Lee, Jae Ho; Lee, Su Jae; Kim, Ji Young; Nam, Seon Young; An, Sungkwan

    2015-01-01

    Exposure to high-dose ionizing radiation, including γ-radiation, induces severe skin disorders. However, the biological consequences and molecular mechanisms responsible for the response of human skin to low-dose γ-radiation (LDR) are largely unknown. In the present study, we demonstrate that LDR (0.1 Gy) induces distinct cellular responses in normal human dermal fibroblasts (NHDFs) depending on the post-irradiation time point. A MTT-based cell viability assay and propidium iodide staining-based cell cycle assay revealed that the viability and proportion of the cells in the G2/M phase were differed at 6 and 24 h post-irradiation. Reverse transcription quantitative PCR (RT-qPCR) revealed that LDR significantly upregulated the mRNA expression of collagen type I alpha 1 (COL1A1), but downregulated the mRNA expression of matrix metalloproteinase 1 (MMP1) at 24 h post-irradiation. MicroRNA (miRNA) microarray analysis further demonstrated that LDR induced changes in the expression profiles of specific miRNAs and that some of the deregulated miRNAs were specific to either the early or late radio-adaptive response. Our results suggest that LDR generates dual radio-adaptive responses depending on the post-irradiation time by altering specific miRNA expression profiles in NHDFs. PMID:25384363

  20. Post-irradiation viability and cytotoxicity of natural killer cells isolated from human peripheral blood using different methods.

    PubMed

    Hietanen, Tenho; Pitkänen, Maunu; Kapanen, Mika; Kellokumpu-Lehtinen, Pirkko-Liisa

    2016-01-01

    Purpose We compared the pre- and post-irradiation viability and cytotoxicity of human peripheral natural killer cell (NK) populations obtained using different isolation methods. Material and methods Three methods were used to enrich total NK cells from buffy coats: (I) a Ficoll-Paque gradient, plastic adherence and a nylon wool column; (II) a discontinuous Percoll gradient; or (III) the Dynal NK cell isolation kit. Subsequently, CD16(+) and CD56(+) NK cell subsets were collected using (IV) flow cytometry or (V) magnetic-activated cell sorting (MACS) NK cell isolation kits. The yield, viability, purity and cytotoxicity of the NK cell populations were measured using trypan blue exclusion, flow cytometry using propidium iodide and (51)Cr release assays after enrichments as well as viability and cytotoxicity after a single radiation dose. Results The purity of the preparations, as measured by the CD16(+) and CD56(+) cell content, was equally good between methods I-III (p = 0.323), but the content of CD16(+) and CD56(+) cells using these methods was significantly lower than that using methods IV and V (p = 0.005). The viability of the cell population enriched via flow cytometry (85.5%) was significantly lower than that enriched via other methods (99.4-98.0%, p = 0.003). The cytotoxicity of NK cells enriched using methods I-III was significantly higher than that of NK cells enriched using methods IV and V (p = 0.000). In vitro the NK cells did not recover cytotoxic activity following irradiation. In addition, we detected considerable inter-individual variation in yield, cytotoxicity and radiation sensitivity between the NK cells collected from different human donors. Conclusions The selection of the appropriate NK cell enrichment method is very important for NK cell irradiation studies. According to our results, the Dynal and MACS NK isolation kits best retained the killing capacity and the viability of irradiated NK cells. PMID:26634866

  1. The effects of professional irradiation, fields of research, results

    SciTech Connect

    Okladnikova, N.D.; Pesternikova, V.S.; Sumina, M.V.

    1993-12-31

    Main results of research of after effects of professional irradiation of the personnel of the first atomic power industry enterprise in the country ({open_quotes}Mayak{close_quotes}) are presented. The earliest determinated effects (chronic and acute radiation sickness, local radiation traumae, plutonium pneumosclerosis) and the late effects of external gamma-irradiation and combined (pu-239, tritium) radiation effect in a wide range of doses have been studied. The basis of the paper are the results of a complex medical research of the personnel: the state of haemopoietic, nerve, cardiovascular systems, alimentary canal, other organs and systems, immunity, somatic cells genome and the frequency of tumor and non-tumor diseases. The observation and research period covered is 40 years from the first contact with the ionized radiation source.

  2. Radiation resistance and post-irradiation proliferation of Listeria monocytogenes on ready-to-eat deli meat in the presence of pectin/nisin films

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this study, the ability of pectin/nisin films in combination with ionizing radiation to eliminate Listeria monocytogenes and inhibit its post-irradiation proliferation was evaluated. Pectin films containing 0.025% nisin were made by extrusion. The surface of a read-to-eat (RTE) turkey meat sample...

  3. Neutron irradiation effects on high Nicalon silicon carbide fibers

    SciTech Connect

    Osborne, M.C.; Steiner, D.; Snead, L.L.

    1996-10-01

    The effects of neutron irradiation on the mechanical properties and microstructure of SiC and SiC-based fibers is a current focal point for the development of radiation damage resistant SiC/SiC composites. This report discusses the radiation effects on the Nippon Carbon Hi-Nicalon{trademark} fiber system and also discusses an erratum on earlier results published by the authors on this material. The radiation matrix currently under study is also summarized.

  4. Effect of ultrasonic tip designs on intraradicular post removal

    PubMed Central

    Aguiar, Anny Carine Barros; de Meireles, Daniely Amorim; Marques, André Augusto Franco; Sponchiado Júnior, Emílio Carlos; Garrido, Angela Delfina Bitencourt

    2014-01-01

    Objectives To evaluate the effect of different ultrasonic tip designs on intraradicular post removal. Materials and Methods The crowns of forty human canine teeth were removed, and after biomechanical preparation and filling, the roots were embedded in acrylic resin blocks. The post spaces were made, and root canal molding was performed with self-cured acrylic resin. After casting (Cu-Al), the posts were cemented with zinc phosphate cement. The specimens were randomly separated into 4 groups (n = 10), as follows: G1 - no ultrasonic vibration (control); G2 - ultrasonic vibration using an elongated cylindrical-shaped and active rounded tip; G3 - ultrasonic vibration with a flattened convex and linear active tip; G4 - ultrasonic vibration with active semicircular tapered tip. Ultrasonic vibration was applied for 15 seconds on each post surface and tensile test was performed in a Universal Testing Machine (Instron 4444 - 1 mm/min). Results G4 presented the highest mean values, however, with no statistically significant difference in comparison to G3 (P > 0.05). G2 presented the lowest mean values with statistically significant difference to G3 and G4 (P < 0.05). Conclusions Ultrasonic vibration with elongated cylindrical-shaped and active rounded tip was most effective in reducing force required for intraradicular post removal. PMID:25383344

  5. Light irradiance and spectral distribution effects on cyanobacterial hydrogen production

    NASA Astrophysics Data System (ADS)

    Fatihah Salleh, Siti; Kamaruddin, Azlina; Hekarl Uzir, Mohamad; Rahman Mohamed, Abdul; Halim Shamsuddin, Abdul

    2016-03-01

    Light is an essential energy source for photosynthetic cyanobacteria. Changes in both light irradiance and spectral distribution will affect their photosynthetic productivity. Compared to the light irradiance, little investigations have been carried out on the effect of light spectra towards cyanobacterial hydrogen production. Hence, this work aims to investigate the effects of both light quantity and quality on biohydrogen productivity of heterocystous cyanobacterium, A.variabilis. Under white light condition, the highest hydrogen production rate of 31 µmol H2 mg chl a -1 h-1 was achieved at 70 µE m-2 s-1. When the experiment was repeated at the same light irradiance but different light spectra of blue, red and green, the accumulations of hydrogen were significantly lower than the white light except for blue light. As the light irradiance was increased to 350 µE m-2 s-1, the accumulated hydrogen under the blue light doubled that of the white light. Besides that, an unusual prolongation of the hydrogen production up to 120 h was observed. The results obtained suggest that blue light could be the most desirable light spectrum for cyanobacterial hydrogen production.

  6. Biomodulatory effects of laser irradiation on dental pulp cells in vitro

    NASA Astrophysics Data System (ADS)

    Milward, Michael R.; Hadis, Mohammed A.; Cooper, Paul R.; Gorecki, Patricia; Carroll, James D.; Palin, William M.

    2015-03-01

    Low level laser/light therapy (LLLT) or photobiomodulation is a biophysical approach that can be used to reduce pain, inflammation and modulate tissue healing and repair. However, its application has yet to be fully realized for dental disease treatment. The aim of this study was to assess the modulation of dental pulp cell (DPC) responses using two LLLT lasers with wavelengths of 660nm and 810nm. Human DPCs were isolated and cultured in phenol-red-free α- MEM/10%-FCS at 37°C in 5% CO2. Central wells of transparent-based black walled 96-microplates were seeded with DPCs (passages 2-4; 150μL; 25,000 cell/ml). At 24h post-seeding, cultures were irradiated using a Thor Photomedicine LLLT device (THOR Photomedicine, UK) at 660nm (3, 6 or 13s to give 2, 5 and 10J/cm2) or 810nm (for 1, 2 or 5s to deliver 5, 10 and 20J/cm2). Metabolic activity was assessed via a modified MTT assay 24h post-irradiation. Statistical differences were identified using analysis of variance and post-hoc Tukey tests (P=0.05) and compared with nonirradiated controls. Significantly higher MTT activity was obtained for both lasers (P<0.05) using the high and intermediate radiant exposure (5-20J/cm2). The MTT response significantly decreased (P<0.05) at lower radiant exposures with no statistical significance from control (P>0.05). Consequently, enhanced irradiation parameters was apparent for both lasers. These parameters should be further optimised to identify the most effective for therapeutic application.

  7. Preliminary results of post-irradiation examination of the AGR-1 TRISO fuel compacts

    SciTech Connect

    Paul Demkowicz; John Hunn; Robert Morris; Jason Harp; Philip Winston; Charles Baldwin; Fred Montgomery; Scott Ploger; Isabella van Rooyen

    2012-10-01

    Five irradiated fuel compacts from the AGR-1 experiment have been examined in detail in order to assess in-pile fission product release behavior. Compacts were electrolytically deconsolidated and analyzed using the leach-burn-leach technique to measure fission product inventory in the compact matrix and identify any particles with a defective SiC layer. Loose particles were then gamma counted to measure the fission product inventory. One particle with a defective SiC layer was found in the five compacts examined. The fractional release of Ag 110m from the particles was significant. The total fraction of silver released from all the particles within a compact ranged from 0-0.63 and individual particles within a single compact often exhibited a very wide range of silver release. The average fractional release of Eu-154 from all particles in a compact was 2.4×10-4—1.3×10-2, which is indicative of release through intact coatings. The fractional Cs-134 inventory in the compact matrix was <2×10-5 when all coatings remained intact, indicating good cesium retention. Approximately 1% of the palladium inventory was found in the compact matrix for two of the compacts, indicating significant release through intact coatings.

  8. Numerical simulation of piezoelectric effect of bone under ultrasound irradiation

    NASA Astrophysics Data System (ADS)

    Hosokawa, Atsushi

    2015-07-01

    The piezoelectric effect of bone under ultrasound irradiation was numerically simulated using an elastic finite-difference time-domain method with piezoelectric constitutive equations (PE-FDTD method). First, to demonstrate the validity of the PE-FDTD method, the ultrasound propagation in piezoelectric ceramics was simulated and then compared with the experimental results. The simulated and experimental waveforms propagating through the ceramics were in good agreement. Next, the piezoelectric effect of human cortical bone on the ultrasound propagation was investigated by PE-FDTD simulation. The simulated result showed that the difference between the waveforms propagating through the bone without and with piezoelectricity was negligible. Finally, the spatial distributions of the electric fields in a human femur induced by ultrasound irradiation were simulated. The electric fields were changed by a bone fracture, which depended on piezoelectric anisotropy. In conclusion, the PE-FDTD method is considered to be useful for investigating the piezoelectric effect of bone.

  9. How to Use Technology Effectively in Post-Compulsory Education

    ERIC Educational Resources Information Center

    Clarke, Alan

    2011-01-01

    The use of technology within the lifelong learning sector brings many benefits to learners, teachers and managers. Aimed at trainee and practising teachers, this book contains clear, practical guidance on how to use technology and e-learning effectively to enhance all aspects of teaching and learning in the post-compulsory sector. Alan Clarke…

  10. Post-irradiation annealing behavior of neutron-irradiated FeCu, FeMnNi and FeMnNiCu model alloys investigated by means of small-angle neutron scattering

    NASA Astrophysics Data System (ADS)

    Bergner, F.; Ulbricht, A.; Lindner, P.; Keiderling, U.; Malerba, L.

    2014-11-01

    Neutron irradiation of reactor pressure vessel steels gives rise to the formation of thermodynamically stable and unstable nano-features. The present work is focused on the stability of Cu-, Mn- and Ni-containing solute clusters in model alloys exposed to post-irradiation annealing. Fe0.1Cu, Fe1.2Mn0.7Ni and Fe1.2Mn0.7Ni0.1Cu (wt%) model alloys irradiated up to neutron exposures of 0.1 and 0.19 dpa (displacements per atom) were annealed at stepwise increasing temperatures in the range from 300 °C (i.e. near irradiation temperature) to 500 °C and characterized by means of small-angle neutron scattering (SANS). We have found characteristic differences in the annealing behavior of the alloys. In particular, there is a non-trivial (synergistic-antagonistic) interplay of Mn/Ni and Cu.

  11. Bystander Effects Induced by Medium From Irradiated Cells: Similar Transcriptome Responses in Irradiated and Bystander K562 Cells

    SciTech Connect

    Herok, Robert; Konopacka, Maria; Polanska, Joanna; Swierniak, Andrzej; Rogolinski, Jacek; Jaksik, Roman; Hancock, Ronald; Rzeszowska-Wolny, Joanna

    2010-05-01

    Purpose: Cells exposed to ionizing radiation release factors that induce deoxyribonucleic acid damage, chromosomal instability, apoptosis, and changes in the proliferation rate of neighboring unexposed cells, phenomena known as bystander effects. This work analyzes and compares changes in global transcript levels induced by direct irradiation and by bystander effects in K562 (human erythroleukemia) cells. Methods and Materials: Cells were X-irradiated with 4 Gy or transferred into culture medium collected from cells 1 h after irradiation (irradiation-conditioned medium). Global transcript profiles were assessed after 36 h of growth by use of Affymetrix microarrays (Affymetrix, Santa Clara, CA) and the kinetics of change of selected transcripts by quantitative reverse transcriptase-polymerase chain reaction. Results: The level of the majority (72%) of transcripts changed similarly (increase, decrease, or no change) in cells grown in irradiation-conditioned medium or irradiated, whereas only 0.6% showed an opposite response. Transcript level changes in bystander and irradiated cells were significantly different from those in untreated cells grown for the same amount of time and were confirmed by quantitative reverse transcriptase-polymerase chain reaction for selected genes. Signaling pathways in which the highest number of transcripts changed in both conditions were found in the following groups: neuroactive ligand-receptor, cytokine-cytokine receptor interaction, Janus Kinase-Signal Transducers and Activators of Transcription (JAK-STAT) and Mitogen-Activated Protein Kinase (MAPK) In control cells more transcripts were downregulated than in irradiated and bystander cells with transcription factors YBX1 and STAT5B, heat shock protein HSPA1A, and ribonucleic acid helicase DDX3X as examples. Conclusions: The transcriptomes of cells grown in medium from X-irradiated cells or directly irradiated show very similar changes. Signals released by irradiated cells may cause

  12. Summary of the results from post-irradiation examination of spent targets at the FZ-Juelich

    NASA Astrophysics Data System (ADS)

    Chen, J.; Bauer, G. S.; Broome, T.; Carsughi, F.; Dai, Y.; Maloy, S. A.; Roedig, M.; Sommer, W. F.; Ullmaier, H.

    2003-05-01

    The lifetime of structural components of spallation targets (beam window, liquid metal container, return hull) is determined by the irradiation-induced changes of the mechanical properties of their materials. An extensive test program was initiated using specimens obtained from spent target components from operating spallation facilities (Los Alamos Neutron Science Center, LANSCE and the Spallation Neutron Source at Rutherford-Appleton Laboratory, ISIS). The investigated materials include a nickel-based alloy (IN 718), an austenitic stainless steel (AISI 304L), a martensitic stainless steel (DIN 1.4926) and a refractory metal (tantalum). The materials experienced 800 MeV proton irradiation to maximum fluences of >10 25 p/m 2. The mechanical property changes were investigated by microhardness measurements, three-point bending tests and tensile tests at temperatures ranging from room temperature (RT) to 250 °C. Subsequent scanning electron microscopy was employed to investigate the fracture surfaces. Generally, irradiation hardening and a decrease in ductility with increasing proton fluence was observed. Nevertheless, all materials except IN 718 tested at RT, retained some ductility up to the maximum doses explored. The transmission electron microscopy investigation showed that a high density of 'black dots' and dislocation loops appeared in all materials. No effect of long-range radiation-induced segregation at grain boundaries was detected by energy dispersive X-ray investigation on AISI 304L and IN718 which failed by intergranular fracture.

  13. Effects of electron irradiation on LDPE/MWCNT composites

    NASA Astrophysics Data System (ADS)

    Yang, Jianqun; Li, Xingji; Liu, Chaoming; Rui, Erming; Wang, Liqin

    2015-12-01

    In this study, mutiwalled carbon nanotubes (MWCNTs) were incorporated into low density polyethylene (LDPE) in different concentrations (2%, 4% and 8%) using a melt blending process. Structural, thermal stability and tensile property of the unirradiated/irradiated LDPE/MWCNT composites by 110 keV electrons were investigated by means of scanning electron microscopy (SEM), small angle X-ray scattering (SAXS), Raman spectroscopy, electron paramagnetic resonance (EPR) spectroscopy, thermogravimetric analysis (TGA) and uniaxial tensile techniques. Experimental results show that the addition of MWCNTs obviously increases the ultimate tensile strength of LDPE and decreases the elongation at break, which is attributed to the homogeneous distribution of the MWCNTs in LDPE and intense interaction between MWCNTs and LDPE matrix. Also, the electron irradiation further increases the ultimate tensile strength of LDPE/MWCNT composites, which can be ascribed to the more intense interaction between MWCNTs and LDPE matrix, and the formation of crosslinking sites in LDPE matrix induced by the electron irradiation. The addition of MWCNTs significantly enhances thermal stability of the LDPE due to the hindering effect and the scavenging free radicals, while the electron irradiation decreases thermal stability of the LDPE/MWCNT composites since the structure of the MWCNTs and LDPE matrix damages.

  14. Effects of irradiation for cervical cancer on subsequent breast cancer

    SciTech Connect

    Harlan, L.C.M.

    1985-01-01

    Previous research suggests that cervical cancer patients have a lower risk of breast cancer than women in the general population. Possible explanations include opposing risk factors for cervical cancer and breast cancer, the effect of irradiation used to treat cervical cancer, or both. The purpose of this study was to explore the relationship between irradiation for cervical cancer and the subsequent development of breast cancer. There was no statistically significant relationship between radiation to the ovarian area and the risk of breast cancer in this study. However, the results were consistent with a 19% reduction in risk for women irradiated for cervical cancer when compared to nonirradiated women. In a dose-response analysis, there was a nonsignificant trend of decreased risk of breast cancer with increased radiation up to 1800 rad. There was no consistent pattern for higher doses. The trend, although nonsignificant, differed by age. Women <60 years of age at irradiation were generally at a lower risk of breast cancer than nonirradiated women. Women over 59 years were at an increased risk. There are some potentially important findings from this study which might influence medical care. These should be examined in the larger International Radiation Study.

  15. Effect of different laser irradiation on the dysentery bacilli

    NASA Astrophysics Data System (ADS)

    Ou, Lin; Chen, Rong; Chen, Yanjiao; Li, Depin; Wen, Caixia

    1998-08-01

    The S. flexnesi, which have high drug-resistance especially in Cm, Sm, Tc, SD, were irradiated by Ar+ laser at 488 nm and semiconductor laser at 808 nm. The experiment results have shown that both Ar+ laser and semiconductor laser with power density of 1.7 w/cm2 and irradiation dose of 2000 J/cm2 can conduce to the bacterial lethality and increase the mutation rates of the bacterial drug-sensitivity, and 'Colony Count' method have the superiority over the 'Inhibacteria Ring' method. At the mean time it further indicate that the high power semiconductor laser would play an important role in the sciences of laser biological medicine. But the effect of the near infrared semiconductor laser is far lower than that of Ar+ laser of shorter wavelength at the same irradiation dose. It is clear that the output and irradiation dose of near infrared semiconductor laser shall be increased in order to get the same rates of the bacterial lethality and the drug-sensitivity mutation as Ar+ laser's.

  16. Hall effect measurements on proton-irradiated ROSE samples

    SciTech Connect

    Biggeri, U.; Bruzzi, M.; Borchi, E.

    1997-01-01

    Bulk samples obtained from two wafers of a silicon monocrystal material produced by Float-Zone refinement have been analyzed using the four-point probe method. One of the wafers comes from an oxygenated ingot; two sets of pure and oxygenated samples have been irradiated with 24 GeV/c protons in the fluence range from 10{sup 13} p/cm{sup 2} to 2x10{sup 14} p/cm{sup 2}. Van der Pauw resistivity and Hall coefficient have been measured before and after irradiation as a function of the temperature. A thermal treatment (30 minutes at 100C) has been performed to accelerate the reverse annealing effect in the irradiated silicon. The irradiated samples show the same exponential dependence of the resistivity and of the Hall coefficient on the temperature from 370K to 100K, corresponding to the presence of radiation-induced deep energy levels around 0.6-0.7eV in the silicon gap. The free carrier concentrations (n, p) have been evaluated in the investigated fluence range. The inversion of the conductivity type from n to p occurred respectively at 7x10{sup 13} p/cm{sup 2} and at 4x10{sup 13} p/cm{sup 2} before and after the annealing treatment, for both the two sets. Only slight differences have been detected between the pure and oxygenated samples.

  17. [Therapeutic Effects of Multipotent Mesenchymal Stromal Cells after Irradiation].

    PubMed

    Kalmykova, N V; Alexandrova, S A

    2016-01-01

    Multipotent mesenchymal stromal cells (MSC) are now considered to be a perspective multifunctional treatment option for radiation side effects. At present.a great number of sufficient evidence has been collected in favor of therapeutic effects of MSCs in acute radiation reactions. It has been shown that MSC-based products injected locally or systemically have therapeutic effects on irradiated organs and tissues. This review presents summarized experimental and clinical data about protective and regenerative effects of MSCs on different radiation-injured organs and tissues; the main probable therapeutic mechanisms of their action are also discussed. PMID:27534063

  18. [CYTOGENETIC EFFECTS IN MICE BONE MARROW AFTER IRRADIATION BY FAST NEUTRONS].

    PubMed

    Vorozhtsova, S V; Bulynina, T M; Ivanov, A A

    2016-01-01

    Mechanisms of damaging mice bone marrow cells by 1.5 MeV neutrons at the dose of 25-250 cGy, dose rate of 23.9 cGy/s and γ-quants ⁶⁰Co as a standard radiation were studied. The mitotic index and aberrant mitoses in marrow preparations were counted in 24 and 72 hours after irradiation. Coefficients of relative biological effectiveness (RBE) of fast neutrons 24 and 72 hours post irradiation calculated from mitotic index reduction and aberrant mitoses formation were within the range from 4.1 ± 0.1 to 7.3 ± 0.1. Mean time of the existence of chromosomal aberrations in marrow cells was determined. For the specified doses from γ-rays, the period of aberrations existence was 1.4-1.1 cycles and for neutrons, 1.0-0.6 cycles. Morphologic analysis of neutron-induced damages and ratio of the most common breaks demonstrated a high production of bridges, which outnumbered cells with fragments in 3 to 4 times suggesting a more destructive effect on the genetic structures of cells. RBE of fast neutrons is a variable that grows with a radiation dose. Moreover, RBE estimated after 72 hours exceeded values it had 24 hours after irradiation. PMID:27347593

  19. Quantifying effects of post-processing with visual grading regression

    NASA Astrophysics Data System (ADS)

    Smedby, Örjan; Fredrikson, Mats; De Geer, Jakob; Sandborg, Michael

    2012-02-01

    For optimization and evaluation of image quality, one can use visual grading experiments, where observers rate some aspect of image quality on an ordinal scale. To take into account the ordinal character of the data, ordinal logistic regression is used in the statistical analysis, an approach known as visual grading regression (VGR). In the VGR model one may include factors such as imaging parameters and post-processing procedures, in addition to patient and observer identity. In a single-image study, 9 radiologists graded 24 cardiac CTA images acquired with ECG-modulated tube current using standard settings (310 mAs), reduced dose (62 mAs) and reduced dose after post-processing. Image quality was assessed using visual grading with five criteria, each with a five-level ordinal scale from 1 (best) to 5 (worst). The VGR model included one term estimating the dose effect (log of mAs setting) and one term estimating the effect of postprocessing. The model predicted that 115 mAs would be required to reach an 80% probability of a score of 1 or 2 for visually sharp reproduction of the heart without the post-processing filter. With the post-processing filter, the corresponding figure would be 86 mAs. Thus, applying the post-processing corresponded to a dose reduction of 25%. For other criteria, the dose-reduction was estimated to 16-26%. Using VGR, it is thus possible to quantify the potential for dose-reduction of post-processing filters.

  20. Effects of Scorpion venom peptide B5 on hematopoietic recovery in irradiated mice and the primary mechanisms.

    PubMed

    Wang, Caixia; Zhou, Meixun; Li, Ting; Wang, Yan; Xing, Baiqian; Kong, Tianhan; Dong, Weihua

    2015-01-01

    Scorpion venom peptide B5 (SVP-B5) stimulates recovery of hematopoiesis after exposure to radiation. However, its radioprotective effects and mechanisms are still unclear. The aim of this study was to investigate the effects of SVP-B5 on hematopoietic recovery in mice after total body irradiation (TBI) at a dose of 7.5 Gy and 6 Gy and to explore the possible primary mechanisms. SVP-B5 at a dose of 2.63 μg/kg significantly reduced the mortality rate of mice after TBI (p < 0.05). It showed markedly protective effects against radiation injury. SVP-B5 also significantly increased the number of bone marrow nucleated cells (BMNCs) and increased the colony forming unit (CFU) number in irradiated mice, accelerated the post-irradiation recovery of peripheral blood leukocytes and platelets in mice. SVP-B5 treatment markedly reduced the Reactive Oxygen Species (ROS) levels in BMNCs after TBI, reduced γH2AX levels, and decreased the relative expression levels of p16 and p21 mRNA at day 14 (d14) after irradiation. Our study indicated that SVP-B5 could partially mitigate radiation-induced DNA damage, enhance the post-radiation hematopoietic recovery, and improve the survival rate probably through the ROS-p16/p21 pathway. PMID:26482294

  1. Effects of Scorpion venom peptide B5 on hematopoietic recovery in irradiated mice and the primary mechanisms

    PubMed Central

    Wang, Caixia; Zhou, Meixun; Li, Ting; Wang, Yan; Xing, Baiqian; Kong, Tianhan; Dong, Weihua

    2015-01-01

    Scorpion venom peptide B5 (SVP-B5) stimulates recovery of hematopoiesis after exposure to radiation. However, its radioprotective effects and mechanisms are still unclear. The aim of this study was to investigate the effects of SVP-B5 on hematopoietic recovery in mice after total body irradiation (TBI) at a dose of 7.5Gy and 6Gy and to explore the possible primary mechanisms. SVP-B5 at a dose of 2.63 μg/kg significantly reduced the mortality rate of mice after TBI (p < 0.05). It showed markedly protective effects against radiation injury. SVP-B5 also significantly increased the number of bone marrow nucleated cells (BMNCs) and increased the colony forming unit (CFU) number in irradiated mice, accelerated the post-irradiation recovery of peripheral blood leukocytes and platelets in mice. SVP-B5 treatment markedly reduced the Reactive Oxygen Species (ROS) levels in BMNCs after TBI, reduced γH2AX levels, and decreased the relative expression levels of p16 and p21 mRNA at day14 (d14) after irradiation. Our study indicated that SVP-B5 could partially mitigate radiation-induced DNA damage, enhance the post-radiation hematopoietic recovery, and improve the survival rate probably through the ROS-p16/p21 pathway. PMID:26482294

  2. Effect of free electron laser (FEL) irradiation on tooth dentine

    NASA Astrophysics Data System (ADS)

    Ogino, Seiji; Awazu, Kunio; Tomimasu, Takio

    1996-12-01

    Free electron laser (FEL) gives high efficiency for the photo-induced effects when the laser is tuned to the absorption maximum of target materials. The effect on dentine was investigated using the FEL tuned to 9.4 micrometers , which is an absorption maximum of phosphoric acid in infrared region. As a result, irradiated dentine surface which was amorphous had changed to the recrystalized structure by the spectroscopic analysis of IR absorption and x-ray diffraction. Furthermore, the atomic ratio of P/Ca had reduced from 0.65 to 0.60. These results indicated that 9.4micrometers -FEL irradiation caused the selective ablation of phosphoric acid ion and the reconstruction of disordered atoms.

  3. Effect of irradiated pork on physicochemical properties of meat emulsions

    NASA Astrophysics Data System (ADS)

    Choi, Yun-Sang; Sung, Jung-Min; Jeong, Tae-Jun; Hwang, Ko-Eun; Song, Dong-Heon; Ham, Youn-Kyung; Kim, Hyun-Wook; Kim, Young-Boong; Kim, Cheon-Jei

    2016-02-01

    The effect of pork irradiated with doses up to 10 kGy on meat emulsions formulated with carboxy methyl cellulose (CMC) was investigated. Raw pork was vacuums packaged at a thickness of 2.0 cm and irradiated by X-ray linear accelerator (15 kW, 5 MeV). The emulsion had higher lightness, myofibrillar protein solubility, total protein solubility, and apparent viscosity with increasing doses, whereas cooking loss, total expressible fluid separation, and hardness decreased. There were no significant differences in fat separation, sarcoplasmic protein solubility, springiness, and cohesiveness. Our results indicated that it is treatment by ionizing radiation which causes the effects the physicochemical properties of the final raw meat product.

  4. Effects of glycyrrhizin on UVB-irradiated melanoma cells.

    PubMed

    Rossi, Tiziana; Benassi, Luisa; Magnoni, Cristina; Ruberto, Antonio Ippazio; Coppi, Andrea; Baggio, Giosué

    2005-01-01

    It is known that liquorice root is rich in compounds which exert several pharmacological actions. In the present study, we evaluated the effect of glycyrrhizin (the main constituent of liquorice root) and of its metabolite aglycone, 18beta-glycyrrhetinic acid, on UVB-irradiated human melanoma cells: SKMEL-2 from metastatic tissue and SKMEL-28 from primary malignant melanoma. Tests performed (Trypan blue exclusion test, MTT and Western blot) showed that glycyrrhizin is not toxic for both types of cells. In SKMEL-28 cells, Bcl-2 expression was low after UVB irradiation, but it was increased when treated with glycyrrhizin. On the contrary, in the SKMEL-2 cell culture, Bcl-2 expression was not modified by the substances under study. The results show that glycyrrhizin treatment might offer protection from the damage induced in humans by UVB radiation, while it seems to be ineffective on metastatic cells. Further studies must be performed to understand the mechanism of the protective effect. PMID:15796192

  5. Effective ultraviolet irradiance measurements from artificial tanning devices in Greece.

    PubMed

    Petri, Aspasia; Karabetsos, Efthymios

    2015-12-01

    Artificial tanning remains very popular worldwide, despite the International Agency for Research on Cancer classification of ultraviolet (UV) radiation from sunbeds as 'carcinogenic to humans'. Greek Atomic Energy Commission has initiated a surveillance action of the artificial tanning devices in Greece in order to record the effective irradiance levels from the sunbeds and to inform and synchronise the domestic artificial tanning business sector with the requirements of the European Standard EN 60335-2-27:2010. In this direction, in situ measurements of UV emissions from sunbeds in solaria businesses all over Greece were performed from October 2013 until July 2014, with a radiometer and a portable single-monochromator spectrophotometer. Analysis of the measurements' results revealed that effective irradiance in ∼60 % of the measured sunbeds exceeded the 0.3 W m(-2) limit value set by EN 60335-2-27:2010 and only 20 % of the devices could be categorised as UV type 3. PMID:25468991

  6. Effect of post-deposition treatment on energy conversion efficiency of nanostructured CdS/Cu2S thin films

    NASA Astrophysics Data System (ADS)

    Taur, Vidya S.; Joshi, Rajesh A.; Sharma, Ramphal

    2013-02-01

    In the present manuscript we report about synthesis of nanostructured CdS/Cu2S thin films by economically viable soft chemical route and effect of post deposition treatments such as annealing in air and swift heavy ion irradiation on solar energy conversion efficiency of the heterojunction device. These as grown, annealed and irradiated thin films are characterized for structural, morphological, optical and I-V properties. X-ray diffraction pattern (XRD) represents structural as well as crystallite modifications, atomic force microscopy (AFM) shows improvement in surface appearance of the materials. The solar energy conversion efficiency calculated from I-V exhibited increase in conversion efficiency i. e. 0.09, 0.24 and 0.48 % for as grown, annealed and SHI irradiated thin films.

  7. Bactericidal effect of Nd:YAG laser irradiation in endodontics

    NASA Astrophysics Data System (ADS)

    Aun, Carlos E.; Barberini, Alexandre F.; Camargo, Selma C. C.; Silva Kfouri, Luciana; Lorenzetti Simionato, Maria R.

    1999-05-01

    The success of endodontic therapy is based on the elimination of bacterial colonization from the endodontic system and periapical tissues. Recent studies have been showing the bactericidal effect of laser in root canal treatment. The propose of the study is to evaluate the effect of Nd:YAG laser irradiation in contaminated root canal treatment. The propose of the study is to evaluate the effect of Nd:YAG laser irradiation in contaminated root canals from upper central incisor. For the experiment 12 teeth were selected, respect at the apical third, sterilized, and 10 μm Streptococcus sanguis liquid culture were inoculated in the root canals. The laser test groups were irradiated with Nd:YAG laser at standard setting of 15Hz, 100mj and 1,5 W for 10, 20 and 30 seconds each in slow helicoidal movements from the apex to the top using a 300 micrometers fiber. After the procedure the specimens were placed in Tryptic Soy Agar, the number of colony forming units was evaluated. The experiment showed a significant reduction on viability of Streptococcus sanguis at the respective time of 20 and 30 seconds.

  8. Irradiation effect on deuterium behaviour in low-dose HFIR neutron-irradiated tungsten

    DOE PAGESBeta

    Shimada, Masashi; Cao, G.; Otsuka, T.; Hara, M.; Kobayashi, M.; Oya, Y.; Hatano, Y.

    2014-12-01

    Tungsten samples were irradiated by neutrons in the High Flux Isotope Reactor, Oak Ridge National Laboratory at reactor coolant temperatures of 50-70°C to low displacement damage of 0.025 and 0.3 dpa under the framework of the US-Japan TITAN program (2007-2013). After cooling down, the HFIR neutron-irradiated tungsten samples were exposed to deuterium plasmas in the Tritium Plasma Experiment, Idaho National Laboratory at 100, 200 and 500 °C twice at the ion fluence of 5×10²⁵ m⁻² to reach a total ion fluence of 1×10²⁶ m⁻² in order to investigate the near surface deuterium retention and saturation via nuclear reaction analysis. Finalmore » thermal desorption spectroscopy was performed to elucidate irradiation effect on total deuterium retention. Nuclear reaction analysis results showed that the maximum near surface (<5 µm depth) deuterium concentration increased from 0.5 at % D/W in 0.025 dpa samples to 0.8 at. % D/W in 0.3 dpa samples. The large discrepancy between the total retention via thermal desorption spectroscopy and the near surface retention via nuclear reaction analysis indicated the deuterium was migrated and trapped in bulk (at least 50 µm depth for 0.025 dpa and 35 µm depth for 0.025 dpa) at 500 °C case even in the relatively low ion fluence of 10²⁶ m⁻².« less

  9. Irradiation effect on deuterium behaviour in low-dose HFIR neutron-irradiated tungsten

    SciTech Connect

    Shimada, Masashi; Cao, G.; Otsuka, T.; Hara, M.; Kobayashi, M.; Oya, Y.; Hatano, Y.

    2014-12-01

    Tungsten samples were irradiated by neutrons in the High Flux Isotope Reactor, Oak Ridge National Laboratory at reactor coolant temperatures of 50-70°C to low displacement damage of 0.025 and 0.3 dpa under the framework of the US-Japan TITAN program (2007-2013). After cooling down, the HFIR neutron-irradiated tungsten samples were exposed to deuterium plasmas in the Tritium Plasma Experiment, Idaho National Laboratory at 100, 200 and 500 °C twice at the ion fluence of 5×10²⁵ m⁻² to reach a total ion fluence of 1×10²⁶ m⁻² in order to investigate the near surface deuterium retention and saturation via nuclear reaction analysis. Final thermal desorption spectroscopy was performed to elucidate irradiation effect on total deuterium retention. Nuclear reaction analysis results showed that the maximum near surface (<5 µm depth) deuterium concentration increased from 0.5 at % D/W in 0.025 dpa samples to 0.8 at. % D/W in 0.3 dpa samples. The large discrepancy between the total retention via thermal desorption spectroscopy and the near surface retention via nuclear reaction analysis indicated the deuterium was migrated and trapped in bulk (at least 50 µm depth for 0.025 dpa and 35 µm depth for 0.025 dpa) at 500 °C case even in the relatively low ion fluence of 10²⁶ m⁻².

  10. Irradiation hardening of Fe-9Cr-based alloys and ODS Eurofer: Effect of helium implantation and iron-ion irradiation at 300 °C including sequence effects

    NASA Astrophysics Data System (ADS)

    Heintze, C.; Bergner, F.; Hernández-Mayoral, M.; Kögler, R.; Müller, G.; Ulbricht, A.

    2016-03-01

    Single-beam, dual-beam and sequential iron- and/or helium-ion irradiations are widely accepted to emulate more application-relevant but hardly accessible irradiation conditions of generation-IV fission and fusion candidate materials for certain purposes such as material pre-selection, identification of basic mechanisms or model calibration. However, systematic investigations of sequence effects capable to critically question individual approaches are largely missing. In the present study, sequence effects of iron-ion irradiations at 300 °C up to 5 dpa and helium implantations up to 100 appm He are investigated by means of post-irradiation nanoindentation of an Fe9%Cr model alloy, ferritic/martensitic 9%Cr steels T91 and Eurofer97 and oxide dispersion strengthened (ODS) Eurofer. Different types of sequence effects, both synergistic and antagonistic, are identified and tentative interpretations are suggested. It is found that different accelerated irradiation approaches have a great impact on the mechanical hardening. This stresses the importance of experimental design in attempts to emulate in-reactor conditions.