► Microstructural changes in stainless steel electroslag weld-overlay cladding. ► Thermal aging caused progress of spinodal decomposition and precipitation of G phases in the δ-ferrite phase. ► The ...degree of the spinodal decomposition had a linear relationship to the hardness.
The effect of thermal aging on microstructural changes was investigated in stainless steel weld-overlay cladding composed of 90% austenite and 10% δ-ferrite phases using atom probe tomography (APT). In as-received materials subjected to cooling process after post-welding heat treatments (PWHT), a slight fluctuation of the Cr concentration was already observed due to spinodal decomposition in the ferrite phase but not in the austenitic phase. Thermal aging at 400
°C for 10,000
h caused not only an increase in the amplitude of spinodal decomposition but also the precipitation of G phases with composition ratios of Ni:Si:Mn
=
16:7:6 in the ferrite phase. The chemical compositions of M
23C
6 type carbides seemed to be formed at the austenite/ferrite interface were analyzed. The analyses of the magnitude of the spinodal decomposition and the hardness implied that the spinodal decomposition was the main cause of the hardening.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
An IAEA coordinated research project that began in 2012 and ended in 2016 was primarily dedicated to the compilation, evaluation and recommendation of cross-section data for the production of medical ...radionuclides. One significant part of this work focused on diagnostic positron emitters. These particular studies consist of 69 reactions for direct and indirect or generator production of
44
Sc(
44
Ti),
52m
Mn(
52
Fe),
52g
Mn,
55
Co,
61
Cu,
62
Cu(
62
Zn),
66
Ga,
68
Ga(
68
Ge),
72
As(
72
Se),
73
Se,
76
Br,
82
Rb(
82
Sr),
82m
Rb,
86
Y,
89
Zr,
90
Nb,
94m
Tc,
110m
In(
110
Sn),
118
Sb(
118
Te),
120
I,
122
I(
122
Xe),
128
Cs(
128
Ba), and
140
Pr(
140
Nd) medical radionuclides. The resulting reference cross-section data were obtained from Padé fits to selected and corrected experimental data, and integral thick target yields were subsequently deduced. Uncertainties in the fitted results were estimated via a Padé least-squares method with the addition of a 4% assessed systematic uncertainty. Experimental data were also compared with theoretical predictions available from the TENDL-2015 and TENDL-2017 libraries. All of the numerical reference cross-section data with their corresponding uncertainties and deduced integral thick target yields are available on-line at the IAEA-NDS medical portal
www-nds.iaea.org/medicalportal
and also at the IAEA-NDS web page
www-nds.iaea.org/medical/positron_emitters.html
.
Background and purpose
Akinetic mutism is thought to be an appropriate therapeutic end‐point in patients with sporadic Creutzfeldt−Jakob disease (sCJD). However, prognostic factors for akinetic ...mutism are unclear and clinical signs or symptoms that precede this condition have not been defined. The goal of this study was to identify prognostic factors for akinetic mutism and to clarify the order of clinical sign and symptom development prior to its onset.
Methods
The cumulative incidence of akinetic mutism and other clinical signs and symptoms was estimated based on Japanese CJD surveillance data (455 cases) collected from 2003 to 2008. A proportional hazards model was used to identify prognostic factors for the time to onset of akinetic mutism and other clinical signs and symptoms.
Results
Periodic synchronous discharges on electroencephalography were present in the majority of cases (93.5%). The presence of psychiatric symptoms or cerebellar disturbance at sCJD diagnosis was associated with the development of akinetic mutism hazard ratio (HR) 1.50, 95% confidence interval (CI) 1.14–1.99, and HR 2.15, 95% CI1.61–2.87, respectively. The clinical course from cerebellar disturbance to myoclonus or akinetic mutism was classified into three types: (i) direct path, (ii) path via pyramidal or extrapyramidal dysfunction and (iii) path via psychiatric symptoms or visual disturbance.
Conclusions
The presence of psychiatric symptoms or cerebellar disturbance increased the risk of akinetic mutism of sCJD cases with probable MM/MV subtypes. Also, there appear to be sequential associations in the development of certain clinical signs and symptoms of this disease.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Reaction kinetic analysis of reactor surveillance data Yoshiie, T.; Kinomura, A.; Nagai, Y.
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
02/2017, Volume:
393
Journal Article
Peer reviewed
Open access
In the reactor pressure vessel surveillance data of a European-type pressurized water reactor (low-Cu steel), it was found that the concentration of matrix defects was very high, and a large number ...of precipitates existed. In this study, defect structure evolution obtained from surveillance data was simulated by reaction kinetic analysis using 15 rate equations. The saturation of precipitation and the growth of loops were simulated, but it was not possible to explain the increase in DBTT on the basis of the defect structures. The sub-grain boundary segregation of solutes was discussed for the origin of the DBTT increase.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The diffusion coefficient and the solubility limit of copper in ferromagnetic iron were directly measured using atom probe tomography at lower temperatures than in previous studies. Cu–Fe diffusion ...couples were annealed at temperatures from 550 to 750°C. The diffusion coefficient was determined to be D=0.48exp(−Q/kBT)ms−1 (Q=3.22eV), which, below 650°C, is about 1.3 times higher than the extrapolation from a previous study considering the magnetic effect. The measured Cu solubility limit is in good agreement with literature.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Finding solutions to mitigate the impact of pollution on living systems is a matter of great interest. Homeopathic preparations of toxic substances have been described in the literature as ...attenuation factors for intoxication. Herein, an experimental study using
and mercury chloride was developed as a model to identify aspects related to bioresilience.
The aim of the study was to describe the effects of homeopathic
(MC) on
cysts hatching and on mercury bioavailability.
cysts were exposed to 5.0 µg/mL of mercury chloride during the hatching phase. MC potencies (6cH, 30cH, and 200cH) were prepared in sterile purified water and poured into artificial sea water. Different controls were used (non-challenged cysts and challenged cysts treated with water, succussed water, and
1cH). Four series of nine experiments were performed to evaluate the percentage of cyst hatching. Soluble total mercury (THg) levels and precipitated mercury content were also evaluated. Solvatochromic dyes were used to check for eventual physicochemical markers of MC biological activity.
Significant delay (
< 0.0001) in cyst hatching was observed only after treatment with MC 30cH, compared with controls. This result was associated with an increase of THg concentration in water (
= 0.0018) and of chlorine/oxygen ratio (
< 0.0001) in suspended micraggregates, suggesting changes in mercury bioavailability. A specific interaction of MC 30cH with the solvatochromic dye ET33 (
= 0.0017) was found.
Changes in hatching rate and possible changes in Hg bioavailability are postulated as protective effects of MC 30cH on
, by improving its natural bioresilience processes.
The correlation of microstructure evolution and hardening was studied in two kinds of A533B-1 steel with high and low levels of Cu irradiated in a range of dose from 0.32 to 9.9
×
10
19
n
cm
−2 (
E
>
...1
MeV) under a high flux of about 1.7
×
10
13
n
cm
−2
s
−1 using three-dimensional local electrode atom probe (3DAP), positron annihilation (PA) techniques, and Vickers microhardness. The early rapid hardening was found to be caused by mainly matrix defects such as mono- or di-vacancies (
V
1
−
V
2) and/or dislocations indicated by the PA analysis. The 3DAP analysis showed that dense dispersion of dilute Cu rich clusters and lean distribution of Mn–Ni–Si rich clusters, which
were
identified to possess the same dislocation-pinning effect
by applying a Russell and Brown model,
were responsible for large and small hardening in high- and low-Cu steels irradiated above 0.59
×
10
19
n
cm
2, respectively.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
ABSTRACT The X17.0 solar flare of 2005 September 7 released high-energy neutrons that were detected by the Solar Neutron Telescope (SNT) at Sierra Negra, Mexico. In three separate and independent ...studies of this solar neutron event, several of its unique characteristics were studied; in particular, a power-law energy spectra was estimated. In this paper, we present an alternative analysis, based on improved numerical simulations of the detector using GEANT4, and a different technique for processing the SNT data. The results indicate that the spectral index that best fits the neutron flux is around 3, in agreement with previous works. Based on the numerically calculated neutron energy deposition on the SNT, we confirm that the detected neutrons might have reached an energy of 1 GeV, which implies that 10 GeV protons were probably produced; these could not be observed at Earth, as their parent flare was an east limb event.
The dopant distributions in an n-type metal-oxide-semiconductor field effect transistor (MOSFET) structure were analyzed by atom probe tomography. The dopant distributions of As, P, and B atoms in a ...MOSFET structure (gate, gate oxide, channel, source/drain extension, and halo) were obtained. P atoms were segregated at the interface between the poly-Si gate and the gate oxide, and on the grain boundaries of the poly-Si gate, which had an elongated grain structure along the gate height direction. The concentration of B atoms was enriched near the edge of the source/drain extension where the As atoms were implanted.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Microstructural changes in the stainless steel weld overlay cladding of reactor pressure vessels subjected to neutron irradiation with a fluence of 7.2×1023nm−2 (E>1MeV) and a flux of 1.1×1017nm−2 ...s−1 at 290°C were investigated by atom probe tomography. The results showed a difference in the microstructural changes that result from neutron irradiation and thermal aging. Neutron irradiation resulted in the slight progression of Cr spinodal decomposition and an increase in the fluctuation of the Si, Ni, and Mn concentrations in the ferrite phases, with formation of γ′-like clusters in the austenite phases. On the other hand, thermal aging resulted in the considerable progression of the Cr spinodal decomposition, formation of G-phases, and a decrease in the Si and an increase in the Ni and Mn concentration fluctuations at the matrix in the ferrite phases, without the microstructural changes in the austenite phases.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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