A method to calculate light curves of the gravitational microlensing of the Ellis wormhole is derived in the weak-field limit. In this limit, lensing by the wormhole produces one image outside the ...Einstein ring and another image inside. The weak-field hypothesis is a good approximation in Galactic lensing if the throat radius is less than 1011 km. The light curves calculated have gutters of approximately 4% immediately outside the Einstein ring crossing times. The magnification of the Ellis wormhole lensing is generally less than that of Schwarzschild lensing. The optical depths and event rates are calculated for the Galactic bulge and Large Magellanic Cloud fields according to bound and unbound hypotheses. If the wormholes have throat radii between 100 and 107 km, are bound to the galaxy, and have a number density that is approximately that of ordinary stars, detection can be achieved by reanalyzing past data. If the wormholes are unbound, detection using past data is impossible.
The coarsening behavior of martensite lath has been investigated by means of transmission electron microscopy for tempered martensitic 9
wt.% Cr–(0, 1, 2, 4
wt.%) W steels during creep at 823–923
K. ...During creep, the recovery of excess dislocations, the agglomeration of carbides and the coarsening of laths take place. The coarsening of laths with absorbing excess dislocations is the major process in the creep acceleration. The coarsening rate of lath decreases with increasing W concentration, which is correlated with the rate of Ostwald ripening of M
23C
6 carbides. The progressive local-coalescence of two adjacent laths boundaries near the Y-junction causes the movement of Y-junction, resulting in the coarsening of lath.
ABSTRACT We report the results of the statistical analysis of planetary signals discovered in MOA-II microlensing survey alert system events from 2007 to 2012. We determine the survey sensitivity as ...a function of planet-star mass ratio, q, and projected planet-star separation, s, in Einstein radius units. We find that the mass-ratio function is not a single power law, but has a change in slope at q ∼ 10−4, corresponding to ∼20 M⊕ for the median host-star mass of ∼0.6 . We find significant planetary signals in 23 of the 1474 alert events that are well-characterized by the MOA-II survey data alone. Data from other groups are used only to characterize planetary signals that have been identified in the MOA data alone. The distribution of mass ratios and separations of the planets found in our sample are well fit by a broken power-law model of the form for q > qbr and for q < qbr, where qbr is the mass ratio of the break. We also combine this analysis with the previous analyses of Gould et al. and Cassan et al., bringing the total sample to 30 planets. This combined analysis yields , n = −0.93 0.13, , and for qbr 1.7 × 10−4. The unbroken power-law model is disfavored with a p-value of 0.0022, which corresponds to a Bayes factor of 27 favoring the broken power-law model. These results imply that cold Neptunes are likely to be the most common type of planets beyond the snow line.
A successful example of high-Cr oxide dispersion strengthened (ODS) steels development is introduced with showing key technologies to overcome the issues to meet material requirements for next ...generation nuclear systems as well as fusion blanket systems. Corrosion issue requires Cr concentration more than 14wt.%, but aging embrittlement issue requires it less than 16wt.%. An addition of 4wt.%Al is effective to improve corrosion resistance of 16wt.%Cr-ODS steel in supercritical water (SCW) and lead–bismuth eutectics (LBE), while it is detrimental to high-temperature strength. An addition of small amount of Zr or Hf results in a significant increase in creep strength at 973K in Al-added ODS steels. Feasibility of high-Cr ODS steel without Al addition is assessed for fusion application in terms of corrosion resistance in SCW.
We present measurements of the microlensing optical depth and event rate toward the Galactic Bulge (GB) based on two years of the MOA-II survey. Our event rate and optical depth analysis uses 474 ...events with well-defined microlensing parameters. We find that the event rate is maximized at low latitudes and a longitude of l approximately 1degrees. The main difference is the lack of long duration events in the RCG sample due to a known selection effect. Our results are consistent with previous optical depth measurements, but they are somewhat lower than previous all-source measurements, and slightly higher than previous RCG optical depth measurements. This suggests that the previously observed difference in optical depth measurements between all-source and RCG samples may largely be due to statistical fluctuations. These event rate measurements toward the central GB are necessary to predict the microlensing event rate and to optimize the survey fields in future space missions such as Wide Field Infrared Space Telescope.
In order to improve creep strength of tempered martensitic 9Cr steel at 650
°C, alloy design for a dispersion of fine and thermally stable precipitate particles has been investigated for ...9Cr–3W–3Co–VNb steel and 9Cr–2W–VNbTi steel. Creep tests were carried out at 650
°C for up to about 10
000
h. By reducing carbon concentration below 0.02%, a dispersion of nano-size MX nitrides of vanadium and niobium along boundaries as well as in the matrix is achieved in 9Cr–3W–3Co–VNb steel with 0.05% nitrogen. This gives rise to excellent creep strength at 650
°C, as shown by much higher creep rupture strength than conventional 9Cr steels P92 and T91. Excess addition of nitrogen, 0.07 and 0.1%, promotes the coarsening of MX nitrides and the formation of Z-phase during creep. A dispersion of nano-size TiC carbides is also achieved in 9Cr–2W–VNb steel containing 0.05% Ti by high-temperature normalizing at 1300
°C followed by tempering. This effectively decreases minimum creep rate and improves creep life.
The mechanism of type IV failure has been investigated by using a conventional 9Cr ferritic heat-resistant steel Gr.92. In order to clarify the main cause of type IV failure, different heat ...treatments were performed on the base metal in order to change the prior austenite grain (PAG) size and precipitate distribution after applying the heat-affected zone (HAZ) simulated thermal cycle at the peak temperature of around
A
c
3
(
A
c
3
HAZ thermal cycle) and postweld heat treatment (PWHT). The microstructural evolution during the
A
c
3
HAZ thermal cycle and PWHT was investigated by means of scanning electron microscope (SEM), electron backscatter diffraction (EBSD), electron probe microanalysis (EPMA), and transmission electron microscope (TEM). It was found that M
23
C
6
carbides were scarcely precipitated at the newly formed fine PAG, block, and lath boundaries in
A
c
3
HAZ-simulated Gr.92, because the carbide forming elements such as Cr and C were segregated at the former PAG and block boundaries of the base metal. On the other hand, if all the boundaries were covered by sufficient M
23
C
6
carbides by homogenization of the alloying elements prior to applying the HAZ thermal cycle, the creep strength was much improved even if the fine PAG was formed. From these results, it is concluded that fine-grained microstructure cannot account for the occurrence of type IV failure, and it only has a small effect during long-term creep. The most important factor is the precipitate formation behavior at various boundaries. Without sufficient boundary strengthening by precipitates, the microstructure of
A
c
3
HAZ undergoes severe changes even during PWHT and causes premature failure during creep.
Hsp70: J-domain protein (JDP) machines, along with the cellular protein degradation systems play a central role in regulating cellular proteostasis. An equally robust surveillance system operates at ...the plasma membrane too that affects proper sorting, stability as well as the turnover of membrane proteins. Although plausible, a definitive role of the Hsp70: JDP machine in regulating the stability of plasma membrane proteins is not well understood in Saccharomyces cerevisiae. Here we show that a moderate over-expression of Caj1, one of the thirteen JDPs residing in the nucleo-cytosolic compartment of S. cerevisiae reduced the cold sensitivity of tryptophan auxotrophic yeast cells by stabilizing tryptophan permeases, Tat1 and Tat2 in a J-domain dependent manner. Concomitantly, higher Caj1 levels also caused slow growth and increased plasma membrane damage at elevated temperatures possibly due to the stabilization of thermolabile plasma membrane proteins. Finally, we show that although majorly cytosolic, Caj1 also co-localizes with the membrane dye FM4-64 at the cellular periphery suggesting that Caj1 might interact with the plasma membrane. Based on the results presented in this study, we implicate the Hsp70: Caj1 chaperone machine in regulating the stability or turnover of plasma membrane proteins in budding yeast.
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•Caj1 is the first J-domain protein to associate with plasma membrane.•Caj1 overexpression rescues cold sensitivity of Trp1 auxotrophic strains and causes toxicity at elevated temperatures.•Caj1 overexpression stabilizes amino acid permeases possibly by negatively regulating Rsp5-mediated protein degradation.•Caj1 may have both J-domain dependent as well as J-domain independent functions.
In order to improve the long-term creep strength of 9%Cr steel, the stabilization of martensitic microstructure in the vicinity of prior austenite grain boundaries during creep has been investigated ...by the addition of boron and by a dispersion of nano-size MX nitrides. Creep tests were carried out at 923
K for up to about 3×10
4
h. Boron is enriched in the M
23C
6 carbides during aging and creep, especially in the vicinity of prior austenite grain boundaries. This reduces the coarsening rate of M
23C
6 carbides, which effectively stabilizes the martensitic microstructure in the vicinity of prior austenite grain boundaries. A dispersion of nano-sized MX nitrides but no M
23C
6 along boundaries also gives rise to excellent pinning force for migrating boundaries during creep, as shown by approximately two orders of magnitude longer time to rupture than ASME-P92. The stabilization of martensitic microstructure retards the onset of tertiary or acceleration creep, which results in lower minimum creep rate and longer time to rupture.
The effect of Co on the microstructure of advanced 9Cr–3W–0/5Co–0.2V–0.05Nb–0.08C–0.05N steel, designed for application at highly efficient ultra-supercritical power plants, has been systematically ...studied, using specimens containing 0%, 1%, 3% and 5% Co. Calculation by Thermo-Calc suggested and observation of microstructure after heat treatment confirmed the presence of about 6% and 0.4% of δ-ferrite in Co-free and 1% Co steel, respectively. Coarse primary Nb-rich MX particles preferentially form inside δ-ferrite, as according to Thermo-Calc Nb solubility in the body-centered cubic phase is approximately double of that in the face-centered cubic phase. Detailed examination of precipitates was conducted on samples after heat treatment. The total amount of precipitation increases with increasing Co content, which is especially significant between 1% and 3% Co steels. Precipitate density around prior austenitic grain boundaries is highest for 3% Co steel, and lowest for 1% Co steel. The mean diameter of precipitates does not differ significantly.
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