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We have performed 1-dimensional calculations for explosive nucleosynthesis in collapse-driven supernova and investigated its sensitivity to the initial form of the shock wave. We have found the tendency that the peak temperature becomes higher around the mass cut if the input energy is injected more in the form of kinetic energy rather than internal energy. Then, the mass cut becomes larger, and, as a result, neutron-rich matter is less included in the ejecta; this is favorable for producing the observational data compared with a previous model. Our results imply that the standard method to treat various processes for stellar evolution, such as convection and electron capture during the silicon burning stage, are still compatible with the calculation of explosive nucleosynthesis., 20 pages, 6 figures, LaTex

The p-process has been studied by now in a quite large variety of astrophysical situations. This review concerns the p-nuclidic yields from the explosion of massive stars either as SNII, or as pair-creation supernovae. The nucleosynthetic predictions rely on detailed stellar models, on quantitative p-process seed abundances, as well as on extended nuclear reaction networks. The impact of some key nuclear physics and astrophysics uncertainties on the p-process yields is also investigated. In addition, a first quantitative evaluation of the metallicity dependence of the amount of ejected p-nuclides is provided by the study of SN1987A. This represents the first step in the construction of a reliable model for the evolution of the galactic content of the p-nuclides. Our predictions are confronted with the bulk solar system composition, as well as with isotopic anomalies attributed to p-nuclides observed in various meteoritic materials. The possibility of developing a p-process chronometry on the short-lived r...

Explosive nucleosynthesis under the axisymmetric explosion in Type II supernova has been performed by means of two dimensional hydrodynamical calculations. We have compared the results with the observations of SN 1987A. Our chief findings are as follows: (1) $^{44}Ti$ is synthesized so much as to explain the tail of the bolometric light curve of SN 1987A. We think this is because the alpha-rich freezeout takes place more actively under the axisymmetric explosion. (2) $^{57}Ni$ and $^{58}Ni$ tend to be overproduced compared with the observations. However, this tendency relies strongly on the progenitor's model. We have also compared the abundance of each element in the mass number range $A= 16-73$ with the solar values. We have found three outstanding features. (1) For the nuclei in the range $A=16-40$, their abundances are insensitive to the initial form of the shock wave. This insensitivity is favored since the spherical calculations thus far can explain the solar system abundances in this mass range. (2) There is an enhancement around A=45 in the axisymmetric explosion compared with the spherical explosion fairly well. In particular, $^{44}Ca$, which is underproduced in the present spherical calculations, is enhanced significantly. (3) In addition, there is an enhancement around A=65. This tendency does not rely on the form of the mass cut but of the initial shock wave. This enhancement may be the problem of the overproduction in this mass range, although this effect would be relatively small since Type I supernovae are chiefly responsible for this mass number range., Comment: 32 pages, 12 figures, LaTex

We perform two-dimensional axisymmetric hydrodynamic simulations of matter mixing in aspherical core-collapse supernova explosions of a 16.3 $M_{\odot}$ star with a compact hydrogen envelope. Observations of SN 1987A have provided evidence that $^{56}$Ni synthesized by explosive nucleosynthesis is mixed into fast moving matter ($\gtrsim$ 3,500 km s$^{-1}$) in the exploding star. In order to clarify the key conditions for reproducing such high velocity of $^{56}$Ni, we revisit matter mixing in aspherical core-collapse supernova explosions. Explosions are initiated artificially by injecting thermal and kinetic energies around the interface between the iron core and the silicon-rich layer. Perturbations of 5% or 30% amplitude in the radial velocities are introduced at several points in time. We found that no high velocity $^{56}$Ni can be obtained if we consider bipolar explosions with perturbations (5% amplitude) of pre-supernova origins. If large perturbations (30% amplitude) are introduced or exist due to some unknown mechanism in a later phase just before the shock wave reaches the hydrogen envelope, $^{56}$Ni with a velocity of 3,000 km s$^{-1}$ can be obtained. Aspherical explosions that are asymmetric across the equatorial plane with clumpy structures in the initial shock waves are investigated. We found that the clump sizes affect the penetration of $^{56}$Ni. Finally, we report that an aspherical explosion model that is asymmetric across the equatorial plane with multiple perturbations of pre-supernova origins can cause the penetration of $^{56}$Ni clumps into fast moving matter of 3,000 km s$^{-1}$. We show that both aspherical explosion with clumpy structures and perturbations of pre-supernova origins may be necessary to reproduce the observed high velocity of $^{56}$Ni. To confirm this, more robust three-dimensional simulations are required., 29 pages, 28 figures, 2 tables, submitted in ApJ

This is the first case of Plasmodium knowlesi infection in a Japanese traveller returning from Malaysia. In September 2012, a previously healthy 35-year-old Japanese man presented to National Center for Global Health and Medicine in Tokyo with a two-day history of daily fever, mild headaches and mild arthralgia. Malaria parasites were found in the Giemsa-stained thin blood smear, which showed band forms similar to Plasmodium malariae. Although a nested PCR showed the amplification of the primer of Plasmodium vivax and Plasmodium knowlesi, he was finally diagnosed with P. knowlesi mono-infection by DNA sequencing. He was treated with mefloquine, and recovered without any complications. DNA sequencing of the PCR products is indispensable to confirm P. knowlesi infection, however there is limited access to DNA sequencing procedures in endemic areas. The extent of P. knowlesi transmission in Asia has not been clearly defined. There is limited availability of diagnostic tests and routine surveillance system for reporting an accurate diagnosis in the Asian endemic regions. Thus, reporting accurately diagnosed cases of P. knowlesi infection in travellers would be important for assessing the true nature of this emerging human infection.

We investigate the presupernova evolution and the explosive nucleosynthesis in massive stars from 13 to 70 M⊙. The explosion energy is assumed to be 1–1.5×1051 erg. We found that the amount of 56Ni produced ranges from 0.07 to 0.15 M⊙. The ratio between the produced and solar abundance agrees with each other within factor 2–3 for A≤32. For the 12C(α,γ)16O rate, our results indicate that the higher rate in 1985 will be better than the lower one.

We have calculated nucleosynthesis during neon nova explosions over wide ranges of the white dwarfs and envelope masses. As the results, we found considerably high mass ratio of 26Al can be produced in some nova events with higher masses of the white dwarfs and the envelopes. In addition, such novae produce substantial amount of 22Na, which has been expected to be detected by CGRO, as well as the clue of the Ne‐E problem.

The maximum angular velocity of uniformly rotating nuetron stars is investigated. If we consider a hot neutron star stage after the birth from supernova explosions, an upper limit of the angular velocity for uniformly rotating neutron stars becomes a little smaller than that obtained by the equation of state for cold neutron matters.

Durability of simulated high-level waste glass in continuously-flowing J-13 tuff groundwater has been examined at 90°C under gamma-irradiation. The results obtained are compared with those without gamma-irradiation. The effects of groundwater radiolysis on the glass durability are discussed based on the Eh-pH excursion obtained in the present system. It is found that the groundwater tends to be reduced under gamma-irradiat ion, however, this may not influence the solubility of multivalent cations leached from the glass.

The superhorizon region has been supported by the Wilkinson Microwave Anisotropy Probe experimental data. In this paper, we point out that the conventional entanglement criterion cannot be applied in the superhorizon region.

A synthesis of N-formyl-4,5,6,7-tetrahydrothieno[3,2-c]pyridines (5) was achieved in a highly efficient manner via trifluoroacetic acid catalyzed cyclization of formyliminium ion (4), which was produced by imination of 2-(2-thienyl)ethylamine (1) and a carbonyl compound (2) using titanium(IV) tetraisopropoxide followed by formylation with acetic-formic anhydride in a one-pot procedure. This modified Pictet-Spengler reaction provides a convenient method for preparing 4,5,6,7-tetahydrothieno[3,2-c]pyridines (6) possessing various substituents at C-4.

The astrophysically most plausible site for the synthesis of the (Z ≥ 34) neutron deficient isotopes (the “p-nuclei”) seems to be the deep interior of highly evolved massive stars. There, (γ, n.) photodisintegrations of preexisting more neutron rich (s— and r—) species, possibly followed by cascades of (γ, p) and (γ, α) reactions, lead to the production of p—nuclei for temperatures ranging roughly from 2 to 3.2 x 109 K. Such a p—process is expected to occur in O/Ne layers during a type II supernova explosion (Woosley and Howard, 1978), as well as during a presupernova hydrostatic oxygen burning phase (Arnould, 1976), where radiative proton captures might also contribute to the production of some light p—nuclei.

Primordial nucleosynthesis is examined with evaporating black holes. A low density model of the universe is preferable because of the heating by the evaporation.

There exist many original and review articles about the mechanisms of type I and type II supernovae (SNI and SNII, e.g. Nomoto, Thielemann, Yokoi 1984; Nomoto 1986; Bruenn 1989; Cooperstein and Baron 1989; Wilson et al. 1986; Woosley and Weaver 1986) and a number of contributions to this conference (Nomoto, Woosley, Cooperstein and Baron, Mayle and Wilson), so that we do not intend to repeat this discussion here. We rather want to concentrate on the accompanying nucleosynthesis processes. This introduction contains a general presentation of the nucleosynthesis processes, while the application to both types of supernova events is given in sections 2 and 3. Section 4 includes a comparison of both contributions to the enrichment of heavy elements in the interstellar medium and a general conclusion. For a discussion of the nuclear physics input in the present nucleosynthesis calculations see Thielemann (1989) and Thielemann, Hashimoto, Nomoto (1990). One of the major free parameters in stellar evolution is the still uncertain 12C(α,γ)16O reaction (see Filippone, Humblet, Langanke 1989; Caughlan et al. 1985; Caughlan and Fowler 1988). The present calculations were performed with the rate of Caughlan et al. (1985).

We have performed x-ray photoemission spectroscopy (XPS) measurements on the high-Tc superconductor La2-xSrxCuO4 (LSCO) at various temperatures. From the shifts of core-level spectra, we have deduced the temperature dependence of the chemical potential in this system. In the underdoped region, the chemical potential shifts upwards with increasing temperature, whereas it shows an opposite shift in the overdoped region. These results qualitatively agree with the predictions of the t-J and tight-binding model calculations as well as thermodynamic quantities but a large quantitative discrepancy exists.

The final evolution of 8-10 M ○. stars in the AGB phase is recalculated to clarify whether these stars undergo collapse or thermonuclear explosion. New electron capture rates based on the shell model wave functions are employed for the evolution of the degenerate O+Ne+Mg core. It is found that the difference between the old and new rates are too small to alter the earlier conclusion that the O+Ne+Mg core collapses. The optical appearance of the resultant supernova explosion of AGB stars are discussed for observational diagnostics. In particular, a possible connection of the AGB star model with SN 1993J is examined

The ring discovered around SN 1987A is likely to be related to the rotation of the progenitor. Two rotational effects of the progenitor of SN 1987A have been studied : (1) mass-shedding from the equator and (2) an aspherical mass distribution in a stellar wind due to the direction-dependent mass loss. With approximate models for a rotating star and a wind, the following results have been obtained. First, if the rotational velocity of the progenitor at the main sequence exceeds 270 km/s, mass-shedding can occur (i.e., the angular velocity can exceed the critical angular velocity) at the blue supergiant stage. Second, the stellar wind combined with the rotation forms an aspherical mass distribution in the distant region from the star

The applicability of theoretical models of He-star explosions to type Ib SN explosions is explored. Particular attention is given to light curves and mixing, Rayleigh-Taylor instabilities and mixing, and nucleosynthesis and the mass of Ni-56. Typical numerical results are presented in graphs, and it is concluded that the explosions of SN 1983N and SN 1983I can be accurately represented in terms of explosions of He stars with M(alpha) of 3-4 solar mass. A strong M(alpha) dependence of light-curve shape, photospheric velocity, and Ni-56 mass is found. 44 refs.

The 20 solar mass model of Nomoto and Hashimoto (1988) is utilized with a 6 solar mass. He core is used to perform explosive nucleosynthesis calculations. The employed explosion energy of 10 to the 51st ergs lies within the uncertainty range inferred from the bolometric light curve. The nucleosynthesis processes and their burning products are discussed in detail. The results are compared with abundances from IR observations of SN 1987A and the average nucleosynthesis expected for Type II supernovae in Galactic chemical evolution. The abundances of long-lived radioactive nuclei and their importance for the late light curve and gamma-ray observations are predicted. The position of the mass cut between the neutron star and the ejecta is deduced from the total amount of ejected Ni-56. This requires a neutron star with a baryonic mass of 1.6 + or - 0.045 solar mass, which corresponds to a gravitational mass of 1.43 + or - 0.05 solar mass after subtracting the binding energy of a nonrotating neutron star.

If the accreting white dwarf increases its mass to the Chandrasekhar mass, it will either explode as a Type I supernova or collapse to form a neutron star. In fact, there is a good agreement between the exploding white dwarf model for Type I supernovae and observations. We describe various types of evolution of accreting white dwarfs as a function of binary parameters (i.e, composition, mass, and age of the white dwarf, its companion star, and mass accretion rate), and discuss the conditions for the precursors of exploding or collapsing white dwarfs, and their relevance to cataclysmic variables. Particular attention is given to helium star cataclysmics which might be the precursors of some Type I supernovae or ultrashort period X-ray binaries. Finally we present new evolutionary calculations using the updated nuclear reaction rates for the formation of O+Ne+Mg white dwarfs, and discuss the composition structure and their relevance to the model for neon novae.

Neutrino bursts from the supernova SN1987A have been reported1–3 which provide qualitatively new information as to the time interval between the core collapse and the optical flaring of the supernova up to about 6 mag4. The interval that we take as three hours1,2 imposes conditions on the radius of the progenitor star and the energetics of the explosion. As for the brightness and its time change, the relatively less bright visual magnitude at the plateau in the light curve during the initial eight days or so (refs 5, 29) as well. The subsequent light curve after eight days is quite unique; the bolometric luminosity increases until ∼65 days (ref. 29) but thereafter it seems to level off gradually (J. Walsh and R. Stathakis, personal communication; M.A. Dopita, personal communication). To maintain the bolometric luminosity of the star means that certain conditions should be imposed on the energy source. By computing the propagation of shock wave, the subsequent expansion of ejected matter and the optical light curve, we find that the early light curve can be accounted for by the diffusive release of energy deposited by the shock wave, that the progenitor's radius should be as small as ∼(1–3) × 1012 cm, and that the explosion energy per unit mass should be relatively large, ∼(2–3)× 1051 erg for the ejected matter of 7–10 M⊙. The light curve after eight days is well reproduced by using a model with constant energy input. The energy input may be due to the activity of an embedded pulsar. The light curves calculated by invoking the radioactive decay of 56Ni and 56Co are less satisfactory in accounting for the nearly flat portion observed after 65 days. Supposing Sk–69 202 is the progenitor of SN1987A13,14, its explosion energy should be >2×l051erg; this suggests that a prompt shock mechanism forms a neutron star.

We summarise recent developments in modelling SN 1987A including the progenitor’s evolution, explosive nucleosynthesis, optical, X- and γ-ray light curves, and dust formation. The distribution of heavy elements in the ejecta is inferred from the light curves. The pre-peak optical light curve as well as early emergence of X- and γ-ray indicate the mixing of 56Ni into the hydrogen-rich envelope. The plateau-like peak of the optical light curve is well reproduced if hydrogen is mixed into the deep core. The flat X-ray light curve observed by Ginga would be due to the clumpy structure of the core. The progenitor’s blue-red-blue evolution and nitrogen abundance suggest that the progenitor’s hydrogen-rich envelope had mass Menv = 7 − 11 M⊙ and was almost completely mixed.

Presupernova evolution of the progenitor of SN 1987A, hydrodynamics of explosion (shock propagation, explosive nucleosynthesis), optical light curve due to shock heating and 56Co decay, and X-ray and γ-ray light curves are calculated and compared with the observations of SN 1987A. Constraints on the mass of the hydrogen-rich envelope Menv (i.e., mass loss history) and the helium abundance in the envelope are obtained from the progenitor’s blue-red-blue evolution as well as from the light curve. The explosion energy E and the mass and distribution of 56Ni are inferred from the light curves. Models and observations are in reasonable agreement for E/Menv = 1.5 ± 0.5 × 1050 erg/M⊙, Menv = 5 - 10 M⊙, and MNi ∼ 0.07 M⊙. Mixing of 56Ni into the envelope is indicated.Light curves of exploding bare helium stars are also calculated to see whether the observed Type Ib supernova light curves can be accounted for.

New presupernova evolutionary models of massive stars are presented. Improvements compared with the previous models are the inclusion of Coulomb interaction in the equation of state, electron capture from the beginning of oxygen burning, and many links between the silicon and iron quasi-equilibrium clusters during silicon burning. The iron core is found to be significantly smaller than in the previous models, especially for stars smaller than 15 M⊙.

Presupernova evolution and explosive nucleosynthesis in massive stars for main-sequence masses from 13 Mʘ to 70 Mʘ are calculated. We examine the dependence of the supernova yields on the stellar mass, 12C(α, γ)16O rate, and explosion energy. The supernova yields integrated over the initial mass function are compared with the solar abundances.

In the future renewable energy systems where hydrogen is used as secondary energy carrier, bearings, seals, and valves may operate in hydrogen. It is important in ensuring reliability and safety to know any deviation of their tribological behaviors from those in normal atmosphere. It is well known that hydrogen causes embrittlement in many of commercially available steels, and the bearing steels are not the exception.Copyright © 2005 by ASME