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Sample records for nucleosynthesis bbn offers

  1. BBN with light dark matter

    SciTech Connect (OSTI)

    Berezhiani, Zurab [Dipartimento di Fisica, Università dell'Aquila, Via Vetoio, 67100 Coppito, L'Aquila (Italy); Dolgov, Aleksander; Tkachev, Igor, E-mail: Zurab.Berezhiani@aquila.infn.it, E-mail: dolgov@fe.infn.it, E-mail: tkachev@ms2.inr.ac.ru [Laboratory of Cosmology and Elementary Particles, Novosibirsk State University, Pirogov street 2, 630090 Novosibirsk (Russian Federation)

    2013-02-01

    Effects of light millicharged dark matter particles on primordial nucleosynthesis are considered. It is shown that if the mass of such particles is much smaller than the electron mass, they lead to strong overproduction of Helium-4. An agreement with observations can be achieved by non-vanishing lepton asymmetry. Baryon-to-photon ratio at BBN and neutrino-to-photon ratio both at BBN and at recombination are noticeably different as compared to the standard cosmological model. The latter ratio and possible lepton asymmetry could be checked by Planck. For higher mass of new particles the effect is much less pronounced and may even have opposite sign.

  2. Primordial Nucleosynthesis

    E-Print Network [OSTI]

    Alain Coc

    2012-08-23

    Primordial nucleosynthesis, or Big-Bang Nucleosynthesis (BBN), is one of the three evidences for the Big-Bang model, together with the expansion of the Universe and the Cosmic Microwave Background. There is a good global agreement over a range of nine orders of magnitude between abundances of 4He, D, 3He and 7Li deduced from observations, and calculated in primordial nucleosynthesis. This comparison was used to determine the baryonic density of the Universe. For this purpose, it is now superseded by the analysis of the Cosmic Microwave Background (CMB) radiation anisotropies. However, there remain, a yet unexplained, discrepancy of a factor 3-5, between the calculated and observed lithium primordial abundances, that has not been reduced, neither by recent nuclear physics experiments, nor by new observations. We review here the nuclear physics aspects of BBN for the production of 4He, D, 3He and 7Li, but also 6Li, 9Be, 11B and up to CNO isotopes. These are, for instance, important for the initial composition of the matter at the origin of the first stars. Big-Bang nucleosynthesis, that has been used, to first constrain the baryonic density, and the number of neutrino families, remains, a valuable tool to probe the physics of the early Universe, like variation of "constants" or alternative theories of gravity.

  3. Big-Bang Nucleosynthesis verifies classical Maxwell-Boltzmann distribution

    E-Print Network [OSTI]

    S. Q. Hou; J. J. He; A. Parikh; K. Daid; C. Bertulani

    2014-08-15

    We provide the most stringent constraint to date on possible deviations from the usually-assumed Maxwell-Boltzmann (MB) velocity distribution for nuclei in the Big-Bang plasma. The impact of non-extensive Tsallis statistics on thermonuclear reaction rates involved in standard models of Big-Bang Nucleosynthesis (BBN) has been investigated. We find that the non-extensive parameter $q$ may deviate by, at most, $|\\delta q|$=6$\\times$10$^{-4}$ from unity for BBN predictions to be consistent with observed primordial abundances; $q$=1 represents the classical Boltzmann-Gibbs statistics. This constraint arises primarily from the {\\em super}sensitivity of endothermic rates on the value of $q$, which is found for the first time. As such, the implications of non-extensive statistics in other astrophysical environments should be explored. This may offer new insight into the nucleosynthesis of heavy elements.

  4. Big Bang Nucleosynthesis

    E-Print Network [OSTI]

    Keith A. Olive

    1997-12-11

    The concordance of standard big bang nucleosynthesis theory and the related observations of the light element isotopes (including some new higher \\he4 abundances) will be reviewed. Implications of BBN on chemical evolution, dark matter and constraints on particle properties will be discussed.

  5. Big Bang Nucleosynthesis: 2015

    E-Print Network [OSTI]

    Cyburt, Richard H; Olive, Keith A; Yeh, Tsung-Han

    2015-01-01

    Big-bang nucleosynthesis (BBN) describes the production of the lightest nuclides via a dynamic interplay among the four fundamental forces during the first seconds of cosmic time. We briefly overview the essentials of this physics, and present new calculations of light element abundances through li6 and li7, with updated nuclear reactions and uncertainties including those in the neutron lifetime. We provide fits to these results as a function of baryon density and of the number of neutrino flavors, N_nu. We review recent developments in BBN, particularly new, precision Planck cosmic microwave background (CMB) measurements that now probe the baryon density, helium content, and the effective number of degrees of freedom, n_eff. These measurements allow for a tight test of BBN and of cosmology using CMB data alone. Our likelihood analysis convolves the 2015 Planck data chains with our BBN output and observational data. Adding astronomical measurements of light elements strengthens the power of BBN. We include a ...

  6. Neutrinos, WMAP, and BBN

    E-Print Network [OSTI]

    Lawrence M. Krauss; Cecilia Lunardini; Christel Smith

    2010-11-18

    New data from WMAP have appeared, related to both the fractional energy density in relativistic species at decoupling and also the primordial helium abundance, at the same time as other independent observational estimates suggest a higher value of the latter than previously estimated. All the data are consistent with the possibility that the effective number of relativistic species in the radiation gas at the time of Big Bang Nucleosynthesis may exceed the value of 3, as expected from a CP-symmetric population of the known neutrino species. Here we explore the possibility that new neutrino physics accounts for such an excess. We explore different realizations, including neutrino asymmetry and new neutrino species, as well as their combination, and describe how existing constraints on neutrino physics would need to be relaxed as a result of the new data, as well as possible experimental tests of these possibilities.

  7. Big bang nucleosynthesis: An update

    SciTech Connect (OSTI)

    Olive, Keith A. [William I. Fine Theoretical Physics Institute, School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)] [William I. Fine Theoretical Physics Institute, School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)

    2013-07-23

    An update on the standard model of big bang nucleosynthesis (BBN) is presented. With the value of the baryon-tophoton ratio determined to high precision by WMAP, standard BBN is a parameter-free theory. In this context, the theoretical prediction for the abundances of D, {sup 4}He, and {sup 7}Li is discussed and compared to their observational determination. While concordance for D and {sup 4}He is satisfactory, the prediction for {sup 7}Li exceeds the observational determination by a factor of about four. Possible solutions to this problem are discussed.

  8. Constraining spacetime noncommutativity with primordial nucleosynthesis

    E-Print Network [OSTI]

    Raul Horvat; Josip Trampetic

    2009-04-01

    We discuss a constraint on the scale $\\Lambda_{\\rm NC}$ of noncommutative (NC) gauge field theory arising from consideration of the big bang nucleosynthesis (BBN) of light elements. The propagation of neutrinos in the NC background described by an antisymmetric tensor $\\theta^{\\mu\

  9. Light WIMPs, Equivalent Neutrinos, BBN, and the CMB

    E-Print Network [OSTI]

    Gary Steigman; Kenneth M. Nollett

    2014-01-21

    Recent updates to the observational determinations of the primordial abundances of helium and deuterium are compared to the predictions of BBN to infer the universal ratio of baryons to photons (or, the present Universe baryon mass density parameter Omega_B h^2), as well as to constrain the effective number of neutrinos (N_eff) and the number of equivalent neutrinos (Delta N_nu). These BBN results are compared to those derived independently from the Planck CMB data. In the absence of a light WIMP (chi), N_eff = 3.05(1 + Delta N_nu/3). In this case, there is excellent agreement between BBN and the CMB, but the joint fit finds that Delta N_nu = 0.40 +/- 0.17, disfavoring standard big bang nucleosynthesis (SBBN: Delta N_nu = 0) at 2.4 sigma, as well as a sterile neutrino (Delta N_nu = 1) at 3.5 sigma. In the presence of a light WIMP, the relation between N_eff and Delta N_nu depends on the WIMP mass, leading to degeneracies among N_eff, Delta N_nu, and m_chi. The complementary and independent BBN and CMB data can break some of these degeneracies. Depending on the nature of the light WIMP (Majorana or Dirac fermion, real or complex scalar) the joint BBN + CMB analyses set a lower bound to m_chi in the range from 0.5 to 5 MeV, and they identify best fit values for m_chi in the range from 5 to 10 MeV. The joint BBN + CMB analyses find a best fit value for the number of equivalent neutrinos, Delta N_nu = 0.65, nearly independent of the nature of the WIMP. The best fit still disfavors the absence of dark radiation (Delta N_nu = 0 at 95% confidence), while allowing for the presence of a sterile neutrino (Delta N_nu = 1 at less than 1 sigma). For all cases considered here, the lithium problem persists. These results, presented at the 2013 Rencontres de l'Observatoire de Paris - ESO Workshop, are based on Nollett & Steigman 2013 (arXiv:1312.5725 [astro-ph.CO]).

  10. Constraints on Light Dark Matter from Big Bang Nucleosynthesis

    E-Print Network [OSTI]

    Brian Henning; Hitoshi Murayama

    2012-05-29

    We examine the effects of relic dark matter annihilations on big bang nucleosynthesis (BBN). The magnitude of these effects have scale simply with the dark matter mass and annihilation cross-section, which we derive. Estimates based on these scaling behaviors indicate that BBN severely constrains hadronic and radiative dark matter annihilation channels in the previously unconsidered dark matter mass region MeV $\\lesssim m_{\\chi} \\lesssim 10$ GeV. Interestingly, we find that BBN constraints on hadronic annihilation channels are competitive with similar bounds derived from the cosmic microwave background.

  11. Dark Radiation from Particle Decays during Big Bang Nucleosynthesis

    E-Print Network [OSTI]

    Menestrina, Justin L

    2011-01-01

    Cosmic microwave background (CMB) observations suggest the possibility of an extra dark radiation component, while the current evidence from big bang nucleosynthesis (BBN) is more ambiguous. Dark radiation from a decaying particle can affect these two processes differently. Early decays add an additional radiation component to both the CMB and BBN, while late decays can alter the radiation content seen in the CMB while having a negligible effect on BBN. Here we quantify this difference and explore the intermediate regime by examining particles decaying during BBN, i.e., particle lifetimes \\tau_X satisfying 0.1 sec 1000 sec), \\Delta N_{BBN} is dominated by the energy density of the nonrelativistic particles before they decay, so that \\Delta N_{BBN} remains nonzero and becomes independent of the particle lifetime. By varying both the particle energy density and lifetime, one can obtain any desired combination of \\Delta N_{BBN} and \\Delta N_{CMB}, subject to the constraint that \\Delta N_{CMB} >= \\Delta N_{BBN}.

  12. New Nuclear Physics for Big Bang Nucleosynthesis

    E-Print Network [OSTI]

    Richard N. Boyd; Carl R. Brune; George M. Fuller; Christel J. Smith

    2010-08-04

    We discuss nuclear reactions which could play a role in Big Bang Nucleosynthesis (BBN). Most of these reactions involve lithium and beryllium isotopes and the rates for some of these have not previously been included in BBN calculations. Few of these reactions are well studied in the laboratory. We also discuss novel effects in these reactions, including thermal population of nuclear target states, resonant enhancement, and non-thermal neutron reaction products. We perform sensitivity studies which show that even given considerable nuclear physics uncertainties, most of these nuclear reactions have minimal leverage on the standard BBN abundance yields of 6Li and 7Li. Although a few have the potential to alter the yields significantly, we argue that this is unlikely.

  13. Nuclear weak interaction rates in primordial nucleosynthesis

    E-Print Network [OSTI]

    George M. Fuller; Christel J. Smith

    2010-09-01

    We calculate the weak interaction rates of selected light nuclei during the epoch of Big Bang Nucleosynthesis (BBN), and we assess the impact of these rates on nuclear abundance flow histories and on final light element abundance yields. We consider electron and electron antineutrino captures on 3He and 7Be, and the reverse processes of positron capture and electron neutrino capture on 3H and 7Li. We also compute the rates of positron and electron neutrino capture on 6He. We calculate beta and positron decay transitions where appropriate. As expected, the final standard BBN abundance yields are little affected by addition of these weak processes, though there can be slight alterations of nuclear flow histories. However, non-standard BBN scenarios, e.g., those involving out of equilibrium particle decay with energetic final state neutrinos, may be affected by these processes.

  14. Long Lived Charged Massive Particles and Big Bang Nucleosynthesis

    E-Print Network [OSTI]

    Kazunori Kohri; Fumihiro Takayama

    2006-11-06

    We consider Big Bang Nucleosynthesis(BBN) with long lived charged massive particles. Before decaying, the long lived massive particles recombines with a light element to form a bound state like a hydrogen atom. We discuss the possible change of primordial light element abundances due to formations of such bound states.

  15. Neutrino energy transport in weak decoupling and big bang nucleosynthesis

    E-Print Network [OSTI]

    Grohs, E; Kishimoto, C T; Paris, M W; Vlasenko, A

    2015-01-01

    We calculate the evolution of the early universe through the epochs of weak decoupling, weak freeze-out and big bang nucleosynthesis (BBN) by simultaneously coupling a full strong, electromagnetic, and weak nuclear reaction network with a multi-energy group Boltzmann neutrino energy transport scheme. Such an approach allows a detailed accounting of the evolution of the $\

  16. Big bang nucleosynthesis as a probe of fundamental "constants"

    E-Print Network [OSTI]

    Thomas Dent; Steffen Stern

    2007-10-25

    Big Bang nucleosynthesis (BBN) is the earliest sensitive probe of the values of many fundamental particle physics parameters. We have found the leading linear dependences of primordial abundances on all relevant parameters of the standard BBN code, including binding energies and nuclear reaction rates. This enables us to set limits on possible variations of fundamental parameters. We find that 7Li is expected to be significantly more sensitive than other species to many fundamental parameters, a result which also holds for variations of coupling strengths in grand unified (GUT) models. Our work also indicates which areas of nuclear theory need further development if the values of ``constants'' are to be more accurately probed.

  17. Nucleosynthesis in barium stars

    E-Print Network [OSTI]

    Trimble, V; Trimble, V

    1984-01-01

    problem of apparent nucleosynthesis in barium stars, thoughSE24 9JF. Astronomy Nucleosynthesis in barium stars fromopportunity to see that nucleosynthesis really is taking

  18. Dark/visible parallel universes and Big Bang nucleosynthesis

    SciTech Connect (OSTI)

    Bertulani, C. A.; Frederico, T.; Fuqua, J.; Hussein, M. S.; Oliveira, O.; Paula, W. de [Department of Physics and Astronomy, Texas A and M University-Commerce, Commerce TX 75429 (United States); Departamento de Fisica, Instituto Tecnologico de Aeronautica, DCTA 12.228-900, Sao Jose dos Campos, SP (Brazil); Department of Physics and Astronomy, Texas A and M University-Commerce, Commerce TX 75429 (United States); Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, 05314-970 Sao Paulo, SP (Brazil); Departamento de Fisica, Instituto Tecnologico de Aeronautica, DCTA 12.228-900, Sao Jose dos Campos, SP, Brazil and Departamento de Fisica, Universidade de Coimbra, 3004-516 Coimbra (Portugal); Departamento de Fisica, Instituto Tecnologico de Aeronautica, DCTA 12.228-900, Sao Jose dos Campos, SP (Brazil)

    2012-11-20

    We develop a model for visible matter-dark matter interaction based on the exchange of a massive gray boson called herein the Mulato. Our model hinges on the assumption that all known particles in the visible matter have their counterparts in the dark matter. We postulate six families of particles five of which are dark. This leads to the unavoidable postulation of six parallel worlds, the visible one and five invisible worlds. A close study of big bang nucleosynthesis (BBN), baryon asymmetries, cosmic microwave background (CMB) bounds, galaxy dynamics, together with the Standard Model assumptions, help us to set a limit on the mass and width of the new gauge boson. Modification of the statistics underlying the kinetic energy distribution of particles during the BBN is also discussed. The changes in reaction rates during the BBN due to a departure from the Debye-Hueckel electron screening model is also investigated.

  19. Meyer and Zinner: Nucleosynthesis 69 Nucleosynthesis

    E-Print Network [OSTI]

    Floss, Christine

    Meyer and Zinner: Nucleosynthesis 69 69 Nucleosynthesis Bradley S. Meyer Clemson University Ernst these topics in cosmochemistry and their implications for our ideas about stellar nucleosynthesis. 1 nucleosynthesis. After the Big Bang the universe consisted only of H and He and trace amounts of Li, Be, and B

  20. The NACRE Thermonuclear Reaction Compilation and Big Bang Nucleosynthesis

    E-Print Network [OSTI]

    Richard H. Cyburt; Brian D. Fields; Keith A. Olive

    2001-05-17

    The theoretical predictions of big bang nucleosynthesis (BBN) are dominated by uncertainties in the input nuclear reaction cross sections. In this paper, we examine the impact on BBN of the recent compilation of nuclear data and thermonuclear reactions rates by the NACRE collaboration. We confirm that the adopted rates do not make large overall changes in central values of predictions, but do affect the magnitude of the uncertainties in these predictions. Therefore, we then examine in detail the uncertainties in the individual reaction rates considered by NACRE. When the error estimates by NACRE are treated as 1\\sigma limits, the resulting BBN error budget is similar to those of previous tabulations. We propose two new procedures for deriving reaction rate uncertainties from the nuclear data: one which sets lower limits to the error, and one which we believe is a reasonable description of the present error budget. We propagate these uncertainty estimates through the BBN code, and find that when the nuclear data errors are described most accurately, the resulting light element uncertainties are notably smaller than in some previous tabulations, but larger than others. Using these results, we derive limits on the cosmic baryon-to-photon ratio $\\eta$, and compare this to independent limits on $\\eta$ from recent balloon-borne measurements of the cosmic microwave background radiation (CMB). We discuss means to improve the BBN results via key nuclear reaction measurements and light element observations.

  1. Explosive nucleosynthesis

    E-Print Network [OSTI]

    M. Hernanz

    2001-03-26

    Many radioactive nuclei relevant for gamma-ray astrophysics are synthesized during explosive events, such as classical novae and supernovae. A review of recent results of explosive nucleosynthesis in these scenarios is presented, with a special emphasis on the ensuing gamma-ray emission from individual nova and supernova explosions. The influence of the dynamic properties of the ejecta on the gamma-ray emission features, as well as the still remaining uncertainties in nova and supernova models is also reviewed.

  2. Refined scenario of standard Big Bang nucleosynthesis allowing for nonthermal nuclear reactions in the primordial plasma

    SciTech Connect (OSTI)

    Voronchev, Victor T.; Nakao, Yasuyuki; Nakamura, Makoto; Tsukida, Kazuki [Institute of Nuclear Physics, Moscow State University, Moscow 119991 (Russian Federation); Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Motooka, Fukuoka 819-0395 (Japan); Division of Advanced Plasma Research, Japan Atomic Energy Agency, 2-166 Oaza-Obuchi-Aza-Omotedate, Rokkasho, Kamikita, Aomori 039-3212 (Japan); Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Motooka, Fukuoka 819-0395 (Japan)

    2012-11-12

    The standard scenario of big bang nucleosynthesis (BBN) is generalized to take into account nonthermal nuclear reactions in the primordial plasma. These reactions are naturally triggered in the BBN epoch by fast particles generated in various exoergic processes. It is found that, although such particles can appreciably enhance the rates of some individual reactions, their influence on the whole process of element production is not significant. The nonthermal corrections to element abundances are obtained to be 0.1% ({sup 3}H), -0.03% ({sup 7}Li), and 0.34 %-0.63% (CNO group).

  3. Primordial nucleosynthesis and neutrino physics

    E-Print Network [OSTI]

    Smith, Christel Johanna

    2009-01-01

    Chapter 4 Big Bang Nucleosynthesis Weak Rate1 1.1.2 Big Bang Nucleosynthesis . . . . . . . . . . . . .5 1.1.3 Nucleosynthesis Predictions and Comparison to

  4. Big bang nucleosynthesis constrains the total annihilation cross section of neutralino dark matter

    E-Print Network [OSTI]

    Xiao-Jun Bi

    2008-04-17

    Assuming the lightest neutralino forms dark matter, we study its residual annihilation after freeze-out at the early universe. If taking place after the big bang nucleosynthesis (BBN) the annihilation products, especially at the hadronic modes, may cause nonthermal nuclear reaction and change the prediction of the primordial abundance of light elements in the standard BBN scenario. We therefore put constraints on the neutralino annihilation cross section. These constraints are free of the uncertainties of the dark matter profile today suffered by direct or indirect detection of dark matter. We find the constraints by BBN is important, especially when taking large $\\tan\\beta$. If the light element abundances can be determined with higher precision in the future the constraint will become very strong, so that a majority of the parameter space allowed by the relic density requirement may be excluded.

  5. Nucleosynthesis in Thermonuclear Supernovae

    SciTech Connect (OSTI)

    Claudia, Travaglio [Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Torino; Hix, William Raphael [ORNL

    2013-01-01

    We review our understanding of the nucleosynthesis that occurs in thermonuclear supernovae and their contribution to Galactic Chemical evolution. We discuss the prospects to improve the modeling of the nucleosynthesis within simulations of these events.

  6. Effect of Long-lived Strongly Interacting Relic Particles on Big Bang Nucleosynthesis

    E-Print Network [OSTI]

    Motohiko Kusakabe; Toshitaka Kajino; Takashi Yoshida; Grant J. Mathews

    2009-06-18

    It has been suggested that relic long-lived strongly interacting massive particles (SIMPs, or $X$ particles) existed in the early universe. We study effects of such long-lived unstable SIMPs on big bang nucleosynthesis (BBN) assuming that such particles existed during the BBN epoch, but then decayed long before they could be detected. The interaction strength between an $X$ particle and a nucleon is assumed to be similar to that between nucleons. We then calculate BBN in the presence of the unstable neutral charged $X^0$ particles taking into account the capture of $X^0$ particles by nuclei to form $X$-nuclei. We also study the nuclear reactions and beta decays of $X$-nuclei. We find that SIMPs form bound states with normal nuclei during a relatively early epoch of BBN. This leads to the production of heavy elements which remain attached to them. Constraints on the abundance of $X^0$ particles during BBN are derived from observationally inferred limits on the primordial light element abundances. Particle models which predict long-lived colored particles with lifetimes longer than $\\sim$ 200 s are rejected based upon these constraints.

  7. BBN And The CMB Constrain Neutrino Coupled Light WIMPs

    E-Print Network [OSTI]

    Kenneth M. Nollett; Gary Steigman

    2015-02-12

    (abridged) In the presence of a light WIMP (mass m_chi 35 MeV, equivalent to no light WIMP at all. All masses below 4--9 MeV (depending on spin) are excluded. Without any light WIMP, BBN alone prefers Delta N_nu = 0.50 +- 0.23, favoring neither Delta N_nu = 0, nor a fully thermalized sterile neutrino (Delta N_nu = 1). This result is consistent with the CMB constraint, N_eff = 3.30 +- 0.27, limiting "new physics" between BBN and recombination. Combining BBN and CMB data gives Delta N_nu = 0.35 +- 0.16 and N_eff = 3.40 +- 0.16; while BBN and the CMB combined require Delta N_nu > 0 at ~98% confidence, they disfavor Delta N_nu > 1 at > 99% confidence. Allowing a neutrino-coupled light WIMP extends the allowed range slightly downward for Delta N_nu and slightly upward for N_eff simultaneously, leaving best-fit values unchanged.

  8. Constraint on slepton intergenerational mixing from big-bang nucleosynthesis

    SciTech Connect (OSTI)

    Kohri, Kazunori; Ohta, Shingo; Sato, Joe; Shimomura, Takashi; Yamanaka, Masato [Theory Center, Institute of Particle and Nuclear Studies, KEK (High Energy Accelerator Research Organization), 1-1 Oho, Tsukuba 305-0801 (Japan); Department of Physics, Saitama University, Shimo-okubo, Sakura-ku, Saitama, 338-8570 (Japan); Department of Physics, Niigata University, Niigata, 950-8502 (Japan) and Max-Planck-Institut fur Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Maskawa Institute for Science and Culture, Kyoto Sangyo University, Kyoto 603-8555 (Japan)

    2012-07-27

    We find constraint on intergenerational mixing of slepton from big-bang nucleosynthesis (BBN). Today, we know that there exist lepton flavor violation (LFV) from the observation of neutrino oscillation, though there do not exist LFV in the standard model of particle physics (SM). LFV in charged lepton sector (cLFV) have also been expected to exist. From theoretical point of view, the effects of long-lived stau on BBN have been investigated and it is known that the stau can solve the cosmological 7Li problem. However, in the study so far, tau flavor is exactly conserved and it contradict with the existence of cLFV. In this study, we generalize the flavor to be violated and call the stau as slepton. Even if the violation is tiny, it drastically changes the lifetime and the evolution of relic density of the slepton. Thus we analyze the effects of the long-lived slepton on BBN, and constrain the magnitude of the cLFV.

  9. 4. Nucleosynthesis I. Aretxaga

    E-Print Network [OSTI]

    Aretxaga, Itziar

    4. Nucleosynthesis I. Aretxaga 2014 #12;We have that MR-3 radR-4 There must be a z at which M= rad Taking into account that nucleosynthesis predicts n=0.68 n , then rad=4.2 x 10-5 h-2 1+zeq = 23900mh2 radiation to matter dominated Universe at z~3100 (t~60000 yr): recombination nucleosynthesis #12;Epochs

  10. Limits on Cosmological Variation of Strong Interaction and Quark Masses from Big Bang Nucleosynthesis, Cosmic, Laboratory and Oklo Data

    E-Print Network [OSTI]

    V. V. Flambaum; E. V. Shuryak

    2002-02-18

    Recent data on cosmological variation of the electromagnetic fine structure constant from distant quasar (QSO) absorption spectra have inspired a more general discussion of possible variation of other constants. We discuss variation of strong scale and quark masses. We derive the limits on their relative change from (i) primordial Big-Bang Nucleosynthesis (BBN); (ii) Oklo natural nuclear reactor, (iii) quasar absorption spectra, and (iv) laboratory measurements of hyperfine intervals.

  11. Constraints on modified Gauss-Bonnet gravity during big bang nucleosynthesis

    E-Print Network [OSTI]

    Kusakabe, Motohiko; Kim, K S; Cheoun, Myung-Ki

    2015-01-01

    The modified gravity is considered to be one of possible explanations of the accelerated expansions of the present and the early universe. We study effects of the modified gravity on big bang nucleosynthesis (BBN). If effects of the modified gravity are significant during the BBN epoch, they should be observed as changes of primordial light element abundances. We assume a $f(G)$ term with the Gauss-Bonnet term $G$, during the BBN epoch. A power-law relation of $df/dG \\propto t^p$ where $t$ is the cosmic time was assumed for the function $f(G)$ as an example case. We solve time evolutions of physical variables during BBN in the $f(G)$ gravity model numerically, and analyzed calculated results. It is found that a proper solution for the cosmic expansion rate can be lost in some parameter region. In addition, we show that calculated results of primordial light element abundances can be significantly different from observational data. Especially, observational limits on primordial D abundance leads to the stronge...

  12. Constraints on modified Gauss-Bonnet gravity during big bang nucleosynthesis

    E-Print Network [OSTI]

    Motohiko Kusakabe; Seoktae Koh; K. S. Kim; Myung-Ki Cheoun

    2015-07-20

    The modified gravity is considered to be one of possible explanations of the accelerated expansions of the present and the early universe. We study effects of the modified gravity on big bang nucleosynthesis (BBN). If effects of the modified gravity are significant during the BBN epoch, they should be observed as changes of primordial light element abundances. We assume a $f(G)$ term with the Gauss-Bonnet term $G$, during the BBN epoch. A power-law relation of $df/dG \\propto t^p$ where $t$ is the cosmic time was assumed for the function $f(G)$ as an example case. We solve time evolutions of physical variables during BBN in the $f(G)$ gravity model numerically, and analyzed calculated results. It is found that a proper solution for the cosmic expansion rate can be lost in some parameter region. In addition, we show that calculated results of primordial light element abundances can be significantly different from observational data. Especially, observational limits on primordial D abundance leads to the strongest constraint on the $f(G)$ gravity. We then derive constraints on parameters of the $f(G)$ gravity taking into account the existence of the solution of expansion rate and final light element abundances.

  13. Neutron-induced nucleosynthesis

    E-Print Network [OSTI]

    H. Oberhummer; H. Herndl; T. Rauscher; H. Beer

    1996-08-20

    Neutron--induced nucleosynthesis plays an important role in astrophysical scenarios like in primordial nucleosynthesis in the early universe, in the s--process occurring in Red Giants, and in the $\\alpha$--rich freeze--out and r--process taking place in supernovae of type II. A review of the three important aspects of neutron--induced nucleosynthesis is given: astrophysical background, experimental methods and theoretical models for determining reaction cross sections and reaction rates at thermonuclear energies. Three specific examples of neutron capture at thermal and thermonuclear energies are discussed in some detail.

  14. Constraining scalar dark matter with Big Bang nucleosynthesis and atomic spectroscopy

    E-Print Network [OSTI]

    Stadnik, Y V

    2015-01-01

    Scalar dark matter can interact with Standard Model (SM) particles, altering the fundamental constants of Nature in the process. Changes in the fundamental constants during and before Big Bang nucleosynthesis (BBN) produce changes in the primordial abundances of the light elements. In particular, the primordial abundance of $^{4}$He is predominantly determined by the ratio of the neutron-proton mass difference to freeze-out temperature at the time of the weak interaction freeze-out prior to BBN, which is a sensitive function of the fundamental constants. By comparing the measured and calculated (within the SM) primordial abundance of $^{4}$He, we are able to derive stringent constraints on the mass of a scalar dark matter particle $\\phi$ together with its interactions with photons, light quarks and massive vector bosons via linear and quadratic couplings in $\\phi$. We also derive constraints on the quadratic interaction of $\\phi$ with photons from recent atomic dysprosium spectroscopy measurements.

  15. Constraining scalar dark matter with Big Bang nucleosynthesis and atomic spectroscopy

    E-Print Network [OSTI]

    Y. V. Stadnik; V. V. Flambaum

    2015-04-12

    Scalar dark matter can interact with Standard Model (SM) particles, altering the fundamental constants of Nature in the process. Changes in the fundamental constants during and prior to Big Bang nucleosynthesis (BBN) produce changes in the primordial abundances of the light elements. By comparing the measured and calculated (within the SM) primordial abundance of $^{4}$He, which is predominantly determined by the ratio of the neutron-proton mass difference to freeze-out temperature at the time of weak interaction freeze-out prior to BBN, we are able to derive stringent constraints on the mass of a scalar dark matter particle $\\phi$ together with its interactions with the photon, light quarks and massive vector bosons via quadratic couplings in $\\phi$, as well as its interactions with massive vector bosons via linear couplings in $\\phi$. We also derive a stringent constraint on the quadratic interaction of $\\phi$ with the photon from recent atomic dysprosium spectroscopy measurements.

  16. Standard big bang nucleosynthesis and primordial CNO abundances after Planck

    SciTech Connect (OSTI)

    Coc, Alain [Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), CNRS/IN2P3, Université Paris Sud 11, UMR 8609, Bâtiment 104, F–91405 Orsay Campus (France); Uzan, Jean-Philippe; Vangioni, Elisabeth, E-mail: coc@csnsm.in2p3.fr, E-mail: uzan@iap.fr, E-mail: vangioni@iap.fr [Institut d'Astrophysique de Paris, UMR-7095 du CNRS, Université Pierre et Marie Curie, 98 bis bd Arago, 75014 Paris (France)

    2014-10-01

    Primordial or big bang nucleosynthesis (BBN) is one of the three historical strong evidences for the big bang model. The recent results by the Planck satellite mission have slightly changed the estimate of the baryonic density compared to the previous WMAP analysis. This article updates the BBN predictions for the light elements using the cosmological parameters determined by Planck, as well as an improvement of the nuclear network and new spectroscopic observations. There is a slight lowering of the primordial Li/H abundance, however, this lithium value still remains typically 3 times larger than its observed spectroscopic abundance in halo stars of the Galaxy. According to the importance of this ''lithium problem{sup ,} we trace the small changes in its BBN calculated abundance following updates of the baryonic density, neutron lifetime and networks. In addition, for the first time, we provide confidence limits for the production of {sup 6}Li, {sup 9}Be, {sup 11}B and CNO, resulting from our extensive Monte Carlo calculation with our extended network. A specific focus is cast on CNO primordial production. Considering uncertainties on the nuclear rates around the CNO formation, we obtain CNO/H ? (5-30)×10{sup -15}. We further improve this estimate by analyzing correlations between yields and reaction rates and identified new influential reaction rates. These uncertain rates, if simultaneously varied could lead to a significant increase of CNO production: CNO/H?10{sup -13}. This result is important for the study of population III star formation during the dark ages.

  17. Big Bang Nucleosynthesis with Independent Neutrino Distribution Functions

    E-Print Network [OSTI]

    Christel J. Smith; George M. Fuller; Michael S. Smith

    2008-12-06

    We have performed new Big Bang Nucleosynthesis calculations which employ arbitrarily-specified, time-dependent neutrino and antineutrino distribution functions for each of up to four neutrino flavors. We self-consistently couple these distributions to the thermodynamics, the expansion rate and scale factor-time/temperature relationship, as well as to all relevant weak, electromagnetic, and strong nuclear reaction processes in the early universe. With this approach, we can treat any scenario in which neutrino or antineutrino spectral distortion might arise. These scenarios might include, for example, decaying particles, active-sterile neutrino oscillations, and active-active neutrino oscillations in the presence of significant lepton numbers. Our calculations allow lepton numbers and sterile neutrinos to be constrained with observationally-determined primordial helium and deuterium abundances. We have modified a standard BBN code to perform these calculations and have made it available to the community.

  18. Nucleosynthesis and Neutrinos

    SciTech Connect (OSTI)

    Kajino, Toshitaka [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Department of Astronomy, Graduate School of Science, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2011-05-06

    Neutrinos play the critical roles in nucleosynthesis of light-to-heavy mass nuclei in core-collapse supernovae. We study the nucleosynthesis induced by neutrino interactions and find suitable average neutrino temperatures in order to explain the observed solar system abundances of several isotopes {sup 7}Li, {sup 11}B, {sup 138}La and {sup 180}Ta. These isotopes are predominantly synthesized by the supernova {nu}-process. We also study the neutrino oscillation effects on their abundances and propose a method to determine the unknown neutrino oscillation parameters, i.e. {theta}{sub 13} and mass hierarchy.

  19. Nucleosynthesis Without a Computer

    E-Print Network [OSTI]

    V. Mukhanov

    2003-03-04

    I derive completely analytically the time evolution and final abundances of the light elements (up to Be-7) formed in the big-bang nucleosynthesis.This highlights an interesting physics taking place during the formation of light elements in the early universe.

  20. REVISED BIG BANG NUCLEOSYNTHESIS WITH LONG-LIVED, NEGATIVELY CHARGED MASSIVE PARTICLES: UPDATED RECOMBINATION RATES, PRIMORDIAL {sup 9}Be NUCLEOSYNTHESIS, AND IMPACT OF NEW {sup 6}Li LIMITS

    SciTech Connect (OSTI)

    Kusakabe, Motohiko; Kim, K. S. [School of Liberal Arts and Science, Korea Aerospace University, Goyang 412-791 (Korea, Republic of); Cheoun, Myung-Ki [Department of Physics, Soongsil University, Seoul 156-743 (Korea, Republic of); Kajino, Toshitaka [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Kino, Yasushi [Department of Chemistry, Tohoku University, Sendai 980-8578 (Japan); Mathews, Grant J., E-mail: motohiko@kau.ac.kr, E-mail: kyungsik@kau.ac.kr, E-mail: cheoun@ssu.ac.kr, E-mail: kajino@nao.ac.jp, E-mail: y.k@m.tohoku.ac.jp, E-mail: gmathews@nd.edu [Center for Astrophysics, Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States)

    2014-09-01

    We extensively reanalyze the effects of a long-lived, negatively charged massive particle, X {sup –}, on big bang nucleosynthesis (BBN). The BBN model with an X {sup –} particle was originally motivated by the discrepancy between the {sup 6,} {sup 7}Li abundances predicted in the standard BBN model and those inferred from observations of metal-poor stars. In this model, {sup 7}Be is destroyed via the recombination with an X {sup –} particle followed by radiative proton capture. We calculate precise rates for the radiative recombinations of {sup 7}Be, {sup 7}Li, {sup 9}Be, and {sup 4}He with X {sup –}. In nonresonant rates, we take into account respective partial waves of scattering states and respective bound states. The finite sizes of nuclear charge distributions cause deviations in wave functions from those of point-charge nuclei. For a heavy X {sup –} mass, m{sub X} ? 100 GeV, the d-wave ? 2P transition is most important for {sup 7}Li and {sup 7,} {sup 9}Be, unlike recombination with electrons. Our new nonresonant rate of the {sup 7}Be recombination for m{sub X} = 1000 GeV is more than six times larger than the existing rate. Moreover, we suggest a new important reaction for {sup 9}Be production: the recombination of {sup 7}Li and X {sup –} followed by deuteron capture. We derive binding energies of X nuclei along with reaction rates and Q values. We then calculate BBN and find that the amount of {sup 7}Be destruction depends significantly on the charge distribution of {sup 7}Be. Finally, updated constraints on the initial abundance and the lifetime of the X {sup –} are derived in the context of revised upper limits to the primordial {sup 6}Li abundance. Parameter regions for the solution to the {sup 7}Li problem and the primordial {sup 9}Be abundances are revised.

  1. Effect of quark-mass variation on big bang nucleosynthesis

    E-Print Network [OSTI]

    J. C. Berengut; V. F. Dmitriev; V. V. Flambaum

    2009-07-14

    We calculate the effect of variation in the light-current quark mass, $m_q$, on standard big bang nucleosynthesis. A change in $m_q$ at during the era of nucleosynthesis affects nuclear reaction rates, and hence primordial abundances, via changes the binding energies of light nuclei. It is found that a relative variation of $\\delta m_q/m_q = 0.016 \\pm 0.005$ provides better agreement between observed primordial abundances and those predicted by theory. This is largely due to resolution of the existing discrepancies for 7Li. However this method ignores possible changes in the position of resonances in nuclear reactions. The predicted 7Li abundance has a strong dependence on the cross-section of the resonant reactions 3He(d,p)4He and t(d,n)4He. We show that changes in $m_q$ at the time of BBN could shift the position of these resonances away from the Gamow window and lead to an increased production of 7Li, exacerbating the lithium problem.

  2. Big Bang nucleosynthesis in scalar tensor gravity: the key problem of the $^7$Li abundance

    E-Print Network [OSTI]

    Julien Larena; Jean-Michel Alimi; Arturo Serna

    2006-11-20

    Combined with other CMB experiments, the WMAP survey provides an accurate estimate of the baryon density of the Universe. In the framework of the standard Big Bang Nucleosynthesis (BBN), such a baryon density leads to predictions for the primordial abundances of $^{4}$He and D in good agreement with observations. However, it also leads to a significant discrepancy between the predicted and observed primordial abundance of $^{7}$Li. Such a discrepancy is often termed as 'the lithium problem'. In this paper, we analyze this problem in the framework of scalar-tensor theories of gravity. It is shown that an expansion of the Universe slightly slower than in General Relativity before BBN, but faster during BBN, solves the lithium problem and leads to $^4$He and D primordial abundances consistent with the observational constraints. This kind of behavior is obtained in numerous scalar-tensor models, both with and without a self-interaction potential for the scalar field. In models with a self-interacting scalar field, the convergence towards General Relativity is ensured without any condition, thanks to an attraction mechanism which starts to work during the radiation-dominated epoch.

  3. Effects of power law primordial magnetic field on big bang nucleosynthesis

    E-Print Network [OSTI]

    Dai G. Yamazaki; Motohiko Kusakabe

    2012-12-12

    Big bang nucleosynthesis (BBN) is affected by the energy density of a primordial magnetic field (PMF). For an easy derivation of constraints on models for PMF generations, we assume a PMF with a power law (PL) distribution in wave number defined with a field strength, a PL index, and maximum and minimum scales at a generation epoch. We then show a relation between PL-PMF parameters and the scale invariant (SI) strength of PMF for the first time. We perform a BBN calculation including PMF effects, and show abundances as a function of baryon to photon ratio $\\eta$. The SI strength of the PMF is constrained from observational constraints on abundances of $^4$He and D. The minimum abundance of $^7$Li/H as a function of $\\eta$ slightly moves to a higher $^7$Li/H value at a larger $\\eta$ value when a PMF exists during BBN. We then discuss degeneracies between the PL-PMF parameters in the PMF effect. In addition, we assume a general case in which both the existence and the dissipation of PMF are possible. It is then found that an upper limit on the SI strength of the PMF can be derived from a constraint on $^4$He abundance, and that a lower limit on the allowed $^7$Li abundance is significantly higher than those observed in metal-poor stars.

  4. Explosive Nucleosynthesis: Prospects

    E-Print Network [OSTI]

    David Arnett

    1999-08-16

    Explosive nucleosynthesis is a combination of the nuclear physics of thermonuclear reactions, and the hydrodynamics of the plasma in which the reactions occur. It depends upon the initial conditions---the stellar evolution up to the explosive instability, and the nature of the explosion mechanism. Some key issues for explosive nucleosynthesis are the interaction of burning with hydrodynamics, the degree of microscopic mixing in convective zones, and the breaking of spherical symmetry by convection and rotation. Recent experiments on high intensity lasers provides new opportunities for laboratory testing of astrophysical hydrodynamic codes. Implications of SN1987A, SN1998bw (GRB980425?), and eta Carina are discussed, as well as the formation of black holes or neutron stars.

  5. Nucleosynthesis in classical novae

    E-Print Network [OSTI]

    M. Hernanz; J. Jose; A. Coc

    2001-01-19

    A general review of the relevance of classical novae for the chemical evolution of the Galaxy, as well as for Galactic radioactivity is presented. A special emphasis is put on the pioneering work done by Jim Truran in this field of research. The impact of recent developments in nuclear astrophysics on nova nucleosynthesis, together with the prospects for observability of novae radioactivities with the INTEGRAL satellite are discussed.

  6. STANDARD BIG BANG NUCLEOSYNTHESIS UP TO CNO WITH AN IMPROVED EXTENDED NUCLEAR NETWORK

    SciTech Connect (OSTI)

    Coc, Alain [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse (CSNSM), CNRS/IN2P3, Universite Paris Sud, UMR 8609, Batiment 104, F-91405 Orsay Campus (France); Goriely, Stephane; Xu, Yi [Institut d'Astronomie et d'Astrophysique, Universite Libre de Bruxelles, CP 226, Boulevard du Triomphe, B-1050 Bruxelles (Belgium); Saimpert, Matthias; Vangioni, Elisabeth [Institut d'Astrophysique de Paris, UMR 7095 CNRS, Universite Pierre et Marie Curie, 98 bis Boulevard Arago, Paris 75014 (France)

    2012-01-10

    Primordial or big bang nucleosynthesis (BBN) is one of the three strong pieces of evidence for the big bang model together with the expansion of the universe and cosmic microwave background radiation. In this study, we improve the standard BBN calculations taking into account new nuclear physics analyses and enlarge the nuclear network up to sodium. This is, in particular, important to evaluate the primitive value of CNO mass fraction that could affect Population III stellar evolution. For the first time we list the complete network of more than 400 reactions with references to the origin of the rates, including Almost-Equal-To 270 reaction rates calculated using the TALYS code. Together with the cosmological light elements, we calculate the primordial beryllium, boron, carbon, nitrogen, and oxygen nuclei. We performed a sensitivity study to identify the important reactions for CNO, {sup 9}Be, and boron nucleosynthesis. We re-evaluated those important reaction rates using experimental data and/or theoretical evaluations. The results are compared with precedent calculations: a primordial beryllium abundance increase by a factor of four compared to its previous evaluation, but we note a stability for B/H and for the CNO/H abundance ratio that remains close to its previous value of 0.7 Multiplication-Sign 10{sup -15}. On the other hand, the extension of the nuclear network has not changed the {sup 7}Li value, so its abundance is still 3-4 times greater than its observed spectroscopic value.

  7. Supernova neutrinos and nucleosynthesis

    E-Print Network [OSTI]

    G. Martínez-Pinedo; T. Fischer; L. Huther

    2013-09-21

    Observations of metal-poor stars indicate that at least two different nucleosynthesis sites contribute to the production of r-process elements. One site is responsible for the production of light r-process elements Zwinds from core-collapse supernova are the main site for the production of these elements. We explore this possibility by performing nucleosynthesis calculations based on long term Boltzmann neutrino transport simulations. They are based on an Equation of State that reproduces recent constrains on the nuclear symmetry energy. We predict that the early ejecta is neutron-rich with Ye ~ 0.48, it becomes proton rich around 4 s and reaches Ye = 0.586 at 9 s when our simulation stops. The nucleosynthesis in this model produces elements between Zn and Mo, including 92Mo. The elemental abundances are consistent with the observations of the metal-poor star HD 12263. For the elements between Ge and Mo, we produce mainly the neutron-deficient isotopes. This prediction can be confirmed by observations of isotopic abundances in metal-poor stars. No elements heavier than Mo (Z=42) and no heavy r-process elements are produced in our calculations.

  8. Explosive Nucleosynthesis in Hypernovae

    E-Print Network [OSTI]

    Takayoshi Nakamura; Hideyuki Umeda; Koichi Iwamoto; Ken'ichi Nomoto; Masa-aki Hashimoto; W. Raphael Hix; Friedrich-Karl Thielemann

    2001-03-25

    We examine the characteristics of nucleosynthesis in 'hypernovae', i.e., supernovae with very large explosion energies ($ \\gsim 10^{52} $ ergs). We carry out detailed nucleosynthesis calculations for these energetic explosions and compare the yields with those of ordinary core-collapse supernovae. We find that both complete and incomplete Si-burning takes place over more extended, lower density regions, so that the alpha-rich freezeout is enhanced and produces more Ti in comparison with ordinary supernova nucleosynthesis. In addition, oxygen and carbon burning takes place in more extended, lower density regions than in ordinary supernovae. Therefore, the fuel elements O, C, Al are less abundant while a larger amount of Si, S, Ar, and Ca ("Si") are synthesized by oxygen burning; this leads to larger ratios of "Si"/O in the ejecta. Enhancement of the mass ratio between complete and incomplete Si-burning regions in the ejecta may explain the abundance ratios among iron-peak elements in metal-poor stars. Also the enhanced "Si"/O ratio may explain the abundance ratios observed in star burst galaxies. We also discuss other implications of enhanced [Ti/Fe] and [Fe/O] for Galactic chemical evolution and the abundances of low mass black hole binaries.

  9. Galactic cosmic rays and nucleosynthesis

    SciTech Connect (OSTI)

    Kiener, Juergen [CSNSM, CNRS-IN2P3 and Universite Paris-Sud, Bat. 104-108, 91405 Orsay Campus (France)

    2010-03-01

    The nucleosynthesis of the light elements Li, Be and B by galactic cosmic rays is presented. Observations of cosmic rays and the nuclear reactions responsible for Li, Be and B nucleosynthesis are described, followed by some words on propagation. At the end, some open questions concerning galactic cosmic rays are discussed.

  10. Neutrinos and Big Bang Nucleosynthesis

    E-Print Network [OSTI]

    A. D. Dolgov

    2002-03-18

    The role of neutrinos in big bang nucleosynthesis is discussed. The bounds on the number of neutrino families, neutrino degeneracy, parameters of neutrino oscillations are presented. A model of chemically inhomogeneous, while energetically smooth, universe created by inhomogeneous cosmological neutrino asymmetry is described. Nucleosynthesis limits on production of right-handed neutrinos are considered.

  11. Nucleosynthesis results from INTEGRAL

    E-Print Network [OSTI]

    G. Weidenspointner

    2006-01-15

    Since its launch in October 2002, ESA's INTEGRAL observatory has enabled significant advances to be made in the study of Galactic nucleosynthesis. In particular, the imaging Ge spectrometer SPI combines for the first time the diagnostic powers of high resolution gamma-ray line spectroscopy and moderate spatial resolution. This review summarizes the major nucleosynthesis results obtained with INTEGRAL so far. Positron annihilation in our Galaxy is being studied in unprecented detail. SPI observations yield the first sky maps in both the 511 keV annihilation line and the positronium continuum emission, and the most accurate spectrum at 511 keV to date, thereby imposing new constraints on the source(s) of Galactic positrons which still remain(s) unidentified. For the first time, the imprint of Galactic rotation on the centroid and shape of the 1809 keV gamma-ray line due to the decay of 26Al has been seen, confirming the Galactic origin of this emission. SPI also provided the most accurate determination of the gamma-ray line flux due to the decay of 60Fe. The combined results for 26Al and 60Fe have important implications for nucleosynthesis in massive stars, in particular Wolf-Rayet stars. Both IBIS and SPI are searching the Galactic plane for young supernova remnants emitting the gamma-ray lines associated with radioactive 44Ti. None have been found so far, which raises important questions concerning the production of 44Ti in supernovae, the Galactic supernova rate, and the Galaxy's chemical evolution.

  12. Pygmy resonances and nucleosynthesis

    E-Print Network [OSTI]

    Nadia Tsoneva; Horst Lenske

    2014-11-14

    A microscopic theoretical approach based on a self-consistent density functional theory for the nuclear ground state and QRPA formalism extended with multi-phonon degrees of freedom for the nuclear excited states is implemented in investigations of new low-energy modes called pygmy resonances. Advantage of the method is the unified description of low-energy multiphonon excitations, pygmy resonances and core polarization effects. This is found of crucial importance for the understanding of the fine structure of nuclear response functions at low energies. Aspects of the precise knowledge of nuclear response functions around the neutron threshold are discussed in a connection to nucleosynthesis.

  13. Nucleosynthesis in stellar flares

    E-Print Network [OSTI]

    V. Tatischeff; J. -P. Thibaud; I. Ribas

    2008-01-11

    Nuclear interactions of ions accelerated at the surface of flaring stars can produce fresh isotopes in stellar atmospheres. Although this nucleosynthesis is not significant for the chemical evolution of the Galaxy, it can be important for a number of measurements of "anomalously" high 6-Li and 7-Li abundances. We discuss the possible role of stellar flares to explain the recent report of high 6-Li abundances in metal-poor halo stars and the well-established correlation between Li abundance and stellar activity in young open clusters. We then study the possibility of observing directly Li production during flares of nearby and active dwarfs of spectral type M.

  14. New Results on Nucleosynthesis in Massive Stars; Nuclear Data Needs for Nucleosynthesis

    E-Print Network [OSTI]

    Rauscher, Thomas

    New Results on Nucleosynthesis in Massive Stars; Nuclear Data Needs for Nucleosynthesis Robert reaction rates needed to study nucleosynthesis in massive stars. Results for the calculated nucleosynthesis( ) © Mg, and their effect on the structure of the star and resultant nucleosynthesis. Both have been

  15. Precision Measurements of d(d,p)t and d(d,n)^3He Total Cross Sections at Big-Bang Nucleosynthesis Energies

    E-Print Network [OSTI]

    D. S. Leonard; H. J. Karwowski; C. R. Brune; B. M. Fisher; E. J. Ludwig

    2006-06-01

    Recent Wilkinson Microwave Anisotropy Probe (WMAP) measurements have determined the baryon density of the Universe $\\Omega_b$ with a precision of about 4%. With $\\Omega_b$ tightly constrained, comparisons of Big Bang Nucleosynthesis (BBN) abundance predictions to primordial abundance observations can be made and used to test BBN models and/or to further constrain abundances of isotopes with weak observational limits. To push the limits and improve constraints on BBN models, uncertainties in key nuclear reaction rates must be minimized. To this end, we made new precise measurements of the d(d,p)t and d(d,n)^3He total cross sections at lab energies from 110 keV to 650 keV. A complete fit was performed in energy and angle to both angular distribution and normalization data for both reactions simultaneously. By including parameters for experimental variables in the fit, error correlations between detectors, reactions, and reaction energies were accurately tabulated by computational methods. With uncertainties around 2% +/- 1% scale error, these new measurements significantly improve on the existing data set. At relevant temperatures, using the data of the present work, both reaction rates are found to be about 7% higher than those in the widely used Nuclear Astrophysics Compilation of Reaction Rates (NACRE). These data will thus lead not only to reduced uncertainties, but also to modifications in the BBN abundance predictions.

  16. Destructions of {sup 7}Be and {sup 7}Li in Big Bang nucleosynthesis through reactions with exotic long-lived sub-strongly interacting massive particles

    SciTech Connect (OSTI)

    Kusakabe, Motohiko; Kawasaki, Masahiro [Institute for Cosmic Ray Research, University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Institute for Cosmic Ray Research, University of Tokyo, Kashiwa, Chiba 277-8582, Japan and Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa, Chiba 277-8582 (Japan)

    2012-11-12

    An observed plateau abundance of {sup 7}Li in metal-poor halo stars indicates its primordial origin. The {sup 7}Li abundances are about a factor of three smaller than that predicted in standard big bang nucleosynthesis (BBN) model. In addition, some of the stars possibly contain {sup 6}Li in abundances larger than standard BBN prediction. Particle models sometimes include heavy longlived colored particles which are confined in exotic strongly interacting massive particles (SIMPs). We have found reactions which destroy {sup 7}Be and {sup 7}Li during BBN in the scenario of BBN affected by a long-lived sub-strongly interactingmassive particle (sub-SIMP, X). The reactions are non radiative X captures of {sup 7}Be and {sup 7}Li which can operate if the X particle interacts with nuclei strongly enough to drive {sup 7}Be destruction but not strongly enough to form a bound state with {sup 4}He of relative angular momentum L = 1. The processes can be a cause of the {sup 7}Li problem. In this paper we suggest new possible reactions for {sup 6}Li production. Especially, a {sup 6}Li production through the deuteron capture of {sup 4}He bound to X can operate in the parameter region solving the {sup 7}Li problem.

  17. Nucleosynthesis in slowly evolving Cosmologies

    E-Print Network [OSTI]

    Pranav Kumar; Daksh Lohiya

    2008-02-08

    We explore aspects of Cosmological Nucleosynthesis in an FRW universe in which the scale factor evolves linearly with time: $a(t) \\sim t$. A high Lepton number density during the period when significant nucleosynthesis takes place would lead to a dominant screening of the Coulomb potential of colliding nucleii. This would lead to a significant enhancement of nucleosynthesis rates. We demonstrate how adequate amount of $^4He$ and a collataral metallicity, close to the lowest metallicity observed in metal poor Pop II stars and clouds, can be produced with such an evolution.

  18. Neutrinos and Nucleosynthesis in Supernova

    E-Print Network [OSTI]

    U. Solis; J. C. D'Olivo; L. G. Cabral-Rosetti

    2005-11-12

    The type II supernova is considered as a candidate site for the production of heavy elements. The nucleosynthesis occurs in an intense neutrino flux, we calculate the electron fraction in this environment.

  19. Nucleosynthesis In Core Collapse Supernovae

    E-Print Network [OSTI]

    M. Limongi; A. Chieffi

    2006-01-10

    We present the basic properties of the yields of our latest set of presupernova evolution and explosive nucleosynthesis of massive stars in the range between 11 and 120 Msun having solar and zero metallicity.

  20. A revised thermonuclear rate of $^{7}$Be($n$,$\\alpha$)$^{4}$He relevant to Big-Bang nucleosynthesis

    E-Print Network [OSTI]

    Hou, S Q; Kubono, S; Chen, Y S

    2015-01-01

    In the standard Big-Bang nucleosynthesis (BBN) model, the primordial $^7$Li abundance is overestimated by about a factor of 2--3 comparing to the astronomical observations, so called the pending cosmological lithium problem. The $^7$Be($n$,$\\alpha$)$^4$He reaction, which may affect the $^7$Li abundance, was regarded as the secondary important reaction in destructing the $^7$Be nucleus in BBN. However, the thermonuclear rate of $^7$Be($n$,$\\alpha$)$^4$He has not been well studied so far. This reaction rate was firstly estimated by Wagoner in 1969, which has been generally adopted in the current BBN simulations and the reaction rate library. This simple estimation involved only a direct-capture reaction mechanism, but the resonant contribution should be also considered according to the later experimental results. In this work, we have revised this rate based on the indirect cross-section data available for the $^4$He($\\alpha$,$n$)$^7$Be and $^4$He($\\alpha$,$p$)$^7$Li reactions, with the charge symmetry and deta...

  1. Big Bang Nucleosynthesis and the Helium Isotope Ratio

    E-Print Network [OSTI]

    Cooke, Ryan

    2015-01-01

    The conventional approach to search for departures from the standard model of physics during Big Bang Nucleosynthesis involves a careful, and subtle measurement of the mass fraction of baryons consisting of helium. Recent measurements of this quantity tentatively support new physics beyond the standard model but, historically, this method has suffered from hidden systematic uncertainties. In this letter, I show that a combined measurement of the primordial deuterium abundance and the primordial helium isotope ratio has the potential to provide a complementary and reliable probe of new physics beyond the standard model. Using the recent determination of the primordial deuterium abundance and assuming that the measured pre-solar 3He/4He meteoritic abundance reflects the primordial value, a bound can be placed on the effective number of neutrino species, Neff(BBN) = 3.01 (+0.95 -0.76, with 95 per cent confidence). Although this value of Neff supports the standard model, it is presently unclear if the pre-solar 3...

  2. A revised thermonuclear rate of $^{7}$Be($n$,$?$)$^{4}$He relevant to Big-Bang nucleosynthesis

    E-Print Network [OSTI]

    S. Q. Hou; J. J. He; S. Kubono; Y. S. Chen

    2015-02-13

    In the standard Big-Bang nucleosynthesis (BBN) model, the primordial $^7$Li abundance is overestimated by about a factor of 2--3 comparing to the astronomical observations, so called the pending cosmological lithium problem. The $^7$Be($n$,$\\alpha$)$^4$He reaction, which may affect the $^7$Li abundance, was regarded as the secondary important reaction in destructing the $^7$Be nucleus in BBN. However, the thermonuclear rate of $^7$Be($n$,$\\alpha$)$^4$He has not been well studied so far. This reaction rate was firstly estimated by Wagoner in 1969, which has been generally adopted in the current BBN simulations and the reaction rate library. This simple estimation involved only a direct-capture reaction mechanism, but the resonant contribution should be also considered according to the later experimental results. In this work, we have revised this rate based on the indirect cross-section data available for the $^4$He($\\alpha$,$n$)$^7$Be and $^4$He($\\alpha$,$p$)$^7$Li reactions, with the charge symmetry and detailed-balance principle. Our new result shows that the previous rate (acting as an upper limit) is overestimated by about a factor of ten. The BBN simulation shows that the present rate leads to a 1.2\\% increase in the final $^7$Li abundance compared to the result using the Wagoner rate, and hence the present rate even worsens the $^7$Li problem. By the present estimation, the role of $^7$Be($n$,$\\alpha$)$^4$He in destroying $^7$Be is weakened from the secondary importance to the third, and the $^7$Be($d$,$p$)2$^4$He reaction becomes of secondary importance in destructing $^7$Be.

  3. New effects of a long-lived negatively charged massive particle on big bang nucleosynthesis

    SciTech Connect (OSTI)

    Kusakabe, Motohiko [School of Liberal Arts and Science, Korea Aerospace University, Goyang 412-791, Korea and Department of Physics, Soongsil University, Seoul 156-743 (Korea, Republic of); Kim, K. S. [School of Liberal Arts and Science, Korea Aerospace University, Goyang 412-791 (Korea, Republic of); Cheoun, Myung-Ki [Department of Physics, Soongsil University, Seoul 156-743 (Korea, Republic of); Kajino, Toshitaka [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan and Department of Astronomy, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Kino, Yasushi [Department of Chemistry, Tohoku University, Sendai 980-8578 (Japan); Mathews, Grant J. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan and Center for Astrophysics, Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States)

    2014-05-02

    Primordial {sup 7}Li abundance inferred from observations of metal-poor stars is a factor of about 3 lower than the theoretical value of standard big bang nucleosynthesis (BBN) model. One of the solutions to the Li problem is {sup 7}Be destruction during the BBN epoch caused by a long-lived negatively charged massive particle, X{sup ?}. The particle can bind to nuclei, and X-bound nuclei (X-nuclei) can experience new reactions. The radiative X{sup ?} capture by {sup 7}Be nuclei followed by proton capture of the bound state of {sup 7}Be and X{sup ?} ({sup 7}Be{sub x}) is a possible {sup 7}Be destruction reaction. Since the primordial abundance of {sup 7}Li originates mainly from {sup 7}Li produced via the electron capture of {sup 7}Be after BBN, the {sup 7}Be destruction provides a solution to the {sup 7}Li problem. We suggest a new route of {sup 7}Be{sub x} formation, that is the {sup 7}Be charge exchange at the reaction of {sup 7}Be{sup 3+} ion and X{sup ?}. The formation rate depends on the ionization fraction of {sup 7}Be{sup 3+} ion, the charge exchange cross section of {sup 7}Be{sup 3+}, and the probability that excited states {sup 7}Be{sub x}* produced at the charge exchange are converted to the ground state. We find that this reaction can be equally important as or more important than ordinary radiative recombination of {sup 7}Be and X{sup ?}. The effect of this new route is shown in a nuclear reaction network calculation.

  4. Neutron Capture Nucleosynthesis in Early Galactic Environments #

    E-Print Network [OSTI]

    Cowan, John

    Neutron Capture Nucleosynthesis in Early Galactic Environments # James W. Truran 1 , John J. Cowan we can extract useful clues to and constraints upon the star formation and nucleosynthesis history that provide the site for s­process nucleosynthesis during the AGB phase of their evolution. We review recent

  5. Nucleosynthesis in AGB Stars Maria Lugaro

    E-Print Network [OSTI]

    Nucleosynthesis in AGB Stars Maria Lugaro A thesis submitted for the degree of Doctor of Philosophy.1 Evolution prior and through the AGB phase . . . . . . . . . . . . . . . 1 1.2 Nucleosynthesis and mixing and models 15 2.1 The Monash Stellar Nucleosynthesis code . . . . . . . . . . . . . . . . . 15 2.1.1 Nuclear

  6. Nucleosynthesis in AGB Stars John Lattanzio

    E-Print Network [OSTI]

    Lattanzio, John

    Nucleosynthesis in AGB Stars John Lattanzio Dept of Mathematics and Statistics, Monash University of the nucleosynthesis occurring in AGB stars. We the summarise some new calculations of intermediate mass stars which include all thermal pulses until the star is about to leave the AGB, as well as a detailed nucleosynthesis

  7. Nucleosynthesis in a simmering univeerse

    E-Print Network [OSTI]

    Daksh Lohiya; Annu Batra; Shobhit Mahajan; Amitabha Mukherjee

    1998-08-11

    Primordial nucleosynthesis is considered a success story of the standard big bang (SBB) cosmology. The cosmological and elementary particle physics parameters are believed to be severely constrained by the requirement of correct abundances of light elements. We explore nucleosynthesis in a class of models very different from SBB. In these models the cosmological scale factor increases linearly with time right through the period during which nucleosynthesis occurs till the present. It turns out that weak interactions remain in thermal equilibrium upto temperatures which are two orders of magnitude lower than the corresponding (weak interaction decoupling) temperature in SBB. Inverse beta decay of the proton can ensure adequate production of several light elements while producing primordial metalicity much higher than that produced in SBB. Other attractive features of these models are the absence of the horizon, flatness and the age problems and consistency with classical cosmological tests.

  8. Nucleosynthesis in a Simmering Universe

    E-Print Network [OSTI]

    Daksh Lohiya; Shobhit Mahajan; A. Mukherjee; Annu Batra

    1996-06-13

    Primordial nucleosynthesis is considered a success story of the standard big bang (SBB) cosmology. The cosmological and elementary particle physics parameters are believed to be severely constrained by the requirement of correct abundances of light elements. We demonstrate nucleosynthesis in a class of models very different from SBB. In these models the cosmological scale factor increases linearly with time from the period during which nucleosynthesis occurs. It turns out that weak interactions remain in thermal equilibrium upto temperatures which are two orders of magnitude lower than the corresponding temperatures in SBB. Inverse beta decay of the proton can ensure adequate production of several light elements while producing primordial metallicity much higher than that produced in SBB. Other attractive features of these models are the absence of the horizon, flatness and initial singularity problems, consistency with the age of globular clusters and consistent relationships between redshift and luminosity distance, angular diameter distance and the galaxy number count.

  9. Chemical interaction in the B-BN system at high pressures and temperatures

    SciTech Connect (OSTI)

    Solozhenko, Vladimir L.; Kurakevych, Oleksandr O.

    2009-06-15

    Chemical interaction and phase transformations in the B-BN system have been in situ studied by X-ray diffraction with synchrotron radiation at pressures up to 5.3 GPa and temperatures up to 2800 K using multianvil press. New rhombohedral boron subnitride B{sub 13}N{sub 2} has been synthesized by crystallization from the B-BN melt at 5 GPa. The structure of B{sub 13}N{sub 2} belongs to the R-3m space group (a=5.4455(2) A, c=12.2649(9) A) and represents a new structural type. The subnitride is an individual compound and not a solid solution, in contrast to boron carbide. Besides, the formation of two other boron-rich B-N phases denoted as 'B{sub 6}N' and 'B{sub 50}N{sub 2}' has been observed. Their structures seem to be much more sophisticated and have not been even resolved to present time. - Graphical abstract: Chemical interaction and phase transformations in the B-BN system have been in situ studied by X-ray diffraction with synchrotron radiation at pressures up to 5.3 GPa and temperatures up to 2800 K using multianvil press. Three boron subnitrides have been synthesized and characterized.

  10. Modified GR and Helium Nucleosynthesis

    E-Print Network [OSTI]

    A. S. Al-Rawaf

    2006-06-12

    We show that a previously proposed cosmological model based on general relativity with non vanishing divergence for the energy-momentum tensor is consistent with the observed values for the nucleosynthesis of helium for some values of the arbitrary parameter $\\alpha$ presented in this model. Further more values of $\\alpha$ can be accommodated if we adopt the Randall-Sundrum single brane model.

  11. Nucleosynthesis in Type II Supernovae

    E-Print Network [OSTI]

    K. Nomoto; M. Hashimoto; T. Tsujimoto; F. -K. Thielemann; N. Kishimoto; Y. Kubo

    1997-06-03

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

  12. HOW MANY NUCLEOSYNTHESIS PROCESSES EXIST AT LOW METALLICITY?

    SciTech Connect (OSTI)

    Hansen, C. J. [Landessternwarte, ZAH, Heidelberg University, Königstuhl 12, D-69117 Heidelberg (Germany); Montes, F. [Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, MI 48824 (United States); Arcones, A., E-mail: cjhansen@lsw.uni-heidelberg.de, E-mail: cjhansen@dark-cosmology.dk, E-mail: montes@nscl.msu.edu, E-mail: almudena.arcones@physik.tu-darmstadt.de [Institut für Kernphysik, Technische Universität Darmstadt, Schlossgartenstr. 2, Darmstadt D-64289 (Germany)

    2014-12-20

    Abundances of low-metallicity stars offer a unique opportunity to understand the contribution and conditions of the different processes that synthesize heavy elements. Many old, metal-poor stars show a robust abundance pattern for elements heavier than Ba, and a less robust pattern between Sr and Ag. Here we probe if two nucleosynthesis processes are sufficient to explain the stellar abundances at low metallicity, and we carry out a site independent approach to separate the contribution from these two processes or components to the total observationally derived abundances. Our approach provides a method to determine the contribution of each process to the production of elements such as Sr, Zr, Ba, and Eu. We explore the observed star-to-star abundance scatter as a function of metallicity that each process leads to. Moreover, we use the deduced abundance pattern of one of the nucleosynthesis components to constrain the astrophysical conditions of neutrino-driven winds from core-collapse supernovae.

  13. HydrodynamicallyBased Overshoot Treatment and Nucleosynthesis

    E-Print Network [OSTI]

    Hydrodynamically­Based Overshoot Treatment and Nucleosynthesis in AGB Stars F. Herwig 1 , T. Bl dominated by 12 C. This leads to the nucleosynthesis of 13 C via 12 C(p; fl) 13 N(fi; + š) 13 C and is prob­ ably the major source of neutrons ( 13 C(ff; n) 16 O) for subsequent s­process nucleosynthesis. We

  14. Undergraduate offer guide 2 Undergraduate Offer Guide

    E-Print Network [OSTI]

    Miall, Chris

    Undergraduate offer guide 2015­2016 #12;2 Undergraduate Offer Guide YOUR OFFER, YOUR GUIDE AS A BIRMINGHAM STUDENT, ALONG WITH A GUIDE TO THE NEXT STEPS IN THE PROCESS. Your offer letter and offer guide have been delivered. Take a moment to read the `Your offer explained' section to make sure you

  15. Nucleosynthesis in Early Neutrino Driven Winds

    E-Print Network [OSTI]

    R. D. Hoffman; J. L. Fisker; J. Pruet; S. E. Woosley; H. -T. Janka; R. Buras

    2008-01-11

    Nucleosynthesis in early neutrino winds is investigated. Presented is a brief overview of two recent problems of supernova nucleosynthesis. In the first part we investigate the effect of nuclear parameters on the synthesis of Mo92 and Mo94. Based on recent experimental results, we find that the proton rich winds of the model investigated here can not be the source of solar Mo92 and Mo94. In the second part we investigate the nucleosynthesis from neutron rich bubbles and show that they do not contribute to the overall nucleosynthesis.

  16. Big Bang Nucleosynthesis and the Helium Isotope Ratio

    E-Print Network [OSTI]

    Ryan Cooke

    2015-10-09

    The conventional approach to search for departures from the standard model of physics during Big Bang Nucleosynthesis involves a careful, and subtle measurement of the mass fraction of baryons consisting of helium. Recent measurements of this quantity tentatively support new physics beyond the standard model but, historically, this method has suffered from hidden systematic uncertainties. In this letter, I show that a combined measurement of the primordial deuterium abundance and the primordial helium isotope ratio has the potential to provide a complementary and reliable probe of new physics beyond the standard model. Using the recent determination of the primordial deuterium abundance and assuming that the measured pre-solar 3He/4He meteoritic abundance reflects the primordial value, a bound can be placed on the effective number of neutrino species, Neff(BBN) = 3.01 (+0.95 -0.76, with 95 per cent confidence). Although this value of Neff supports the standard model, it is presently unclear if the pre-solar 3He/4He ratio reflects the primordial value. New astrophysical measurements of the helium isotope ratio in near-pristine environments, together with updated calculations and experimental values of several important nuclear reactions (some of which are already being attempted), will lead to much improved limits on possible departures from the standard model. To this end, I describe an analysis strategy to measure the 3He I flux emitted from nearby low metallicity H II regions. The proposed technique can be attempted with the next generation of large telescopes, and will be easier to realize in metal-poor H II regions with quiescent kinematics.

  17. Quark mass variation constraints from Big Bang nucleosynthesis...

    Office of Scientific and Technical Information (OSTI)

    Quark mass variation constraints from Big Bang nucleosynthesis Citation Details In-Document Search Title: Quark mass variation constraints from Big Bang nucleosynthesis We study...

  18. Big-Bang Nucleosynthesis and Gamma-Ray Constraints on Cosmic Strings with a large Higgs condensate

    E-Print Network [OSTI]

    H. F. Santana Mota; Mark Hindmarsh

    2015-01-06

    We consider constraints on cosmic strings from their emission of Higgs particles, in the case that the strings have a Higgs condensate with amplitude of order the string mass scale, assuming that a fraction of the energy of condensate can be turned into radiation near cusps. The injection of energy by the decaying Higgs particles affects the light element abundances predicted by standard Big-Bang Nucleosynthesis (BBN), and also contributes to the Diffuse Gamma-Ray Background (DGRB) in the universe today. We examine the two main string scenarios (Nambu-Goto and field theory), and find that the primordial Helium abundance strongly constrains the string tension and the efficiency of the emission process in the NG scenario, while the strongest BBN constraint in the FT scenario comes from the Deuterium abundance. The Fermi-LAT measurement of the DGRB constrains the field theory scenario even more strongly than previously estimated from EGRET data, requiring that the product of the string tension {\\mu} and Newton's constant G is bounded by G{\\mu} < 2.7x10^{-11}{\\beta}_{ft}^{-2}, where {\\beta}_{ft}^2 is the fraction of the strings' energy going into Higgs particles.

  19. Nuclear Reactions For Nucleosynthesis Beyond Fe

    E-Print Network [OSTI]

    Rauscher, T

    2015-01-01

    Many more nuclear transitions have to be known in the determination of stellar reactivities for trans-iron nucleosynthesis than for reactions of light nuclei. This requires different theoretical and experimental approaches. Some of the issues specific for trans-iron nucleosynthesis are discussed.

  20. Nuclear Reactions For Nucleosynthesis Beyond Fe

    E-Print Network [OSTI]

    T. Rauscher

    2015-08-26

    Many more nuclear transitions have to be known in the determination of stellar reactivities for trans-iron nucleosynthesis than for reactions of light nuclei. This requires different theoretical and experimental approaches. Some of the issues specific for trans-iron nucleosynthesis are discussed.

  1. Neutrino-induced nucleosynthesis of A>64 nuclei: The nu p-process

    E-Print Network [OSTI]

    C. Fröhlich; G. Martínez-Pinedo; M. Liebendörfer; F. -K. Thielemann; E. Bravo; W. R. Hix; K. Langanke; N. T. Zinner

    2005-11-12

    We present a new nucleosynthesis process, that we denote nu p-process, which occurs in supernovae (and possibly gamma-ray bursts) when strong neutrino fluxes create proton-rich ejecta. In this process, antineutrino absorptions in the proton-rich environment produce neutrons that are immediately captured by neutron-deficient nuclei. This allows for the nucleosynthesis of nuclei with mass numbers A >64. Making this process a possible candidate to explain the origin of the solar abundances of 92,94Mo and 96,98Ru. This process also offers a natural explanation for the large abundance of Sr seen in an hyper-metal-poor star.

  2. From (p)reheating to nucleosynthesis

    E-Print Network [OSTI]

    Karsten Jedamzik

    2001-12-10

    This article gives a brief qualitative description of the possible evolution of the early Universe between the end of an inflationary epoch and the end of Big Bang nucleosynthesis. After a general introduction, establishing the minimum requirements cosmologists impose on this cosmic evolutionary phase, namely, successful baryogenesis, the production of cosmic dark matter, and successful light-element nucleosynthesis, a more detailed discussion on some recent developments follows. This latter includes the physics of preheating, the putative production of (alternative) dark matter, and the current status of Big Bang nucleosynthesis.

  3. Neutrino Nucleosynthesis of radioactive nuclei in supernovae

    E-Print Network [OSTI]

    Sieverding, A; Langanke, K; Martínez-Pinedo, G; Heger, A

    2015-01-01

    We study the neutrino-induced production of nuclides in explosive supernova nucleosynthesis for progenitor stars with solar metallicity and initial main sequence masses between 15 M$_\\odot$ and 40 M$_\\odot$. We improve previous investigations i) by using a global set of partial differential cross sections for neutrino-induced charged- and neutral-current reactions on nuclei with charge numbers $Z nucleosynthesis studies. We confirm the production of $^7$Li, $^{11}$B, $^{138}$La, and $^{180}$Ta by neutrino nucleosynthesis, albeit at slightly smaller abundances due to the changed neutrino spectra. We find that for stars with a mass smaller than 20 M$_\\odot$, $^{19}$F is produced mainly by explosive nucleosynthesis while for higher mass stars it is produced by the $\

  4. Nucleosynthesis in O-Ne-Mg Supernovae

    E-Print Network [OSTI]

    R. D. Hoffman; B. Muller; H. -T. Janka

    2007-12-27

    We have studied detailed nucleosynthesis in the shocked surface layers of an Oxygen-Neon-Magnesium core collapse supernova with an eye to determining if the conditions are suitable for r process nucleosynthesis. We find no such conditions in an unmodified model, but do find overproduction of N=50 nuclei (previously seen in early neutron-rich neutrino winds) in amounts that, if ejected, would pose serious problems for galactic chemical evolution.

  5. Proton-rich nucleosynthesis and nuclear physics

    SciTech Connect (OSTI)

    Rauscher, T.; Froehlich, C. [Dept. of Physics, University of Basel, 4056 Basel (Switzerland); Dept. of Physics, NCSU, Raleigh, NC 27695 (United States)

    2012-11-12

    Although the detailed conditions for explosive nucleosynthesis are derived from astrophysical modeling, nuclear physics determines fundamental patterns in abundance yields, not only for equilibrium processes. Focussing on the {nu}p- and the {gamma}-process, general nucleosynthesis features within the range of astrophysical models, but (mostly) independent of details in the modelling, are presented. Remaining uncertainties due to uncertain Q-values and reaction rates are discussed.

  6. Nucleosynthesis in O-Ne-Mg Supernovae

    SciTech Connect (OSTI)

    Hoffman, R D; Janka, H; Muller, B

    2007-12-18

    We have studied detailed nucleosynthesis in the shocked surface layers of an oxygen-neon-magnesium core collapse supernova with an eye to determining whether the conditions are suitable for r-process nucleosynthesis. We find no such conditions in an unmodified model, but do find overproduction of N=50 nuclei (previously seen in early neutron-rich neutrino winds) in amounts that, if ejected, would pose serious problems for Galactic chemical evolution.

  7. Supernova neutrinos and explosive nucleosynthesis

    SciTech Connect (OSTI)

    Kajino, T. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan and Department of Astronomy, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033 (Japan); Aoki, W. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Cheoun, M.-K. [Department of Physics, Soongsil University, Seoul 156-743 (Korea, Republic of); Hayakawa, T. [Japan Atomic Energy Agency, Shirakara-Shirane 2-4, Tokai-mura, Ibaraki 319-1195 (Japan); Hidaka, J.; Hirai, Y.; Shibagaki, S. [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Mathews, G. J. [Center for Astrophysics, Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Nakamura, K. [Faculty of Science and Engineering, Waseda University, Ohkubo 3-4-1, Shinjuku, Tokyo 169-8555 (Japan); Suzuki, T. [Department of Physics, College of Humanities and Sciences, Nihon University, Sakurajosui 3-25-40, Setagaya-ku, Tokyo 156-8550 (Japan)

    2014-05-09

    Core-collapse supernovae eject huge amount of flux of energetic neutrinos. We studied the explosive nucleosyn-thesis in supernovae and found that several isotopes {sup 7}Li, {sup 11}B, {sup 92}Nb, {sup 138}La and {sup 180}Ta as well as r-process nuclei are affected by the neutrino interactions. The abundance of these isotopes therefore depends strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. We discuss first how to determine the neutrino temperatures in order to explain the observed solar system abundances of these isotopes, combined with Galactic chemical evolution of the light nuclei and the heavy r-process elements. We then study the effects of neutrino oscillation on their abundances, and propose a novel method to determine the still unknown neutrino oscillation parameters, mass hierarchy and ?{sub 13}, simultaneously. There is recent evidence that SiC X grains from the Murchison meteorite may contain supernova-produced light elements {sup 11}B and {sup 7}Li encapsulated in the presolar grains. Combining the recent experimental constraints on ?{sub 13}, we show that our method sug-gests at a marginal preference for an inverted neutrino mass hierarchy. Finally, we discuss supernova relic neutrinos that may indicate the softness of the equation of state (EoS) of nuclear matter as well as adiabatic conditions of the neutrino oscillation.

  8. Nucleosynthesis in Type Ia Supernovae

    E-Print Network [OSTI]

    K. Nomoto; K. Iwamoto; N. Nakasato; F. -K. Thielemann; F. Brachwitz; T. Tsujimoto; Y. Kubo; N. Kishimoto

    1997-06-03

    Among the major uncertainties involved in the Chandrasekhar mass models for Type Ia supernovae are the companion star of the accreting white dwarf (or the accretion rate that determines the carbon ignition density) and the flame speed after ignition. We present nucleosynthesis results from relatively slow deflagration (1.5 - 3 % of the sound speed) to constrain the rate of accretion from the companion star. Because of electron capture, a significant amount of neutron-rich species such as ^{54}Cr, ^{50}Ti, ^{58}Fe, ^{62}Ni, etc. are synthesized in the central region. To avoid the too large ratios of ^{54}Cr/^{56}Fe and ^{50}Ti/^{56}Fe, the central density of the white dwarf at thermonuclear runaway must be as low as \\ltsim 2 \\e9 \\gmc. Such a low central density can be realized by the accretion as fast as $\\dot M \\gtsim 1 \\times 10^{-7} M_\\odot yr^{-1}$. These rapidly accreting white dwarfs might correspond to the super-soft X-ray sources.

  9. Second-chance offers

    E-Print Network [OSTI]

    Garratt, Rodney J.; Troger, Thomas

    2013-01-01

    B J (2008), ‘Second chance offers versus sequential auc-Second-chance offers By Rodney J. Garratt and ThomasWe study the second-price offer feature of eBay auctions in

  10. Neutron-capture nucleosynthesis in the first stars

    SciTech Connect (OSTI)

    Roederer, Ian U. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Preston, George W.; Thompson, Ian B.; Shectman, Stephen A. [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Sneden, Christopher, E-mail: iur@umich.edu [Department of Astronomy, University of Texas at Austin, 1 University Station C1400, Austin, TX 78712 (United States)

    2014-04-01

    Recent studies suggest that metal-poor stars enhanced in carbon but containing low levels of neutron-capture elements may have been among the first to incorporate the nucleosynthesis products of the first generation of stars. We have observed 16 stars with enhanced carbon or nitrogen using the MIKE Spectrograph on the Magellan Telescopes at Las Campanas Observatory and the Tull Spectrograph on the Smith Telescope at McDonald Observatory. We present radial velocities, stellar parameters, and detailed abundance patterns for these stars. Strontium, yttrium, zirconium, barium, europium, ytterbium, and other heavy elements are detected. In four stars, these heavy elements appear to have originated in some form of r-process nucleosynthesis. In one star, a partial s-process origin is possible. The origin of the heavy elements in the rest of the sample cannot be determined unambiguously. The presence of elements heavier than the iron group offers further evidence that zero-metallicity rapidly rotating massive stars and pair instability supernovae did not contribute substantial amounts of neutron-capture elements to the regions where the stars in our sample formed. If the carbon- or nitrogen-enhanced metal-poor stars with low levels of neutron-capture elements were enriched by products of zero-metallicity supernovae only, then the presence of these heavy elements indicates that at least one form of neutron-capture reaction operated in some of the first stars.

  11. High-energy break-up of 6Li as a tool to study the Big-Bang nucleosynthesis reaction 2H(alpha,gamma)6Li

    E-Print Network [OSTI]

    F. Hammache; M. Heil; S. Typel; D. Galaviz; K. Sümmerer; A. Coc; F. Uhlig; F. Attallah; M. Caamano; D. Cortina; H. Geissel; M. Hellström; N. Iwasa; J. Kiener; P. Koczon; B. Kohlmeyer; P. Mohr; E. Schwab; K. Schwarz; F. Schümann; P. Senger; O. Sorlin; V. Tatischeff; J. P. Thibaud; E. Vangioni; A. Wagner; W. Walus

    2010-11-29

    The recently claimed observations of non-negligible amounts of 6Li in old halo stars have renewed interest in the Big-Bang Nucleosynthesis (BBN) of 6Li. One important ingredient in the predicted BBN abundance of 6Li is the low-energy 2H(alpha,gamma)6Li cross section. Up to now, the only available experimental result for this cross section showed an almost constant astrophysical S-factor below 400 keV, contrary to theoretical expectations. We report on a new measurement of the 2H(alpha,gamma)6Li reaction using the break-up of 6Li at 150 A MeV. Even though we cannot separate experimentally the Coulomb contribution from the nuclear one, we find clear evidence for Coulomb-nuclear interference by analyzing the scattering-angular distributions. This is in-line with our theoretical description which indicates a drop of the S_24-factor at low energies as predicted also by most other models. Consequently, we find even lower upper limits for the calculated primordial 6Li abundance than before.

  12. Lecture Notes on CMB Theory: From Nucleosynthesis to Recombination

    E-Print Network [OSTI]

    Hu, Wayne

    Lecture Notes on CMB Theory: From Nucleosynthesis to Recombination by Wayne Hu arXiv:0802.3688v1[astro-ph]25Feb2008 #12;Contents CMB Theory from Nucleosynthesis to Recombination page 1 1 Introduction 1 2 Brief Thermal History 1 2.1 Nucleosynthesis and Prediction of the CMB 1 2.2 Thermalization

  13. Abundance Ratio Trends and Nucleosynthesis in Elliptical Galaxies and Spheroids

    E-Print Network [OSTI]

    Worthey, Guy

    Abundance Ratio Trends and Nucleosynthesis in Elliptical Galaxies and Spheroids Guy Worthey 1, nucleosynthesis, abundances --- galaxies: abundances --- galaxies: elliptical and lenticular, cD --- galaxies of the discussion to other elements in section 3. The fourth section discusses nucleosynthesis and possible hints

  14. IMPLICATIONS OF NON-MAXWELLIAN DISTRIBUTIONS ON BIG BANG NUCLEOSYNTHESIS

    E-Print Network [OSTI]

    Bertulani, Carlos A. - Department of Physics and Astronomy, Texas A&M University

    #12;IMPLICATIONS OF NON-MAXWELLIAN DISTRIBUTIONS ON BIG BANG NUCLEOSYNTHESIS A Thesis by JOHN FUQUA ON BIG BANG NUCLEOSYNTHESIS A Thesis by JOHN FUQUA Approved by: Advisor: Carlos Bertulani Committee-MAXWELLIAN DISTRIBUTIONS ON BIG BANG NUCLEOSYNTHESIS John Fuqua, MS Texas A&M University-Commerce, 2013 Advisor: Carlos

  15. Nucleosynthesis and the Chemical Evolution of the Universe

    E-Print Network [OSTI]

    Liske, Jochen

    AS2001 Nucleosynthesis and the Chemical Evolution of the Universe Tutorial 3 ­ Answers Question 1. Primordial nucleosynthesis ­ neutrons and protons get together to form the light nuclei D, 3 He, 4 He and 7 instability. Stellar nucleosynthesis ­ all other elements are synthesized inside stars or during supernova

  16. Deuterium Nucleosynthesis in AGN: Is D Cosmological? D. A. Lubowicha

    E-Print Network [OSTI]

    Millar, Tom

    Deuterium Nucleosynthesis in AGN: Is D Cosmological? D. A. Lubowicha , N. Kunob , H. Robertsc , T or cosmic-ray luminosity > 1042 erg/s. If jet-cloud nucleosynthesis produces significant amounts of D on the temperature and baryonic density during the epoch of nucleosynthesis (first 1000 seconds). Thus any

  17. SUPERNOVA NUCLEOSYNTHESIS AS A TOOL TO ANALYZE THE EXPLOSION MECHANISM

    E-Print Network [OSTI]

    Rauscher, Thomas

    SUPERNOVA NUCLEOSYNTHESIS AS A TOOL TO ANALYZE THE EXPLOSION MECHANISM F.­K. Thielemann 1;4 , F for the explosion and ejection of matter. This affects the nucleosynthesis products via two main uncertainties, (i energy responsible for explosive nucleosynthesis. Thus, observations can constrain these quantities. Type

  18. Primordial nucleosynthesis: A cosmological point of view

    SciTech Connect (OSTI)

    Mathews, G. J.; Kusakabe, M.; Cheoun, M.-K.

    2014-05-09

    Primordial nucleosynthesis remains as one of the pillars of modern cosmology. It is the test-ing ground upon which all cosmological models must ultimately rest. It is our only probe of the universe during the first few minutes of cosmic expansion and in particular during the important radiation-dominated epoch. These lectures review the basic equations of space-time, cosmology, and big bang nucleosynthesis. We will then review the current state of observational constraints on primordial abundances along with the key nuclear reactions and their uncertainties. We summarize which nuclear measure-ments are most crucial during the big bang. We also review various cosmological models and their constraints. In particular, we summarize the constraints that big bang nucleosynthesis places upon the possible time variation of fundamental constants, along with constraints on the nature and origin of dark matter and dark energy, long-lived supersymmetric particles, gravity waves, and the primordial magnetic field.

  19. The connection between mass loss and nucleosynthesis

    E-Print Network [OSTI]

    Jacco Th. van Loon

    2008-01-03

    I discuss the relationship between mass loss and nucleosynthesis on the Asymptotic Giant Branch (AGB). Because of thermal pulses and possibly other mixing processes, products of nucleosynthesis can be brought to the surface of AGB stars, increasingly so as the star becomes more luminous, cooler, and unstable against pulsation of its tenuous mantle. As a result, mass loss is at its most extreme when dredge-up is too. As the high rate of mass loss truncates AGB evolution, it determines the enrichment of interstellar space with the AGB nucleosynthesis products. The changing composition of the stellar atmosphere also affects the mass-loss process, most obviously in the formation of dust grains - which play an important role in driving the wind of AGB stars.

  20. Nucleosynthesis in intermediate mass AGB stars

    E-Print Network [OSTI]

    John Lattanzio; Corinne Charbonnel; Manuel Forestini

    1999-12-15

    We present a summary of the main sites for nucleosynthesis in intermediate mass Asymptotic Giant Branch (AGB) stars. We then discuss some detailed evolutionary models and how these have been used to create a synthetic evolution code which calculates the nucleosynthesis very rapidly, enabling us to investigate changes in some uncertain parameters in AGB evolution, such as mass-loss and dredge-up. We then present results for C, C/O, Mg and Al. We also discuss the changes due to the recent NACRE compilation of reaction rates.

  1. Relating gravitational wave constraints from primordial nucleosynthesis, pulsar timing, laser interferometers, and the CMB: implications for the early universe

    E-Print Network [OSTI]

    Latham A. Boyle; Alessandra Buonanno

    2007-08-18

    We derive a general master equation relating the gravitational-wave observables r and Omega_gw(f). Here r is the tensor-to-scalar ratio, constrained by cosmic-microwave-background (CMB) experiments; and Omega_gw(f) is the energy spectrum of primordial gravitational-waves, constrained e.g. by pulsar-timing measurements, laser-interferometer experiments, and Big Bang Nucleosynthesis (BBN). Differentiating the master equation yields a new expression for the tilt d(ln Omega_gw(f))/d(ln f). The relationship between r and Omega_gw(f) depends sensitively on the uncertain physics of the early universe, and we show that this uncertainty may be encapsulated (in a model-independent way) by two quantities: w_hat(f) and nt_hat(f), where nt_hat(f) is a certain logarithmic average over nt(k) (the primordial tensor spectral index); and w_hat(f) is a certain logarithmic average over w_tilde(a) (the effective equation-of-state in the early universe, after horizon re-entry). Here the effective equation-of-state parameter w_tilde(a) is a combination of the ordinary equation-of-state parameter w(a) and the bulk viscosity zeta(a). Thus, by comparing constraints on r and Omega_gw(f), one can obtain (remarkably tight) constraints in the [w_hat(f), nt_hat(f)] plane. In particular, this is the best way to constrain (or detect) the presence of a ``stiff'' energy component (with w > 1/3) in the early universe, prior to BBN. Finally, although most of our analysis does not assume inflation, we point out that if CMB experiments detect a non-zero value for r, then we will immediately obtain (as a free by-product) a new upper bound w_hat < 0.55 on the logarithmically averaged effective equation-of-state parameter during the ``primordial dark age'' between the end of inflation and the start of BBN.

  2. NUCLEAR ASPECTS OF STELLAR AND EXPLOSIVE NUCLEOSYNTHESIS

    E-Print Network [OSTI]

    Rauscher, Thomas

    NUCLEAR ASPECTS OF STELLAR AND EXPLOSIVE NUCLEOSYNTHESIS Thomas Rauscher 1 , Friedrich. of Astron. and Astroph., Univ. of California, Santa Cruz, CA 95064 Abstract The majority of nuclear­Feshbach). The global parametrizations of the nuclear properties needed for predictions far off stability probe our

  3. Green Power Offer (Maine)

    Broader source: Energy.gov [DOE]

    This chapter establishes requirements, standards and procedures and a competitive bidding process to implement the green power offer program. The program is designed to make renewable energy...

  4. Nucleosynthesis in asymptotic giant branch stars

    SciTech Connect (OSTI)

    El Eid, Mounib F., E-mail: meid@aub.edu.lb [American University of Beirut, Department of Physics, P.O. Box 11-0236, Riad El-Solh, Beirut (Lebanon)

    2014-05-09

    The nucleosynthesis in asymptotic giant branch stars (briefly: AGB)is a challenging and fascinating subject in the theory of stellar evolution and important for observations as well. This is because about of half the heavy elements beyond iron are synthesized during thermal pulsation phases of these stars. Furthermore, the understanding of the production of the heavy elements and some light elements like carbon and fluorine represent a powerful tool to get more insight into the internal structure of these stars. The diversity of nuclear processing during the AGB phases may also motivate experimental activities in measuring important nuclear reactions. In this contribution, we emphasize several interesting feature of the nucleosynthesis in AGB stars which still needs further elaboration especially from theoretical point of view.

  5. Magic ultramagnetized nuclei in explosive nucleosynthesis

    SciTech Connect (OSTI)

    Kondratyev, V. N., E-mail: vkondra@univ.kiev.ua [Ukraine JINR, Taras Shevchenko National University Kiev (Russian Federation)

    2012-11-15

    Direct evidence of the presence of {sup 44}Ti and content of the isotope in the supernova remnant Cassiopeia A are obtained from the analysis of gamma-ray spectrum of the remnant. A significant excess of observational {sup 44}Ti volume on predictions of supernova models can be explained as the magnetization effect in the process of explosive nucleosynthesis. The formation of chemical elements is considered accounting for superstrong magnetic fields predicted for supernovae and neutron stars. Using the arguments of nuclear statistical equilibrium, a significant effect of magnetic field on the nuclear shell energy is demonstrated. The magnetic shift of the most tightly 'bound' nuclei from the transition metals of iron series to titanium leads to an exponential increase in the portion of {sup 44}Ti and, accordingly to a significant excess of the yield of these products of nucleosynthesis.

  6. Nuclear quests for supernova dynamics and nucleosynthesis

    SciTech Connect (OSTI)

    Langanke, K. [GSI Helmholtzzentrum fuer Schwerionenstreuung, Darmstadt, Germany, Institute fuer Kernphysik, Technical University of Darmstadt, Germany and Frankfurt Institute for Advanced Studies, Frankfurt (Germany); Martinez-Pinedo, G. [GSI Helmholtzzentrum fuer Schwerionenstreuung, Darmstadt (Germany)

    2011-10-28

    Nuclear physics plays a crucial role in various aspects of core collapse supernovae. The collapse dynamics is strongly influenced by electron captures. Using modern many-body theory improved capture rates have been derived recently with the important result that the process is dominated by capture on nuclei until neutrino trapping is achieved. Following the core bounce the ejected matter is the site of interesting nucleosynthesis. The early ejecta are proton-rich and give rise to the recently discovered {nu}p-process. Later ejecta might be neutron-rich and can be one site of the r-process. The manuscript discusses recent progress in describing nuclear input relevant for the supernova dynamics and nucleosynthesis.

  7. Modeling The Nucleosynthesis Of Massive Stars

    E-Print Network [OSTI]

    T. Rauscher

    2003-09-09

    This overview discusses issues relevant to modeling nucleosynthesis in type II supernovae and implications of detailed studies of the ejecta. After a brief presentation of the most common approaches to stellar evolution and parameterized explosions, the relevance of a number of nuclei to obtain information on the evolution and explosion mechanisms is discussed. The paper is concluded by an outlook on multi-dimensional simulations.

  8. Dark Radiation Emerging After Big Bang Nucleosynthesis?

    E-Print Network [OSTI]

    Willy Fischler; Joel Meyers

    2011-02-28

    We show how recent data from observations of the cosmic microwave background may suggest the presence of additional radiation density which appeared after big bang nucleosynthesis. We propose a general scheme by which this radiation could be produced from the decay of non-relativistic matter, we place constraints on the properties of such matter, and we give specific examples of scenarios in which this general scheme may be realized.

  9. Dark radiation emerging after big bang nucleosynthesis?

    SciTech Connect (OSTI)

    Fischler, Willy; Meyers, Joel [Theory Group, Department of Physics, University of Texas, Austin, Texas 78712 (United States) and Texas Cosmology Center, University of Texas, Austin, Texas 78712 (United States)

    2011-03-15

    We show how recent data from observations of the cosmic microwave background may suggest the presence of additional radiation density which appeared after big bang nucleosynthesis. We propose a general scheme by which this radiation could be produced from the decay of nonrelativistic matter, we place constraints on the properties of such matter, and we give specific examples of scenarios in which this general scheme may be realized.

  10. Primordial nucleosynthesis in higher dimensional cosmology

    E-Print Network [OSTI]

    S. Chatterjee

    2009-11-13

    We investigate nucleosynthesis and element formation in the early universe in the framework of higher dimensional cosmology. For this purpose we utilize a previous solution of the present author, which may be termed as the generalized Friedmann-Robertson-Walker model. We find that temperature decays less rapidly in higher dimensional cosmology, which we believe may have nontrivial consequences \\emph{vis-a-vis} primordial physics.

  11. Big Bang Nucleosynthesis and Primordial Black Holes

    E-Print Network [OSTI]

    C. Sivaram; Kenath Arun

    2010-06-28

    There are ongoing efforts in detecting Hawking radiation from primordial black holes (PBH) formed during the early universe. Here we put an upper limit on the PBH number density that could have been formed prior to the big bang nucleosynthesis era, based on the constraint that the PBH evaporation energy consisting of high energy radiation not affect the observed abundances' of elements, by disintegrating the nuclei.

  12. c-Ray lenses taking a deeper look at sites of nucleosynthesis Cornelia B. Wunderer

    E-Print Network [OSTI]

    California at Berkeley, University of

    c-Ray lenses ­ taking a deeper look at sites of nucleosynthesis Cornelia B. Wunderer Space Sciences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 617 5. Using lenses to study nucleosynthesis of nucleosynthesis, namely massive stars, novae, and superno

  13. Nucleosynthesis in Magnetohydrodynamical Jets from Collapsars

    SciTech Connect (OSTI)

    Ono, M.; Hashimoto, M. [Department of Physics, Kyushu University Fukuoka 812-8581 (Japan); Fujimoto, S. [Kumamoto National College of Technology, Kumamoto 861-1102 (Japan); Kotake, K. [Division of Theoretical Astronomy/Center for Computational Astrophysics, National Astronomical Observatory of Japan, Mitaka 181-8588 (Japan); Yamada, S. [Advanced Research Institute for Science and Engineering, Waseda University, Tokyo 169-8555 (Japan)

    2011-10-28

    We investigate the heavy-element nucleosynthesis of a massive star whose mass in the main sequence stage is M{sub ms} = 70 M{sub {center_dot}}. Detailed calculations of the nucleosynthesis are performed during the hydrostatic stellar evolution until the core composed of iron-group nuclei begins to collapse. As a supernova explosion model, a collapsar model is constructed whose jets are driven by magnetohydrodynamical effects of a differentially rotating core. The heavy-element nucleosynthesis inside the jet of a collapsar model is followed along the trajectories of stream lines of the jet. We combine the results of both hydrostatic and heavy-element nucleosyntheses to compare with the solar abundances. We find that neutron-rich elements of 70140.

  14. Nucleosynthesis Basics and Applications to Supernovae

    E-Print Network [OSTI]

    F. -K. Thielemann; T. Rauscher; C. Freiburghaus; K. Nomoto; M. Hashimoto; B. Pfeiffer; K. -L. Kratz

    1998-02-06

    This review concentrates on nucleosynthesis processes in general and their applications to massive stars and supernovae. A brief initial introduction is given to the physics in astrophysical plasmas which governs composition changes. We present the basic equations for thermonuclear reaction rates and nuclear reaction networks. The required nuclear physics input for reaction rates is discussed, i.e. cross sections for nuclear reactions, photodisintegrations, electron and positron captures, neutrino captures, inelastic neutrino scattering, and beta-decay half-lives. We examine especially the present state of uncertainties in predicting thermonuclear reaction rates, while the status of experiments is discussed by others in this volume (see M. Wiescher). It follows a brief review of hydrostatic burning stages in stellar evolution before discussing the fate of massive stars, i.e. the nucleosynthesis in type II supernova explosions (SNe II). Except for SNe Ia, which are explained by exploding white dwarfs in binary stellar systems (which will not be discussed here), all other supernova types seem to be linked to the gravitational collapse of massive stars (M$>$8M$_\\odot$) at the end of their hydrostatic evolution. SN1987A, the first type II supernova for which the progenitor star was known, is used as an example for nucleosynthesis calculations. Finally, we discuss the production of heavy elements in the r-process up to Th and U and its possible connection to supernovae.

  15. Standard Offer Program

    Broader source: Energy.gov [DOE]

    Note: H.B. 40, enacted in June 2015, changes the name of the Sustainably Priced Energy Enterprise Development (SPEED) Program to the Standard Offer Program and replaces the associated state...

  16. Undergraduate Offer Pack 2015 2016

    E-Print Network [OSTI]

    Undergraduate Offer Pack 2015 ­ 2016 #12;#12;Graduate Offer Pack 2015-2016 5 Welcome from the Dean of Undergraduate Studies 5 What you need to do now 6-11 Your Checklist 7 Types of Offer 9 Accepting your Offer 9 Meeting the conditions of your Offer 10 Deferring your Offer 11 Rejecting an Offer 11 Financial

  17. Neutrinos and Big-Bang Nucleosynthesis

    E-Print Network [OSTI]

    T. KAJINO; M. ORITO

    1998-04-17

    Observations of clusters and super clusters of galaxies have indicated that the Universe is more dominated by baryons than ever estimated in the homogeneous cosmological model for primordial nucleosynthesis. Recent detections of possibly low deuterium abundance in Lyman-$\\alpha$ clouds along the line of sight to high red-shift quasars have raised another potential difficulty that \\he4 is overproduced in any cosmological models which satisfy the low deuterium abundance constraint. We show that the inhomogeneous cosmological model with degenerate electron-neutrino can resolve these two difficulties.

  18. Nucleosynthesis in gamma-ray bursts outflows

    E-Print Network [OSTI]

    M. Lemoine

    2002-06-19

    It is shown that fusion of neutrons and protons to He-4 nuclei occurs in gamma-ray burst outflows in a process similar to big-bang nucleosynthesis in the early Universe. Only the surviving free neutrons can then decouple kinematically from the charged fluid so that the multi-GeV neutrino signal predicted from inelastic nuclear n-p collisions is significantly reduced. It is also argued that a sizeable fraction of ultra-high energy cosmic rays accelerated in gamma-ray bursts should be He-4 nuclei.

  19. Planetary nebulae, tracers of stellar nucleosynthesis

    E-Print Network [OSTI]

    Grazyna Stasinska

    2007-08-31

    We review the information that planetary nebulae and their immediate progenitors, the post-AGB objects, can provide to probe the nucleosynthesis and mixing in low and intermediate mass stars. We emphasize new approaches based on high signal-to-noise spectroscopy of planetary nebulae and of their central stars. We mention some of the problems still to overcome. We emphasize that, as found by several authors, planetary nebulae in low metallicity environments cannot be used to probe the oxygen abundance in the interstellar medium out of which their progenitors were formed, because of abundance modification during stellar evolution.

  20. Nucleosynthesis: a field with still many open nuclear physics questions

    SciTech Connect (OSTI)

    Goriely, S. [Institut d'Astronomie et d'Astrophysique, Universite Libre de Bruxelles, Campus de la Plaine, CP 226 1050 Brussels (Belgium)

    2010-06-01

    Stellar nucleosynthesis is a vastly interdisciplinary field. There is a large number of different problems invoked calling for a variety of different and complementary research fields. Impressive progress has been made for the last decades in the various fields related to nucleosynthesis, especially in experimental and theoretical nuclear physics, as well as in ground-based or space astronomical observations and astrophysical modellings. In spite of that success, major problems and puzzles remain. The three major nucleosynthesis processes called for to explain the origin of the elements heavier than iron are described and the major pending questions discussed. As far as nuclear physics is concerned, good quality nuclear data is known to be a necessary condition for a reliable modelling of stellar nucleosynthesis. Through some specific examples, the need for further theoretical or experimental developments is also critically discussed in view of their impact on nucleosynthesis predictions.

  1. Constraining spacetime noncommutativity with primordial nucleosynthesis

    SciTech Connect (OSTI)

    Horvat, Raul; Trampetic, Josip

    2009-04-15

    We discuss a constraint on the scale {lambda}{sub NC} of noncommutative (NC) gauge field theory arising from consideration of the big bang nucleosynthesis of light elements. The propagation of neutrinos in the NC background described by an antisymmetric tensor {theta}{sup {mu}}{sup {nu}} does result in a tree-level vectorlike coupling to photons in a generation-independent manner, raising thus a possibility to have an appreciable contribution of three light right-handed (RH) fields to the energy density of the Universe at nucleosynthesis time. Considering elastic scattering processes of the RH neutrinos off charged plasma constituents at a given cosmological epoch, we obtain for a conservative limit on an effective number of additional doublet neutrinos {delta}N{sub {nu}}=1, a bound {lambda}{sub NC} > or approx. 3 TeV. With a more stringent requirement, {delta}N{sub {nu}} < or approx. 0.2, the bound is considerably improved, {lambda}{sub NC} > or approx. 10{sup 3} TeV. For our bounds the {theta} expansion of the NC action stays always meaningful, since the decoupling temperature of the RH species is perseveringly much less than the inferred bound for the scale of noncommutativity.

  2. Study of the beta delayed particle emission from 48Mn and its relevance for explosive nucleosynthesis

    E-Print Network [OSTI]

    Martel, I

    2015-01-01

    Study of the beta delayed particle emission from 48Mn and its relevance for explosive nucleosynthesis

  3. Neutrino Nucleosynthesis of radioactive nuclei in supernovae

    E-Print Network [OSTI]

    A. Sieverding; L. Huther; K. Langanke; G. Martínez-Pinedo; A. Heger

    2015-05-05

    We study the neutrino-induced production of nuclides in explosive supernova nucleosynthesis for progenitor stars with solar metallicity and initial main sequence masses between 15 M$_\\odot$ and 40 M$_\\odot$. We improve previous investigations i) by using a global set of partial differential cross sections for neutrino-induced charged- and neutral-current reactions on nuclei with charge numbers $Z nuclides $^{22}$Na and $^{26}$Al. Both nuclei are prime candidates for gamma-ray astronomy. Other prime targets, $^{44}$Ti and $^{60}$Fe, however, are insignificantly produced by neutrino-induced reactions. We also find a large increase in the production of the long-lived nuclei $^{92}$Nb and $^{98}$Tc due to charged-current neutrino capture.

  4. Electron capture cross sections for stellar nucleosynthesis

    E-Print Network [OSTI]

    P. G. Giannaka; T. S. Kosmas

    2015-02-25

    In the first stage of this work, we perform detailed calculations for the cross sections of the electron capture on nuclei under laboratory conditions. Towards this aim we exploit the advantages of a refined version of the proton-neutron quasi-particle random-phase approximation (pn-QRPA) and carry out state-by-state evaluations of the rates of exclusive processes that lead to any of the accessible transitions within the chosen model space. In the second stage of our present study, we translate the above mentioned $e^-$-capture cross sections to the stellar environment ones by inserting the temperature dependence through a Maxwell-Boltzmann distribution describing the stellar electron gas. As a concrete nuclear target we use the $^{66}Zn$ isotope, which belongs to the iron group nuclei and plays prominent role in stellar nucleosynthesis at core collapse supernovae environment.

  5. Nucleosynthesis and the rp-process

    SciTech Connect (OSTI)

    Nabi, Jameel-Un [Faculty of Engineering Sciences, GIK Institute of Engineering Sciences and Technology, Topi 23640, Swabi, Khyber Pakhtunkhwa (Pakistan)

    2012-11-20

    Production of elements heavier than iron, their abundance and cite of production remain an active field of research to-date. In this paper I would present a brief review of the nucleosynthesis process and then focus further on the proton capture processes with particular emphasis on the nuclear physics aspects of the rp-process. The present calculation clearly shows that the electron capture rates on waiting point nuclei are at least of similar magnitude as the competing positron decay rates under rp-process conditions. The study strongly suggests that electron capture rates form an integral part of weak-interaction mediated rates under rp-process conditions and should not be neglected in nuclear reaction network calculations as done in past.

  6. R-process Nucleosynthesis in Supernova Explosion

    SciTech Connect (OSTI)

    Saruwatari, M.; Hashimoto, M. [Department of Physics, School of Sciences, Kyushu University, Fukuoka 812-8581 (Japan); Kotake, K. [Division of Theoretical Astronomy, National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Yamada, S. [Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjyuku, Tokyo, 169-8555 (Japan)

    2011-10-28

    We investigate the possibility of the r-process during the magnetohydrodynamical (MHD) explosion of supernova in a massive star of 13 M{sub {center_dot}} with the effects of neutrinos included. Contrary to the case of the spherical explosion, jet-like explosion due to the combined effects of rotation and magnetic field lowers the electron fraction significantly inside the layers. We find that the ejected material of low electron fraction responsible for the r-process comes out from the inner deep region of the core that is made up of iron-group nuclei. This leads to the production of the second to third peak in the solar r-process elements. We suggest that there are some variations in the r-process nucleosynthesis according to the initial conditions of rotational and magnetic fields.

  7. Beta decay rates for nuclei with 115 nucleosynthesis

    E-Print Network [OSTI]

    Kamales Kar; Soumya Chakravarti; V. R. Manfredi

    2006-03-19

    For r-process nucleosynthesis the beta decay rates for a number of neutron-rich intermediate heavy nuclei are calculated. The model for the beta strength function is able to reproduce the observed half~lives quite well.

  8. LiBeB and Big Bang Nucleosynthesis

    E-Print Network [OSTI]

    Keith A. Olive; Brian D. Fields

    1999-02-20

    The dual origin of population II Li7, in both big bang nucleosynthesis and galactic cosmic-ray nucleosynthesis is discussed. It is argued that with additional Li6 data, stringent limits on the degree of Li7 depletion can be obtained. Li7 depletion is also constrained by the concordance of big bang predictions with observational determinations of light element abundances. Stringent limits can also be obtained for a fixed primordial D/H abundance.

  9. ACCEPTANCE OF OFFER CLINICAL FACULTY

    E-Print Network [OSTI]

    ACCEPTANCE OF OFFER CLINICAL FACULTY 2015 - 2016 By accepting this appointment I represent of offer, I fail to satisfy the above requirements, I understand that this letter of offer obtained if it is required as a condition of my employment. #12;This offer and my acceptance are subject

  10. Neutrino Capture and r-Process Nucleosynthesis

    E-Print Network [OSTI]

    Bradley S. Meyer; Gail C. McLaughlin; George M. Fuller

    1998-09-18

    We explore neutrino capture during r-process nucleosynthesis in neutrino-driven ejecta from nascent neutron stars. We focus on the interplay between charged-current weak interactions and element synthesis, and we delineate the important role of equilibrium nuclear dynamics. During the period of coexistence of free nucleons and light and/or heavy nuclei, electron neutrino capture inhibits the r-process. At all stages, capture on free neutrons has a larger impact than capture on nuclei. However, neutrino capture on heavey nuclei by itself, if it is very strong, is also detrimental to the r-process until large nuclear equilibrium clusters break down and the classical neutron-capture phase of the r-process begins. The sensitivity of the r-process to neutrino irradiation means that neutrino-capture effects can strongly constrain the r-process site, neutrino physics, or both. These results apply also to r-process scenarios other than neutrino-heated winds.

  11. Abundances for p-process nucleosynthesis

    SciTech Connect (OSTI)

    De Laeter, John R.

    2008-04-15

    An important constraint in developing models of p-process nucleosynthesis is that the abundances of many of the p-process nuclides are not well known. A recent review of the p-process has identified six p-process nuclides that are of particular significance to p-process theorists [M. Arnould and S. Goriely, Phys. Rep. 384, 1 (2003)]. These nuclides are {sup 92,94}Mo, {sup 96,98}Ru, {sup 138}La, and {sup 180}Ta{sup m}. The absence of accurate abundances for these isotopes is due to the fact that the isotopic composition of the elements concerned have not been corrected for isotope fractionation induced by the thermal ionization mass spectrometric instruments used to measure them. To remedy this deficiency, a VG 354 mass spectrometer was calibrated using gravimetric mixtures of enriched isotopes to enable the absolute isotopic compositions of these elements to be obtained. Although the isotopic abundances of {sup 92,94}Mo, {sup 138}La, and {sup 180}Ta{sup m} have previously been reported, the absolute abundances of {sup 96,98}Ru are reported for the first time in this article, with a significant reduction in the magnitude of the values as compared to existing abundances.

  12. Challenges in explosive nucleosynthesis of heavy elements

    SciTech Connect (OSTI)

    Pinedo, Gabriel Martinez; Fischer, T.; Lohs, A.; Huther, L.

    2012-10-20

    We show that a treatment of charged-current neutrino interactions in hot and dense matter that is consistent with the nuclear equation of state has a strong impact on the spectra of the neutrinos emitted during the deleptonization period of a protoneutron star formed in a core-collapse supernova. We compare results of simulations including and neglecting mean field effects on the neutrino opacities. Their inclusion reduces the luminosities of all neutrino flavors and enhances the spectral differences between electron neutrino and antineutrino. The magnitude of the difference depends on the equation of state and in particular on the symmetry energy at sub-nuclear densities. These modifications reduce the proton-to-nucleon ratio of the neutrino-driven outflow, increasing slightly their entropy. They are expected to have a substantial impact on the nucleosynthesis in neutrino-driven winds, even though they do not result in conditions that favor an r-process. Contrarily to previous findings, our simulations show that the spectra of electron neutrinos remain substantially different from those of other (anti)neutrino flavors during the entire deleptonization phase of the protoneutron star. The obtained luminosity and spectral changes are also expected to have important consequences for neutrino flavor oscillations and neutrino detection on Earth.

  13. Presolar Stardust in the Solar System: Implications for Nucleosynthesis and Galactic

    E-Print Network [OSTI]

    Nittler, Larry R.

    Presolar Stardust in the Solar System: Implications for Nucleosynthesis and Galactic Chemical, interstellar dust, nucleosynthesis, galactic chemical evolution, isotopes PACS: 96.30.Za, 96.30.Vb, 97.10.Cv

  14. ACCEPTANCE OF OFFER CLINICAL FACULTY

    E-Print Network [OSTI]

    ACCEPTANCE OF OFFER CLINICAL FACULTY 2015 - 2016 By accepting this appointment I represent and final approval by the Board of Supervisors of the letter of offer, I fail to satisfy the above requirements, I understand that this letter of offer will automatically be null, void, and is deemed rescinded

  15. Argumentative Alternating Offers Nabila Hadidi

    E-Print Network [OSTI]

    Moraitis, Pavlos

    Argumentative Alternating Offers Nabila Hadidi LIPADE Paris Descartes University 45 rue des Saints This paper presents an argumentative version of the well known alternating offers negotiation protocol strategic issues. Such issues are the offer that is proposed at each round, acceptance or refusal

  16. NUCLEOSYNTHESIS IN INTERMEDIATE MASS STARS JOHN C. LATTANZIO AND CHERYL A. FROST

    E-Print Network [OSTI]

    Lattanzio, John

    NUCLEOSYNTHESIS IN INTERMEDIATE MASS STARS JOHN C. LATTANZIO AND CHERYL A. FROST Department AND PETER R. WOOD Mount Stromlo and Siding Springs Observatories, ANU Abstract. We discuss nucleosynthesis lagging somewhat behind. Studies are desperately needed of the nucleosynthesis which occurs during

  17. Abundance Signatures in Halo Stars: Clues to Nucleosynthesis in the First Stars

    E-Print Network [OSTI]

    Cowan, John

    Abundance Signatures in Halo Stars: Clues to Nucleosynthesis in the First Stars John J. Cowan-based telescopes to make extensive studies of Galactic halo stars. These stars contain the nucleosynthesis products the earliest Galactic r-process nucleosynthesis. These in turn will help to identify the characteristics

  18. Nucleosynthesis Supernova Explosions Final Stages of Stellar Evolution For Take Away Final Stages of Stellar Evolution

    E-Print Network [OSTI]

    Hörandel, Jörg R.

    Nucleosynthesis Supernova Explosions Final Stages of Stellar Evolution For Take Away Final Stages.XII.2006 Seminar on Astroparticle Physics - Cosmic Rays #12;Nucleosynthesis Supernova Explosions Final are supernova explosions and which different types exist? Where do heavy elements come from? #12;Nucleosynthesis

  19. PHYSICAL REVIEW C 83, 018801 (2011) Electron screening and its effects on big-bang nucleosynthesis

    E-Print Network [OSTI]

    Bertulani, Carlos A. - Department of Physics and Astronomy, Texas A&M University

    2011-01-01

    PHYSICAL REVIEW C 83, 018801 (2011) Electron screening and its effects on big-bang nucleosynthesis screening on nuclear reaction rates occurring during the big-bang nucleosynthesis epoch. The sensitivity. This work rules out electron screening as a relevant ingredient to big-bang nucleosynthesis, confirming

  20. Nucleosynthesis of Elements in Low to Intermediate Mass Stars through the

    E-Print Network [OSTI]

    Lattanzio, John

    Nucleosynthesis of Elements in Low to Intermediate Mass Stars through the AGB Phase John C on the nucleosynthesis and mixing mechanisms in low­ and intermediate­ mass stars. In addition to explicit studies grains from meteorites. This places strong constraints on nucleosynthesis and mixing in low

  1. NUCLEOSYNTHESIS IN THE EARLY GALAXY F. Montes,1,2,3

    E-Print Network [OSTI]

    Cowan, John

    NUCLEOSYNTHESIS IN THE EARLY GALAXY F. Montes,1,2,3 T. C. Beers,2,4 J. Cowan,5 T. Elliot,2,3,6 K the observations. Subject headinggs: Galaxy: abundances -- nuclear reactions, nucleosynthesis, abundances -- stars-abundances and subtracting them from the observed solar system abundances. If there is an addi- tional nucleosynthesis

  2. Neutrinos and nucleosynthesis in core-collapse supernovae

    SciTech Connect (OSTI)

    Fröhlich, C.; Casanova, J. [Department of Physics, North Carolina State University, Raleigh, NC, 27695 (United States); Hempel, M.; Liebendörfer, M. [Departement für Physik, Universität Basel, CH-4056 Basel (Switzerland); Melton, C. A. [Department of Physics, North Carolina State University, Raleigh, NC 27695 (United States); Perego, A. [Institut für Kernphysik, Technische Universität Darmstadt, D-64289 Darmstadt (Germany)

    2014-01-01

    Massive stars (M > 8-10 M{sub ?}) undergo core collapse at the end of their life and explode as supernova with ~ 10?¹ erg of kinetic energy. While the detailed supernova explosion mechanism is still under investigation, reliable nucleosynthesis calculations based on successful explosions are needed to explain the observed abundances in metal-poor stars and to predict supernova yields for galactic chemical evolution studies. To predict nucleosynthesis yields for a large number of progenitor stars, computationally efficient explosion models are required. We model the core collapse, bounce and subsequent explosion of massive stars assuming spherical symmetry and using detailed microphysics and neutrino physics combined with a novel method to artificially trigger the explosion (PUSH). We discuss the role of neutrinos, the conditions in the ejecta, and the resulting nucleosynthesis.

  3. Big bang nucleosynthesis revisited via Trojan Horse method measurements

    SciTech Connect (OSTI)

    Pizzone, R. G.; Spartá, R.; Spitaleri, C.; La Cognata, M.; Tumino, A. [INFN—Laboratori Nazionali del Sud, Via Santa Sofia 62, I-95123 Catania (Italy); Bertulani, C. A.; Lalmansingh, J. [Department of Physics and Astronomy, Texas A and M University, Commerce, TX 75025 (United States); Lamia, L. [Dipartimento di Fisica e Astronomia, Università degli Studi di Catania, Via Santa Sofia 64, I-95123 Catania (Italy); Mukhamedzhanov, A., E-mail: rgpizzone@lns.infn.it [Cyclotron Institute, Texas A and M University, College Station, TX 77843 (United States)

    2014-05-10

    Nuclear reaction rates are among the most important input for understanding primordial nucleosynthesis and, therefore, for a quantitative description of the early universe. An up-to-date compilation of direct cross-sections of {sup 2}H(d, p){sup 3}H, {sup 2}H(d, n){sup 3}He, {sup 7}Li(p, ?){sup 4}He, and {sup 3}He(d, p){sup 4}He reactions is given. These are among the most uncertain cross-sections used and input for big bang nucleosynthesis calculations. Their measurements through the Trojan Horse method are also reviewed and compared with direct data. The reaction rates and the corresponding recommended errors in this work were used as input for primordial nucleosynthesis calculations to evaluate their impact on the {sup 2}H, {sup 3,4}He, and {sup 7}Li primordial abundances, which are then compared with observations.

  4. Dirac Fields in Loop Quantum Gravity and Big Bang Nucleosynthesis

    E-Print Network [OSTI]

    Martin Bojowald; Rupam Das; Robert J. Scherrer

    2008-03-19

    Big Bang nucleosynthesis requires a fine balance between equations of state for photons and relativistic fermions. Several corrections to equation of state parameters arise from classical and quantum physics, which are derived here from a canonical perspective. In particular, loop quantum gravity allows one to compute quantum gravity corrections for Maxwell and Dirac fields. Although the classical actions are very different, quantum corrections to the equation of state are remarkably similar. To lowest order, these corrections take the form of an overall expansion-dependent multiplicative factor in the total density. We use these results, along with the predictions of Big Bang nucleosynthesis, to place bounds on these corrections.

  5. Offered: Offered: Position(s): Position(s)

    E-Print Network [OSTI]

    New Hampshire, University of

    Company: Industry: Website: Majors: Offered: Offered: Position(s): Position(s): Description the future for streamlined operations. B2W Software solutions effectively leverage the latest technologies into a unified system approach for estimating and bidding, field tracking and analysis, resource planning

  6. Astrophysical Models of r-Process Nucleosynthesis: An Update

    E-Print Network [OSTI]

    Yong-Zhong Qian

    2012-01-24

    An update on astrophysical models for nucleosynthesis via rapid neutron capture, the r process, is given. A neutrino-induced r process in supernova helium shells may have operated up to metallicities of ~10^-3 times the solar value. Another r-process source, possibly neutron star mergers, is required for higher metallicities.

  7. Constraints on massive gravity theory from big bang nucleosynthesis

    E-Print Network [OSTI]

    G. Lambiase

    2012-08-27

    The massive gravity cosmology is studied in the scenario of big bang nucleosynthesis. By making use of current bounds on the deviation from the fractional mass, we derive the constraints on the free parameters of the theory. The cosmological consequences of the model are also discussed in the framework of the PAMELA experiment.

  8. Astrophysical models of r-process nucleosynthesis: An update

    SciTech Connect (OSTI)

    Qian Yongzhong [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)

    2012-11-12

    An update on astrophysical models for nucleosynthesis via rapid neutron capture, the r process, is given. A neutrino-induced r process in supernova helium shells may have operated up to metallicities of {approx} 10{sup -3} times the solar value. Another r-process source, possibly neutron star mergers, is required for higher metallicities.

  9. Lecture Notes on CMB Theory: From Nucleosynthesis to Recombination

    E-Print Network [OSTI]

    Wayne Hu

    2008-02-25

    These lecture notes comprise an informal but pedagogical introduction to the well established physics and phenomenology of the cosmic microwave background (CMB) between big bang nucleosynthesis and recombination. The dominant properties of the spectrum, temperature anisotropy and polarization anisotropy of the CMB all arise from this period. We review the physical processes involved and show how they are related to the observed phenomenology.

  10. Wind energy offers considerable promise

    E-Print Network [OSTI]

    Langendoen, Koen

    Wind energy offers considerable promise: the wind itself is free, wind power is clean, wind power is clean, and it is inexhaustible. In recent years, research on wind energy has accelerated that are offered are: Wind Physics · Atmospheric aerodynamics and turbulence · Wind farm aerodynamics Rotor Design

  11. Big Bang Nucleosynthesis, Implications of Recent CMB Data and Supersymmetric Dark Matter

    E-Print Network [OSTI]

    Keith A. Olive

    2002-03-01

    The BBN predictions for the abundances of the light element isotopes is reviewed and compared with recent observational data. The single unknown parameter of standard BBN is the baryon-to-photon ratio, \\eta, and can be determined by the concordance between theory and observation. Recent CMB anisotropy measurements also lead to a determination of \\eta and these results are contrasted with those from BBN. In addition, the CMB data indicate that the Universe is spatially flat. Thus it is clear that some form of non-baryonic dark matter or dark energy is necessary. Here I will also review the current expectations for cold dark matter from minimal supersymmetric models. The viability of detecting supersymmetric dark matter will also be discussed.

  12. Graduate Offer Pack 2 University College Dublin

    E-Print Network [OSTI]

    Graduate Offer Pack 2015-2016 #12;2 University College Dublin #12;Graduate Offer Pack 2015-2016 3 Welcome from the Dean of Graduate Studies 5 What you need to do now 6-11 Your Checklist 7 Types of Offer 9 Accepting your Offer 9 Meeting the conditions of your Offer 10 Deferring your Offer 11 Rejecting an Offer 11

  13. Effects of axions on Nucleosynthesis in massive stars

    E-Print Network [OSTI]

    Aoyama, Shohei

    2015-01-01

    We investigate the effect of the axion cooling on the nucleosynthesis in a massive star with $16M_{\\odot}$ by standard stellar evolution calculation. We find that the axion cooling suppresses the nuclear reactions in carbon, oxygen and silicon burning phases because of the extraction of the energy. As a result, larger amounts of the already synthesized neon and magnesium remain without being consumed to produce further heavier elements. Even in the case with the axion-photon coupling constant $g_{a\\gamma}= 10^{-11}$ GeV$^{-1}$, which is six times smaller than the current upper limit, the amount of neon and magnesium that remain just before the core-collapse supernova explosion is considerably larger than the standard value. This implies that we could give a more stringent constraint on $g_{a\\gamma}$ from the nucleosynthesis of heavy elements in massive stars.

  14. Statistical Methods for Thermonuclear Reaction Rates and Nucleosynthesis Simulations

    E-Print Network [OSTI]

    Iliadis, Christian; Coc, Alain; Timmes, F X; Champagne, Art E

    2014-01-01

    Rigorous statistical methods for estimating thermonuclear reaction rates and nucleosynthesis are becoming increasingly established in nuclear astrophysics. The main challenge being faced is that experimental reaction rates are highly complex quantities derived from a multitude of different measured nuclear parameters (e.g., astrophysical S-factors, resonance energies and strengths, particle and gamma-ray partial widths). We discuss the application of the Monte Carlo method to two distinct, but related, questions. First, given a set of measured nuclear parameters, how can one best estimate the resulting thermonuclear reaction rates and associated uncertainties? Second, given a set of appropriate reaction rates, how can one best estimate the abundances from nucleosynthesis (i.e., reaction network) calculations? The techniques described here provide probability density functions that can be used to derive statistically meaningful reaction rates and final abundances for any desired coverage probability. Examples ...

  15. Electron screening and its effects on big-bang nucleosynthesis

    SciTech Connect (OSTI)

    Wang Biao; Bertulani, C. A.; Balantekin, A. B. [Department of Physics, Texas A and M University, Commerce, Texas 75429 (United States); Physics Department, University of Wisconsin-Madison, 1150 University Avenue, Madison, Wisconsin 53706 (United States)

    2011-01-15

    We study the effects of electron screening on nuclear reaction rates occurring during the big-bang nucleosynthesis epoch. The sensitivity of the predicted elemental abundances on electron screening is studied in detail. It is shown that electron screening does not produce noticeable results in the abundances unless the traditional Debye-Hueckel model for the treatment of electron screening in stellar environments is enhanced by several orders of magnitude. This work rules out electron screening as a relevant ingredient to big-bang nucleosynthesis, confirming a previous study [see Itoh et al., Astrophys. J. 488, 507 (1997)] and ruling out exotic possibilities for the treatment of screening beyond the mean-field theoretical approach.

  16. ?-decay spectroscopy for the r-process nucleosynthesis

    SciTech Connect (OSTI)

    Nishimura, Shunji [RIKEN Nishina Center, Wako, Saitama 351-0198 (Japan); Collaboration: RIBF Decay Collaborations

    2014-05-09

    Series of decay spectroscopy experiments, utilizing of high-purity Ge detectors and double-sided silicon-strip detectors, have been conducted to harvest the decay properties of very exotic nuclei relevant to the r-process nucleosynthesis at the RIBF. The decay properties such as ?-decay half-lives, low-lying states, ?-delayed neutron emissions, isomeric states, and possibly Q{sub ?} of the very neutron-rich nuclei are to be measured to give significant constraints in the uncertainties of nuclear properties for the r-process nucleosynthesis. Recent results of ?? spectroscopy study using in-flight fission of {sup 238}U-beam will be presented together with our future perspectives.

  17. Nucleosynthesis in the ejecta of neutron star mergers

    SciTech Connect (OSTI)

    Wanajo, Shinya [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Sekiguchi, Yuichiro; Kiuchi, Kenta; Shibata, Masaru [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan); Nishimura, Nobuya [Astrophysics Group, iEPSAM, Keele University, Keele, ST5 5BG (United Kingdom); Kyutoku, Koutarou [Department of Physics, University of Wisconsin-Milwaukee, P.O. Box 413, Milwaukee, WI 53201 (United States)

    2014-05-02

    We present, for the first time, the result of nucleosynthesis calculations based on the fully general-relativistic simulation of a NS-NS merger with approximate neutrino transport taken into account. It is found that the bulk of the dynamical ejecta are appreciably shock-heated and neutrino-processed, resulting in a wide range of electron fraction, Y{sub e} ? 0.1-0.4. The mass-averaged abundance distribution of calculated nucleosynthesis yields is in remarkable agreement with the full-mass range (A ? 90-240) of the solar r-process curve. This implies, if our model is representative of such events, that the dynamical ejecta of NS-NS mergers can be the origin of the Galactic r-process nuclei.

  18. Decline Offer Survey Revised June 2015 Decline Offer Survey

    E-Print Network [OSTI]

    Doty, Sharon Lafferty

    ) University of Connecticut (408) University of Denver (409) University of Florida (410) University the University of Washington during your search for a graduate degree program. We understand that many factors the University of Washington's offer? Plan to attend another university or program (1) Decided not to pursue

  19. Possible evidence for "dark radiation" from Big Bang Nucleosynthesis Data

    E-Print Network [OSTI]

    V. V. Flambaum; E. V. Shuryak

    2006-02-06

    We address the emerging discrepancy between the Big Bang Nucleosynthesis data and standard cosmology, which asks for a bit longer evolution time. If this effect is real, one possible implication (in a framework of brane cosmology model) is that there is a ``dark radiation'' component which is negative and makes few percents of ordinary matter density. If so, all scales of this model can be fixed, provided brane-to-bulk leakage problem is solved.

  20. Constraints on massive gravity theory from big bang nucleosynthesis

    SciTech Connect (OSTI)

    Lambiase, G., E-mail: lambiase@sa.infn.it [Dipartimento di Fisica 'E. R.Caianiello', Università di Salerno, 84081 Baronissi (Italy)

    2012-10-01

    The massive gravity cosmology is studied in the scenario of big bang nucleosynthesis. By making use of current bounds on the deviation from the fractional mass, we derive the constraints on the free parameters of the theory. The cosmological consequences of the model are also analyzed in the framework of the PAMELA experiment, i.e. an excess of positron events, that the conventional cosmology and particle physics cannot explain.

  1. Nucleosynthesis in Metal-Free and Metal-Poor Stars

    E-Print Network [OSTI]

    Yong-Zhong Qian

    2008-07-04

    There have been a number of important recent developments in theoretical and observational studies of nucleosynthesis, especially regarding nucleosynthetic sources at low metallicities. Those selected for discussion here include the origin of Li6, the primary production of N, the s-process, and the supernova sources for three groups of metals: (1) C to Zn with mass numbers A<70, (2) Sr to Ag with A~90-110, and (3) r-process nuclei with A~130 and above.

  2. Nucleosynthesis in the accretion disks of Type II collapsars

    E-Print Network [OSTI]

    Indrani Banerjee; Banibrata Mukhopadhyay

    2013-05-08

    We investigate nucleosynthesis inside the gamma-ray burst (GRB) accretion disks formed by the Type II collapsars. In these collapsars, the core collapse of massive stars first leads to the formation of a proto-neutron star and a mild supernova explosion is driven. However, this supernova ejecta lack momentum and falls back onto the neutron star which gets transformed to a stellar mass black hole. In order to study the hydrodynamics and nucleosynthesis of such an accretion disk formed from the fallback material of the supernova ejecta, we use the well established hydrodynamic models. In such a disk neutrino cooling becomes important in the inner disk where the temperature and density are higher. Higher the accretion rate (dot{M}), higher is the density and temperature in the disks. In this work we deal with accretion disks with relatively low accretion rates: 0.001 M_sun s^{-1} \\lesssim dot{M} \\lesssim 0.01 M_sun s^{-1} and hence these disks are predominantly advection dominated. We use He-rich and Si-rich abundances as the initial condition of nucleosynthesis at the outer disk, and being equipped with the disk hydrodynamics and the nuclear network code, we study the abundance evolution as matter inflows and falls into the central object. We investigate the variation in the nucleosynthesis products in the disk with the change in the initial abundance at the outer disk and also with the change in the mass accretion rate. We report the synthesis of several unusual nuclei like {31}P, {39}K, {43}Sc, {35}Cl, and various isotopes of titanium, vanadium, chromium, manganese and copper. We also confirm that isotopes of iron, cobalt, nickel, argon, calcium, sulphur and silicon get synthesized in the disk, as shown by previous authors. Much of these heavy elements thus synthesized are ejected from the disk via outflows and hence they should leave their signature in observed data.

  3. Nucleosynthesis in neutrino-driven winds in hypernovae

    E-Print Network [OSTI]

    Fujibayashi, Sho; Sekiguchi, Yuichiro

    2015-01-01

    We investigate the nucleosynthesis in the neutrino-driven winds blown off from a $3M_\\odot$ massive proto-neutron star temporarily formed during the collapse of a $100M_\\odot$ star. Such massive proto-neutron stars would be formed in hypernovae. We construct steady and spherically symmetric wind solutions. We set large neutrino luminosities of $\\sim 10^{53}\\ {\\rm erg\\ s^{-1}}$ and average energies of electron neutrinos and antineutrinos in the ranges of $\\epsilon_{\

  4. Nucleosynthesis in early supernova winds III: No significant contribution from neutron-rich pockets

    E-Print Network [OSTI]

    R. D. Hoffman; J. Pruet; J. L. Fisker; H. -T. Janka; R. Burras; S. E. Woosley

    2007-12-18

    Recent nucleosynthesis calculations of Type II supernovae using advanced neutrino transport determine that the early neutrino winds are proton-rich. However, a fraction of the ejecta emitted at the same time is composed of neutron-rich pockets. In this paper we calculate the nucleosynthesis contribution from the neutron-rich pockets in the hot convective bubbles of a core-collapse supernova and show that they do not contribute significantly to the total nucleosynthesis.

  5. Nuclear Ashes: Reviewing Thirty Years of Nucleosynthesis in Classical Novae

    E-Print Network [OSTI]

    Jordi Jose

    2002-09-10

    One of the observational evidences in support of the "thermonuclear runaway model" for the classical nova outburst relies on the accompanying nucleosynthesis. In this paper, we stress the relevant role played by nucleosynthesis in our understanding of the nova phenomenon by constraining models through a comparison with both the atomic abundance determinations from the ejecta and the isotopic ratios measured in presolar grains of a likely nova origin. Furthermore, the endpoint of nova nucleosynthesis provides hints for the understanding of the mixing process responsible for the enhanced metallicities found in the ejecta, and reveals also information on the properties of the underlying white dwarf (mass, luminosity...). We discuss first the interplay between nova outbursts and the Galactic chemical abundances: Classical nova outbursts are expected to be the major source of 13C, 15N and 17O in the Galaxy, and to contribute to the abundances of other species with A < 40, such as 7Li or 26Al. We describe the main nuclear path during the course of the explosion, with special emphasis on the synthesis of radioactive species, of particular interest for the gamma-ray output predicted from novae (7Li, 18F, 22Na, 26Al). An overview of the recent discovery of presolar nova candidate grains, as well as a discussion of the role played by nuclear uncertainties associated with key reactions of the NeNa-MgAl and Si-Ca regions, are also given.

  6. Nucleosynthesis and Remnants in Massive Stars of Solar Metallicity

    E-Print Network [OSTI]

    Woosley, S E

    2007-01-01

    Hans Bethe contributed in many ways to our understanding of the supernovae that happen in massive stars, but, to this day, a first principles model of how the explosion is energized is lacking. Nevertheless, a quantitative theory of nucleosynthesis is possible. We present a survey of the nucleosynthesis that occurs in 32 stars of solar metallicity in the mass range 12 to 120 solar masses. The most recent set of solar abundances, opacities, mass loss rates, and current estimates of nuclear reaction rates are employed. Restrictions on the mass cut and explosion energy of the supernovae based upon nucleosynthesis, measured neutron star masses, and light curves are discussed and applied. The nucleosynthetic results, when integrated over a Salpeter initial mass function (IMF), agree quite well with what is seen in the sun. We discuss in some detail the production of the long lived radioactivities, 26Al and 60Fe, and why recent model-based estimates of the ratio 60Fe/26Al are overly large compared with what satelli...

  7. Quantification of nuclear uncertainties in nucleosynthesis of elements beyond Iron

    E-Print Network [OSTI]

    T. Rauscher

    2014-12-22

    Nucleosynthesis beyond Fe poses additional challenges not encountered when studying astrophysical processes involving light nuclei. Generally higher temperatures and nuclear level densities lead to stronger contributions of transitions on excited target states. This may prevent cross section measurements to determine stellar reaction rates and theory contributions remain important. Furthermore, measurements often are not feasible in the astrophysically relevant energy range. Sensitivity analysis allows not only to determine the contributing nuclear properties but also is a handy tool for experimentalists to interpret the impact of their data on predicted cross sections and rates. It can also speed up future input variation studies of nucleosynthesis by simplifying an intermediate step in the full calculation sequence. Large-scale predictions of sensitivities and ground-state contributions to the stellar rates are presented, allowing an estimate of how well rates can be directly constrained by experiment. The reactions 185W(n,gamma) and 186W(gamma,n) are discussed as application examples. Studies of uncertainties in abundances predicted in nucleosynthesis simulations rely on the knowledge of reaction rate errors. An improved treatment of uncertainty analysis is presented as well as a recipe for combining experimental data and theory to arrive at a new reaction rate and its uncertainty. As an example, it is applied to neutron capture rates for the s-process, leading to larger uncertainties than previously assumed.

  8. Statistical Methods for Thermonuclear Reaction Rates and Nucleosynthesis Simulations

    E-Print Network [OSTI]

    Christian Iliadis; Richard Longland; Alain Coc; F. X. Timmes; Art E. Champagne

    2014-09-19

    Rigorous statistical methods for estimating thermonuclear reaction rates and nucleosynthesis are becoming increasingly established in nuclear astrophysics. The main challenge being faced is that experimental reaction rates are highly complex quantities derived from a multitude of different measured nuclear parameters (e.g., astrophysical S-factors, resonance energies and strengths, particle and gamma-ray partial widths). We discuss the application of the Monte Carlo method to two distinct, but related, questions. First, given a set of measured nuclear parameters, how can one best estimate the resulting thermonuclear reaction rates and associated uncertainties? Second, given a set of appropriate reaction rates, how can one best estimate the abundances from nucleosynthesis (i.e., reaction network) calculations? The techniques described here provide probability density functions that can be used to derive statistically meaningful reaction rates and final abundances for any desired coverage probability. Examples are given for applications to s-process neutron sources, core-collapse supernovae, classical novae, and big bang nucleosynthesis.

  9. Nucleosynthesis and Remnants in Massive Stars of Solar Metallicity

    E-Print Network [OSTI]

    S. E. Woosley; A. Heger

    2007-02-06

    Hans Bethe contributed in many ways to our understanding of the supernovae that happen in massive stars, but, to this day, a first principles model of how the explosion is energized is lacking. Nevertheless, a quantitative theory of nucleosynthesis is possible. We present a survey of the nucleosynthesis that occurs in 32 stars of solar metallicity in the mass range 12 to 120 solar masses. The most recent set of solar abundances, opacities, mass loss rates, and current estimates of nuclear reaction rates are employed. Restrictions on the mass cut and explosion energy of the supernovae based upon nucleosynthesis, measured neutron star masses, and light curves are discussed and applied. The nucleosynthetic results, when integrated over a Salpeter initial mass function (IMF), agree quite well with what is seen in the sun. We discuss in some detail the production of the long lived radioactivities, 26Al and 60Fe, and why recent model-based estimates of the ratio 60Fe/26Al are overly large compared with what satellites have observed. A major source of the discrepancy is the uncertain nuclear cross sections for the creation and destruction of these unstable isotopes.

  10. Getting the Offer: Sex Discrimination in Hiring

    E-Print Network [OSTI]

    Petersen, Trond; Togstad, Thea

    2004-01-01

    positions. In each of positions 1-10, one offer was given.In each of positions 11-14, two offers were given.In position 15, 12 offers were given. Of the 30 offers made,

  11. Getting the Offer: Sex Discrimation in Hiring

    E-Print Network [OSTI]

    Petersen, Trond; Togstad, Thea

    2006-01-01

    positions. In each of positions 1-10, one offer was given.In each of positions 11-14, two offers were given.In position 15, 12 offers were given. Of the 30 offers made,

  12. Wind energy offers considerable promise

    E-Print Network [OSTI]

    Langendoen, Koen

    Wind energy offers considerable promise: the wind itself is free, wind power is clean: the wind itself is free, wind power is clean, and it is inexhaustible. In recent years, research on wind · Wind farm aerodynamics Rotor Design · Aerodynamics · Structure and design · Composite design, material

  13. Offered Fall Semester: Biological Physics

    E-Print Network [OSTI]

    Collins, Gary S.

    Offered Fall Semester: Biological Physics Physics 466 / Physics 566 (conjoint) provides a fundamental physical understanding of the operation of cells, biomolecules and molecular machines. MWF 4:10-5:00pm, Webster 11 (3 cr) Instructor: Fred Gittes, Clinical Professor of Physics and Astronomy: gittes

  14. arXiv:1012.0242v1[astro-ph.SR]1Dec2010 Nucleosynthesis and chemical evolution of

    E-Print Network [OSTI]

    Maciel, Walter Junqueira

    arXiv:1012.0242v1[astro-ph.SR]1Dec2010 Nucleosynthesis and chemical evolution of intermediate to investigate the nucleosynthesis and chemical evolution of intermediate mass stars. In these objects accurate) are an excellent laboratory to investigate the nucleosynthesis and chemical evolution of intermediate mass stars

  15. Collaborative Research: Neutrinos & Nucleosynthesis in Hot Dense Matter

    SciTech Connect (OSTI)

    Reddy, Sanjay

    2013-09-06

    It is now firmly established that neutrinos, which are copiously produced in the hot and dense core of the supernova, play a role in the supernova explosion mechanism and in the synthesis of heavy elements through a phenomena known as r-process nucleosynthesis. They are also detectable in terrestrial neutrino experiments, and serve as a probe of the extreme environment and complex dynamics encountered in the supernova. The major goal of the UW research activity relevant to this project was to calculate the neutrino interaction rates in hot and dense matter of relevance to core collapse supernova. These serve as key input physics in large scale computer simulations of the supernova dynamics and nucleosynthesis being pursued at national laboratories here in the United States and by other groups in Europe and Japan. Our calculations show that neutrino production and scattering rate are altered by the nuclear interactions and that these modifications have important implications for nucleosynthesis and terrestrial neutrino detection. The calculation of neutrino rates in dense matter are difficult because nucleons in the dense matter are strongly coupled. A neutrino interacts with several nucleons and the quantum interference between scattering off different nucleons depends on the nature of correlations between them in dense matter. To describe these correlations we used analytic methods based on mean field theory and hydrodynamics, and computational methods such as Quantum Monte Carlo. We found that due to nuclear effects neutrino production rates at relevant temperatures are enhanced, and that electron neutrinos are more easily absorbed than anti-electron neutrinos in dense matter. The latter, was shown to favor synthesis of heavy neutron-rich elements in the supernova.

  16. Experimental studies of reactions relevant for ?-process nucleosynthesis

    SciTech Connect (OSTI)

    Scholz, P.; Endres, J.; Hennig, A.; Mayer, J.; Netterdon, L.; Zilges, A. [Institute for Nuclear Physics, University of Cologne (Germany); Sauerwein, A. [Institute for Applied Physics, Goethe University, Frankfurt am Main, Germany and Institute for Nuclear Physics, University of Cologne (Germany)

    2014-05-09

    We report on our recent experimental studies of reactions relevant for the ? process nucleosynthesis. Applying the activation method using the Cologne Clover Counting Setup total cross sections of the reactions {sup 168}Yb(?,?), {sup 168}Yb(?,n), and {sup 187}Re(?,n) could be obtained. Furthermore, the reaction {sup 89}Y(p,?) was investigated via the in-beam technique with HPGe detectors at the high-efficiency g-ray spectrometer HORUS in Cologne in order to determine partial and total cross sections.

  17. Neutron capture rates and r-process nucleosynthesis

    E-Print Network [OSTI]

    R. Surman; M. Mumpower; G. C. McLaughlin; R. Sinclair; W. R. Hix; K. L. Jones

    2013-08-31

    Simulations of r-process nucleosynthesis require nuclear physics information for thousands of neutron-rich nuclear species from the line of stability to the neutron drip line. While arguably the most important pieces of nuclear data for the r-process are the masses and beta decay rates, individual neutron capture rates can also be of key importance in setting the final r-process abundance pattern. Here we consider the influence of neutron capture rates in forming the A~80 and rare earth peaks.

  18. Citrus Offers Year-Round Options

    E-Print Network [OSTI]

    Martin, Orin

    2008-01-01

    Center’s Alan Chadwick Garden, offers ideas for choosing andSystems, UC Santa Cruz Citrus Offers Year-Round Options Tvarietal descriptions offer an idea of the wide range of

  19. Sharyland Utilities- Commercial Standard Offer Program (Texas)

    Broader source: Energy.gov [DOE]

    Sharyland Utilities offers the Residential and "Hard-to-Reach" Standard Offer Programs, which encourage residential customers to pursue energy saving measures and equipment upgrades in their homes....

  20. Eight National Labs Offer Streamlined Partnership Agreements...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Eight National Labs Offer Streamlined Partnership Agreements to Help Industry Bring New Technologies to Market Eight National Labs Offer Streamlined Partnership Agreements to Help...

  1. Peptoid Nanosheets Offer a Diversity of Functionalities

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Peptoid Nanosheets Offer a Diversity of Functionalities Peptoid Nanosheets Offer a Diversity of Functionalities Print Wednesday, 29 April 2015 00:00 Researchers at the ALS have...

  2. Inhomogeneous big bang nucleosynthesis with late-decaying massive particles

    E-Print Network [OSTI]

    J. Lopez-Suarez; R. Canal

    1998-04-22

    We investigate the possibility of accounting for the currently inferred primordial abundances of D, 3He, 4He, and 7Li by big bang nucleosynthesis in the presence of baryon density inhomogeneities plus the effects of late-decaying massive particles (X), and we explore the allowed range of baryonic fraction of the closure density Omega_b in such context. We find that, depending on the parameters of this composite model (characteristic size and density contrast of the inhomogeneities; mass-density, lifetime, and effective baryon number in the decay of the X-particles), values as high as \\Omega_{b}h_{50}^{2}\\simeq 0.25-0.35 could be compatible with the primordial abundances of the light nuclides. We include diffusion of neutrons and protons at all stages, and we consider the contribution of the X particles to the energy density, the entropy production by their decay, the possibility that the X-products could photodissociate the light nuclei produced during the previous stages of nucleosynthesis, and also the possibility that the decay products of the X-particles would include a substantial fraction of hadrons. Specific predictions for the primordial abundance of Be are made.

  3. Neutrino-driven wind simulations and nucleosynthesis of heavy elements

    E-Print Network [OSTI]

    A. Arcones; F. -K. Thielemann

    2012-07-11

    Neutrino-driven winds, which follow core-collapse supernova explosions, present a fascinating nuclear astrophysics problem that requires understanding advanced astrophysics simulations, the properties of matter and neutrino interactions under extreme conditions, the structure and reactions of exotic nuclei, and comparisons against forefront astronomical observations. The neutrino-driven wind has attracted vast attention over the last 20 years as it was suggested to be a candidate for the astrophysics site where half of the heavy elements are produced via the r-process. In this review, we summarize our present understanding of neutrino-driven winds from the dynamical and nucleosynthesis perspectives. Rapid progress has been made during recent years in understanding the wind with improved simulations and better micro physics. The current status of the fields is that hydrodynamical simulations do not reach the extreme conditions necessary for the r-process and the proton or neutron richness of the wind remains to be investigated in more detail. However, nucleosynthesis studies and observations point already to neutrino-driven winds to explain the origin of lighter heavy elements, such as Sr, Y, Zr.

  4. Nucleosynthesis in the Ejecta of Neutron Star Mergers

    E-Print Network [OSTI]

    Dirk Martin; Albino Perego; Almudena Arcones; Oleg Korobkin; Friedrich-Karl Thielemann

    2015-09-25

    Heavy elements like gold, platinum or uranium are produced in the r-process, which needs neutron-rich and explosive environments. Neutron star mergers are a promising candidate for an r-process site. They exhibit three different channels for matter ejection fulfilling these conditions: dynamic ejecta due to tidal torques, neutrino-driven winds and evaporating matter from the accretion disk. We present a first study of the integrated nucleosynthesis for a neutrino-driven wind from a neutron star merger with a hyper-massive neutron star. Trajectories from a recent hydrodynamical simulation are divided into four different angle regions and post-processed with a reaction network. We find that the electron fraction varies around $Y_e \\approx 0.1 - 0.4$, but its distribution differs for every angle of ejection. Hence, the wind ejecta do not undergo a robust r-process, but rather possess distinct nucleosynthesis yields depending on the angle range. Compared to the dynamic ejecta, a smaller amount of neutron-rich matter gets unbound, but the production of lighter heavy elements with $A \\lesssim 130$ in the neutrino-driven wind can complement the strong r-process of the dynamic ejecta.

  5. Nucleosynthesis in the Outflow from Gamma Ray Burst Accretion Disks

    E-Print Network [OSTI]

    R. Surman; G. C. McLaughlin; W. R. Hix

    2005-09-13

    We examine the nucleosynthesis products that are produced in the outflow from rapidly accreting disks. We find that the type of element synthesis varies dramatically with the degree of neutrino trapping in the disk and therefore the accretion rate of the disk. Disks with relatively high accretion rates such as 10 M_solar/s can produce very neutron rich nuclei that are found in the r process. Disks with more moderate accretion rates can produce copious amounts of Nickel as well as the light elements such as Lithium and Boron. Disks with lower accretion rates such as 0.1 M_solar/s produce large amounts of Nickel as well as some unusual nuclei such as Ti-49, Sc-45, Zn-64, and Mo-92. This wide array of potential nucleosynthesis products is due to the varying influence of electron neutrinos and antineutrinos emitted from the disk on the neutron-to-proton ratio in the outflow. We use a parameterization for the outflow and discuss our results in terms of entropy and outflow acceleration.

  6. Primordial Lithium Abundance in Catalyzed Big Bang Nucleosynthesis

    E-Print Network [OSTI]

    Chris Bird; Kristen Koopmans; Maxim Pospelov

    2008-05-19

    There exists a well known problem with the Li7+Be7 abundance predicted by standard big bang nucleosynthesis being larger than the value observed in population II stars. The catalysis of big bang nucleosynthesis by metastable, \\tau_X \\ge 10^3 sec, charged particles X^- is capable of suppressing the primordial Li7+Be7, abundance and making it consistent with the observations. We show that to produce the correct abundance, this mechanism of suppression places a requirement on the initial abundance of X^- at temperatures of 4\\times 10^8 K to be on the order of or larger than 0.02 per baryon, which is within the natural range of abundances in models with metastable electroweak-scale particles. The suppression of Li7+Be7, is triggered by the formation of (Be7X^-), compound nuclei, with fast depletion of their abundances by catalyzed proton reactions, and in some models by direct capture of X^- on Be7. The combination of Li7+Be7 and Li6 constraints favours the window of lifetimes, 1000s \\la tau_X \\leq 2000 s.

  7. Comprehensive nucleosynthesis analysis for ejecta of compact binary mergers

    E-Print Network [OSTI]

    Just, Oliver; Pulpillo, Ricard Ardevol; Goriely, Stephane; Janka, H -Thomas

    2015-01-01

    We present a comprehensive study of r-process element nucleosynthesis in the ejecta of compact binary mergers (CBMs) and their relic black-hole (BH)-torus systems. The evolution of the BH-accretion tori is simulated for seconds with a Newtonian hydrodynamics code including viscosity effects, pseudo-Newtonian gravity for rotating BHs, and an energy-dependent two-moment closure scheme for the transport of electron neutrinos and antineutrinos. The investigated cases are guided by relativistic double neutron star (NS-NS) and NS-BH merger models, producing ~3-6 Msun BHs with rotation parameters of A~0.8 and tori of 0.03-0.3 Msun. Our nucleosynthesis analysis includes the dynamical (prompt) ejecta expelled during the CBM phase and the neutrino and viscously driven outflows of the relic BH-torus systems. While typically ~20-25% of the initial accretion-torus mass are lost by viscously driven outflows, neutrino-powered winds contribute at most another ~1%, but neutrino heating enhances the viscous ejecta significantl...

  8. METALLICITY-DEPENDENT GALACTIC ISOTOPIC DECOMPOSITION FOR NUCLEOSYNTHESIS

    SciTech Connect (OSTI)

    West, Christopher; Heger, Alexander, E-mail: west0482@umn.edu, E-mail: alexander.heger@monash.edu [Minnesota Institute for Astrophysics, School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)

    2013-09-01

    All stellar evolution models for nucleosynthesis require an initial isotopic abundance set to use as a starting point. Generally, our knowledge of isotopic abundances of stars is fairly incomplete except for the Sun. We present a first model for a complete average isotopic decomposition as a function of metallicity. Our model is based on the underlying nuclear astrophysics processes, and is fitted to observational data, rather than traditional forward galactic chemical evolution modeling which integrates stellar yields beginning from big bang nucleosynthesis. We first decompose the isotopic solar abundance pattern into contributions from astrophysical sources. Each contribution is then assumed to scale as a function of metallicity. The resulting total isotopic abundances are summed into elemental abundances and fitted to available halo and disk stellar data to constrain the model's free parameter values. This procedure allows us to use available elemental observational data to reconstruct and constrain both the much needed complete isotopic evolution that is not accessible to current observations, and the underlying astrophysical processes. As an example, our model finds a best fit for Type Ia contributing {approx_equal} 0.7 to the solar Fe abundance, and Type Ia onset occurring at [Fe/H] {approx_equal} -1.1, in agreement with typical values.

  9. Photon-induced Nucleosynthesis: Current Problems and Experimental Approaches

    E-Print Network [OSTI]

    P. Mohr; Zs. Fulop; H. Utsunomiya

    2007-05-16

    Photon-induced reactions play a key role in the nucleosynthesis of rare neutron-deficient p-nuclei. The paper focuses on (gamma,alpha), (gamma,p), and (gamma,n) reactions which define the corresponding p-process path. The relation between stellar reaction rates and laboratory cross sections is analyzed for photon-induced reactions and their inverse capture reactions to evaluate various experimental approaches. An improved version S_C(E) of the astrophysical S-factor is suggested which is based on the Coulomb wave functions. S_C(E) avoids the apparent energy dependence which is otherwise obtained for capture reactions on heavy nuclei. It is found that a special type of synchrotron radiation available at SPring-8 that mimics stellar blackbody radiation at billions of Kelvin is a promising tool for future experiments. By using the blackbody synchrotron radiation, sufficient event rates for (gamma,alpha) and (gamma,p) reactions in the p-process path can be expected. These experiments will provide data to improve the nuclear parameters involved in the statistical model and thus reduce the uncertainties of nucleosynthesis calculations.

  10. Challenges in nucleosynthesis of trans-iron elements

    SciTech Connect (OSTI)

    Rauscher, T. [Centre for Astrophysics Research, School of Physics, Astronomy and Mathematics, Hatfield AL10 9AB, United Kingdom and Department of Physics, University of Basel, CH-4056 Basel (Switzerland)] [Centre for Astrophysics Research, School of Physics, Astronomy and Mathematics, Hatfield AL10 9AB, United Kingdom and Department of Physics, University of Basel, CH-4056 Basel (Switzerland)

    2014-04-15

    Nucleosynthesis beyond Fe poses additional challenges not encountered when studying astrophysical processes involving light nuclei. Astrophysical sites and conditions are not well known for some of the processes involved. On the nuclear physics side, different approaches are required, both in theory and experiment. The main differences and most important considerations are presented for a selection of nucleosynthesis processes and reactions, specifically the s-, r-, ?-, and ?p-processes. Among the discussed issues are uncertainties in sites and production conditions, the difference between laboratory and stellar rates, reaction mechanisms, important transitions, thermal population of excited states, and uncertainty estimates for stellar rates. The utility and limitations of indirect experimental approaches are also addressed. The presentation should not be viewed as confining the discussed problems to the specific processes. The intention is to generally introduce the concepts and possible pitfalls along with some examples. Similar problems may apply to further astrophysical processes involving nuclei from the Fe region upward and/or at high plasma temperatures. The framework and strategies presented here are intended to aid the conception of future experimental and theoretical approaches.

  11. ACCEPTANCE OF OFFER BASIC SCIENCE FACULTY

    E-Print Network [OSTI]

    ACCEPTANCE OF OFFER BASIC SCIENCE FACULTY 2015 - 2016 By accepting this appointment I represent of the letter of offer, I fail to satisfy the above requirements, I understand that this letter of offer obtained if it is required as a condition of my employment. This offer and my acceptance are subject

  12. Offer Guidelines and Policies Colorado State University

    E-Print Network [OSTI]

    Offer Guidelines and Policies Colorado State University We ask that all employers abide Association of Colleges and Employers (NACE). Extending Offers We ask that employers convey final hiring the offer is made to make their decision. We ask that employers making full-time offers to interns

  13. Explosive Nucleosynthesis in GRB Jets Accompanied by Hypernovae

    SciTech Connect (OSTI)

    Nagataki, Shigehiro; /Kyoto U., Yukawa Inst., Kyoto /KIPAC, Menlo Park; Mizuta, Akira; /Garching, Max Planck Inst.; Sato, Katsuhiko; /Tokyo U. /Tokyo U., RESCEU

    2006-09-21

    Two-dimensional hydrodynamic simulations are performed to investigate explosive nucleosynthesis in a collapsar using the model of MacFadyen and Woosley (1999). It is shown that {sup 56}Ni is not produced in the jet of the collapsar sufficiently to explain the observed amount of a hypernova when the duration of the explosion is {approx} 10 sec, which is considered to be the typical timescale of explosion in the collapsar model. Even though a considerable amount of {sup 56}Ni is synthesized if all explosion energy is deposited initially, the opening angles of the jets become too wide to realize highly relativistic outflows and gamma-ray bursts in such a case. From these results, it is concluded that the origin of {sup 56}Ni in hypernovae associated with GRBs is not the explosive nucleosynthesis in the jet. We consider that the idea that the origin is the explosive nucleosynthesis in the accretion disk is more promising. We also show that the explosion becomes bi-polar naturally due to the effect of the deformed progenitor. This fact suggests that the {sup 56}Ni synthesized in the accretion disk and conveyed as outflows are blown along to the rotation axis, which will explain the line features of SN 1998bw and double peaked line features of SN 2003jd. Some fraction of the gamma-ray lines from {sup 56}Ni decays in the jet will appear without losing their energies because the jet becomes optically thin before a considerable amount of {sup 56}Ni decays as long as the jet is a relativistic flow, which may be observed as relativistically Lorentz boosted line profiles in future. We show that abundance of nuclei whose mass number {approx} 40 in the ejecta depends sensitively on the energy deposition rate, which is a result of incomplete silicon burning and alpha-rich freezeout. So it may be determined by observations of chemical composition in metal poor stars which model is the proper one as a model of a gamma-ray burst accompanied by a hypernova.

  14. Nucleosynthesis in Type I X-ray Bursts

    E-Print Network [OSTI]

    A. Parikh; J. José; G. Sala; C. Iliadis

    2012-11-26

    Type I X-ray bursts are thermonuclear explosions that occur in the envelopes of accreting neutron stars. Detailed observations of these phenomena have prompted numerous studies in theoretical astrophysics and experimental nuclear physics since their discovery over 35 years ago. In this review, we begin by discussing key observational features of these phenomena that may be sensitive to the particular patterns of nucleosynthesis from the associated thermonuclear burning. We then summarize efforts to model type I X-ray bursts, with emphasis on determining the nuclear physics processes involved throughout these bursts. We discuss and evaluate limitations in the models, particularly with regard to key uncertainties in the nuclear physics input. Finally, we examine recent, relevant experimental measurements and outline future prospects to improve our understanding of these unique environments from observational, theoretical and experimental perspectives.

  15. Nucleosynthesis of heavy elements in gamma ray bursts

    E-Print Network [OSTI]

    ,

    2015-01-01

    The ultrarelativistic jets responsible for prompt and afterglow emission in gamma ray bursts are presumably driven by a central engine that consists of a dense accretion disk around a spinning black hole. We consider such engine, composed of free nucleons, electron-positron pairs, Helium nuclei, and cooled by neutrino emission. A significant number density of neutrons in the disk provide conditions for neutron rich plasma in the outflows and jets. Heavy nuclei are also formed in the accretion flow, at the distances 150-250 gravitational radii from the black hole. We study the process of nucleosynthesis in the GRB engine, depending on its physical properties. Our results may have important observational implications for the jet deceleration process and heavy elements observed in the spectra of GRB afterglows.

  16. Fission Cycling in Supernova Nucleosynthesis: Active-Sterile Neutrino Oscillations

    E-Print Network [OSTI]

    J. Beun; G. C. McLaughlin; R. Surman; W. R. Hix

    2006-02-26

    We investigate nucleosynthesis in the supernovae post-core bounce neutrino-driven wind environment in the presence of active-sterile neutrino transformation. We consider active-sterile neutrino oscillations for a range of mixing parameters: vacuum mass-squared differences of 0.1 eV^2 10^-4. We find a consistent r-process pattern for a large range of mixing parameters that is in rough agreement with the halo star CS 22892-052 abundances and the pattern shape is determined by fission cycling. We find that the allowed region for the formation of the r-process peaks overlaps the LSND and NSBL (3+1) allowed region.

  17. On Solar System and Cosmic Rays Nucleosynthesis and Spallation Processes

    E-Print Network [OSTI]

    Stepan G. Mashnik

    2000-08-24

    A brief survey of nuclide abundances in the solar-system and in cosmic rays and of the believed mechanisms of their synthesis is given. The role of spallation processes in nucleosynthesis is discussed. A short review of recent measurements, compilations, calculations, and evaluations of spallation cross sections relevant to nuclear astrophysics is given as well. It is shown that in some past astrophysical simulations, old experimental nuclear data and theoretical cross sections that are in poor agreement with recent measurements and calculations were used. New astrophysical simulations using recently measured and reliably calculated nuclear cross sections, further researches in obtaining better cross sections, and production of evaluated spallation cross sections libraries for astrophysics are suggested.

  18. BIG BANG NUCLEOSYNTHESIS WITH A NON-MAXWELLIAN DISTRIBUTION

    SciTech Connect (OSTI)

    Bertulani, C. A. [GSI Helmholtzzentrum fuer Schwerionenforschung, D-64291 Darmstadt (Germany)] [GSI Helmholtzzentrum fuer Schwerionenforschung, D-64291 Darmstadt (Germany); Fuqua, J. [Texas A and M University-Commerce, Commerce, TX 75429-3011 (United States)] [Texas A and M University-Commerce, Commerce, TX 75429-3011 (United States); Hussein, M. S. [Instituto de Estudos Avancados, Universidade de Sao Paulo, C.P. 72.012, 05508-970 Sao Paulo (Brazil)] [Instituto de Estudos Avancados, Universidade de Sao Paulo, C.P. 72.012, 05508-970 Sao Paulo (Brazil)

    2013-04-10

    The abundances of light elements based on the big bang nucleosynthesis model are calculated using the Tsallis non-extensive statistics. The impact of the variation of the non-extensive parameter q from the unity value is compared to observations and to the abundance yields from the standard big bang model. We find large differences between the reaction rates and the abundance of light elements calculated with the extensive and the non-extensive statistics. We found that the observations are consistent with a non-extensive parameter q = 1{sub -} {sub 0.12}{sup +0.05}, indicating that a large deviation from the Boltzmann-Gibbs statistics (q = 1) is highly unlikely.

  19. PRESUPERNOVA EVOLUTION AND EXPLOSIVE NUCLEOSYNTHESIS OF ZERO METAL MASSIVE STARS

    SciTech Connect (OSTI)

    Limongi, M. [Istituto Nazionale di Astrofisica-Osservatorio Astronomico di Roma, Via Frascati 33, I-00040, Monteporzio Catone, Roma (Italy); Chieffi, A., E-mail: marco.limongi@oa-roma.inaf.it, E-mail: alessandro.chieffi@inaf.it [Centre for Stellar and Planetary Astrophysics, School of Mathematical Sciences, P.O. Box, 28M, Monash University, Victoria 3800 (Australia)

    2012-04-01

    We present a new set of zero metallicity models in the range 13-80 M{sub Sun} together to the associated explosive nucleosynthesis. These models are fully homogeneous with the solar metallicity set we published in Limongi and Chieffi and will be freely available at the Online Repository for the FRANEC Evolutionary Output Web site. A comparison between these yields and an average star that represents the average behavior of most of the very metal-poor stars in the range -5.0 < [Fe/H] < -2.5 confirms previous findings that only a fraction of the elemental [X/Fe] may be fitted by the ejecta of standard core collapse supernovae.

  20. Supporting Our Veterans Anger Course Offered

    E-Print Network [OSTI]

    Oliver, Douglas L.

    Supporting Our Veterans Anger Course Offered Veterans receiving treatment for post-traumatic stress on cognitive-behavioral treatment and offers a wide range of practical skills and tools to help veterans learn

  1. erson offering to a current UC

    E-Print Network [OSTI]

    of the followin a former UC emp ness offering goo C employee and I ness offering goo ncial interest in th ve of a current U ve ve of a current U e University. ve ness offering goo ncial interest in th rnia, Santa Barb

  2. Sample Job Offer Letter Best Company, Inc.

    E-Print Network [OSTI]

    Awtar, Shorya

    Sample Job Offer Letter Best Company, Inc. 1553 Job Street, Ann Arbor, MI 48105 (Tel) (734) 000 would like to offer (student's name here) an internship position. Below is the information you requested: 1553 Job Street, Ann Arbor, MI 48105 Number of hours worked per week: 40 Official offer beginning

  3. Summary of Curricula Offered Course Information

    E-Print Network [OSTI]

    Gallo, Linda C.

    PART FIVE Summary of Curricula Offered Course Information · Accreditation · Course Abbreviations Courses and Curricula #12;78 SDSU GRADUATE BULLETIN 2015-2016 Types of Curricula Offered San Diego State University offers the following types of curricula: Undergraduate Curricula. Undergraduate curricula provide

  4. Conditional Offer Letter Executive/Senior Administrative

    E-Print Network [OSTI]

    Acton, Scott

    Conditional Offer Letter Web Form Executive/Senior Administrative University Staff Introduction below will generate a standard conditional offer letter based on information entered by the user. This conditional offer letter web form is specific to the hiring of E&SA University Staff employees

  5. MULTIPLE BUYING OR SELLING WITH VECTOR OFFERS

    E-Print Network [OSTI]

    Ferguson, Thomas S.

    MULTIPLE BUYING OR SELLING WITH VECTOR OFFERS F. THOMAS BRUSS , Universit´e Libre de Bruxelles of the house-selling problem to selling k houses. Let the offers, X1, X2, . . ., be independent, identically with recall of past offers and to problems with a discount. KEYWORDS: OPTIMAL STOPPING, HOUSE-SELLING, JOB

  6. Primordial nucleosynthesis as a probe of fundamental physics parameters

    E-Print Network [OSTI]

    Thomas Dent; Steffen Stern; Christof Wetterich

    2007-08-10

    We analyze the effect of variation of fundamental couplings and mass scales on primordial nucleosynthesis in a systematic way. The first step establishes the response of primordial element abundances to the variation of a large number of nuclear physics parameters, including nuclear binding energies. We find a strong influence of the n-p mass difference (for the 4He abundance), of the nucleon mass (for deuterium) and of A=3,4,7 binding energies (for 3He, 6Li and 7Li). A second step relates the nuclear parameters to the parameters of the Standard Model of particle physics. The deuterium, and, above all, 7Li abundances depend strongly on the average light quark mass hat{m} \\equiv (m_u+m_d)/2. We calculate the behaviour of abundances when variations of fundamental parameters obey relations arising from grand unification. We also discuss the possibility of a substantial shift in the lithium abundance while the deuterium and 4He abundances are only weakly affected.

  7. Nucleosynthesis in neutrino-driven winds after neutron star mergers

    E-Print Network [OSTI]

    Martin, Dirk; Arcones, Almudena; Thielemann, Friedrich-Karl; Korobkin, Oleg; Rosswog, Stephan

    2015-01-01

    We present a comprehensive nucleosynthesis study of the neutrino-driven wind in the aftermath of a binary neutron star merger. Our focus is the initial remnant phase when a massive central neutron star is present. Using tracers from a recent hydrodynamical simulation, we determine total masses and integrated abundances to characterize the composition of unbound matter. We find that the nucleosynthetic yields depend sensitively on both the life time of the massive neutron star and the polar angle. Matter in excess of up to $9 \\cdot 10^{-3} M_\\odot$ becomes unbound until $\\sim 200~{\\rm ms}$. Due to electron fractions of $Y_{\\rm e} \\approx 0.2 - 0.4$ mainly nuclei with mass numbers $A < 130$ are synthesized, complementing the yields from the earlier dynamic ejecta. Mixing scenarios with these two types of ejecta can explain the abundance pattern in r-process enriched metal-poor stars. Additionally, we calculate heating rates for the decay of the freshly produced radioactive isotopes. The resulting light curve...

  8. Chaos and turbulent nucleosynthesis prior to a supernova explosion

    SciTech Connect (OSTI)

    Arnett, W. D., E-mail: darnett@as.arizona.edu; Meakin, C., E-mail: cmeakin@as.arizona.edu [Steward Observatory, University of Arizona, 933 N. Cherry Avenue, Tucson AZ 85721 (United States); Viallet, M., E-mail: mviallet@mpa-garching.mpg.de [Max-Planck Institut für Astrophysik, Karl Schwarzschild Strasse 1, Garching, D-85741 (Germany)

    2014-04-15

    Three-dimensional (3D), time dependent numerical simulations of flow of matter in stars, now have sufficient resolution to be fully turbulent. The late stages of the evolution of massive stars, leading up to core collapse to a neutron star (or black hole), and often to supernova explosion and nucleosynthesis, are strongly convective because of vigorous neutrino cooling and nuclear heating. Unlike models based on current stellar evolutionary practice, these simulations show a chaotic dynamics characteristic of highly turbulent flow. Theoretical analysis of this flow, both in the Reynolds-averaged Navier-Stokes (RANS) framework and by simple dynamic models, show an encouraging consistency with the numerical results. It may now be possible to develop physically realistic and robust procedures for convection and mixing which (unlike 3D numerical simulation) may be applied throughout the long life times of stars. In addition, a new picture of the presupernova stages is emerging which is more dynamic and interesting (i.e., predictive of new and newly observed phenomena) than our previous one.

  9. Supernova nucleosynthesis and the physics of neutrino oscillation

    SciTech Connect (OSTI)

    Kajino, Toshitaka [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan) and Department of Astronomy, Graduate School of Science, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2012-11-20

    We studied the explosive nucleosynthesis in core-collapse supernovae and found that several isotopes of rare elements like {sup 7}Li, {sup 11}B, {sup 138}La, {sup 180}Ta and others are predominantly produced by the neutrino interactions with several abundant nuclei. These isotopes are strongly affected by the neutrino flavor oscillation due to the MSW (Mikheyev-Smirnov-Wolfenstein) effect. We here first study how to know the suitable average neutrino temperatures in order to explain the observed solar system abundances of these isotopes, combined with Galactic chemical evolution of the light nuclei and the heavy r-process elements. We then study the neutrino oscillation effects on their abundances, and propose a new novel method to determine the neutrino oscillation parameters, {theta}{sub 13} and mass hierarchy, simultaneously. There is recent evidence that some SiC X grains from the Murchison meteorite may contain supernova-produced neutrino-process {sup 11}B and {sup 7}Li encapsulated in the grains. Combining the recent experimental constraints on {theta}{sub 13}, we show that although the uncertainties are still large, our method hints at a marginal preference for an inverted neutrino mass hierarchy for the first time.

  10. Restrictions on the lifetime of sterile neutrinos from primordial nucleosynthesis

    SciTech Connect (OSTI)

    Ruchayskiy, Oleg [Physics Department, Theory Division, CERN, CH-1211 Geneva 23 (Switzerland); Ivashko, Artem, E-mail: oleg.ruchayskiy@epfl.ch, E-mail: ivashko@lorentz.leidenuniv.nl [Instituut-Lorentz for Theoretical Physics, Universiteit Leiden, Niels Bohrweg 2, Leiden (Netherlands)

    2012-10-01

    We analyze the influence of sterile neutrinos with the masses in the MeV range on the primordial abundances of Helium-4 and Deuterium. We solve explicitly the Boltzmann equations for all particle species, taking into account neutrino flavour oscillations and demonstrate that the abundances are sensitive mostly to the sterile neutrino lifetime and only weakly to the way the active-sterile mixing is distributed between flavours. The decay of these particles also perturbs the spectra of (decoupled) neutrinos and heats photons, changing the ratio of neutrino to photon energy density, that can be interpreted as extra neutrino species at the recombination epoch. We derive upper bounds on the lifetime of sterile neutrinos based on both astrophysical and cosmological measurements of Helium-4 and Deuterium. We also demonstrate that the recent results of Izotov and Thuan [1], who find 2? higher than predicted by the standard primordial nucleosynthesis value of Helium-4 abundance, are consistent with the presence in the plasma of sterile neutrinos with the lifetime 0.01–2 seconds.

  11. The r-process nucleosynthesis: Nuclear physics challenges

    SciTech Connect (OSTI)

    Goriely, S.

    2012-10-20

    About half of the nuclei heavier than iron observed in nature are produced by the socalled rapid neutron capture process, or r-process, of nucleosynthesis. The identification of the astrophysics site and the specific conditions in which the r-process takes place remains, however, one of the still-unsolved mysteries of modern astrophysics. Another underlying difficulty associated with our understanding of the r-process concerns the uncertainties in the predictions of nuclear properties for the few thousands exotic neutron-rich nuclei involved and for which essentially no experimental data exist. The present contribution emphasizes some important future challenges faced by nuclear physics in this problem, particularly in the determination of the nuclear structure properties of exotic neutron-rich nuclei as well as their radiative neutron capture rates and their fission probabilities. These quantities are particularly relevant to determine the composition of the matter resulting from the r-process. Their impact on the r-abundance distribution resulting from the decompression of neutron star matter is discussed.

  12. JOBAID- WITHDRAWING FROM A SCHEDULED OFFERING

    Broader source: Energy.gov [DOE]

    The purpose of this job aid is to guide users through the step-by-step process of withdrawing from a scheduled offering.

  13. Denton Municipal Electric- Standard Offer Rebate Program

    Broader source: Energy.gov [DOE]

    Within the GreenSense program, Denton Municipal Electric's Standard Offer Program provides rebates to large commercial and industrial customers for lighting retrofits, HVAC upgrades and motor...

  14. Peptoid Nanosheets Offer a Diversity of Functionalities

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Peptoid Nanosheets Offer a Diversity of Functionalities Print Researchers at the ALS have recently observed peptoid nanosheets-two-dimensional biomimetic materials with...

  15. Tosic et al. Web Service Offerings Infrastructure (WSOI) -... 1 Web Service Offerings Infrastruc-

    E-Print Network [OSTI]

    Tosic et al. Web Service Offerings Infrastructure (WSOI) - ... 1 Web Service Offerings Infrastruc Engineering, Carleton University, Ottawa, Canada August 16, 2003 #12;Tosic et al. Web Service Offerings Infrastructure (WSOI) - ... 2 #12;Tosic et al. Web Service Offerings Infrastructure (WSOI) - ... 3 Web Service

  16. 2012-2013 GEISEL SCHOOL OF MEDICINE Elective & SubInternship Offerings Email:Offered

    E-Print Network [OSTI]

    Myers, Lawrence C.

    1 2012-2013 GEISEL SCHOOL OF MEDICINE Elective & SubInternship Offerings Pre Req: Email:Offered LosebyCoordinator: 603-653-0516ANESDept: Pre Req: Email:Offered: None Terry. Surgenor, MDFaculty: Terry JohnsonCoordinator: 603-650-4642ANESDept: Pre Req: Email:Offered: S/C Surgery

  17. Pirate Tutoring Center SUMMER 2015 Daytime Offerings Appointments are offered for

    E-Print Network [OSTI]

    Gopalakrishnan, K.

    Pirate Tutoring Center SUMMER 2015 Daytime Offerings Appointments are offered for: Summer Session 1, 2173, 2228, 2283 PHYS 1250, 1260, 2360 SPAN 1001-1004 Blackboard Tutoring Tutorial Videos offered-737-3009 for a tutoring appointment. PTC location: 2300 Old Cafeteria Complex Find the PTC on the second floor. PTC offers

  18. The Effects of Thermonuclear Reaction Rate Variations on Nova Nucleosynthesis: A Sensitivity Study

    E-Print Network [OSTI]

    Christian Iliadis; Art Champagne; Jordi Jose; Sumner Starrfield; Paul Tupper

    2002-06-03

    We investigate the effects of thermonuclear reaction rate uncertainties on nova nucleosynthesis. One-zone nucleosynthesis calculations have been performed by adopting temperature-density-time profiles of the hottest hydrogen-burning zone (i.e., the region in which most of the nucleosynthesis takes place). We obtain our profiles from 7 different, recently published, hydrodynamic nova simulations covering peak temperatures in the range from Tpeak=0.145-0.418 GK. For each of these profiles, we individually varied the rates of 175 reactions within their associated errors and analyzed the resulting abundance changes of 142 isotopes in the mass range below A=40. In total, we performed 7350 nuclear reaction network calculations. We use the most recent thermonuclear reaction rate evaluations for the mass ranges A=1-20 and A=20-40. For the theoretical astrophysicist, our results indicate the extent to which nova nucleosynthesis calculations depend on presently uncertain nuclear physics input, while for the experimental nuclear physicist our results represent at least a qualitative guide for future measurements at stable and radioactive ion beam facilities. We find that present reaction rate estimates are reliable for predictions of Li, Be, C and N abundances in nova nucleosynthesis. However, rate uncertainties of several reactions have to be reduced significantly in order to predict more reliable O, F, Ne, Na, Mg, Al, Si, S, Cl and Ar abundances. Results are presented in tabular form for each adopted nova simulation.

  19. 20% Discount PrePub Offer

    E-Print Network [OSTI]

    Sørensen, Michael

    20% Discount Pre­Pub Offer List Price: $69.95 (tent.) Special Price: $55.96 + shipping & handling Please mention reference #Y402 when placing your order! Offer Valid Until August 31, 2002 Table. 2002 / Approx. 400 pp. / Hardcover ISBN 0­8176­4201­3/ List Price US$69.95 (tent.) SPECIAL PRICE: US$55

  20. 3270 Film and Video Program Offered

    E-Print Network [OSTI]

    Dhamala, Mukesh

    3270 Film and Video Program Offered: Bachelor of Arts in Film and Video Department of Communication of the mass media, and the skills necessary for communication careers. Majors are offered in the areas of film and video, journalism, and speech. The major in film and video is designed to provide the student

  1. ...offers early cost-effectiveness check

    E-Print Network [OSTI]

    Oakley, Jeremy

    that an innovation is a `must' ­ offering lower costs for enhanced health outcomes. Or it might turn outMATCH Tool ...offers early cost- effectiveness check on innovations ® Medical Device Evaluation and costs persuade the NHS to buy the innovation? In just three hours, the company was able to check out its

  2. Hot Bottom Burning Nucleosynthesis in 6 M fi Stellar Models J. C. Lattanzio and C. A. Frost a , R. C. Cannon b , and P. R. Wood c .

    E-Print Network [OSTI]

    Lattanzio, John

    1 Hot Bottom Burning Nucleosynthesis in 6 M fi Stellar Models J. C. Lattanzio and C. A. Frost a , R, Australia We present a brief summary of some nucleosynthesis calculations for 6 M fi stellar models. Theoretical studies are desperately needed to quantify the nucleosynthesis which occurs in intermediate mass

  3. Probing the Neutron-Capture Nucleosynthesis History of Galactic James W. Truran 1 , John J. Cowan 2 , Catherine A. Pilachowski 3 and Christopher Sneden 4

    E-Print Network [OSTI]

    Cowan, John

    Probing the Neutron-Capture Nucleosynthesis History of Galactic Matter James W. Truran 1 , John J formation and nucleosynthesis history of Galactic matter. Of particular interest in this regard; ) stars that provide the site for the main s-process nucleosynthesis component during the AGB phase

  4. FE ISOTOPE NUCLEOSYNTHESIS: CONSTRAINTS FROM FE ISOTOPIC ANALYSES OF PRESOLAR SILICATE GRAINS FROM ACFER 094. W. J. Ong and C. Floss. Laboratory for Space Sciences

    E-Print Network [OSTI]

    Floss, Christine

    FE ISOTOPE NUCLEOSYNTHESIS: CONSTRAINTS FROM FE ISOTOPIC ANALYSES OF PRESOLAR SILICATE GRAINS FROM information about fundamental astrophysical processes, such as stellar nucleosynthesis and galactic chemical evolution. Iron is of particular interest because of its importance in s-process nucleosynthesis. However

  5. Post-AGB stars as testbeds of nucleosynthesis in AGB stars

    E-Print Network [OSTI]

    G. Stasinska; R. Szczerba; M. Schmidt; N. Siodmiak

    2006-01-23

    We construct a data base of 125 post-AGB objects (including R CrB and extreme helium stars) with published photospheric parameters (effective temperature and gravity) and chemical composition. We estimate the masses of the post-AGB stars by comparing their position in the (log Teff, log g) plane with theoretical evolutionary tracks of different masses. We construct various diagrams, with the aim of finding clues to AGB nucleosynthesis. This is the first time that a large sample of post-AGB stars has been used in a systematic way for such a purpose and we argue that, in several respects, post-AGB stars should be more powerful than planetary nebulae to test AGB nucleosynthesis. Our main findings are that: the vast majority of objects which do not show evidence of N production from primary C have a low stellar mass (M* nucleosynthesis.

  6. Nucleosynthesis in a massive star associated with magnetohydrodynamical jets from collapsars

    SciTech Connect (OSTI)

    Ono, M.; Hashimoto, M.; Fujimoto, S.; Kotake, K.; Yamada, S. [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502, Japan and Department of Physics, Kyushu University, Fukuoka 812-8581 (Japan); Department of Physics, Kyushu University, Fukuoka 812-8581 (Japan); Kumamoto National College of Technology, Kumamoto 861-1102 (Japan); Division of Theoretical Astronomy/Center for Computational Astrophysics, National Astronomical Observatory of Japan, Tokyo 181-8588 (Japan); Advanced Research Institute for Science and Engineering, Waseda University, Tokyo 169-8555 (Japan)

    2012-11-12

    We investigate the nucleosynthesis during the stellar evolution and the jet-like supernova explosion of a massive star of 70 M{sub Circled-Dot-Operator} having the solar metallicity in the main sequence stage. The nucleosynthesis calculations have been performed with large nuclear reaction networks, where the weak s-, p-, and r-processes are taken into account. As a result s-elements of 60 > A > 90 and r-elements of 90 > A > 160 are highly overproduced relative to the solar system abundances. We find that the Sr-Y-Zr isotopes are primarily synthesized in the explosive nucleosynthesis which could be one of the sites of the lighter element primary process (LEPP).

  7. Light-Element Reaction Flow and the Conditions for r-Process Nucleosynthesis

    E-Print Network [OSTI]

    T. Sasaqui; K. Otsuki; T. Kajino; G. J. Mathews

    2006-03-18

    We deduce new constraints on the entropy per baryon ($s/k$), dynamical timescale ($\\tau_{dyn}$), and electron fraction ($Y_{e}$) consistent with heavy element nucleosynthesis in the r-process. We show that the previously neglected reaction flow throu gh the reaction sequence \\atg (n,$\\gamma$)\\Li~ significantly enhances the production of seed nuclei. We analyze the r-process nucleosynthesis in the context of a schematic exponential wi nd model. We show that fewer neutrons per seed nucleus implies that the entropy per baryon required for successful r-process nucleosynthesis must be more than a factor of two higher than previous estimates. This places new constraints on dynamical mo dels for the r-process.

  8. Sensitivity study of explosive nucleosynthesis in Type Ia supernovae: I. Modification of individual thermonuclear reaction rates

    E-Print Network [OSTI]

    Eduardo Bravo; Gabriel Martínez-Pinedo

    2012-04-09

    We explore the sensitivity of the nucleosynthesis due to type Ia supernovae with respect to uncertainties in nuclear reaction rates. We have adopted a standard one-dimensional delayed detonation model of the explosion of a Chandrasekhar-mass white dwarf, and have post-processed the thermodynamic trajectories of every mass-shell with a nucleosynthetic code, with increases (decreases) by a factor of ten on the rates of 1196 nuclear reactions. We have computed as well hydrodynamic models for different rates of the fusion reactions of 12C and of 16O. For selected reactions, we have recomputed the nucleosynthesis with alternative prescriptions for their rates taken from the JINA REACLIB database, and have analyzed the temperature ranges where modifications of their rates have the strongest effect on nucleosynthesis. The nucleosynthesis resulting from the Type Ia supernova models is quite robust with respect to variations of nuclear reaction rates, with the exception of the reaction of fusion of 12C nuclei. The energy of the explosion changes by less than \\sim4%. The changes in the nucleosynthesis due to the modification of the rates of fusion reactions are as well quite modest, for instance no species with a mass fraction larger than 0.02 experiences a variation of its yield larger than a factor of two. We provide the sensitivity of the yields of the most abundant species with respect to the rates of the most intense reactions with protons, neutrons, and alphas. In general, the yields of Fe-group nuclei are more robust than the yields of intermediate-mass elements. Among the charged particle reactions, the most influential on supernova nucleosynthesis are 30Si + p \\rightleftarrows 31P + {\\gamma}, 20Ne + {\\alpha} \\rightleftarrows 24Mg + {\\gamma}, and 24Mg + {\\alpha} \\rightleftarrows 27Al + p. The temperatures at which a modification of their rate has a larger impact are in the range 2 < T < 4 GK. (abridged)

  9. Supernova SN1987A Bound on Neutrino Spectra for R-Process Nucleosynthesis

    E-Print Network [OSTI]

    C. J. Horowitz

    2002-01-31

    The neutrino driven wind during a core collapse supernova is an attractive site for r-process nucleosynthesis. The electron fraction $Y_e$ in the wind depends on observable neutrino energies and luminosities. The mean antineutrino energy is limited by supernova SN1987A data while lepton number conservation constrains the ratio of antineutrino to neutrino luminosities. If $Y_e$, in the wind, is to be suitable for rapid neutron capture nucleosynthesis, then the mean electron neutrino energy may be significantly lower then that predicted in present supernova simulations, or there may be new neutrino physics such as oscillations to sterile neutrinos.

  10. NEUTRINO SPECTRA FROM ACCRETION DISKS: NEUTRINO GENERAL RELATIVISTIC EFFECTS AND THE CONSEQUENCES FOR NUCLEOSYNTHESIS

    SciTech Connect (OSTI)

    Caballero, O. L.; McLaughlin, G. C. [Department of Physics, North Carolina State University, Raleigh, NC 27695 (United States); Surman, R., E-mail: lcaballe@uw.edu, E-mail: olcaball@ncsu.edu, E-mail: gail_mclaughlin@ncsu.edu, E-mail: surmanr@union.edu [Department of Physics and Astronomy, Union College, Schenectady, NY 12308 (United States)

    2012-02-01

    Black hole (BH) accretion disks have been proposed as good candidates for a range of interesting nucleosynthesis, including the r-process. The presence of the BH influences the neutrino fluxes and affects the nucleosynthesis resulting from the interaction of the emitted neutrinos and hot outflowing material ejected from the disk. We study the impact of general relativistic effects on the neutrinos emitted from BH accretion disks. We present abundances obtained by considering null geodesics and energy shifts for two different disk models. We find that both the bending of the neutrino trajectories and the energy shifts have important consequences for the nucleosynthetic outcome.

  11. Non-universal scalar-tensor theories and big bang nucleosynthesis

    E-Print Network [OSTI]

    Alain Coc; Keith A. Olive; Jean-Philippe Uzan; Elisabeth Vangioni

    2008-11-12

    We investigate the constraints that can be set from big-bang nucleosynthesis on two classes of models: extended quintessence and scalar-tensor theories of gravity in which the equivalence principle between standard matter and dark matter is violated. In the latter case, and for a massless dilaton with quadratic couplings, the phase space of theories is investigated. We delineate those theories where attraction toward general relativity occurs. It is shown that big-bang nucleosynthesis sets more stringent constraints than those obtained from Solar system tests.

  12. Neutrino Spectra from Accretion Disks: Neutrino General Relativistic Effects and the Consequences for Nucleosynthesis

    E-Print Network [OSTI]

    O. L Caballero; G. C. McLaughlin; R. Surman

    2011-05-31

    Black hole accretion disks have been proposed as good candidates for a range of interesting nucleosynthesis, including the r-process. The presence of the black hole influences the neutrino fluxes and affects the nucleosynthesis resulting from the interaction of the emitted neutrinos and hot outflowing material ejected from the disk. We study the impact of general relativistic effects on the neutrinos emitted from black hole accretion disks. We present abundances obtained by considering null geodesics and energy shifts for two different disk models. We find that both the bending of the neutrino trajectories and the energy shifts have important consequences for the nucleosynthetic outcome

  13. ORIGINAL ARTICLE Offer Shai Efim Mohr

    E-Print Network [OSTI]

    Shai, Offer

    ORIGINAL ARTICLE Offer Shai Æ Efim Mohr Transforming engineering knowledge through graph introduces an approach for trans- forming methods and knowledge between different engineering fields through ways of conducting engineering research by enabling a systematic derivation of engineering knowledge

  14. University Archives offers Orange Bowl Exhibit

    E-Print Network [OSTI]

    2007-12-11

    University Archives offers Orange Bowl Exhibit KU's University Archives, located in Spencer Research Library, has brought together items from its collections relating to the 1948 and 1969 Orange Bowl games. Included in the small exhibit are a souvenir KU '68...

  15. BEST OFFER EVER ACCELERATED TEXAS UPGRADES | Department of Energy

    Energy Savers [EERE]

    upgrades. Program Design: Historically, Austin Energy customers had taken advantage of rebate-only offers more often than loan-only offers. Austin Energy's Best Offer Ever allowed...

  16. Attachment 2: Solicitation for Offers with New and Revised Green...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2: Solicitation for Offers with New and Revised Green Lease Text Attachment 2: Solicitation for Offers with New and Revised Green Lease Text PDF icon Solicitation for Offers...

  17. Offer patterns of nationally placed livers by donation service area

    E-Print Network [OSTI]

    Lai, JC; Feng, S; Vittinghoff, E; Roberts, JP

    2013-01-01

    affect the number of offers that would be expected to arise404–410, 2013 ORIGINAL ARTICLE Offer Patterns of Nationallyevaluated all national offers of nationally placed livers (

  18. Berkeley Program Offers New Option for Financing Residential PV Systems

    E-Print Network [OSTI]

    Bolinger, Mark A

    2009-01-01

    Berkeley Program Offers New Option for Financing Residentialparticularly those that offer solar rebates. The passage ofthese cities propose to offer their residents the ability to

  19. Young children selectively seek and offer help when solving problems

    E-Print Network [OSTI]

    Cluver, Annette Lynne

    2010-01-01

    Selectively Seek and Offer Help When Solving Problems Achildren selectively seek and offer help on problem-solvingselectively seek and offer help when solving problems in the

  20. Lithium in cool stellar atmospheres: Big bang nucleosynthesis and extrasolar planets

    E-Print Network [OSTI]

    Lithium in cool stellar atmospheres: Big bang nucleosynthesis and extrasolar planets Matthias Steffen and Elisabetta Caffau Sternphysik In metal-poor stellar atmospheres, the Lithium line at 6707 Ã?-NLTE, respectively. The accurate spectroscopic determination of the Lithium abundance and in particular the 6Li/7Li

  1. Big Bang Nucleosynthesis Constraints on the Self-Gravity of Pressure

    E-Print Network [OSTI]

    Saul Rappaport; Josiah Schwab; Scott Burles; Gary Steigman

    2007-10-28

    Using big bang nucleosynthesis and present, high-precision measurements of light element abundances, we constrain the self-gravity of radiation pressure in the early universe. The self-gravity of pressure is strictly non-Newtonian, and thus the constraints we set provide a direct test of this prediction of general relativity and of the standard, Robertson-Walker-Friedmann cosmology.

  2. Dark matter relic abundance and big bang nucleosynthesis in Horava's gravity

    SciTech Connect (OSTI)

    Lambiase, G. [University of Salerno (Italy); INFN, Sezione di Napoli (Italy)

    2011-05-15

    The cosmological consequences of Horava's gravity are reviewed in the frameworks of the PAMELA experiment (which has reported an excess of positron events that likely can be ascribed to weakly interacting massive particles dark matter) and of big bang nucleosynthesis. Constraints on parameters characterizing Horawa's cosmology are derived.

  3. Big Bang Nucleosynthesis with Bound States of Long-lived Charged Particles

    E-Print Network [OSTI]

    Manoj Kaplinghat; Arvind Rajaraman

    2007-01-18

    Charged particles (X) decaying after primordial nucleosynthesis are constrained by the requirement that their decay products should not change the light element abundances drastically. If the decaying particle is negatively charged (X-) then it will bind to the nuclei. We consider the effects of the decay of X when bound to Helium-4 and show that this will modify the Lithium abundances.

  4. Constraints on the Self-Gravity of Radiation Pressure via Big Bang Nucleosynthesis

    E-Print Network [OSTI]

    Saul Rappaport; Josiah Schwab; Scott Burles

    2007-07-24

    Using standard big-bang nucleosynthesis and present, high-precision measurements of light element abundances, we place constraints on the self-gravity of radiation pressure in the early universe. The self-gravity of pressure is strictly non-Newtonian, and thus the constraints we set are a direct test of this aspect of general relativity.

  5. Nucleosynthesis of Elements in Low to Intermediate Mass Stars through the AGB Phase

    E-Print Network [OSTI]

    John C. Lattanzio; Arnold I. Boothroyd

    1997-05-23

    We present a review of the main phases of stellar evolution with particular emphasis on the nucleosynthesis and mixing mechanisms in low- and intermediate-mass stars. In addition to explicit studies of the effects of the first, second and third dredge-up, we also discuss cool bottom processing and hot bottom burning.

  6. The X^- Solution to the ^6Li and ^7Li Big Bang Nucleosynthesis Problems

    E-Print Network [OSTI]

    Motohiko Kusakabe; Toshitaka Kajino; Richard N. Boyd; Takashi Yoshida; Grant J. Mathews

    2008-03-24

    The $^6$Li abundance observed in metal poor halo stars appears to exhibit a plateau as a function of metallicity similar to that for $^7$Li, suggesting a big bang origin. However, the inferred primordial abundance of $^6$Li is $\\sim$1000 times larger than that predicted by standard big bang nucleosynthesis for the baryon-to-photon ratio inferred from the WMAP data. Also, the inferred $^7$Li primordial abundance is 3 times smaller than the big bang prediction. We here describe in detail a possible simultaneous solution to both the problems of underproduction of $^6$Li and overproduction of $^7$Li in big bang nucleosynthesis. This solution involves a hypothetical massive, negatively-charged leptonic particle that would bind to the light nuclei produced in big bang nucleosynthesis, but would decay long before it could be detected. We consider only the $X$-nuclear reactions and assume that the effect of decay products is negligible, as would be the case if lifetime were large or the mass difference between the charged particle and its daughter were small. An interesting feature of this paradigm is that, because the particle remains bound to the existing nuclei after the cessation of the usual big bang nuclear reactions, a second longer epoch of nucleosynthesis can occur among $X$-nuclei. We confirm that reactions in which the hypothetical particle is transferred can occur that greatly enhance the production of $^6$Li while depleting $^7$Li. We also identify a new reaction that destroys large amounts of $^7$Be, and hence reduces the ultimate $^7$Li abundance. Thus, big-bang nucleosynthesis in the presence of these hypothetical particles, together with or without an event of stellar processing, can simultaneously solve the two Li abundance problems.

  7. Microsoft Word - REPSIA template as offered to IOUs.doc

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    4. Establishment of ASC to Activate Participation ... 5. Offer by Customer Name and Purchase by BPA ... 6. Offer by BPA...

  8. BIOENGINEERING at a Glance Degrees Offered

    E-Print Network [OSTI]

    BIOENGINEERING at a Glance Degrees Offered BS, MS, BS/MS, PhD Faculty Total Faculty: 12, 1 Adjunct of Health National Science Foundation The Department of Bioengineering, at the University of California's mission is to forge future leaders in bioengineering while focusing on solutions to critical themes

  9. Human Resource Procedure: Employment Offer Letters Revised May 21, 2014

    E-Print Network [OSTI]

    Stuart, Steven J.

    Human Resource Procedure: Employment Offer Letters 1 Revised ­ May 21, 2014 Purpose An offer letter and employee regarding the employee's employment with Clemson. Therefore, all offer letters need to contain specific and accurate information about the offer of employment. When is an offer letter used? Offer

  10. Constraints on unparticle long range forces from big bang nucleosynthesis bounds on the variation of the gravitational coupling

    E-Print Network [OSTI]

    O. Bertolami; N. M. C. Santos

    2009-06-18

    We use big bang nucleosynthesis bounds on the variation of the gravitational coupling to derive constraints on the strength of the deviation from the gravitational inverse-square law due to tensor and vector unparticle exchange.

  11. Modules Available by Distance Studies and Evening Course Offerings: The following review is based on past course offerings. While the future cannot be predicted, courses offered in the

    E-Print Network [OSTI]

    Lennard, William N.

    1 Modules Available by Distance Studies and Evening Course Offerings: March 2014 The following review is based on past course offerings. While the future cannot be predicted, courses offered distance and/or evening courses. Individual departments decide on which courses they will offer in a given

  12. The impact of individual nuclear properties on $r$-process nucleosynthesis

    E-Print Network [OSTI]

    Mumpower, M R; McLaughlin, G C; Aprahamian, A

    2015-01-01

    The astrophysical rapid neutron capture process or `$r$ process' of nucleosynthesis is believed to be responsible for the production of approximately half the heavy element abundances found in nature. This multifaceted problem remains one of the greatest open challenges in all of physics. Knowledge of nuclear physics properties such as masses, $\\beta$-decay and neutron capture rates, as well as $\\beta$-delayed neutron emission probabilities are critical inputs that go into calculations of $r$-process nucleosynthesis. While properties of nuclei near stability have been established, much still remains unknown regarding neutron-rich nuclei far from stability that may participate in the $r$ process. Sensitivity studies gauge the astrophysical response of a change in nuclear physics input(s) which allows for the isolation of the most important nuclear properties that shape the final abundances observed in nature. This review summarizes the extent of recent sensitivity studies and highlights how these studies play ...

  13. KADoNiS- The Karlsruhe Astrophysical Database of Nucleosynthesis in Stars

    E-Print Network [OSTI]

    I. Dillmann; M. Heil; F. Käppeler; R. Plag; T. Rauscher; F. -K. Thielemann

    2008-05-30

    The "Karlsruhe Astrophysical Database of Nucleosynthesis in Stars" (KADoNiS) project is an online database for experimental cross sections relevant to the s process and p process. It is available under http://nuclear-astrophysics.fzk.de/kadonis and consists of two parts. Part 1 is an updated sequel to the previous Bao et al. compilations from 1987 and 2000 for (n,$\\gamma$) cross sections relevant to the big bang and s-process nucleosynthesis. The second part will be an experimental p-process database, which is expected to be launched in winter 2005/06. The KADoNiS project started in April 2005, and a first partial update is online since August 2005. In this paper we present a short overview of the first update of the s-process database, as well as an overview of the status of stellar (n,$\\gamma$) cross sections of all 32 p isotopes.

  14. Computational Methods for Nucleosynthesis and Nuclear Energy Generation

    E-Print Network [OSTI]

    W. R. Hix; F. -K. Thielemann

    1999-06-29

    This review concentrates on the two principle methods used to evolve nuclear abundances within astrophysical simulations, evolution via rate equations and via equilibria. Because in general the rate equations in nucleosynthetic applications form an extraordinarily stiff system, implicit methods have proven mandatory, leading to the need to solve moderately sized matrix equations. Efforts to improve the performance of such rate equation methods are focused on efficient solution of these matrix equations, by making best use of the sparseness of these matrices. Recent work to produce hybrid schemes which use local equilibria to reduce the computational cost of the rate equations is also discussed. Such schemes offer significant improvements in the speed of reaction networks and are accurate under circumstances where calculations with complete equilibrium fail.

  15. Nucleosynthesis in novae: experimental progress in the determination of nuclear reaction rates

    E-Print Network [OSTI]

    Alain Coc

    2008-01-18

    The sources of nuclear uncertainties in nova nucleosynthesis have been identified using hydrodynamical nova models. Experimental efforts have followed and significantly reduced those uncertainties. This is important for the evaluation of nova contribution to galactic chemical evolution, gamma--ray astronomy and possibly presolar grain studies. In particular, estimations of expected gamma-ray fluxes are essential for the planning of observations with existing or future satellites.

  16. An ERC Starting Grant project on p-process nucleosynthesis concluded

    E-Print Network [OSTI]

    Gyürky, Gy; Szücs, T; Kiss, G G; Fülöp, Zs

    2015-01-01

    In 2008 a Starting Grant project supported by the European Research Council titled "Nuclear reaction studies relevant to the astrophysical p-process nucleosynthesis" was launched. After five years of successful research related to the experimental investigation of proton- and alpha-induced nuclear reaction for the astrophysical p-process, the project came to an end. In this paper a summary of the research and the most important achievements is given.

  17. An ERC Starting Grant project on p-process nucleosynthesis concluded

    E-Print Network [OSTI]

    Gy Gyürky; Z Halász; T Szücs; G G Kiss; Zs Fülöp

    2015-09-03

    In 2008 a Starting Grant project supported by the European Research Council titled "Nuclear reaction studies relevant to the astrophysical p-process nucleosynthesis" was launched. After five years of successful research related to the experimental investigation of proton- and alpha-induced nuclear reaction for the astrophysical p-process, the project came to an end. In this paper a summary of the research and the most important achievements is given.

  18. A Big-Bang Nucleosynthesis Limit on the Neutral Fermion Decays into Neutrinos

    E-Print Network [OSTI]

    Motohiko Kusakabe; A. B. Balantekin; Toshitaka Kajino; Y. Pehlivan

    2013-04-09

    Using the primordial helium abundance, an upper limit to the magnetic moments for Dirac neutrinos had been provided by imposing restrictions on the number of the additional helicity states. Considering non-thermal photons produced in the decay of the heavy sterile mass eigenstates due to the neutrino magnetic moment, we explore the constraints imposed by the observed abundances of all the light elements produced during the Big Bang nucleosynthesis.

  19. POSTGRADUATE UAC OFFERS 2015 Acceptance and Enrolment Information

    E-Print Network [OSTI]

    Fleming, Andrew J.

    POSTGRADUATE UAC OFFERS 2015 Acceptance and Enrolment Information How do I accept my offer? When you receive a Universities Admissions Centre (UAC) offer to study at the University of Newcastle, you must first accept your offer online if you intend to enrol. To accept your offer you will need

  20. Nucleosynthesis in core-collapse supernova explosions triggered by a quark-hadron phase transition

    E-Print Network [OSTI]

    Nobuya Nishimura; Tobias Fischer; Friedrich-Karl Thielemann; Carla Fröhlich; Matthias Hempel; Roger Käppeli; Gabriel Martínez-Pinedo; Thomas Rauscher; Irina Sagert; Christian Winteler

    2012-08-24

    We explore heavy element nucleosynthesis in the explosion of massive stars which are triggered by a quark-hadron phase transition during the early post bounce phase of core-collapse supernovae. The present study is based on general relativistic radiation hydrodynamics simulations with three-flavor Boltzmann neutrino transport in spherical symmetry, which utilize a quark-hadron hybrid equation of state based on the MIT bag model for strange quark matter. The quark-hadron phase transition inside the stellar core forms a shock wave propagating towards the surface of the proto-neutron star. The shock wave results in an explosion and ejects neutron-rich matter which is piled up or accreting on the proto-neutron star. Later, during the cooling phase, the proto-neutron star develops a proton-rich neutrino-driven wind. We present a detailed analysis of the nucleosynthesis outcome in both neutron-rich and proton-rich ejecta and compare our integrated nucleosynthesis with observations of metal poor stars.

  1. NUCLEOSYNTHESIS IN CORE-COLLAPSE SUPERNOVA EXPLOSIONS TRIGGERED BY A QUARK-HADRON PHASE TRANSITION

    SciTech Connect (OSTI)

    Nishimura, Nobuya; Thielemann, Friedrich-Karl; Hempel, Matthias; Kaeppeli, Roger; Rauscher, Thomas; Winteler, Christian [Department of Physics, University of Basel, CH-4056 Basel (Switzerland); Fischer, Tobias; Martinez-Pinedo, Gabriel [GSI, Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Froehlich, Carla [Department of Physics, North Carolina State University, NC 27695 (United States); Sagert, Irina, E-mail: nobuya.nishimura@unibas.ch [Department of Physics and Astronomy, Michigan State University, MI 48824 (United States)

    2012-10-10

    We explore heavy-element nucleosynthesis in the explosion of massive stars that are triggered by a quark-hadron phase transition during the early post-bounce phase of core-collapse supernovae. The present study is based on general-relativistic radiation hydrodynamics simulations with three-flavor Boltzmann neutrino transport in spherical symmetry, which utilize a quark-hadron hybrid equation of state based on the MIT bag model for strange quark matter. The quark-hadron phase transition inside the stellar core forms a shock wave propagating toward the surface of the proto-neutron star. This shock wave results in an explosion and ejects neutron-rich matter from the outer accreted layers of the proto-neutron star. Later, during the cooling phase, the proto-neutron star develops a proton-rich neutrino-driven wind. We present a detailed analysis of the nucleosynthesis outcome in both neutron-rich and proton-rich ejecta and compare our integrated nucleosynthesis with observations of the solar system and metal-poor stars. For our standard scenario, we find that a 'weak' r-process occurs and elements up to the second peak (A {approx} 130) are successfully synthesized. Furthermore, uncertainties in the explosion dynamics could barely allow us to obtain the strong r-process which produces heavier isotopes, including the third peak (A {approx} 195) and actinide elements.

  2. Petrofina offers to buy up Fina

    SciTech Connect (OSTI)

    Vames, S.

    1997-03-05

    Petrofina has offered to buy all publicly held shares of Fina, its US chemical and oil subsidiary. The shares are worth $266 million and amount to about 15% of the unit, which, combined with Petrofina`s existing 85% stake, would give Petrofina full ownership of Fina. While Petrofina does not give a reason for the buyout, analysts say the company may be planning to sell the entire unit outright or spin off some of its less profitable businesses. Ron Haddock, Fina`s CEO, denies the speculation. {open_quotes}This deal is merely a confirmation of Petrofina`s confidence in a commitment to our company.{close_quotes}

  3. Lettuce Offers a Palette of Taste, Textures, and Colors

    E-Print Network [OSTI]

    Martin, Orin

    2008-01-01

    UC Santa Cruz Lettuce Offers a Palette of Tastes, Textures,age and aeration. Sandy soils offer the bene?t of draining,Londonderry, Vermont) now offers it. Because of the small

  4. Nash meets Rubinstein in final-offer arbitration

    E-Print Network [OSTI]

    Yildiz, Muhamet

    I consider a final-offer arbitration model in which the offers are submitted sequentially, the parties are allowed to accept offers, and the arbitrator maximizes Nash's social welfare function. I show that backwards induction ...

  5. Energy Department Offers Conditional Commitment to Cape Wind...

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    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

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  8. Energy Department Offers Conditional Commitment to Cape Wind...

    Energy Savers [EERE]

    Offers Conditional Commitment to Cape Wind Offshore Wind Generation Project Energy Department Offers Conditional Commitment to Cape Wind Offshore Wind Generation Project July 1,...

  9. USDA Offers Renewable Energy Feasibility Studies for Rural Businesses...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

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    Office of Scientific and Technical Information (OSTI)

    Los Alamos offers participants hands-on experience with renewable energy technology Citation Details In-Document Search Title: Los Alamos offers participants hands-on experience...

  11. Attachment 2: Solicitation for Offers with New and Revised Green...

    Energy Savers [EERE]

    Attachment 2: Solicitation for Offers with New and Revised Green Lease Text Attachment 2: Solicitation for Offers with New and Revised Green Lease Text PDF icon Solicitation for...

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    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

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    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

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    Office of Environmental Management (EM)

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    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

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    Office of Environmental Management (EM)

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  20. www.birmingham.ac.uk Postgraduate Offer Guide

    E-Print Network [OSTI]

    Miall, Chris

    www.birmingham.ac.uk Postgraduate Offer Guide 2014 ­ 2015 #12;2 Postgraduate offer guide Welcome to the University of Birmingham Your offer from the University Congratulations! We are delighted to inform you that you have been offered a place to study at the University of Birmingham. We do hope that you decide

  1. We are using both space-based (Hubble Space Telescope, HST) and ground-based telescopes to make extensive studies of Galactic halo stars. These stars contain nucleosynthesis products (from the rapid neutron capture process, r-process) from the

    E-Print Network [OSTI]

    Cowan, John

    to make extensive studies of Galactic halo stars. These stars contain nucleosynthesis products (from Galactic r-process nucleosynthesis. These in turn will help to identify the characteristics and nature ­ particularly the sites and the astrophysical conditions for their formation EARLY GALACTIC NUCLEOSYNTHESIS

  2. Nucleosynthesis in the outflows associated with accretion disks of Type II collapsars

    E-Print Network [OSTI]

    Indrani Banerjee; Banibrata Mukhopadhyay

    2013-09-04

    We investigate nucleosynthesis inside the outflows from gamma-ray burst (GRB) accretion disks formed by the Type II collapsars. In these collapsars, massive stars undergo core collapse to form a proto-neutron star initially and a mild supernova explosion is driven. The supernova ejecta lack momentum and subsequently this newly formed neutron star gets transformed to a stellar mass black hole via massive fallback. The hydrodynamics and the nucleosynthesis in these accretion disks has been studied extensively in the past. Several heavy elements are synthesized in the disk and much of these heavy elements are ejected from the disk via winds and outflows. We study nucleosynthesis in the outflows launched from these disks by using an adiabatic, spherically expanding outflow model, to understand which of these elements thus synthesized in the disk survive in the outflow. While studying this we find that many new elements like isotopes of titanium, copper, zinc etc. are present in the outflows. 56Ni is abundantly synthesized in most of the cases in the outflow which implies that the outflows from these disks in a majority of cases will lead to an observable supernova explosion. It is mainly present when outflow is considered from the He-rich, 56Ni/54Fe rich zones of the disks. However, outflow from the Si-rich zone of the disk remains rich in silicon. Although, emission lines of many of these heavy elements have been observed in the X-ray afterglows of several GRBs by Chandra, BeppoSAX, XMM-Newton etc., Swift seems to have not detected these lines yet.

  3. NUCLEOSYNTHESIS IN THE OUTFLOWS ASSOCIATED WITH ACCRETION DISKS OF TYPE II COLLAPSARS

    SciTech Connect (OSTI)

    Banerjee, Indrani; Mukhopadhyay, Banibrata, E-mail: indrani@physics.iisc.ernet.in, E-mail: bm@physics.iisc.ernet.in [Department of Physics, Indian Institute of Science, Bangalore 560 012 (India)

    2013-11-20

    We investigate nucleosynthesis inside the outflows from gamma-ray burst (GRB) accretion disks formed by the Type II collapsars. In these collapsars, massive stars undergo core collapse to form a proto-neutron star initially, and a mild supernova (SN) explosion is driven. The SN ejecta lack momentum, and subsequently this newly formed neutron star gets transformed to a stellar mass black hole via massive fallback. The hydrodynamics and the nucleosynthesis in these accretion disks have been studied extensively in the past. Several heavy elements are synthesized in the disk, and much of these heavy elements are ejected from the disk via winds and outflows. We study nucleosynthesis in the outflows launched from these disks by using an adiabatic, spherically expanding outflow model, to understand which of these elements thus synthesized in the disk survive in the outflow. While studying this, we find that many new elements like isotopes of titanium, copper, zinc, etc., are present in the outflows. {sup 56}Ni is abundantly synthesized in most of the cases in the outflow, which implies that the outflows from these disks in a majority of cases will lead to an observable SN explosion. It is mainly present when outflow is considered from the He-rich, {sup 56}Ni/{sup 54}Fe-rich zones of the disks. However, outflow from the Si-rich zone of the disk remains rich in silicon. Although emission lines of many of these heavy elements have been observed in the X-ray afterglows of several GRBs by Chandra, BeppoSAX, XMM-Newton, etc., Swift seems to have not yet detected these lines.

  4. r-PROCESS NUCLEOSYNTHESIS IN DYNAMICALLY EJECTED MATTER OF NEUTRON STAR MERGERS

    SciTech Connect (OSTI)

    Goriely, Stephane [Institut d'Astronomie et d'Astrophysique, Universite Libre de Bruxelles, C.P. 226, B-1050 Brussels (Belgium); Bauswein, Andreas; Janka, Hans-Thomas [Max-Planck-Institut fuer Astrophysik, Postfach 1317, D-85741 Garching (Germany)

    2011-09-10

    Although the rapid neutron-capture process, or r-process, is fundamentally important for explaining the origin of approximately half of the stable nuclei with A > 60, the astrophysical site of this process has not been identified yet. Here we study r-process nucleosynthesis in material that is dynamically ejected by tidal and pressure forces during the merging of binary neutron stars (NSs) and within milliseconds afterward. For the first time we make use of relativistic hydrodynamical simulations of such events, defining consistently the conditions that determine the nucleosynthesis, i.e., neutron enrichment, entropy, early density evolution and thus expansion timescale, and ejecta mass. We find that 10{sup -3}-10{sup -2} M{sub sun} are ejected, which is enough for mergers to be the main source of heavy (A {approx}> 140) galactic r-nuclei for merger rates of some 10{sup -5} yr{sup -1}. While asymmetric mergers eject 2-3 times more mass than symmetric ones, the exact amount depends weakly on whether the NSs have radii of {approx}15 km for a 'stiff' nuclear equation of state (EOS) or {approx}12 km for a 'soft' EOS. r-process nucleosynthesis during the decompression becomes largely insensitive to the detailed conditions because of efficient fission recycling, producing a composition that closely follows the solar r-abundance distribution for nuclei with mass numbers A > 140. Estimating the light curve powered by the radioactive decay heating of r-process nuclei with an approximative model, we expect high emission in the B-V-R bands for 1-2 days with potentially observable longer duration in the case of asymmetric mergers because of the larger ejecta mass.

  5. Astrophysical S-factor for destructive reactions of lithium-7 in big bang nucleosynthesis

    SciTech Connect (OSTI)

    Komatsubara, Tetsuro; Kwon, YoungKwan; Moon, JunYoung; Kim, Yong-Kyun [Rare Isotope Science Project, Institute for Basic Science, Daejeon (Korea, Republic of); Moon, Chang-Bum [Hoseo University, Asan, Chungnam (Korea, Republic of); Ozawa, Akira; Sasa, Kimikazu; Onishi, Takahiro; Yuasa, Toshiaki; Okada, Shunsuke; Saito, Yuta [Division of Physics, University of Tsukuba, Tsukuba, Ibaraki (Japan); Hayakawa, Takehito; Shizuma, Toshiyuki [Japan Atomic Energy Agency, Shirakata Shirane, Tokai, Ibaraki (Japan); Kubono, Shigeru [RIKEN, Hirosawa, Wako, Saitama (Japan); Kusakabe, Motohiko [School of Liberal Arts and Science, Korea Aerospace University (Korea, Republic of); Kajino, Toshitaka [National Astronomical Observatory, Osawa, Mitaka, Tokyo (Japan)

    2014-05-02

    One of the most prominent success with the Big Bang models is the precise reproduction of mass abundance ratio for {sup 4}He. In spite of the success, abundances of lithium isotopes are still inconsistent between observations and their calculated results, which is known as lithium abundance problem. Since the calculations were based on the experimental reaction data together with theoretical estimations, more precise experimental measurements may improve the knowledge of the Big Bang nucleosynthesis. As one of the destruction process of lithium-7, we have performed measurements for the reaction cross sections of the {sup 7}L({sup 3}He,p){sup 9}Be reaction.

  6. Production of A=6,7 Nuclides in the Alpha + Alpha Reaction and Cosmic Ray Nucleosynthesis

    E-Print Network [OSTI]

    David J. Mercer; Sam M. Austin; J. A. Brown; S. A. Danczyk; S. E. Hirzebruck; J. H. Kelley; T. Suomijarvi; D. A. Roberts; T. P Walker

    2001-04-03

    Cross sections for production of 6He, 6Li, 7Li, and 7Be in the alpha+alpha reaction were measured at bombarding energies of 159.3, 279.6, and 619.8 MeV, and are found to decrease rapidly with increasing energy. These cross sections are essential for the calculation of the rate of nucleosynthesis of the lithium isotopes in the cosmic rays and thereby play a key role in our understanding of the synthesis of Li, Be, and B. The results for 6Li differ significantly from the tabulated values commonly used in cosmic-ray production calculations and lead to lower production of 6Li.

  7. n+p -> d+gamma for Big-Bang Nucleosynthesis

    E-Print Network [OSTI]

    Jiunn-Wei Chen; Martin J. Savage

    1999-07-09

    The cross section for n+p -> d+gamma is calculated at energies relevant to big bang nucleosynthesis using the recently developed effective field theory that describes the two-nucleon sector. The E1 amplitude is computed up to NNNLO and depends only upon nucleon-nucleon phase shift data. In contrast, the M1 contribution is computed up to NLO, and the four-nucleon-one-magnetic-photon counterterm that enters is determined by the cross section for cold neutron capture. The uncertainty in the calculation for nucleon energies up to E ~ 1 MeV is estimated to be < 4%.

  8. r-Process Nucleosynthesis in Shocked Surface Layers of O-Ne-Mg Cores

    E-Print Network [OSTI]

    H. Ning; Y. -Z. Qian; B. S. Meyer

    2007-08-13

    We demonstrate that rapid expansion of the shocked surface layers of an O-Ne-Mg core following its collapse can result in r-process nucleosynthesis. As the supernova shock accelerates through these layers, it makes them expand so rapidly that free nucleons remain in disequilibrium with alpha-particles throughout most of the expansion. This allows heavy r-process isotopes including the actinides to form in spite of the very low initial neutron excess of the matter. We estimate that yields of heavy r-process nuclei from this site may be sufficient to explain the Galactic inventory of these isotopes.

  9. Neutron injection during primordial nucleosynthesis alleviates the primordial 7Li problem

    E-Print Network [OSTI]

    Daniel Albornoz Vasquez; Alexander Belikov; Alain Coc; Joseph Silk; Elisabeth Vangioni

    2012-08-02

    We present a parametrized study of the effects of free thermal neutron injection on primordial nucleosynthesis, where both the rate and the time scale of injection are varied. This generic approach is found to yield a successful solution for reducing the 7Li abundance without causing significant problems to other elemental abundances. Our analysis demonstrates that hadronic injection, possibly due to decays or annihilations of dark matter particles with a mass of about 1 to 30 GeV, provides a possible solution to an outstanding problem in the standard Big Bang model.

  10. Beta Decays of Isotones with Neutron Magic Number of N=126 and R-process Nucleosynthesis

    E-Print Network [OSTI]

    Toshio Suzuki; Takashi Yoshida; Toshitaka Kajino; Takaharu Otsuka

    2011-12-16

    Beta decays of the isotones with N=126 are studied by shell model calculations taking into account both the Gamow-Teller (GT) and first-forbidden (FF) transitions. The FF transitions are found to be important to reduce the half-lives, by nearly twice to several times, from those by the GT contributions only. Possible implications of the short half-lives of the waiting point nuclei on the r-process nucleosynthesis during the supernova explosions are discussed. A slight shift of the third peak of the element abundances in the r-process toward higher mass region is found.

  11. Low-mass helium star models for type Ib supernovae - Light curves, mixing, and nucleosynthesis

    SciTech Connect (OSTI)

    Shigeyama, Toshikazu; Nomoto, Kenichi; Tsujimoto, Takuji; Hashimoto, Masaki (Tokyo Univ. (Japan) Kyushu Univ., Fukuoka (Japan))

    1990-09-01

    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.

  12. On the introduction of {sup 17}O+p reaction rates evaluated through the THM in AGB nucleosynthesis calculations

    SciTech Connect (OSTI)

    Palmerini, S.; Sergi, M. L.; La Cognata, M.; Pizzone, R. G. [I.N.F.N. Laboratori Nazionali del Sud, via Santa Sofia 62, Catania (Italy); Lamia, L.; Spitaleri, C. [Dipartimento di Fisica e Astronomia, Universitá degli Studi di Catania (Italy)

    2014-05-09

    The rates for the {sup 17}O(p,??{sup 14}N, {sup 17}O(p,?){sup 18}F and {sup 18}O(p,?){sup 15}N reactions deduced trough the Trojan Horse Method (THM) have been introduced into a state-of-the-art asymptotic giant branch (AGB) models for proton-capture nucleosynthesis and cool bottom process. The predicted abundances have been compared with isotopic compositions provided by geochemical analysis of presolar grains. As a result, an improved agreement is found between the models and the isotopic mix of oxide grains of AGB origins, whose composition is the signature of low-temperature proton-capture nucleosynthesis.

  13. Corrected constraints on big bang nucleosynthesis in a modified gravity model of $f(R) \\propto R^n$

    E-Print Network [OSTI]

    Motohiko Kusakabe; Seoktae Koh; K. S. Kim; Myung-Ki Cheoun

    2015-06-29

    Big bang nucleosynthesis in a modified gravity model of $f(R)\\propto R^n$ is investigated. The only free parameter of the model is a power-law index $n$. We find cosmological solutions in a parameter region of $1nucleosynthesis. We compare the results with the latest observational data. It is then found that the power-law index is constrained to be $(n-1)=(-0.86\\pm 1.19)\\times 10^{-4}$ (95 % C.L.) mainly from observations of deuterium abundance as well as $^4$He abundance.

  14. Corrected constraints on big bang nucleosynthesis in a modified gravity model of $f(R) \\propto R^n$

    E-Print Network [OSTI]

    Kusakabe, Motohiko; Kim, K S; Cheoun, Myung-Ki

    2015-01-01

    Big bang nucleosynthesis in a modified gravity model of $f(R)\\propto R^n$ is investigated. The only free parameter of the model is a power-law index $n$. We find cosmological solutions in a parameter region of $1big bang nucleosynthesis. We compare the results with the latest observational data. It is then found that the power-law index is constrained to be $(n-1)=(-0.86\\pm 1.19)\\times 10^{-4}$ (95 % C.L.) mainly from observations of deuterium abundance as well as $^4$He abundance.

  15. The Effects of Variations in Nuclear Processes on Type I X-Ray Burst Nucleosynthesis

    E-Print Network [OSTI]

    Anuj Parikh; Jordi Jose; Fermin Moreno; Christian Iliadis

    2008-02-20

    Type I X-ray bursts are violent stellar events that take place on the H/He-rich envelopes of accreting neutron stars. We have investigated the role played by uncertainties in nuclear processes on the nucleosynthesis accompanying these explosive phenomena. Two different approaches have been adopted, in the framework of post-processing calculations. In the first one, nuclear rates are varied individually within uncertainties. Ten different models, covering the characteristic parameter space for these stellar events, have been considered. The second, somewhat complementary approach involves a Monte Carlo code in which all nuclear rates are randomly varied within uncertainty limits simultaneously. All in all, about 50,000 post-processing calculations, with a network containing 606 nuclides (H to 113Xe) and more than 3500 nuclear processes, have been performed in this work. A brief comparison between both procedures is outlined together with an overall account of the key nuclear reactions whose uncertainties have the largest impact in our X-ray burst nucleosynthesis studies.

  16. Microsoft Word - XX 13 Science and education grants offered by...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Wingert, 503-230-4140 or 503-230-5131 BPA offering 20,000 in science and energy education grants Portland, Ore. - The Bonneville Power Administration is offering 20,000 in...

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    Office of Environmental Management (EM)

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    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

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  19. Unique Energy Management Training Offers Certification and Energy Savings 

    E-Print Network [OSTI]

    Ebbage, R.

    2004-01-01

    The Northwest Energy Education Institute1 (NEEI) has developed and presents a very unique energy efficiency training and certification program. Modeled after a similar course once offered in New Zealand, NEEI offers a two-week energy management...

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    Office of Environmental Management (EM)

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  1. Fact #830: July 21, 2014 Diesel Light Vehicle Offerings Expand

    Broader source: Energy.gov [DOE]

    The number of diesel light vehicles offered for sale by manufacturers has grown since 2000. In model year (MY) 2000 there were only 3 diesel models offered by one manufacturer (VW), but by MY 2014...

  2. Energy Department Offers $50 Million to Advance Fuel Efficient...

    Office of Environmental Management (EM)

    Offers 50 Million to Advance Fuel Efficient Autos Energy Department Offers 50 Million to Advance Fuel Efficient Autos January 29, 2014 - 12:00am Addthis The Energy Department on...

  3. Non-Extensive Statistics, New Solution to the Cosmological Lithium Problem

    E-Print Network [OSTI]

    J. J. He; S. Q. Hou; A. Parikh; D. Kahl; C. A. Bertulani; other collaborators

    2014-12-22

    In the primordial Big Bang nucleosynthesis (BBN), only the lightest nuclides (D, $^3$He, $^4$He, and $^7$Li) were synthesized in appreciable quantities, and these relics provide us a unique window on the early universe. Currently, BBN simulations give acceptable agreement between theoretical and observed abundances of D and $^4$He, but it is still difficult to reconcile the predicted $^7$Li abundance with the observation for the Galactic halo stars. The BBN model overestimates the primordial $^7$Li abundance by about a factor of three, so called the cosmological lithium problem, a long-lasting pending issue in BBN. Great efforts have been paid in the past decades, however, the conventional nuclear physics seems unable to resolve such problem. It is well-known that the classical Maxwell-Boltzmann (MB) velocity distribution has been usually assumed for nuclei in the Big-Bang plasma. In this work, we have thoroughly investigated the impact of non-extensive Tsallis statistics (deviating from the MB) on thermonuclear reaction rates involved in standard models of BBN. It shows that the predicted primordial abundances of D, $^4$He, and $^7$Li agree very well with those observed ones by introducing a non-extensive parameter $q$. It is discovered that the velocities of nuclei in a hot Big-Bang plasma indeed violate the classical Maxwell-Boltzmann (MB) distribution in a very small deviation of about 6.3--8.2%. Thus, we have for the first time found a new solution to the cosmological lithium problem without introducing any mysterious theories. Furthermore, the implications of non-extensive statistics in other exotic high-temperature and density astrophysical environments should be explored, which might offer new insight into the nucleosynthesis of heavy elements.

  4. Summer at the University of Colorado, Boulder offers students

    E-Print Network [OSTI]

    Mojzsis, Stephen J.

    #12;Summer at the University of Colorado, Boulder offers students a variety of opportunities requirements, there are other summer offerings that complement particular areas of interest. For instance, some sites in the nation for alpine research; the School of Education offers many graduate courses designed

  5. 12-MONTH SAMPLE OFFER LETTER VISITING TEACHING FACULTY I, RESEARCH

    E-Print Network [OSTI]

    McQuade, D. Tyler

    12-MONTH SAMPLE OFFER LETTER VISITING TEACHING FACULTY I, RESEARCH FACULTY I, INSTRUCTIONAL SPECIALIST I OR ASSOCIATE IN RESEARCH APPOINTMENT Dear Dr. xxx: I am pleased to offer you a visiting://facultyhandbook.fsu.edu). This offer is also contingent upon your providing the necessary documents to prove your identity

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    E-Print Network [OSTI]

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    E-Print Network [OSTI]

    Toronto, University of

    Matching Unstructured Product Offers to Structured Product Specifications Anitha Kannan Search Labs for millions of products. The search engine receives millions of sales offers from thousands of independent unstructured offers to structured product descriptions must address, drawing upon our experience from building

  8. Summer at the University of Colorado at Boulder offers

    E-Print Network [OSTI]

    Mojzsis, Stephen J.

    #12;Summer at the University of Colorado at Boulder offers students a variety of oppor- tunities requirements, there are other summer offerings that complement particular areas of interest. For instance, some sites in the nation for alpine research; the School of Education offers many graduate courses designed

  9. 9-MONTH SAMPLE OFFER LETTER VISITING TEACHING FACULTY I, RESEARCH

    E-Print Network [OSTI]

    McQuade, D. Tyler

    9-MONTH SAMPLE OFFER LETTER VISITING TEACHING FACULTY I, RESEARCH FACULTY I, INSTRUCTIONAL SPECIALIST I OR ASSOCIATE IN RESEARCH APPOINTMENT Dear Dr. xxx: I am pleased to offer you a visiting of interest, and intellectual property (http://facultyhandbook.fsu.edu). This offer is also contingent upon

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    E-Print Network [OSTI]

    Lennard, William N.

    Mature and Transfer Student Guide #12;Accept Your Offer of Admission to Western's Best Student Experience By offering diverse programs, a flexible curriculum, world-renowned facilities days April 9-30 · Final exams Page 2 | Mature and Transfer Student Guide #12;Step 1 accept Your offer

  11. DEGREES OFFERED M.Ed. in Adult & Higher Education

    E-Print Network [OSTI]

    Maxwell, Bruce D.

    DEGREES OFFERED · M.Ed. in Adult & Higher Education · M.Ed. in Curriculum & Instruction · M.D. in Curriculum & Instruction · Ed.D. in Educational Leadership Certificates Offered: · College Teaching State University offers three main graduate pro- grams that combine well established teaching methods

  12. SAMPLE LETTER ACCEPTING OFFER #1 October 10, 2014

    E-Print Network [OSTI]

    Shyu, Mei-Ling

    #12;SAMPLE LETTER ACCEPTING OFFER #1 NAME ADDRESS TELEPHONE EMAIL October 10, 2014 Mr. Richard 20000 Dear Mr. Cunningham: Thank you for your offer of summer employment with the Civil Rights Division of the United States Department of Justice. I am pleased to accept your offer at a salary of $1,200.00 per week

  13. GIFT OF TRAVEL OFFER FORWARDING MEMORANDUM Page 1 of 2

    E-Print Network [OSTI]

    GIFT OF TRAVEL OFFER FORWARDING MEMORANDUM From: Page 1 of 2 To: President, Naval Postgraduate School Subj: OFFER OF GIFT OF TRAVEL TO THE NAVAL POSTGRADUATE SCHOOL Ref: (a) NPS Gifts of Travel SOP Date(mm/dd/yyyy): (b) SECNAVINST 4001.2J Encl: (1) Offer of Gift of Travel from 1. Enclosure (1

  14. REQUEST FOR OFFERING INDIVIDUAL PROBLEMS AND RESTRICTED ENTRY CARD

    E-Print Network [OSTI]

    Maxwell, Bruce D.

    REQUEST FOR OFFERING INDIVIDUAL PROBLEMS AND RESTRICTED ENTRY CARD Montana State University Office of the Registrar The Department/School of __________________________________________ requests permission to offer to the department offering the course for approval. If approved by the department head, the student may

  15. We offer a full range of surgical expertise. Bariatric Surgery

    E-Print Network [OSTI]

    Mohaghegh, Shahab

    We offer a full range of surgical expertise. Bariatric Surgery Appointments: 304-598-4890 Pediatric are a major tertiary referral center for the region and state, offering the highest level of clinical program offering cardiac surgery for children in the state. Pediatric cardiothoracic surgery Robert A

  16. The Department of Psychology offers both a Bachelor of

    E-Print Network [OSTI]

    Maxwell, Bruce D.

    The Department of Psychology offers both a Bachelor of Science (B.S.) and Master of Science (M CAREERS B.S. in Psychology Our department offers a Bachelor of Science (B.S.) degree in psychology in psychology offers a scientific background. Our undergraduate curriculum introduces students to core areas

  17. NUCLEOSYNTHESIS IN INTERMEDIATE MASS AGB STARS JOHN LATTANZIO 1;2 , MANUEL FORESTINI 2 , CORINNE CHARBONNEL 3

    E-Print Network [OSTI]

    Lattanzio, John

    nucleosynthesis occurring in the helium shell is the production of alpha ele- ments (via helium burning) as well process- es. There are two primary sites for these processes: the helium burning shell and the hydrogen burning shell. The reason that these are of more interest in an AGB star is that the helium shell shows

  18. Explosive Nucleosynthesis of Weak r-Process Elements in Extremely Metal-Poor Core-Collapse Supernovae

    E-Print Network [OSTI]

    N. Izutani; H. Umeda; N. Tominaga

    2008-10-31

    There have been attempts to fit the abundance patterns of extremely metal-poor stars with supernova nucleosynthesis models for the lighter elements than Zn. On the other hand, observations have revealed that the presence of EMP stars with peculiarly high ratio of "weak r-process elements" Sr, Y and Zr. Although several possible processes were suggested for the origin of these elements, the complete solution for reproducing those ratios is not found yet. In order to reproduce the abundance patterns of such stars, we investigate a model with neutron rich matter ejection from the inner region of the conventional mass-cut. We find that explosive nucleosynthesis in a high energy supernova (or "hypernova") can reproduce the high abundances of Sr, Y and Zr but that the enhancements of Sr, Y and Zr are not achieved by nucleosynthesis in a normal supernova. Our results imply that, if these elements are ejected from a normal supernova, nucleosynthesis in higher entropy flow than that of the supernova shock is required.

  19. BBN Concordance: What's the Matter with Li?

    E-Print Network [OSTI]

    Yamamoto, Hirosuke

    ,7 Li - BeB #12;WMAP best fit Bh2 = 0.0227 ± 0.0006 10 = 6.22 ± 0.16 #12;#12;additional factors are used

  20. Big Bang Nucleosynthesis Constraints on Hadronically and Electromagnetically Decaying Relic Neutral Particles

    E-Print Network [OSTI]

    Karsten Jedamzik

    2006-11-10

    Big Bang nucleosynthesis in the presence of decaying relic neutral particles is examined in detail. All non-thermal processes important for the determination of light-element abundance yields of 2H, 3H, 3He, 4He, 6Li, and 7Li are coupled to the thermonuclear fusion reactions to obtain comparatively accurate results. Predicted light-element yields are compared to observationally inferred limits on primordial light-element abundances to infer constraints on the abundances and properties of relic decaying particles with decay times in the interval 0.01 sec < tau < 10^(12) sec. Decaying particles are typically constrained at early times by 4He or 2H, at intermediate times by 6Li, and at large times by the 3He/2H ratio. Constraints are shown for a large number of hadronic branching ratios and decaying particle masses and may be applied to constrain the evolution of the early Universe.

  1. General relativistic effects in the neutrino-driven wind and r-process nucleosynthesis

    E-Print Network [OSTI]

    Christian Y. Cardall; George M. Fuller

    1997-01-22

    We discuss general relativistic effects in the steady-state neutrino-driven ``wind'' which may arise from nascent neutron stars. In particular, we generalize previous analytic estimates of the entropy per baryon $S$, the mass outflow rate $\\dot M$, and the dynamical expansion time scale $\\tau_{dyn}$. We show that $S$ increases and $\\tau_{dyn}$ decreases with increasing values of the mass-to-radius ratio describing the supernova core. Both of these trends indicate that a more compact core will lead to a higher number of neutrons per iron peak seed nucleus. Such an enhancement in the neutron-to-seed ratio may be required for successful r-process nucleosynthesis in neutrino-heated supernova ejecta.

  2. Beta-decay spectroscopy relevant to the r-process nucleosynthesis

    SciTech Connect (OSTI)

    Nishimura, Shunji; Collaboration: RIBF Decay Collaboration

    2012-11-12

    A scientific program of beta-decay spectroscopy relevant to r-process nucleosynthesis has been started using high intensity U-beam at the RIBF. The first results of {beta}-decay half-lives of very neutron-rich Kr to Tc nuclides, all of which lie close to the r-process path, suggest a systematic enhancement of the the {beta}-decay rates of the Zr and Nb isotopes around A110 with respect to the predictions of the deformed quasiparticle-random-phase-approximation model (FRDM + QRPA). An impact of the results on the astrophysical r-process is discussed together with the future perspective of the {beta}-decay spectroscopy with the EURICA.

  3. Toward precision mass measurements of neutron-rich nuclei relevant to $r$-process nucleosynthesis

    E-Print Network [OSTI]

    B. H. Sun; Yu. A. Litvinov; I. Tanihata; Y. H. Zhang

    2015-08-04

    The open question of where, when, and how the heavy elements beyond iron enrich our Universe has triggered a new era in nuclear physics studies.\\ Of all the relevant nuclear physics inputs, the mass of very neutron-rich nuclides is a key quantity for revealing the origin of heavy elements beyond iron.\\ Although the precise determination of this property is a great challenge, enormous progress has been made in recent decades, and it has contributed significantly to both nuclear structure and astrophysical nucleosynthesis studies.\\ In this review, we first survey our present knowledge of the nuclear mass surface, emphasizing the importance of nuclear mass precision in $r$-process calculations.\\ We then discuss recent progress in various methods of nuclear mass measurement with a few selected examples.\\ For each method, we focus on recent breakthroughs and discuss possible ways of improving the weighing of $r$-process nuclides.

  4. The 40Ca(alpha,gamma)44Ti reaction in the energy regime of supernova nucleosynthesis

    E-Print Network [OSTI]

    H. Nassar; M. Paul; I. Ahmad; Y. Ben-Dov; J. Caggiano; S. Ghelberg; S. Goriely; J. P. Greene; M. Hass; A. Heger; A. Heinz; D. J. Henderson; R. V. F. Janssens; C. L. Jiang; Y. Kashiv; B. S. Nara Singh; A. Ofan; R. C. Pardo; T. Pennington; K. E. Rehm; G. Savard; R. Scott; R. Vondrasek

    2006-01-11

    The 44Ti(t1/2 = 59 y) nuclide, an important signature of supernova nucleosynthesis, has recently been observed as live radioactivity by gamma-ray astronomy from the Cas A remnant. We investigate in the laboratory the major 44Ti production reaction, 40Ca(alpha,gamma)44Ti (E_cm = 0.6-1.2 MeV/u), by direct off- line counting of 44Ti nuclei. The yield, significantly higher than inferred from previous experiments, is analyzed in terms of a statistical model using microscopic nuclear inputs. The associated stellar rate has important astrophysical consequences, increasing the calculated supernova 44Ti yield by a factor ~2 over previous estimates and bringing it closer to Cas A observations.

  5. Aspherical nucleosynthesis in a core-collapse supernova with 25 M {sub ?} standard progenitor

    SciTech Connect (OSTI)

    Popov, M. V. [École Normale Supérieure de Lyon, CRAL (UMR CNRS 5574), Université de Lyon 1, 46 allée d'Italie, F-69007 Lyon (France); Filina, A. A.; Baranov, A. A.; Chardonnet, P. [LAPTh, Université de Savoie, 9, Chemin de Bellevue BP 110, F-74941 Annecy-le-Vieux Cedex (France); Chechetkin, V. M. [Keldysh Institute of Applied Mathematics RAS, Miusskaya sq. 4, 125047 Moscow (Russian Federation)

    2014-03-01

    The problem of nucleosynthesis was studied within an aspherical supernova model. The explosive burning was computed in a star of 25 M {sub ?} initial mass on its final stage of evolution. The chemical composition of a presupernova was taken from realistic evolutionary computations. A piecewise parabolic method on a local stencil was applied to simulate the hydrodynamics of the explosion. The gravity was recomputed by a Poisson solver on a fine grid as the explosion developed. A detailed yield of chemical elements was performed as a post-processing step using the tracer particles method. The produced nuclei formed a layer-like structure enclosing large fragments of nickel and iron-group isotopes that were pushed away from the central region by an explosion along the polar direction. The light nuclei were preferentially moving along the equatorial plane forming a torus-like structure.

  6. Sensitivity studies for r-process nucleosynthesis in three astrophysical scenarios

    E-Print Network [OSTI]

    R. Surman; M. Mumpower; J. Cass; I. Bentley; A. Aprahamian; G. C. McLaughlin

    2013-08-31

    In rapid neutron capture, or r-process, nucleosynthesis, heavy elements are built up via a sequence of neutron captures and beta decays that involves thousands of nuclei far from stability. Though we understand the basics of how the r-process proceeds, its astrophysical site is still not conclusively known. The nuclear network simulations we use to test potential astrophysical scenarios require nuclear physics data (masses, beta decay lifetimes, neutron capture rates, fission probabilities) for all of the nuclei on the neutron-rich side of the nuclear chart, from the valley of stability to the neutron drip line. Here we discuss recent sensitivity studies that aim to determine which individual pieces of nuclear data are the most crucial for r-process calculations. We consider three types of astrophysical scenarios: a traditional hot r-process, a cold r-process in which the temperature and density drop rapidly, and a neutron star merger trajectory.

  7. The sensitivity of r-process nucleosynthesis to the properties of neutron-rich nuclei

    E-Print Network [OSTI]

    R. Surman; M. Mumpower; J. Cass; A. Aprahamian

    2013-08-31

    About half of the heavy elements in the Solar System were created by rapid neutron capture, or r-process, nucleosynthesis. In the r-process, heavy elements are built up via a sequence of neutron captures and beta decays in which an intense neutron flux pushes material out towards the neutron drip line. The nuclear network simulations used to test potential astrophysical scenarios for the r-process therefore require nuclear physics data (masses, beta decay lifetimes, neutron capture rates, fission probabilities) for thousands of nuclei far from stability. Only a small fraction of this data has been experimentally measured. Here we discuss recent sensitivity studies that aim to determine the nuclei whose properties are most crucial for r-process calculations.

  8. Nucleosynthesis in neutrino-driven, aspherical supernovae of population III stars

    SciTech Connect (OSTI)

    Fujimoto, Shin-ichiro; Hashimoto, Masa-aki; Ono, Masaomi; Kotake, Kei [Kumamoto National College of Technology, 2659-2 Suya, Goshi 861-1102 (Japan); Department of Physics, School of Sciences, Kyushu University, Fukuoka 810-8560 (Japan); Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan); National Astronomical Observatory Japan, 2-21-1, Osawa, Mitaka, Tokyo, 181-8588 (Japan)

    2012-11-12

    We examine explosive nucleosynthesis during neutrino-driven, aspherical supernovae of Population III stars, based on two-dimensional (2D) hydrodynamic simulations of the explosion of 11-40M{sub Circled-Dot-Operator} stars with zero metallicity. The magnitude and asymmetry of the explosion energy are estimated with the simulations. By post-processing calculations with a large nuclear reaction network, we have evaluated abundances and masses of ejecta from the aspherical SNe. We find that the evaluated abundance patterns are similar to those observed in extremely metal poor stars, as shown in spherical and 2D models, in which the explosion is manually and spherically initiated. Matter mixing induced via standing accretion shock instability is important for the abundances and masses of the SN ejecta.

  9. Toward precision mass measurements of neutron-rich nuclei relevant to $r$-process nucleosynthesis

    E-Print Network [OSTI]

    Sun, B H; Tanihata, I; Zhang, Y H

    2015-01-01

    The open question of where, when, and how the heavy elements beyond iron enrich our Universe has triggered a new era in nuclear physics studies.\\ Of all the relevant nuclear physics inputs, the mass of very neutron-rich nuclides is a key quantity for revealing the origin of heavy elements beyond iron.\\ Although the precise determination of this property is a great challenge, enormous progress has been made in recent decades, and it has contributed significantly to both nuclear structure and astrophysical nucleosynthesis studies.\\ In this review, we first survey our present knowledge of the nuclear mass surface, emphasizing the importance of nuclear mass precision in $r$-process calculations.\\ We then discuss recent progress in various methods of nuclear mass measurement with a few selected examples.\\ For each method, we focus on recent breakthroughs and discuss possible ways of improving the weighing of $r$-process nuclides.

  10. r-Process Nucleosynthesis in Hot Accretion Disk Flows from Black Hole - Neutron Star Mergers

    E-Print Network [OSTI]

    R. Surman; G. C. McLaughlin; M. Ruffert; H. -Th. Janka; W. R. Hix

    2008-06-25

    We consider hot accretion disk outflows from black hole - neutron star mergers in the context of the nucleosynthesis they produce. We begin with a three dimensional numerical model of a black hole - neutron star merger and calculate the neutrino and antineutrino fluxes emitted from the resulting accretion disk. We then follow the element synthesis in material outflowing the disk along parameterized trajectories. We find that at least a weak r-process is produced, and in some cases a main r-process as well. The neutron-rich conditions required for this production of r-process nuclei stem directly from the interactions of the neutrinos emitted by the disk with the free neutrons and protons in the outflow.

  11. s-Process Nucleosynthesis in Advanced Burning Phases of Massive Stars

    E-Print Network [OSTI]

    Lih-Sin The; Mounib F. El Eid; Bradley S. Meyer

    2006-09-28

    We present a detailed study of s-process nucleosynthesis in massive stars of solar-like initial composition and masses 15, 20,25, and 30 Msun. We update our previous results of s-process nucleosynthesis during the core He-burning of these stars and then focus on an analysis of the s-process under the physical conditions encountered during the shell-carbon burning. We show that the recent compilation of the Ne22(alpha,n)Mg25 rate leads to a remarkable reduction of the efficiency of the s-process during core He-burning. In particular, this rate leads to the lowest overproduction factor of Kr80 found to date during core He-burning in massive stars. The s-process yields resulting from shell carbon burning turn out to be very sensitive to the structural evolution of the carbon shell. This structure is influenced by the mass fraction of C12 attained at the end of core helium burning, which in turn is mainly determined by the C12(alpha,gamma)O16 reaction. The still present uncertainty in the rate for this reaction implies that the s-process in massive stars is also subject to this uncertainty. We identify some isotopes like Zn70 and Rb87 as the signatures of the s-process during shell carbon burning in massive stars. In determining the relative contribution of our s-only stellar yields to the solar abundances, we find it is important to take into account the neutron exposure of shell carbon burning. When we analyze our yields with a Salpeter Initial Mass Function, we find that massive stars contribute at least 40% to s-only nuclei with mass A 90, massive stars contribute on average ~7%, except for Gd152, Os187, and Hg198 which are ~14%, \\~13%, and ~11%, respectively.

  12. The neutrino-induced neutron source in helium shell and r-process nucleosynthesis

    E-Print Network [OSTI]

    D. K. Nadyozhin; I. V. Panov; S. I. Blinnikov

    1998-07-06

    The huge neutrino pulse that occurs during the collapse of a massive stellar core, is expected to contribute to the origination of a number of isotopes both of light chemical elements and heavy ones. It is shown that, in general, the heating of stellar matter due to the neutrino scattering off electrons and the heat released from the neutrino-helium breakup followed by the thermonuclear reactions should be taken into account. On the base of kinetic network, using all the important reactions up to Z=8, the main features and the time-dependent character of the neutrino- driven neutron flux are investigated. The time-dependent densities of free neutrons produced in helium breakup, Y_n(t), were used to calculate the r-process nucleosynthesis with another full kinetic network for 3200 nuclides. It was found that in the case of metal-deficient stars, Z neutrons seems to be high enough to drive the r-process efficiently under favorable conditions. But it is impossible to obtain a sufficient amount of heavy nuclei in neutrino-induced r-process in a helium shell at radii R > R_cr \\approx 10^9 cm. We speculate that to make the neutrino-induced r-process work efficiently in the shell, one has to invoke nonstandard presupernova models in which helium hopefully is closer to the collapsed core owing, for instance, to a large scale mixing or/and rotation and magnetic fields. Apart from this exotic possibility, the neutrino-induced nucleosynthesis in the helium shell is certainly not strong enough to explain the observed solar r-process abundances.

  13. Nucleosynthesis in helium-enriched asymptotic giant branch models: Implications for heavy element enrichment in ? Centauri

    SciTech Connect (OSTI)

    Karakas, Amanda I.; Marino, Anna F.; Nataf, David M., E-mail: Amanda.Karakas@anu.edu.au [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia)

    2014-03-20

    We investigate the effect of helium enrichment on the evolution and nucleosynthesis of low-mass asymptotic giant branch (AGB) stars of 1.7 M {sub ?} and 2.36 M {sub ?} with a metallicity of Z = 0.0006 ([Fe/H] ?–1.4). We calculate evolutionary sequences with the primordial helium abundance (Y = 0.24) and with helium-enriched compositions (Y = 0.30, 0.35, 0.40). For comparison, we calculate models of the same mass but at a lower metallicity Z = 0.0003 ([Fe/H] ?–1.8) with Y = 0.24. Post-processing nucleosynthesis calculations are performed on each of the evolutionary sequences to determine the production of elements from hydrogen to bismuth. Elemental surface abundance predictions and stellar yields are presented for each model. The models with enriched helium have shorter main sequence and AGB lifetimes, and they enter the AGB with a more massive hydrogen-exhausted core than the primordial helium model. The main consequences are as follows: (1) low-mass AGB models with enhanced helium will evolve more than twice as fast, giving them the chance to contribute sooner to the chemical evolution of the forming globular clusters, and (2) the stellar yields will be strongly reduced relative to their primordial helium counterparts. An increase of ?Y = 0.10 at a given mass decreases the yields of carbon by up to ?60% and of fluorine by up to 80%; it also decreases the yields of the s-process elements barium and lanthanum by ?45%. While the yields of first s-process peak elements strontium, yttrium, and zirconium decrease by up to 50%, the yields of rubidium either do not change or increase.

  14. THE IMPACT OF HELIUM-BURNING REACTION RATES ON MASSIVE STAR EVOLUTION AND NUCLEOSYNTHESIS

    SciTech Connect (OSTI)

    West, Christopher; Heger, Alexander [Minnesota Institute for Astrophysics, School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Austin, Sam M., E-mail: west0482@umn.edu, E-mail: alexander.heger@monash.edu, E-mail: austin@nscl.msu.edu [Joint Institute for Nuclear Astrophysics, Notre Dame, IN 46556 (United States)

    2013-05-20

    We study the sensitivity of presupernova evolution and supernova nucleosynthesis yields of massive stars to variations of the helium-burning reaction rates within the range of their uncertainties. The current solar abundances from Lodders are used for the initial stellar composition. We compute a grid of 12 initial stellar masses and 176 models per stellar mass to explore the effects of independently varying the {sup 12}C({alpha}, {gamma}){sup 16}O and 3{alpha} reaction rates, denoted R{sub {alpha},12} and R{sub 3{alpha}}, respectively. The production factors of both the intermediate-mass elements (A = 16-40) and the s-only isotopes along the weak s-process path ({sup 70}Ge, {sup 76}Se, {sup 80}Kr, {sup 82}Kr, {sup 86}Sr, and {sup 87}Sr) were found to be in reasonable agreement with predictions for variations of R{sub 3{alpha}} and R{sub {alpha},12} of {+-}25%; the s-only isotopes, however, tend to favor higher values of R{sub 3{alpha}} than the intermediate-mass isotopes. The experimental uncertainty (one standard deviation) in R{sub 3{alpha}}(R{sub {alpha},12}) is approximately {+-}10%({+-}25%). The results show that a more accurate measurement of one of these rates would decrease the uncertainty in the other as inferred from the present calculations. We also observe sharp changes in production factors and standard deviations for small changes in the reaction rates, due to differences in the convection structure of the star. The compactness parameter was used to assess which models would likely explode as successful supernovae, and hence contribute explosive nucleosynthesis yields. We also provide the approximate remnant masses for each model and the carbon mass fractions at the end of core-helium burning as a key parameter for later evolution stages.

  15. New nano-mechanical plasmonic phase modulator offers electronics...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    nano-mechanical plasmonic phase modulator offers electronics potential April 3, 2015 Tweet EmailPrint By using standard semiconductor manufacturing equipment, a team of scientists...

  16. Sandia Energy - Magnetically Stimulated Flow Patterns Offer Strategy...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Magnetically Stimulated Flow Patterns Offer Strategy for Heat-Transfer Problems Home Office of Science Capabilities News News & Events Research & Capabilities Materials Science...

  17. Department of Energy Offers Conditional Loan Guarantee Commitments...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Guarantee Commitments to Support Nearly 4.5 Billion in Loans for Three California Photovoltaic Solar Power Plants Department of Energy Offers Conditional Loan Guarantee...

  18. Obama Administration Offers $59 Million in Conditional Loan Guarantees...

    Energy Savers [EERE]

    assembly plant in Pocatello, Idaho, to produce its one megawatt wind turbine. Beacon Power, an energy storage company, has been offered 43 million to support the construction...

  19. Residential Energy Efficiency Rebate (Offered by Several Cooperative Utilities)

    Broader source: Energy.gov [DOE]

    Associated Electric Cooperative and many of its member cooperatives offer rebates to residential customers who purchase and install energy efficient equipment for the home. Eligible equipment...

  20. FEMP Offers Training on Distributed-Scale Renewable Energy Projects...

    Energy Savers [EERE]

    Training on Distributed-Scale Renewable Energy Projects: From Planning to Project Closeout FEMP Offers Training on Distributed-Scale Renewable Energy Projects: From Planning to...

  1. Department of Energy Offers Conditional Loan Guarantee Commitment...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Commitment for Innovative Photovoltaic Solar Power Plant Department of Energy Offers Conditional Loan Guarantee Commitment for Innovative Photovoltaic Solar Power Plant June 15,...

  2. Department of Energy Offers Conditional Loan Guarantee Commitments...

    Energy Savers [EERE]

    4.5 billion, to support three alternating current Cadmium Telluride (Cd-Te) thin film photovoltaic (PV) solar generation facilities. The Department is offering a conditional...

  3. Federal Energy Management Program Training Offers IACET Continuing Education Units

    Broader source: Energy.gov [DOE]

    Video explains how the Federal Energy Management Program offers International Association for Continuing Education and Training (IACET) continuing education units for eTraining core courses.

  4. Business Energy Efficiency Rebate (Offered by 16 Utilities)

    Broader source: Energy.gov [DOE]

    Bright Energy Solutions offers energy efficiency cash incentive programs to residential and business customers of municipal utilities that are members of Missouri River Energy Services. In Iowa,...

  5. Residential Energy Efficiency Rebate (Offered by 16 Utilities)

    Broader source: Energy.gov [DOE]

    Bright Energy Solutions offers energy efficiency cash incentive programs to residential and business customers of municipal utilities that are members of Missouri River Energy Services. In Iowa,...

  6. DOE Offers $15 Million Geothermal Heat Recovery Opportunity ...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    15 Million Geothermal Heat Recovery Opportunity DOE Offers 15 Million Geothermal Heat Recovery Opportunity August 25, 2010 - 11:11am Addthis Photo of geothermal power plant....

  7. Occ. Med. Offers Staff Flu Vaccines by Appointment | Jefferson...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Occ. Med. Offers Staff Flu Vaccines by Appointment Occupational Medicine is now accepting appointments from Jefferson Lab staff for Influenza vaccinations. If you would like to be...

  8. Residential Energy Efficiency Rebates (Offered by 11 Utilities)

    Broader source: Energy.gov [DOE]

    Rebates are offered for a variety of efficient technologies and measures including: appliances, HVAC, lighting, and custom projects.  Rebates vary from one participating utility to another.  For ...

  9. Reusability Constructs in the Web Service Offerings Language

    E-Print Network [OSTI]

    Reusability Constructs in the Web Service Offerings Language (WSOL) [Second Extended Revision Constructs in the Web Service Offerings Language (WSOL) Vladimir Tosic, Kruti Patel, Bernard Pagurek, K1S 5B6, Canada {vladimir, bernie}@sce.carleton.ca, kruts.patel@lycos.com Abstract. The Web Service

  10. Optimal Power Flow Based Demand Response Offer Price Optimization

    E-Print Network [OSTI]

    Lavaei, Javad

    Optimal Power Flow Based Demand Response Offer Price Optimization Zhen Qiu 1 Introduction-time energy balance. Demand response programs are offered by the utility companies to reduce the load response cost in exchange for load reduction. A considerable amount of papers have discussed the demand

  11. Wind energy offers considerable promise; the wind itself is free,

    E-Print Network [OSTI]

    Langendoen, Koen

    Wind energy offers considerable promise; the wind itself is free, wind power is clean. One of these sources, wind energy, offers considerable promise; the wind itself is free, wind power is clean, and it is virtually inexhaustible. In recent years, research on wind energy has accelerated

  12. Core-Collapse Very Massive Stars: Evolution, Explosion, and Nucleosynthesis of Population III 500 -- 1000 $M_{\\odot}$ Stars

    E-Print Network [OSTI]

    T. Ohkubo; H. Umeda; K. Maeda; K. Nomoto; T. Suzuki; S. Tsuruta; M. J. Rees

    2006-05-09

    We calculate evolution, collapse, explosion, and nucleosynthesis of Population III very-massive stars with 500$M_{\\odot}$ and 1000$M_{\\odot}$. Presupernova evolution is calculated in spherical symmetry. Collapse and explosion are calculated by a two-dimensional code, based on the bipolar jet models. We compare the results of nucleosynthesis with the abundance patterns of intracluster matter, hot gases in M82, and extremely metal-poor stars in the Galactic halo. It was found that both 500$M_{\\odot}$ and 1000$M_{\\odot}$ models enter the region of pair-instability but continue to undergo core collapse. In the presupernova stage, silicon burning regions occupy a large fraction, more than 20% of the total mass. For moderately aspherical explosions, the patterns of nucleosynthesis match the observational data of both intracluster medium and M82. Our results suggest that explosions of Population III core-collapse very-massive stars contribute significantly to the chemical evolution of gases in clusters of galaxies. For Galactic halo stars, our [O/Fe] ratios are smaller than the observational abundances. However, our proposed scenario is naturally consistent with this outcome. The final black hole masses are $\\sim 230M_{\\odot}$ and $\\sim 500M_{\\odot}$ for the $500M_{\\odot}$ and 1000$M_{\\odot}$ models, respectively. This result may support the view that Population III very massive stars are responsible for the origin of intermediate mass black holes which were recently reported to be discovered.

  13. The Effects of Variations in Nuclear Interactions on Nucleosynthesis in Thermonuclear Supernovae

    E-Print Network [OSTI]

    Anuj Parikh; Jordi Jose; Ivo R. Seitenzahl; Friedrich K. Roepke

    2013-06-25

    The impact of nuclear physics uncertainties on nucleosynthesis in thermonuclear supernovae has not been fully explored using comprehensive and systematic studies with multiple models. To better constrain predictions of yields from these phenomena, we have performed a sensitivity study by post-processing thermodynamic histories from two different hydrodynamic, Chandrasekhar-mass explosion models. We have individually varied all input reaction and, for the first time, weak interaction rates by a factor of ten and compared the yields in each case to yields using standard rates. Of the 2305 nuclear reactions in our network, we find that the rates of only 53 reactions affect the yield of any species with an abundance of at least 10^-8 M_sun by at least a factor of two, in either model. The rates of the 12C(a,g), 12C+12C, 20Ne(a,p), 20Ne(a,g) and 30Si(p,g) reactions are among those that modify the most yields when varied by a factor of ten. From the individual variation of 658 weak interaction rates in our network by a factor of ten, only the stellar 28Si(b+)28Al, 32S(b+)32P and 36Ar(b+)36Cl rates significantly affect the yields of species in a model. Additional tests reveal that reaction rate changes over temperatures T > 1.5 GK have the greatest impact, and that ratios of radionuclides that may be used as explosion diagnostics change by a factor of less than two from the variation of individual rates by a factor of 10. Nucleosynthesis in the two adopted models is relatively robust to variations in individual nuclear reaction and weak interaction rates. Laboratory measurements of a limited number of reactions would help to further constrain predictions. As well, we confirm the need for a consistent treatment for relevant stellar weak interaction rates since simultaneous variation of these rates (as opposed to individual variation) has a significant effect on yields in our models.

  14. SYSTEMATICS OF DYNAMICAL MASS EJECTION, NUCLEOSYNTHESIS, AND RADIOACTIVELY POWERED ELECTROMAGNETIC SIGNALS FROM NEUTRON-STAR MERGERS

    SciTech Connect (OSTI)

    Bauswein, A.; Janka, H.-T. [Max Planck Institute for Astrophysics, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany); Goriely, S. [Institut d'Astronomie et d'Astrophysique, Universite Libre de Bruxelles, C.P. 226, B-1050 Brussels (Belgium)

    2013-08-10

    We investigate systematically the dynamical mass ejection, r-process nucleosynthesis, and properties of electromagnetic counterparts of neutron-star (NS) mergers in dependence on the uncertain properties of the nuclear equation of state (EOS) by employing 40 representative, microphysical high-density EOSs in relativistic, hydrodynamical simulations. The crucial parameter determining the ejecta mass is the radius R{sub 1.35} of a 1.35 M{sub Sun} NS. NSs with smaller R{sub 1.35} (''soft'' EOS) eject systematically higher masses. These range from {approx}10{sup -3} M{sub Sun} to {approx}10{sup -2} M{sub Sun} for 1.35-1.35 M{sub Sun} binaries and from {approx}5 Multiplication-Sign 10{sup -3} M{sub Sun} to {approx}2 Multiplication-Sign 10{sup -2} M{sub Sun} for 1.2-1.5 M{sub Sun} systems (with kinetic energies between {approx}5 Multiplication-Sign 10{sup 49} erg and 10{sup 51} erg). Correspondingly, the bolometric peak luminosities of the optical transients of symmetric (asymmetric) mergers vary between 3 Multiplication-Sign 10{sup 41} erg s{sup -1} and 14 Multiplication-Sign 10{sup 41} erg s{sup -1} (9 Multiplication-Sign 10{sup 41} erg s{sup -1} and 14.5 Multiplication-Sign 10{sup 41} erg s{sup -1}) on timescales between {approx}2 hr and {approx}12 hr. If these signals with absolute bolometric magnitudes from -15.0 to -16.7 are measured, the tight correlation of their properties with those of the merging NSs might provide valuable constraints on the high-density EOS. The r-process nucleosynthesis exhibits a remarkable robustness independent of the EOS, producing a nearly solar abundance pattern above mass number 130. By the r-process content of the Galaxy and the average production per event the Galactic merger rate is limited to 4 Multiplication-Sign 10{sup -5} yr{sup -1} (4 Multiplication-Sign 10{sup -4} yr{sup -1}) for a soft (stiff) NS EOS, if NS mergers are the main source of heavy r-nuclei. The production ratio of radioactive {sup 232}Th to {sup 238}U attains a stable value of 1.64-1.67, which does not exclude NS mergers as potential sources of heavy r-material in the most metal-poor stars.

  15. FEMP Offers Updated Training on the Guiding Principles for High...

    Office of Environmental Management (EM)

    Buildings FEMP Offers Updated Training on the Guiding Principles for High-Performance and Sustainable Buildings December 29, 2014 - 2:20pm Addthis The U.S. Department of Energy's...

  16. Music Technology Stetson University offers two degrees combining music with

    E-Print Network [OSTI]

    Miles, Will

    Music Technology Stetson University offers two degrees combining music with emerging technologies for artistic expression. The bachelor of music in music technology integrates music performance (voice, orchestral instruments, piano, organ, guitar) with studies in digital music and audio production

  17. Helium 'balloons' offer new path to control complex materials...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Morgan McCorkle Communications and Media Relations 865.574.7308 Helium 'balloons' offer new path to control complex materials Inserting helium atoms (visualized as a red balloon)...

  18. Department of Energy Offers Conditional Commitment for a Loan...

    Energy Savers [EERE]

    - 12:00am Addthis Washington, D.C. -- The U.S. Department of Energy today announced the offer of a conditional commitment for a 350 million loan guarantee to develop the One...

  19. Spotlight on Austin, Texas: Best Offer Ever Produces 564 Upgrades...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    564 Upgrades in Record Time Spotlight on Austin, Texas: Best Offer Ever Produces 564 Upgrades in Record Time This Better Buildings case study from April 2011 focuses on grantee...

  20. Department of Energy Offers First Conditional Commitment for...

    Energy Savers [EERE]

    Addthis Washington D.C. --- U.S. Energy Secretary Steven Chu today announced the offer of a conditional commitment to Diamond Green Diesel, LLC, the proposed joint venture...

  1. Department of Energy Offers Conditional Commitment for a Loan...

    Office of Environmental Management (EM)

    Addthis Washington D.C. --- U.S. Energy Secretary Steven Chu today announced the offer of a conditional commitment to Record Hill Wind LLC for a 102 million loan guarantee....

  2. Table of Contents Degrees Offered and Associated Departments 334

    E-Print Network [OSTI]

    Varela, Carlos

    Table of Contents Degrees Offered and Associated Departments 334 Overview of Undergraduate Programs Water Institute 409 Inverse Problems at RPI (IPRPI) 410 New York Center for Studies on the Origins

  3. Table of Contents Degrees Offered and Associated Departments 338

    E-Print Network [OSTI]

    Varela, Carlos

    Table of Contents Degrees Offered and Associated Departments 338 Overview of Undergraduate Programs Water Institute 414 Inverse Problems at RPI (IPRPI) 415 New York Center for Studies on the Origins

  4. Silicon Ink Technology Offers Path to Higher Efficiency Solar...

    Broader source: Energy.gov (indexed) [DOE]

    Silicon Ink Technology Offers Path to Higher Efficiency Solar Cells at Lower Cost Partnering with Sunnyvale-based Innovalight, which was acquired by DuPont in July 2011, EERE...

  5. A New Study of s-Process Nucleosynthesis in Massive Stars

    E-Print Network [OSTI]

    L. -S. The; M. F. El Eid; B. S. Meyer

    1998-12-11

    We present a comprehensive study of s-process nucleosynthesis in 15, 20, 25, and 30 $\\msun$ stellar models having solar-like initial composition. The stars are evolved up to ignition of central neon with a 659 species network coupled to the stellar models. In this way, the initial composition from one burning phase to another is consistently determined, especially with respect to neutron capture reactions. The aim of our calculations is to gain a full account of the s-process yield from massive stars. In the present work, we focus primarily on the s-process during central helium burning and illuminate some major uncertainties affecting the calculations. We briefly show how advanced burning can significantly affect the products of the core helium burning s-process and, in particular, can greatly deplete $^{80}$Kr that was strongly overproduced in the earlier core helium burning phase; however, we leave a complete analysis of the s-process during the advanced evolutionary phases (especially in shell carbon burning) to a subsequent paper. Our results can help to constrain the yield of the s-process material from massive stars during their pre-supernova evolution.

  6. Nucleosynthesis and mixing on the Asymptotic Giant Branch. III. Predicted and observed s-process abundances

    E-Print Network [OSTI]

    M. Busso; R. Gallino; D. L. Lambert; C. Travaglio; V. V. Smith

    2001-04-26

    We present the results of s-process nucleosynthesis calculations for AGB stars of different metallicities and initial masses. The computations were based on previously published stellar evolutionary models that account for the III dredge up phenomenon occurring late on the AGB. Neutron production is driven by the 13C(alpha,n)16O reaction during the interpulse periods in a tiny layer in radiative equilibrium at the top of the He- and C-rich shell. The s-enriched material is subsequently mixed with the envelope by the III dredge up, and the envelope composition is computed after each thermal pulse. We follow the changes in the photospheric abundance of the Ba-peak elements (heavy s, or `hs') and that of the Zr-peak ones (light s, or `ls'), whose logarithmic ratio [hs/ls] has often been adopted as an indicator of the s-process efficiency. The theoretical predictions are compared with published abundances of s elements for Galactic AGB giants of classes MS, S, SC, post-AGB supergiants, and for various classes of binary stars. The observations in general confirm the complex dependence of n captures on metallicity. They suggest that a moderate spread exists in the abundance of 13C that is burnt in different stars. Although additional observations are needed, a good understanding has been achieved of s-process operation in AGB. The detailed abundance distribution including the light elements (CNO) of a few s-enriched stars at different metallicity are examined.

  7. The r-process of stellar nucleosynthesis: Astrophysics and nuclear physics achievements and mysteries

    E-Print Network [OSTI]

    M. Arnould; S. Goriely; K. Takahashi

    2007-05-31

    The r-process, or the rapid neutron-capture process, of stellar nucleosynthesis is called for to explain the production of the stable (and some long-lived radioactive) neutron-rich nuclides heavier than iron that are observed in stars of various metallicities, as well as in the solar system. A very large amount of nuclear information is necessary in order to model the r-process. This concerns the static characteristics of a large variety of light to heavy nuclei between the valley of stability and the vicinity of the neutron-drip line, as well as their beta-decay branches or their reactivity. The enormously challenging experimental and theoretical task imposed by all these requirements is reviewed, and the state-of-the-art development in the field is presented. Nuclear-physics-based and astrophysics-free r-process models of different levels of sophistication have been constructed over the years. We review their merits and their shortcomings. For long, the core collapse supernova of massive stars has been envisioned as the privileged r-process location. We present a brief summary of the one- or multidimensional spherical or non-spherical explosion simulations available to-date. Their predictions are confronted with the requirements imposed to obtain an r-process. The possibility of r-nuclide synthesis during the decompression of the matter of neutron stars following their merging is also discussed.

  8. Deep-Ocean Crusts as Telescopes: Using Live Radioisotopes to Probe Supernova Nucleosynthesis

    E-Print Network [OSTI]

    Brian D. Fields; Kathrin A. Hochmuth; John Ellis

    2004-10-22

    Live 60Fe has recently been detected in a deep-ocean ferromanganese crust, isolated in layers dating from about 3 Myr ago. Since 60Fe has a mean life of 2.2 Myr, a near-Earth supernova is the only likely source for such a signal, and we explore here the consequences of a supernova origin. We combine the 60Fe data with several supernova nucleosynthesis models to calculate the supernova distance as a function of progenitor mass, finding an allowed range of 15-120 pc. We also predict the signals expected for several other radioisotopes, which are independent of the supernova distance. Species likely to be present near or above background levels are 10Be, 26Al, 53Mn, 182Hf and 244Pu. Of these, 182Hf and 244Pu are nearly background-free, presenting the best opportunities to provide strong confirmation of the supernova origin of the 60Fe signal, and to demonstrate that at least some supernovae are the source for the r-process. The accuracies of our predictions are hampered by large uncertainties in the predicted 60Fe yields for supernovae of different masses, so the new crust data motivate a redoubled theoretical attack on this problem.

  9. Explosive nucleosynthesis: nuclear physics impact using neutrino-driven wind simulations

    E-Print Network [OSTI]

    A. Arcones; G. Martinez-Pinedo

    2010-12-14

    We present nucleosynthesis studies based on hydrodynamical simulations of core-collapse supernovae and their subsequent neutrino-driven winds. Although the conditions found in these simulations are not suitable for the rapid neutron capture (r-process) to produce elements heavier than A$\\sim$130, this can be solved by artificially increasing the wind entropy. In this way one can mimic the general behavior of an ejecta where the r-process occurs. We study the impact of the long-time dynamical evolution and of the nuclear physics input on the final abundances and show that different nuclear mass models lead to significant variations in the abundances. These differences can be linked to the behavior of nuclear masses far from stability. In addition, we have analyzed in detail the effect of neutron capture and beta-delayed neutron emission when matter decays back to stability. In all our studied cases, freeze out effects are larger than previously estimated and produce substantial changes in the post freeze out abundances.

  10. Neutrino-driven winds in the aftermath of a neutron star merger: nucleosynthesis and electromagnetic transients

    E-Print Network [OSTI]

    Dirk Martin; Albino Perego; Almudena Arcones; Friedrich-Karl Thielemann; Oleg Korobkin; Stephan Rosswog

    2015-09-24

    We present a comprehensive nucleosynthesis study of the neutrino-driven wind in the aftermath of a binary neutron star merger. Our focus is the initial remnant phase when a massive central neutron star is present. Using tracers from a recent hydrodynamical simulation, we determine total masses and integrated abundances to characterize the composition of unbound matter. We find that the nucleosynthetic yields depend sensitively on both the life time of the massive neutron star and the polar angle. Matter in excess of up to $9 \\cdot 10^{-3} M_\\odot$ becomes unbound until $\\sim 200~{\\rm ms}$. Due to electron fractions of $Y_{\\rm e} \\approx 0.2 - 0.4$ mainly nuclei with mass numbers $A < 130$ are synthesized, complementing the yields from the earlier dynamic ejecta. Mixing scenarios with these two types of ejecta can explain the abundance pattern in r-process enriched metal-poor stars. Additionally, we calculate heating rates for the decay of the freshly produced radioactive isotopes. The resulting light curve peaks in the blue band after about $4~{\\rm h}$. Furthermore, high opacities due to heavy r-process nuclei in the dynamic ejecta lead to a second peak in the infrared after $3-4~{\\rm d}$.

  11. Lithium in Very Metal-poor Dwarf Stars - Problems for Standard Big Bang Nucleosynthesis?

    E-Print Network [OSTI]

    David L. Lambert

    2004-10-18

    The standard model of primordial nucleosynthesis by the Big Bang as selected by the WMAP-based estimate of the baryon density ($\\Omega_bh^2$) predicts an abundance of $^7$Li that is a factor of three greater than the generally reported abundance for stars on the Spite plateau, and an abundance of $^6$Li that is about a thousand times less than is found for some stars on the plateau. This review discusses and examines these two discrepancies. They can likely be resolved without major surgery on the standard model of the Big Bang. In particular, stars on the Spite plateau may have depleted their surface lithium abundance over their long lifetime from the WMAP-based predicted abundances down to presently observed abundances, and synthesis of $^6$Li (and $^7$Li) via $\\alpha + \\alpha$ fusion reactions may have occurred in the early Galaxy. Yet, there remain fascinating ways in which to remove the two discrepancies involving aspects of a new cosmology, particularly through the introduction of exotic particles.

  12. Constraints on Lepton Asymmetry from Nucleosynthesis in a Linearly Coasting Cosmology

    E-Print Network [OSTI]

    Parminder Singh; Daksh Lohiya

    2015-05-30

    We study the effect of neutrino degeneracy on primordial nucleosynthesis in a universe in which the cosmological scale factor evolves linearly with time. The degeneracy parameter of electron type neutrinos ($\\xi_e$) determines the $n/p$ (neutron to proton) ratio, which in turn determines the abundance of $^4$He in a manner quite distinct from the Standard Scenario. The observed abundances of $^4$He, $\\mathrm{Y}_P$=0.254$\\pm$0.003, and the minimum metallicity that is essential for fragmentation and cooling processes in star forming prestellar gas clouds (Z = Z$_{cr}$ = 10$^{-6}$Z$_\\odot$), constrain the baryon to photon ratio, $\\eta_B$=(3.927$\\pm$0.292)10$^{-9}$, corresponding to a baryonic matter density, $\\Omega_B$=0.263$\\pm$ 0.026 and $\\xi_e$=-2.165$\\pm$0.171. This closes the dynamic mass estimates of matter in the universe by baryons alone. Useful byproducts are the threshold X(CNO) abundances required to trigger the CNO cycle in the observed low metallicity stars in the universe.

  13. Theoretical neutron-capture cross sections for r-process nucleosynthesis in the $^{48}$Ca region

    E-Print Network [OSTI]

    Rauscher, T; Kratz, K -L; Balogh, W; Oberhummer, H

    2015-01-01

    We calculate neutron capture cross sections for r-process nucleosynthesis in the $^{48}$Ca region, namely for the isotopes $^{40-44}$S, $^{46-50}$Ar, $^{56-66}$Ti, $^{62-68}$Cr, and $^{72-76}$Fe. While previously only cross sections resulting from the compound nucleus reaction mechanism (Hauser-Feshbach) have been considered, we recalculate not only that contribution to the cross section but also include direct capture on even-even nuclei. The level schemes, which are of utmost importance in the direct capture calculations, are taken from quasi-particle states obtained with a folded-Yukawa potential and Lipkin-Nogami pairing. Most recent deformation values derived from experimental data on $\\beta$-decay half lives are used where available. Due to the consideration of direct capture, the capture rates are enhanced and the "turning points" in the r-process path are shifted to slightly higher mass numbers. We also discuss the sensitivity of the direct capture cross sections on the assumed deformation.

  14. The r-process nucleosynthesis during the decompression of neutron star crust material

    SciTech Connect (OSTI)

    Goriely, S. [Institut d'Astronomie et d'Astrophysique, CP-226, Université Libre de Bruxelles, 1050 Brussels (Belgium); Bauswein, A. [Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece and Max-Planck-Institut für Astrophysik, Postfach 1317, 85741 Garching (Germany); Janka, H.-T. [Max-Planck-Institut für Astrophysik, Postfach 1317, 85741 Garching (Germany); Sida, J.-L.; Lemaître, J.-F.; Panebianco, S. [C.E.A. Saclay, Irfu/Service de Physique Nucléaire, 91191 Gif-sur-Yvette (France); Dubray, N.; Hilaire, S. [CEA, DAM, DIF, F-91297 Arpajon (France)

    2014-05-02

    About half of the nuclei heavier than iron observed in nature are produced by the so-called rapid neutron capture process, or r-process, of nucleosynthesis. The identification of the astrophysics site and the specific conditions in which the r-process takes place remains, however, one of the still-unsolved mysteries of modern astrophysics. Another underlying difficulty associated with our understanding of the r-process concerns the uncertainties in the predictions of nuclear properties for the few thousands exotic neutron-rich nuclei involved, for which essentially no experimental data exist. The present paper emphasizes some important future challenges faced by nuclear physics in this problem, particularly in the determination of the nuclear structure properties of exotic neutron-rich nuclei as well as their radiative neutron capture rates and their fission probabilities. These quantities are particularly relevant to determine the composition of the matter resulting from the r-process. Both the astrophysics and the nuclear physics difficulties are critically reviewed with special attention paid to the r-process taking place during the decompression of neutron star matter following the merging of two neutron stars.

  15. Theoretical neutron-capture cross sections for r-process nucleosynthesis in the $^{48}$Ca region

    E-Print Network [OSTI]

    T. Rauscher; W. Böhmer; K. -L. Kratz; W. Balogh; H. Oberhummer

    2015-04-17

    We calculate neutron capture cross sections for r-process nucleosynthesis in the $^{48}$Ca region, namely for the isotopes $^{40-44}$S, $^{46-50}$Ar, $^{56-66}$Ti, $^{62-68}$Cr, and $^{72-76}$Fe. While previously only cross sections resulting from the compound nucleus reaction mechanism (Hauser-Feshbach) have been considered, we recalculate not only that contribution to the cross section but also include direct capture on even-even nuclei. The level schemes, which are of utmost importance in the direct capture calculations, are taken from quasi-particle states obtained with a folded-Yukawa potential and Lipkin-Nogami pairing. Most recent deformation values derived from experimental data on $\\beta$-decay half lives are used where available. Due to the consideration of direct capture, the capture rates are enhanced and the "turning points" in the r-process path are shifted to slightly higher mass numbers. We also discuss the sensitivity of the direct capture cross sections on the assumed deformation.

  16. New Stellar $(n,?)$ Cross Sections and The "Karlsruhe Astrophysical Database of Nucleosynthesis in Stars"

    E-Print Network [OSTI]

    I. Dillmann; R. Plag; C. Domingo-Pardo; M. Heil; F. Käppeler; T. Rauscher; F. -K. Thielemann

    2008-06-12

    Since April 2005 a regularly updated stellar neutron cross section compilation is available online at http://nuclear-astrophysics.fzk.de/kadonis. This online-database is called the "Karlsruhe Astrophysical Database of Nucleosynthesis in Stars" project and is based on the previous Bao et al. compilation from the year 2000. The present version \\textsc{KADoNiS} v0.2 (January 2007) includes recommended cross sections for 280 isotopes between $^{1}$H and $^{210}$Po and 75 semi-empirical estimates for isotopes without experimental information. Concerning stellar $(n,\\gamma)$ cross sections of the 32 stable, proton-rich isotopes produced by the $p$ process experimental information is only available for 20 isotopes, but 9 of them have rather large uncertainties of $\\geq$9%. The first part of a systematic study of stellar $(n,\\gamma)$ cross sections of the $p$-process isotopes $^{74}$Se, $^{84}$Sr, $^{102}$Pd, $^{120}$Te, $^{130}$Ba, $^{132}$Ba, $^{156}$Dy, and $^{174}$Hf is presented. In another application \\textsc{KADoNiS} v0.2 was used for an modification of a reaction library of Basel university. With this modified library $p$-process network calculations were carried out and compared to previous results.

  17. Evolution and nucleosynthesis of helium-rich asymptotic giant branch models

    E-Print Network [OSTI]

    Shingles, Luke J; Karakas, Amanda I; Stancliffe, Richard J; Lattanzio, John C; Lugaro, Maria

    2015-01-01

    There is now strong evidence that some stars have been born with He mass fractions as high as $Y \\approx 0.40$ (e.g., in $\\omega$ Centauri). However, the advanced evolution, chemical yields, and final fates of He-rich stars are largely unexplored. We investigate the consequences of He-enhancement on the evolution and nucleosynthesis of intermediate-mass asymptotic giant branch (AGB) models of 3, 4, 5, and 6 M$_\\odot$ with a metallicity of $Z = 0.0006$ ([Fe/H] $\\approx -1.4$). We compare models with He-enhanced compositions ($Y=0.30, 0.35, 0.40$) to those with primordial He ($Y=0.24$). We find that the minimum initial mass for C burning and super-AGB stars with CO(Ne) or ONe cores decreases from above our highest mass of 6 M$_\\odot$ to $\\sim$ 4-5 M$_\\odot$ with $Y=0.40$. We also model the production of trans-Fe elements via the slow neutron-capture process (s-process). He-enhancement substantially reduces the third dredge-up efficiency and the stellar yields of s-process elements (e.g., 90% less Ba for 6 M$_\\o...

  18. Research news sidebar: Farm Smart offers hands-on experience, insight into where food comes from

    E-Print Network [OSTI]

    Meadows, Robin

    2012-01-01

    Alan Robertson, Caywood offers more than 150 daylongJanuary and February, Caywood offers a similar outreachNancy Caywood Farm Smart offers hands-on experience, insight

  19. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    abundances of light elements created of a variation of the quark masses at the time of Big Bang nucleosynthesis (BBN). In order to navigate through the particle and nuclear...

  20. Offering: Marc Leuthold: A review by Tanya Hartman

    E-Print Network [OSTI]

    Hartman, Tanya

    2011-01-01

    stream_size 9574 stream_content_type text/plain stream_name 13_Leuthold_83[1].pdf.txt stream_source_info 13_Leuthold_83[1].pdf.txt Content-Encoding UTF-8 Content-Type text/plain; charset=UTF-8 Offering A Review by Tanya... grad- ually weakened our country? What can we do to help ourselves? When does it become our duty to take back our government?” His stunning Offering is an attempt to “call attention to these questions”. Walking into marc leuthold’s exhibition...

  1. Evolution and nucleosynthesis of asymptotic giant branch stellar models of low metallicity

    SciTech Connect (OSTI)

    Fishlock, Cherie K.; Karakas, Amanda I.; Yong, David [Research School of Astronomy and Astrophysics, Australian National University, Canberra ACT 2611 (Australia); Lugaro, Maria, E-mail: cherie.fishlock@anu.edu.au, E-mail: amanda.karakas@anu.edu.au, E-mail: david.yong@anu.edu.au, E-mail: maria.lugaro@monash.edu [Monash Centre for Astrophysics, Monash University, Clayton VIC 3800 (Australia)

    2014-12-10

    We present stellar evolutionary tracks and nucleosynthetic predictions for a grid of stellar models of low- and intermediate-mass asymptotic giant branch (AGB) stars at Z = 0.001 ([Fe/H] =–1.2). The models cover an initial mass range from 1 M {sub ?} to 7 M {sub ?}. Final surface abundances and stellar yields are calculated for all elements from hydrogen to bismuth as well as isotopes up to the iron group. We present the first study of neutron-capture nucleosynthesis in intermediate-mass AGB models, including a super-AGB model, of [Fe/H] = –1.2. We examine in detail a low-mass AGB model of 2 M {sub ?} where the {sup 13}C(?,n){sup 16}O reaction is the main source of neutrons. We also examine an intermediate-mass AGB model of 5 M {sub ?} where intershell temperatures are high enough to activate the {sup 22}Ne neutron source, which produces high neutron densities up to ?10{sup 14} n cm{sup –3}. Hot bottom burning is activated in models with M ? 3 M {sub ?}. With the 3 M {sub ?} model, we investigate the effect of varying the extent in mass of the region where protons are mixed from the envelope into the intershell at the deepest extent of each third dredge-up. We compare the results of the low-mass models to three post-AGB stars with a metallicity of [Fe/H] ? – 1.2. The composition is a good match to the predicted neutron-capture abundances except for Pb and we confirm that the observed Pb abundances are lower than what is calculated by AGB models.

  2. EVOLUTION, NUCLEOSYNTHESIS, AND YIELDS OF LOW-MASS ASYMPTOTIC GIANT BRANCH STARS AT DIFFERENT METALLICITIES. II. THE FRUITY DATABASE

    SciTech Connect (OSTI)

    Cristallo, S.; Dominguez, I.; Abia, C. [Departamento de Fisica Teorica y del Cosmos, Universidad de Granada, 18071 Granada (Spain); Piersanti, L.; Straniero, O.; Gallino, R.; Di Rico, G.; Quintini, M. [INAF-Osservatorio Astronomico di Collurania, 64100 Teramo (Italy); Bisterzo, S. [Dipartimento di Fisica Generale, Universita di Torino, 10125 Torino (Italy)

    2011-12-01

    By using updated stellar low-mass stars models, we systematically investigate the nucleosynthesis processes occurring in asymptotic giant branch (AGB) stars. In this paper, we present a database dedicated to the nucleosynthesis of AGB stars: FRANEC Repository of Updated Isotopic Tables and Yields (FRUITY). An interactive Web-based interface allows users to freely download the full (from H to Bi) isotopic composition, as it changes after each third dredge-up (TDU) episode and the stellar yields the models produce. A first set of AGB models, having masses in the range 1.5 {<=}M/M{sub Sun} {<=} 3.0 and metallicities 1 Multiplication-Sign 10{sup -3} {<=} Z {<=} 2 Multiplication-Sign 10{sup -2}, is discussed. For each model, a detailed description of the physical and the chemical evolution is provided. In particular, we illustrate the details of the s-process and we evaluate the theoretical uncertainties due to the parameterization adopted to model convection and mass loss. The resulting nucleosynthesis scenario is checked by comparing the theoretical [hs/ls] and [Pb/hs] ratios to those obtained from the available abundance analysis of s-enhanced stars. On the average, the variation with the metallicity of these spectroscopic indexes is well reproduced by theoretical models, although the predicted spread at a given metallicity is substantially smaller than the observed one. Possible explanations for such a difference are briefly discussed. An independent check of the TDU efficiency is provided by the C-stars luminosity function. Consequently, theoretical C-stars luminosity functions for the Galactic disk and the Magellanic Clouds have been derived. We generally find good agreement with observations.

  3. Nd:YAG laser offers promising treatment option for familial glomuvenous malformation

    E-Print Network [OSTI]

    Phillips, CB; Guerrero, C; Theos, A

    2015-01-01

    2015 Letter Nd:YAG laser offers promising treatment optionlaser therapy appears to offer an effective, well-tolerated,

  4. GENERAL INFORMATION The City College offers the following

    E-Print Network [OSTI]

    Sun, Yi

    Environmental Chemistry Inorganic Chemistry Organic Chemistry Physical Chemistry The M.A. curriculum is flexible: Environmental Chemistry (3 cr.) A1101: Environmental Chemistry Lab (2 cr.) A1200: Environmental Organic42 GENERAL INFORMATION The City College offers the following master's degree in Chemistry: M

  5. AMST courses offered Spring 2014 Tulsa Based Classes

    E-Print Network [OSTI]

    Veiga, Pedro Manuel Barbosa

    AMST courses offered Spring 2014 Tulsa Based Classes: Crime, Law & Am Culture (S) AMST 3333 Liang to crime and the law. Arts and American Society: Tulsa's Public Cultures AMST 3550 Gray T 4:30-7:10p T-NCB 104 Topics vary by semester. This course will focus on Tulsa art, architecture and literature

  6. WSU Professional & Academic Development (PAD) Seminar Series Winter 2015 Offerings

    E-Print Network [OSTI]

    Finley Jr., Russell L.

    for Interdisciplinary Development, Division of Research THU | APRIL 23, 2015 PAD Seminar ­ Conflict Management 1:00pmWSU Professional & Academic Development (PAD) Seminar Series Winter 2015 Offerings The offices this free career development seminar series for WSU faculty, chairs & directors, postdoctoral trainees

  7. Spring 2012 Course Offering EEE 598 Advanced Photovoltaics

    E-Print Network [OSTI]

    Zhang, Junshan

    Spring 2012 Course Offering EEE 598 Advanced Photovoltaics Professor Meng Tao Course Description: The course will cover both technical and broader issues related to photovoltaics for the production for solar energy utilization. Review of solar cell physics. Wafer silicon photovoltaic technology. Survey

  8. Nuclear magnetic resonance offers new insights into Pu 239

    E-Print Network [OSTI]

    - 1 - Nuclear magnetic resonance offers new insights into Pu 239 May 29, 2012 Nuclear magnetic signal of plutonium 239's unique nuclear magnetic resonance signature has been detected by scientists on the subject, "Observation of 239 Pu Nuclear Magnetic Resonance," was published in the May 18 issue of Science

  9. Graduate Programs in Psychology The psychology department offers courses of

    E-Print Network [OSTI]

    Graduate Programs in Psychology The psychology department offers courses of study leading to the Doctor of Philosophy degree. Students may complete requirements for study in human factors psychology, community psychology, or clinical psychology. Students in the doctoral program can be awarded the master

  10. Stormwater Programs offered to Communities in New Hampshire's Coastal Watershed

    E-Print Network [OSTI]

    New Hampshire, University of

    Stormwater Programs offered to Communities in New Hampshire's Coastal Watershed Protecting Water Resources and Managing Stormwater: A Bird's Eye View Provides information about on-the-ground actions for communities to improve stormwater management from landscape to site level scales. Facilitated discussion helps

  11. Flexible plastic solar cells offer great advantages when compared with

    E-Print Network [OSTI]

    Langendoen, Koen

    Flexible plastic solar cells offer great advantages when compared with traditional silicon solar for a solar cell: extremely easy to produce, very cheap and with good perspectives for high efficiencies. Since ten years considerable progress has been made in developing new and very promising types of solar

  12. Tsunami-Made Electric Current Could Offer Warning

    E-Print Network [OSTI]

    Harinarayana, T.

    Tsunami-Made Electric Current Could Offer Warning Killer ocean waves apparently generate electric currents in the ocean that might be used to detect tsunamis quickly. By Larry O'Hanlon | Fri Jan 22, 2010 07:52 AM ET THE GIST: · A new model predicts that tsunamis can generate small surges of electricity

  13. Negotiating a Job Offer: How to Prepare Receiving a job offer can make you feel excited and relieved. After the excitement, you may wonder

    E-Print Network [OSTI]

    Negotiating a Job Offer: How to Prepare Receiving a job offer can make you feel excited what is right in an offer? What are the different dimensions of compensation that can be negotiated structured compensation packages can you offer me? Do you have flexibility on: salary, signing bonus, annual

  14. New Nuclear Reaction Flow during r-Process Nucleosynthesis in Supernovae: Critical Role of Light Neutron-Rich Nuclei

    E-Print Network [OSTI]

    M. Terasawa; K. Sumiyoshi; T. Kajino; G. J. Mathews; I. Tanihata

    2001-07-19

    We study the role of light neutron-rich nuclei during r-process nucleosynthesis in supernovae. Most previous studies of the r-process have concentrated on the reaction flow of heavy unstable nuclei. Although the nuclear reaction network includes a few thousand heavy nuclei, only limited reaction flow through light-mass nuclei near the stability line has been used in those studies. However, in a viable scenario of the r-process in neutrino-driven winds, the initial condition is a high-entropy hot plasma consisting of neutrons, protons, and electron-positron pairs experiencing an intense flux of neutrinos. In such environments light-mass nuclei as well as heavy nuclei are expected to play important roles in the production of seed nuclei and r-process elements. Thus, we have extended our fully implicit nuclear reaction network so that it includes all nuclei up to the neutron drip line for Z $ \\leq 10$, in addition to a larger network for Z $ \\geq 10$. In the present nucleosynthesis study, we utilize a wind model of massive SNeII explosions to study the effects of this extended network. We find that a new nuclear-reaction flow path opens in the very light neutron-rich region. This new nuclear reaction flow can change the final heavy-element abundances by as much as an order of magnitude.

  15. Does breastfeeding offer protection against maternal depressive symptomatology?: A prospective study from pregnancy to 2 years after birth

    E-Print Network [OSTI]

    Hahn-Holbrook, J; Haselton, MG; Dunkel Schetter, C; Glynn, LM

    2013-01-01

    Does breastfeeding offer protection against maternalARTICLE Does breastfeeding offer protection against maternalthat breastfeeding could offer such protective benefits.

  16. Arnett, D. 1996, Supernovae and Nucleosynthesis: An Investigation of the History of Matter, from the Big Bang to the Present. Princeton: Princeton University Press.

    E-Print Network [OSTI]

    Mamajek, Eric E.

    of Matter, from the Big Bang to the Present. Princeton: Princeton University Press. Carroll, B. W., & Ostlie, Principles of Stellar Evolution and Nucleosynthesis. Chicago: University of Chicago Press. Collins, G. W, The Observation and Analysis of Stellar Photospheres, 3rd ed. Cambridge, UK: Cambridge University Press. Hansen, C

  17. BEST OFFER EVER ACCELERATED TEXAS UPGRADES | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE: Alternative FuelsofProgram:Y-12Power, Inc | DepartmentPeer20InsulatedofBEST OFFER EVER ACCELERATED

  18. Solving the discrepancy among the light elements abundances and WMAP

    E-Print Network [OSTI]

    Kazuhide Ichikawa; Masahiro Kawasaki; Fuminobu Takahashi

    2004-06-09

    Within the standard big bang nucleosynthesis (BBN) and cosmic microwave background (CMB) framework, the baryon density measured by the Wilkinson Microwave Anisotropy Probe (WMAP) or the primordial D abundance is much higher than the one measured by the $^4$He or $^7$Li abundances. To solve the discrepancy, we propose a scenario in which additional baryons appear after BBN. We show that simply adding the baryons can not be a solution but the existence of a large lepton asymmetry before BBN makes the scenario successful. These extra baryons and leptons, in addition to the initial baryons which exist before the BBN, can be all produced from $Q$-balls.

  19. Coronary CT angiography offers further risk stratification in the management of patients with normal SPECT results

    E-Print Network [OSTI]

    Budoff, Matthew J.; Hacioglu, Yalcin

    2010-01-01

    Coronary CT angiography offers further risk strati?cation inCoronary CT angiography offers further risk strati?cationCoronary CT angiography offers further risk strati?cation

  20. Garden Beans Offer Year-Round Source of Great Flavor, Nutrition

    E-Print Network [OSTI]

    Martin, Orin

    2008-01-01

    UC Santa Cruz Garden Beans Offer Year-Round Source of Greatis acceptable, the climbers offer much better texture andgreen beans. The climbers offer 2–3 months of cropping, with

  1. Analysis of Assembly Bill 368: Mandate to Offer Coverage of Hearing Aids for Children

    E-Print Network [OSTI]

    California Health Benefits Review Program (CHBRP)

    2007-01-01

    Bill 368: Mandate to Offer Coverage for Hearing Aids forhealth care provider; (2) offer or provide coverage for thedisease or condition; or (3) offer or provide coverage of a

  2. Customer Response to RTP in Competitive Markets: A Study of Niagara Mohawk's Standard Offer Tariff

    E-Print Network [OSTI]

    Boisvert, Richard N.; Cappers, Peter; Goldman, Charles; Neenan, Bernie; Hopper, Nicole

    2006-01-01

    Niagara Mohawk’s Standard Offer Tariff * Richard N. BoisvertRTP the retail standard offer would create opportunities forHowever, some retailers did offer service indexed to the SC-

  3. Summary of CUDCP Policy for Graduate School Offers and Acceptances Information for Applicants

    E-Print Network [OSTI]

    Gelfond, Michael

    Summary of CUDCP Policy for Graduate School Offers and Acceptances Information for Applicants CUDCP (www.cudcp.us) has adopted the following guidelines for offers the status of their application. You may be offered admission, declined admission

  4. Austin's Home Performance with Energy Star Program: Making a Compelling Offer to a Financial Institution Partner

    E-Print Network [OSTI]

    Zimring, Mark

    2011-01-01

    Making a Compelling Offer to a Financial Institution PartnerEnergy recently ran the ‘Best Offer Ever’ promotion in whichwith more details on the ‘Best Offer Ever’ is forthcoming.  

  5. Asian Greens Offer Tasty, Easy-to-Grow Source of Nutrition

    E-Print Network [OSTI]

    Martin, Orin

    2008-01-01

    leafy vegetables. They offer nutritious dark greens high inAnd at full maturity, they offer an amazing amount of high-UC Santa Cruz Asian Greens Offer Tasty, Easy-to-Grow Source

  6. An examination of liver offers to candidates on the liver transplant wait-list

    E-Print Network [OSTI]

    Lai, JC; Feng, S; Roberts, JP

    2012-01-01

    the availability of de- LIVER OFFERS ON THE WAIT–LISTAn Examination of Liver Offers to Candidates on the Liverrange) number of liver offers for all candidates was 5 (

  7. The Uganda Offer, 1902-1905: A Study of Settlement Concessions in British East Africa

    E-Print Network [OSTI]

    Cliansmith, Michael

    1974-01-01

    Hence the name "Uganda Offer." Amery, I~fe, pp. 264-5 . 53.attitude toward Chamberlain's offer may be viewed in severalgreat e:e'tGnt; it consaqwmtZy offers unlimited room for the

  8. Interior Offers First Right-of-Way for Renewable Energy Transmission...

    Energy Savers [EERE]

    Interior Offers First Right-of-Way for Renewable Energy Transmission in Federal Waters Interior Offers First Right-of-Way for Renewable Energy Transmission in Federal Waters...

  9. FEMP First Thursday Seminar Offers Training on New FederalEnergy...

    Office of Environmental Management (EM)

    First Thursday Seminar Offers Training on New Federal Energy-Efficiency Standards FEMP First Thursday Seminar Offers Training on New Federal Energy-Efficiency Standards February...

  10. Precision Mass Measurements of 129-131Cd and Their Impact on Stellar Nucleosynthesis via the Rapid Neutron Capture Process

    E-Print Network [OSTI]

    D. Atanasov; P. Ascher; K. Blaum; R. B. Cakirli; T. E. Cocolios; S. George; F. Herfurth; D. Kisler; M. Kowalska; S. Kreim; Yu. A. Litvinov; D. Lunney; V. Manea; D. Neidherr; M. Rosenbusch; L. Schweikhard; A. Welker; F. Wienholtz; R. N. Wolf; K. Zuber

    2015-12-17

    Masses adjacent to the classical waiting-point nuclide 130Cd have been measured by using the Penning- trap spectrometer ISOLTRAP at ISOLDE/CERN. We find a significant deviation of over 400 keV from earlier values evaluated by using nuclear beta-decay data. The new measurements show the reduction of the N = 82 shell gap below the doubly magic 132Sn. The nucleosynthesis associated with the ejected wind from type-II supernovae as well as from compact object binary mergers is studied, by using state-of-the-art hydrodynamic simulations. We find a consistent and direct impact of the newly measured masses on the calculated abundances in the A = 128 - 132 region and a reduction of the uncertainties from the precision mass input data.

  11. The Sensitivity of Nucleosynthesis in Type I X-ray Bursts to Thermonuclear Reaction-Rate Variations

    E-Print Network [OSTI]

    Anuj Parikh; Jordi Jose; Fermin Moreno; Christian Iliadis

    2008-06-18

    We examine the sensitivity of nucleosynthesis in Type I X-ray bursts to variations in nuclear rates. As a large number of nuclear processes are involved in these phenomena -with the vast majority of reaction rates only determined theoretically due to the lack of any experimental information- our results can provide a means for determining which rates play significant roles in the thermonuclear runaway. These results may then motivate new experiments. For our studies, we have performed a comprehensive series of one-zone post-processing calculations in conjunction with various representative X-ray burst thermodynamic histories. We present those reactions whose rate variations have the largest effects on yields in our studies.

  12. Bino Dark Matter and Big Bang Nucleosynthesis in the Constrained E6SSM with Massless Inert Singlinos

    E-Print Network [OSTI]

    Jonathan P. Hall; Stephen F. King

    2011-05-11

    We discuss a new variant of the E6 inspired supersymmetric standard model (E6SSM) in which the two inert singlinos are exactly massless and the dark matter candidate has a dominant bino component. A successful relic density is achieved via a novel mechanism in which the bino scatters inelastically into heavier inert Higgsinos during the time of thermal freeze-out. The two massless inert singlinos contribute to the effective number of neutrino species at the time of Big Bang Nucleosynthesis, where the precise contribution depends on the mass of the Z' which keeps them in equilibrium. For example for mZ' > 1300 GeV we find Neff \\approx 3.2, where the smallness of the additional contribution is due to entropy dilution. We study a few benchmark points in the constrained E6SSM with massless inert singlinos to illustrate this new scenario.

  13. R-Process Nucleosynthesis In Neutrino-Driven Winds From A Typical Neutron Star With M = 1.4 Msun

    E-Print Network [OSTI]

    M. Terasawa; K. Sumiyoshi; S. Yamada; H. Suzuki; T. Kajino

    2002-06-18

    We study the effects of the outer boundary conditions in neutrino-driven winds on the r-process nucleosynthesis. We perform numerical simulations of hydrodynamics of neutrino-driven winds and nuclear reaction network calculations of the r-process. As an outer boundary condition of hydrodynamic calculations, we set a pressure upon the outermost layer of the wind, which is approaching toward the shock wall. Varying the boundary pressure, we obtain various asymptotic thermal temperature of expanding material in the neutrino-driven winds for resulting nucleosynthesis. We find that the asymptotic temperature slightly lower than those used in the previous studies of the neutrino-driven winds can lead to a successful r-process abundance pattern, which is in a reasonable agreement with the solar system r-process abundance pattern even for the typical proto-neutron star mass Mns ~ 1.4 Msun. A slightly lower asymptotic temperature reduces the charged particle reaction rates and the resulting amount of seed elements and lead to a high neutron-to-seed ratio for successful r-process. This is a new idea which is different from the previous models of neutrino-driven winds from very massive (Mns ~ 2.0 Msun) and compact (Rns ~ 10 km) neutron star to get a short expansion time and a high entropy for a successful r-process abundance pattern. Although such a large mass is sometimes criticized from observational facts on a neutron star mass, we dissolve this criticism by reconsidering the boundary condition of the wind. We also explore the relation between the boundary condition and neutron star mass, which is related to the progenitor mass, for successful r-process.

  14. Impact of neutrino flavor oscillations on the neutrino-driven wind nucleosynthesis of an electron-capture supernova

    E-Print Network [OSTI]

    Else Pllumbi; Irene Tamborra; Shinya Wanajo; H. -Thomas Janka; Lorenz Huedepohl

    2015-06-08

    Neutrino oscillations, especially to light sterile states, can affect the nucleosynthesis yields because of their possible feedback effect on the electron fraction (Ye). For the first time, we perform nucleosynthesis calculations for neutrino-driven wind trajectories from the neutrino-cooling phase of an 8.8 Msun electron-capture supernova, whose hydrodynamic evolution was computed in spherical symmetry with sophisticated neutrino transport and whose Ye evolution was post-processed by including neutrino oscillations both between active and active-sterile flavors. We also take into account the alpha-effect as well as weak magnetism and recoil corrections in the neutrino absorption and emission processes. We observe effects on the Ye evolution which depend in a subtle way on the relative radial positions of the sterile MSW resonances, of collective flavor transformations, and on the formation of alpha particles. For the adopted supernova progenitor, we find that neutrino oscillations, also to a sterile state with eV-mass, do not significantly affect the element formation and in particular cannot make the post-explosion wind outflow neutron rich enough to activate a strong r-process. Our conclusions become even more robust when, in order to mimic equation-of-state dependent corrections due to nucleon potential effects in the dense-medium neutrino opacities, six cases with reduced Ye in the wind are considered. In these cases, despite the conversion of active neutrinos to sterile neutrinos, Ye increases or is not significantly lowered compared to the values obtained without oscillations and active flavor transformations. This is a consequence of a complicated interplay between sterile-neutrino production, neutrino-neutrino interactions, and alpha-effect.

  15. Job Offer Checklist Use this checklist to make sure that no detail is missed when you receive an offer. However, keep in

    E-Print Network [OSTI]

    Job Offer Checklist Use this checklist to make sure that no detail is missed when you receive an offer. However, keep in mind that this is a very comprehensive list; every item may not necessarily apply to you or your specific offer. Topic Area Their Response Potential Questions Title (Is it what

  16. 78 SDSU GRADUATE BULLETIN 2015-2016 Types of Curricula Offered

    E-Print Network [OSTI]

    Gallo, Linda C.

    78 SDSU GRADUATE BULLETIN 2015-2016 Types of Curricula Offered San Diego State University offers Administration offers the Bachelor of Science degree in business administration with majors in seven fields; the College of Engineering offers the Bachelor of Science degree in engineering with majors in six fields

  17. We've got you covered from top to bottom! Discover all we have to offer!

    E-Print Network [OSTI]

    Salvaggio, Carl

    We've got you covered from top to bottom! Discover all we have to offer! Rediscover... a classic Guestrooms including 12 distinctive whirlpool suites. Woodcliff Hotel & Spa offers a variety Experience all we have to offer! Experience all we have to offer! Special Rates Available for RIT's Visitors

  18. Academic Handbook, Admission, Offers of Admission and Deferred Registration Page 1 Issued: 2009 04

    E-Print Network [OSTI]

    Lennard, William N.

    Academic Handbook, Admission, Offers of Admission and Deferred Registration Page 1 Issued: 2009 04 Offers of Admission and Requests for Deferred Registration OFFERS OF EARLY ADMISSION (S.1419, S.2554.1, S.2728) Offers of early admission to suitably qualified applicants from Ontario Secondary Schools

  19. SDSU General Catalog 2015-2016 99 Types of Curricula Offered

    E-Print Network [OSTI]

    Gallo, Linda C.

    SDSU General Catalog 2015-2016 99 Types of Curricula Offered San Diego State University offers Administration offers the Bachelor of Science degree in business administration with majors in seven fields; the College of Engineering offers the Bachelor of Science degree in engineering with majors in six fields

  20. Non-Monotonic-Offers Bargaining Protocol PINATA WINOTO piw410@mail.usask.ca

    E-Print Network [OSTI]

    Vassileva, Julita

    Non-Monotonic-Offers Bargaining Protocol PINATA WINOTO piw410@mail.usask.ca Department of Computer, Canada Abstract. This paper concerns the strengths and weaknesses of non-monotonic-offers in alternating-offer bargaining protocols. It is commonly assumed that bargainers submit monotonic offers over time corre

  1. Nucleosynthesis simulations for the production of the p-nuclei $^{\\text{92}}$Mo and $^{\\text{94}}$Mo in a Supernova type II model

    E-Print Network [OSTI]

    Göbel, Kathrin; Koloczek, Alexander; Pignatari, Marco; Reifarth, René; Schach, René; Sonnabend, Kerstin

    2015-01-01

    We present a nucleosynthesis sensitivity study for the $\\gamma$-process in a Supernova type II model within the NuGrid research platform. The simulations aimed at identifying the relevant local production and destruction rates for the p-nuclei of molybdenum and at determining the sensitivity of the final abundances to these rates. We show that local destruction rates strongly determine the abundance of $^{92}$Mo and $^{94}$Mo, and quantify the impact.

  2. Berkeley Program Offers New Option for Financing Residential PV Systems

    SciTech Connect (OSTI)

    Bolinger, Mark A

    2008-07-06

    Readily accessible credit has often been cited as a necessary ingredient to open up the market for residential photovoltaic (PV) systems. Though financing does not reduce the high up-front cost of PV, by spreading that cost over some portion of the system's life, financing can certainly make PV systems more affordable. As a result, a number of states have, in the past, set up special residential loan programs targeting the installation of renewable energy systems and/or energy-efficiency improvements and often featuring low interest rates, longer terms and no-hassle application requirements. Historically, these loan programs have had mixed success (particularly for PV), for a variety of reasons, including a historical lack of homeowner interest in PV, a lack of program awareness, a reduced appeal in a low-interest-rate environment, and a tendency for early PV adopters to be wealthy and not in need of financing. Some of these barriers have begun to fade. Most notably, homeowner interest in PV has grown in some states, particularly those that offer solar rebates. The passage of the Energy Policy Act of 2005 (EPAct 2005), however, introduced one additional roadblock to the success of low-interest PV loan programs: a residential solar investment tax credit (ITC), subject to the Federal government's 'anti-double-dipping' rules. Specifically, the residential solar ITC--equal to 30% of the system's tax basis, capped at $2000--will be reduced or offset if the system also benefits from what is known as 'subsidized energy financing', which is likely to include most government-sponsored low-interest loan programs. Within this context, it has been interesting to note the recent flurry of announcements from a number of U.S cities concerning a new type of PV financing program. Led by the city of Berkeley, Calif., these cities propose to offer their residents the ability to finance the installation of a PV system using increased property tax assessments, rather than a more-traditional credit vehicle, to recover both system and administrative costs. This approach has a number of features that should appeal to PV owners, including long-term, fixed-cost, attractive financing; loans that are tied to the tax capacity of the property rather than to the owner's credit standing; a repayment obligation that transfers along with the sale of the property; and a potential ability to deduct the repayment obligation from federal taxable income as part of the local property tax deduction. For these reasons, Berkeley's program, which was first announced on October 23, 2007, has received considerable nationwide attention in both the trade and general press. Since the announcement, cities from throughout California and the broader U.S. have expressed keen interest in the possibility of replicating this type of program. In California alone, the cities of Santa Cruz, Santa Monica and Palm Desert are all reportedly considering similar programs, while the city of San Francisco has recently announced its own program, portions of which closely parallel Berkeley's approach. In addition, a bill (AB 811) that would authorize all cities in California, not just charter cities like Berkeley, to create this type of program was approved by the California General Assembly on January 29 and is currently under consideration in the State Senate. A similar bill in Colorado (HB 1350) was signed into law on May 28. Elsewhere, the city of Tucson, Arizona has also considered this financing approach.

  3. Binghamton University offers this worksheet to help you compare costs and financial aid offers and calculate the bottom line. Since financial aid offers can vary greatly from school to school, it is recommended that you review them carefully, ask

    E-Print Network [OSTI]

    Suzuki, Masatsugu

    Must be repaid Binghamton University offers this worksheet to help you compare costs and financial is for 1, 2, 3 or 4 years. + + + Fees + + + Room & Board (Housing & Meals) + + + A. ESTIMATED COST (as.TOTALSTUDENTLOANS = = = A. TOTAL COST OF ATTENDANCE = TOTAL OUT-OF-POCKET COSTS = $ $ $ D. TOTAL FINANCIAL AID OFFER

  4. What product might a renewal of Heavy Ion Fusion development offer that competes with methane microbes and hydrogen HTGRs

    E-Print Network [OSTI]

    2006-01-01

    Ion Fusion development offer that competes with methanethe modular linac approach offers the possibility to reducenow, solenoids appear to offer a more likely way to manage

  5. Proton capture cross section of Sr isotopes and their importance for nucleosynthesis of proton-rich nuclides

    E-Print Network [OSTI]

    Gy. Gyurky; E. Somorjai; Zs. Fulop; S. Harissopulos; P. Demetriou; T. Rauscher

    2001-09-03

    The (p,$\\gamma$) cross sections of three stable Sr isotopes have been measured in the astrophysically relevant energy range. These reactions are important for the $p$-process in stellar nucleosynthesis and, in addition, the reaction cross sections in the mass region up to 100 are also of importance concerning the $rp$-process associated with explosive hydrogen and helium burning. It is speculated that this $rp$-process could be responsible for a certain amount of $p$-nuclei in this mass region. The (p,$\\gamma$) cross sections of $^{84,86,87}$Sr isotopes were determined using an activation technique. The measurements were carried out at the 5 MV Van de Graaff accelerator of the ATOMKI, Debrecen. The resulting cross sections are compared with the predictions of statistical model calculations. The predictions are in good agreement with the experimental results for $^{84}$Sr(p,$\\gamma$)$^{85}$Y whereas the other two reactions exhibit differences that increase with mass number. The corresponding astrophysical reaction rates have also been computed.

  6. NITROGEN ISOTOPES IN ASYMPTOTIC GIANT BRANCH CARBON STARS AND PRESOLAR SiC GRAINS: A CHALLENGE FOR STELLAR NUCLEOSYNTHESIS

    SciTech Connect (OSTI)

    Hedrosa, R. P.; Abia, C.; Dominguez, I.; Palmerini, S. [Departamento de Fisica Teorica y del Cosmos, Universidad de Granada, E-18071 Granada (Spain); Busso, M. [Dipartimento di Fisica, Universita di Perugia, I-06123 Perugia (Italy); Cristallo, S.; Straniero, O. [INAF, Osservatorio di Collurania, I-64100 Teramo (Italy); Plez, B. [Laboratoire Univers et Particules de Montpellier, Universite Montpellier II, CNRS, F-34095 Montpellier (France)

    2013-05-01

    Isotopic ratios of C, N, Si, and trace heavy elements in presolar SiC grains from meteorites provide crucial constraints to nucleosynthesis. A long-debated issue is the origin of the so-called A+B grains, as of yet no stellar progenitor thus far has been clearly identified on observational grounds. We report the first spectroscopic measurements of {sup 14}N/{sup 15}N ratios in Galactic carbon stars of different spectral types and show that J- and some SC-type stars might produce A+B grains, even for {sup 15}N enrichments previously attributed to novae. We also show that most mainstream grains are compatible with the composition of N-type stars, but in some cases might also descend from SC stars. From a theoretical point of view, no astrophysical scenario can explain the C and N isotopic ratios of SC-, J-, and N-type carbon stars together, as well as those of many grains produced by them. This poses urgent questions to stellar physics.

  7. Electronic Resource Management Systems, Part II: Offerings from Serial Vendors and Serial Data Vendors

    E-Print Network [OSTI]

    Duranceau, Ellen

    2005-06-19

    In the September 2004 issue, I reported on the Electronic Resource Management (ERM) offerings of the major ILS vendors, and promised to follow with a second article covering the ERM tools offered by other kinds of companies, ...

  8. FEMP Offers Training on the Five Phases to Success for ESPCs...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    FEMP Offers Training on the Five Phases to Success for ESPCs FEMP Offers Training on the Five Phases to Success for ESPCs August 28, 2014 - 12:38pm Addthis The U.S. Department of...

  9. FEMP Offers New eTraining Core Course on Fundamentals of Life...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Offers New eTraining Core Course on Fundamentals of Life Cycle Costing for Energy Conservation FEMP Offers New eTraining Core Course on Fundamentals of Life Cycle Costing for...

  10. SPECIAL OFFER --SAIrE 2 0 % The Cambridge/ACL Series

    E-Print Network [OSTI]

    , Cambridge CB2 2RU, England Offer avatlahle to ACL members only All orders must be prepaid. #12;Computational

  11. 125 total creditsMar. 15, 2013 (offered Fall/Spring)

    E-Print Network [OSTI]

    Carver, Jeffrey C.

    125 total creditsMar. 15, 2013 CH 101 General Chemistry 4 cr ECE 121 or ENGR 111 1 cr (offered Fall to Linear Algebra 3 cr ECE 285 Prog. for ECE 3 cr (offered Fall/Spring) CS 150 Programming I 2 cr PH106 cr (offered Fall/Spring) CS 351 CS Programming III 2 cr ECE380 Digital Logic 4 cr (offered Fall

  12. 125 total creditsMar. 15, 2013 (offered Fall/Spring)

    E-Print Network [OSTI]

    Carver, Jeffrey C.

    125 total creditsMar. 15, 2013 CH 101 General Chemistry 4 cr ECE 121 or ENGR 111 1 cr (offered Fall to Linear Algebra 3 cr ECE 285 Prog. for ECE 3 cr (offered Fall/Spring) CS 150 Programming I 2 cr PH106 cr (offered Fall/Spring) CS 351 CS Programming III 2 cr ECE 380 Digital Logic 4 cr (offered Fall

  13. Two new complete genome sequences offer insight into host and tissue specificity of plant pathogenic Xanthomonas spp.

    E-Print Network [OSTI]

    2011-01-01

    Complete Genome Sequences Offer Insight into Host and TissueComplete Genome Sequences Offer Insight into Host and Tissue

  14. Huliq:Breaking News Submit News Login Linear Nanotubes Offer Path To High-Performance Electronics

    E-Print Network [OSTI]

    Rogers, John A.

    Huliq:Breaking News Submit News Login Linear Nanotubes Offer Path To High-Performance Electronics.MoSys.com Page 1 of 2Linear nanotubes offer path to high-performance electronics | Huliq: Breaking News 3/28/2007http://www.huliq.com/16423/linear-nanotubes-offer-path-to-high-performance-electronics #12;compared

  15. SOFTWARE ENGINEERING Page 1 of 4 SEMESTER OFFERED COURSE PRE-and/or CO-REQUISITES

    E-Print Network [OSTI]

    SOFTWARE ENGINEERING Page 1 of 4 1st Year SEMESTER OFFERED COURSE PRE- and/or CO-REQUISITES FALL 1-req: AMAT 219 2nd Year Software Engineering: Regular Program SEMESTER OFFERED COURSE PRE- and/or CO Software Engineering - Biomedical Specialization SEMESTER OFFERED COURSE PRE- and/or CO-REQUISITES FALL 1

  16. Donation Offer Form University of Alberta Museums 28 May 2008 Page 1 of 2

    E-Print Network [OSTI]

    Machel, Hans

    Donation Offer Form ­ University of Alberta Museums 28 May 2008 Page 1 of 2 University of Alberta Museums Donation Offer University of Alberta (to be completed by an Authorized Representative) Unit to the Donor(s) at the Donor's expense. In offering the Property as a donation to the University of Alberta

  17. Dear ___________________: On the basis of our recent conversations, I am pleased to offer you an

    E-Print Network [OSTI]

    Bushman, Frederic

    pleased to offer you an appointment as a Visiting Scholar in my laboratory. I look forward to working (available at http://www.med.upenn.edu/postdoc/patent.policy.02.22.05.pdf) which is enclosed with this offer compensation while in the United States. (FOR FOREIGN SCHOLARS) This offer is contingent upon having a valid

  18. Overview of Programs The Harvard Graduate School of Education offers programs

    E-Print Network [OSTI]

    Schrag, Daniel

    66 Overview of Programs The Harvard Graduate School of Education offers programs leading of Education degree (Ed.M.). These programs offer students the opportunity to integrate cutting-edge research offered as part of some degree programs, course proj- ects, and internships, as well as the Field

  19. Joint Stocking and Product Offer Decisions Under the Multinomial Logit Model

    E-Print Network [OSTI]

    Topaloglu, Huseyin

    Joint Stocking and Product Offer Decisions Under the Multinomial Logit Model Huseyin Topaloglu This paper studies a joint stocking and product offer problem. We have access to a number of products to satisfy the demand over a finite selling horizon. Given that customers choose among the set of offered

  20. How-To Guide Tips for Evaluating and Accepting Job Offers

    E-Print Network [OSTI]

    Gering, Jon C.

    How-To Guide Tips for Evaluating and Accepting Job Offers In order to evaluate your options, you will also need to determine what your skills are worth in today's marketplace. First Response to an Offer: Offers are generally first given over the phone, with a follow-up letter explaining it in more detail

  1. Title: SPONSORSHIP OR CE APPROVAL OF NON-SCHOOL OF NURSING CONTINUING EDUCATION OFFERING

    E-Print Network [OSTI]

    Chapman, Michael S.

    1 Title: SPONSORSHIP OR CE APPROVAL OF NON-SCHOOL OF NURSING CONTINUING EDUCATION OFFERING Index: School of Nursing sponsorship and/or approval of a continuing education offering given by individuals by approving offerings given by non-School of Nursing faculty. Implementing Procedures: Responsible Party

  2. Negotiating a Job Offer: Tips and Blunders Top 10 Negotiating Tips

    E-Print Network [OSTI]

    Negotiating a Job Offer: Tips and Blunders Top 10 Negotiating Tips: Listen Carefully: Listening their constraints and desires, as you expect them to recognize yours. Offer solutions: It is your responsibility to offer solutions, which can be the basis for negotiations. Pointing out just the issues or problems

  3. 125 total creditsSept. 29, 2014 (offered Fall/Spring)

    E-Print Network [OSTI]

    Carver, Jeffrey C.

    125 total creditsSept. 29, 2014 CH 101 General Chemistry 4 cr ECE 121 or ENGR 111 1 cr (offered MATH 238 Applied Diff. Equations I 3 cr ECE 225 Electric Circuits 4 cr (offered Fall/Spring) ECE 380 Digital Logic 4 cr (offered Fall/Spring) PH 253 Introduction to Modern Physics 3 cr MATH 355 Theory

  4. 12-MONTH SAMPLE MULTI-YEAR OFFER LETTER TEACHING FACULTY III, RESEARCH FACULTY III,

    E-Print Network [OSTI]

    McQuade, D. Tyler

    12-MONTH SAMPLE MULTI-YEAR OFFER LETTER TEACHING FACULTY III, RESEARCH FACULTY III, INSTRUCTIONAL SPECIALIST III OR SENIOR RESEARCH ASSOCIATE APPOINTMENT Dear Dr. xxx: I am pleased to offer you an ["in://facultyhandbook.fsu.edu). This offer is also contingent upon your providing the necessary documents to prove your identity

  5. New training options in NDT predictive technologies offered through NIAR/WATC

    E-Print Network [OSTI]

    New training options in NDT predictive technologies offered through NIAR/WATC partnership Thursday training program for Nondestructive Testing (NDT) Predictive Technologies. The courses are offered through class. For specifics on course offerings visit the WATC website. The Predictive Technologies program

  6. -News Home Help EU offers 'sweetener' to Japan to let France host nuclear project

    E-Print Network [OSTI]

    -News Home Help EU offers 'sweetener' to Japan to let France host nuclear project Wed Nov 10, 9:45 AM ET BRUSSELS (AFP) - The European Union ( - ) has offered Japan a "sweetener" to allow France think we have made reasonable offers," European Commission ( - ) spokesman Fabio Fabbi told reporters

  7. Summary of CUDCP Policy for Graduate School Offers and Acceptances Information for Applicants

    E-Print Network [OSTI]

    Summary of CUDCP Policy for Graduate School Offers and Acceptances Information for Applicants for offers into doctoral clinical psychology programs. If you are applying to a CUDCP program, you should expect the following policies will apply (http://www.cudcp.us/files/CUDCP%20grad%20offers%20policy

  8. SEMANTIC MATCHING OFFERS AND JOB SEARCHBETWEEN JOB 72, Quai des Carri6res

    E-Print Network [OSTI]

    SEMANTIC MATCHING OFFERS AND JOB SEARCHBETWEEN JOB REQUESTS COLING 90 Jos6 VEGA GSI-ERLI 72, Quai objective of this system which was developed for the LE MONDE daily newspaper, is to offer an efficient tool number of advertisements in the printed press. Traditionally, offers of employment appear in newspapers

  9. 12-MONTH SAMPLE OFFER LETTER TEACHING FACULTY I, RESEARCH FACULTY I,

    E-Print Network [OSTI]

    McQuade, D. Tyler

    12-MONTH SAMPLE OFFER LETTER TEACHING FACULTY I, RESEARCH FACULTY I, INSTRUCTIONAL SPECIALIST I OR ASSOCIATE IN RESEARCH APPOINTMENT Dear Dr. xxx: I am pleased to offer you an ["in-unit" or "out://facultyhandbook.fsu.edu). This offer is also contingent upon your providing the necessary documents to prove your identity

  10. An offer you cannot refuse: obtaining efficiency and fairness in preplay

    E-Print Network [OSTI]

    Goranko, Valentin

    An offer you cannot refuse: obtaining efficiency and fairness in preplay negotiation games with conditional offers Valentin Goranko1 and Paolo Turrini2 1 Technical University of Denmark and University can make binding offers for payments of utility to the other players after the play of the game

  11. EVALUATING AND NEGOTIATING JOB OFFERS A. ASSESS THE SITUATION AND CONSIDER THE VARIOUS

    E-Print Network [OSTI]

    Shyu, Mei-Ling

    #12;EVALUATING AND NEGOTIATING JOB OFFERS A. ASSESS THE SITUATION AND CONSIDER THE VARIOUS FACTORS-size firms tend to have more flexibility. Conduct research prior to a job interview or discussing an offer so that you can market yourself accurately. If you can offer something unique to the employer, you

  12. 9-MONTH SAMPLE MULTI-YEAR OFFER LETTER TEACHING FACULTY III, RESEARCH FACULTY III,

    E-Print Network [OSTI]

    McQuade, D. Tyler

    9-MONTH SAMPLE MULTI-YEAR OFFER LETTER TEACHING FACULTY III, RESEARCH FACULTY III, INSTRUCTIONAL SPECIALIST III OR SENIOR RESEARCH ASSOCIATE APPOINTMENT Dear Dr. xxx: I am pleased to offer you an ["in://facultyhandbook.fsu.edu/). This offer is also contingent upon your providing the necessary documents to prove your identity

  13. 9-MONTH SAMPLE OFFER LETTER TEACHING FACULTY I, RESEARCH FACULTY I,

    E-Print Network [OSTI]

    McQuade, D. Tyler

    9-MONTH SAMPLE OFFER LETTER TEACHING FACULTY I, RESEARCH FACULTY I, INSTRUCTIONAL SPECIALIST I OR ASSISTANT IN RESEARCH APPOINTMENT Dear Dr. xxx: I am pleased to offer you an ["in-unit" or "out://facultyhandbook.fsu.edu/). This offer is also contingent upon your providing the necessary documents to prove your identity

  14. Deutsche Telekom to offer Microsoft Office on a monthly payment plan Jun 11, 2009

    E-Print Network [OSTI]

    Deutschmann, Rainer

    Deutsche Telekom to offer Microsoft Office on a monthly payment plan Jun 11, 2009 · Customers able · Offer available first to T-Mobile Austria mobile broadband customers and Deutsche Telekom business customers in Germany from Q3 2009 · Deutsche Telekom is the first telecommunications provider to offer

  15. 9-MONTH SAMPLE MULTI-YEAR OFFER LETTER TEACHING FACULTY II, RESEARCH FACULTY II,

    E-Print Network [OSTI]

    McQuade, D. Tyler

    9-MONTH SAMPLE MULTI-YEAR OFFER LETTER TEACHING FACULTY II, RESEARCH FACULTY II, INSTRUCTIONAL SPECIALIST II OR ASSOCIATE IN RESEARCH APPOINTMENT Dear Dr. xxx: I am pleased to offer you an ["in://facultyhandbook.fsu.edu/). This offer is also contingent upon your providing the necessary documents to prove your identity

  16. EU Gives Japan Until End-June to Accept Nuclear-Project Offer

    E-Print Network [OSTI]

    Print EU Gives Japan Until End-June to Accept Nuclear- Project Offer March 7 (Bloomberg) -- The European Union gave Japan until the end of June to accept an offer of a ``privileged partnership'' in a 4 must begin this year. The EU made the partnership offer in November to break a deadlock in which China

  17. Calendar of Events: Offered at the Center for Radiation Therapy (1625 Poplar Street)

    E-Print Network [OSTI]

    Kenny, Paraic

    Calendar of Events: JUNE 2015 Offered at the Center for Radiation Therapy (1625 Poplar Street): 2nd Jewelry Making Thursday, June 25th : 2:00 ­ 4:00pm Offered at Montefiore Medical Park (1695 Eastchester-Body Support Group Every Friday: 12:00 ­ 1:30pm Offered at Montefiore Einstein Center for Cancer Care (1521

  18. What courses do we offer Common misconceptions Applications Graduate Destinations Mathematics at Southampton

    E-Print Network [OSTI]

    Molinari, Marc

    What courses do we offer Common misconceptions Applications Graduate Destinations Mathematics 12, 2015 #12;What courses do we offer Common misconceptions Applications Graduate Destinations Outline 1 What courses do we offer Different Types of Courses First Year Second and subsequent years 2

  19. For more than 175 years, Rensselaer has offered a unique and innovative technological educational experience. As

    E-Print Network [OSTI]

    Varela, Carlos

    For more than 175 years, Rensselaer has offered a unique and innovative technological educational in virtually every major offered through Rensselaer's five schools--Engineering, Science, the Lally School Professionals also offers a highly successful distributed delivery program that extends graduate courses

  20. 123 total creditsSept 29, 2014 (offered Fall/Spring)

    E-Print Network [OSTI]

    Carver, Jeffrey C.

    123 total creditsSept 29, 2014 CH 101 General Chemistry 4 cr ECE 121 or ENGR 111 1 cr (offered Fall Applied Diff. Equations I 3 cr ECE 225 Electric Circuits 4 cr (offered Fall/Spring) ECE 380 Digital Logic 4 cr (offered Fall/Spring) MATH 355 Theory of Probability 3 cr ECE 370 Signals & Systems 3 cr

  1. January 27, 2014 Despite UC's offer of significant concessions, AFSCME wants more

    E-Print Network [OSTI]

    Leistikow, Bruce N.

    January 27, 2014 Despite UC's offer of significant concessions, AFSCME wants more The university thinks it's important to set the record straight on what it has offered AFSCME Service employees during negotiations. UC's offer provides for wages and benefits as good or better than what other campus

  2. RECOMMENDED TEMPLATE FOR GRADUATE ASSISTANT (GA) (POSITIONS COVERED BY THE GEO) OFFER LETTERS

    E-Print Network [OSTI]

    Lee, Tonghun

    RECOMMENDED TEMPLATE FOR GRADUATE ASSISTANT (GA) (POSITIONS COVERED BY THE GEO) OFFER LETTERS to offer you a Graduate Assistantship for [insert period of appointment and service dates, e.g. fall. The current wage for the assistantship we are offering you will be at least $ [insert amount] per month

  3. Department: Sociology Course No.: SOCI 281W (also offered as URBN 281W)

    E-Print Network [OSTI]

    Alpay, S. Pamir

    Department: Sociology Course No.: SOCI 281W (also offered as URBN 281W) Credits: 3 Title: Urban Problems Contact: Brad Wright WQ: W Catalog Copy: Soci 281. Urban Problems. (Also offered as URBN 281 issues. Soci 281W. Urban Problems. (Also offered as URBN 281W). Prerequisite: Engl 110 or 111 or 250. W

  4. A method for classifying offer strategies observed in an electricity market

    E-Print Network [OSTI]

    A method for classifying offer strategies observed in an electricity market HyungSeon Oha,*, Robert units will operate at marginal cost when given the ability to offer their power for sale in a uniform they will hedge their profits through higher than marginal cost offers and through withholding units if permitted

  5. 12-MONTH SAMPLE MULTI-YEAR OFFER LETTER TEACHING FACULTY II, RESEARCH FACULTY II,

    E-Print Network [OSTI]

    McQuade, D. Tyler

    12-MONTH SAMPLE MULTI-YEAR OFFER LETTER TEACHING FACULTY II, RESEARCH FACULTY II, INSTRUCTIONAL SPECIALIST II OR ASSOCIATE IN RESEARCH APPOINTMENT Dear Dr. xxx: I am pleased to offer you an ["in://facultyhandbook.fsu.edu). This offer is also contingent upon your providing the necessary documents to prove your identity

  6. Curriculum, Admissions, & Contact Information on Back Rochester Institute of Technology offers Masters and

    E-Print Network [OSTI]

    Zanibbi, Richard

    Curriculum, Admissions, & Contact Information on Back Rochester Institute of Technology offers in digital imaging, color instrumentation, colorant formulation, and basic & applied research. Employers

  7. Suspension of Partial Offers of Less Than 12 Months to Long-Term...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Teams Customer Training Interconnection Notices Rates Standards of Conduct Tariff TF Web Based Training Notice: Suspension of Partial Offers of Less Than 12 Months to...

  8. Austin's Home Performance with Energy Star Program: Making a Compelling Offer to a Financial Institution Partner

    E-Print Network [OSTI]

    Zimring, Mark

    2011-01-01

    financing products. National lenders have been hesitant toto larger financing products. Lenders have been hesitant tothat incentivize private lenders to offer more attractive

  9. Home Product Directory Offer Board Virtual Office Buyer Service Info Centre Audited Suppliers

    E-Print Network [OSTI]

    Home Product Directory Offer Board Virtual Office Buyer Service Info Centre Audited Suppliers Show) | Join Audited Suppliers | Help Home » Info Center » Trade Shows » Agriculture & Food » 2009 China Yiwu

  10. Carbon-enhanced metal-poor stars: a window on AGB nucleosynthesis and binary evolution. II. Statistical analysis of a sample of 67 CEMP-$s$ stars

    E-Print Network [OSTI]

    Abate, C; Izzard, R G; Karakas, A I

    2015-01-01

    Many observed CEMP stars are found in binary systems and show enhanced abundances of $s$-elements. The origin of the chemical abundances of these CEMP-$s$ stars is believed to be accretion in the past of enriched material from a primary star in the AGB phase. We investigate the mechanism of mass transfer and the process of nucleosynthesis in low-metallicity AGB stars by modelling the binary systems in which the observed CEMP-$s$ stars were formed. For this purpose we compare a sample of $67$ CEMP-$s$ stars with a grid of binary stars generated by our binary evolution and nucleosynthesis model. We classify our sample CEMP-$s$ stars in three groups based on the observed abundance of europium. In CEMP$-s/r$ stars the europium-to-iron ratio is more than ten times higher than in the Sun, whereas it is lower than this threshold in CEMP$-s/nr$ stars. No measurement of europium is currently available for CEMP-$s/ur$ stars. On average our models reproduce well the abundances observed in CEMP-$s/nr$ stars, whereas in C...

  11. What Impedes Efficient Adoption of Products? Evidence from Randomized Variation in Sales Offers for Improved Cookstoves in Uganda

    E-Print Network [OSTI]

    Levine, David I.; Beltramo, Theresa; Blalock, Garrick; Cotterman, Carolyn

    2012-01-01

    to pay with the traditional offer as accepted the free trialthe same uptake as the free trial and time payments offer.the Effects of a Novel Offer and Marketing Messages on

  12. Registration Process Thank you for your interest in the Instructional Skills Workshop (ISW) offered for Graduate Students at the

    E-Print Network [OSTI]

    Registration Process Thank you for your interest in the Instructional Skills Workshop (ISW) offered ISW that we offer. We currently offer the maximum number of ISWs available within our budget

  13. Course Course Title and Semester Offered Cr PhD in Public Health, CBHP Concentration, Curriculum (p 1 of 4)

    E-Print Network [OSTI]

    Saldin, Dilano

    Course Course Title and Semester Offered Cr PhD in Public Health, CBHP) until the Biostatistics offerings are expanded to include 710 3 COMMUNITY of Community Interventions ­ Fall, Offered as PH 740 Topics in Fall 2013 3 #12;Ph

  14. Failed Searches: How the choice set of job applicants affects an employer’s likelihood of making an offer

    E-Print Network [OSTI]

    Leung, Ming D.

    2015-01-01

    s likelihood of making an offer Ming D. Leung Cite as: Minglikelihood of making an offer”. IRLE Working Paper No. 111-s likelihood of making an offer* Ming D. Leung Haas School

  15. An Offer You Can't Refuse: Provider-Initiated HIV Testing in Antenatal Clinics in Rural Malawi

    E-Print Network [OSTI]

    Angotti, Nicole; Dionne, Kim Y.; Gaydosh, Lauren

    2008-01-01

    An Offer You Can’t Refuse: Provider-Initiated HIV Testing inWorking Paper Series An Offer You Can’t Refuse: Provider-data from Malawi, we offer an account of the perceptions

  16. What Impedes Efficient Adoption of Products? Evidence from Randomized Variation in Sales Offers for Improved Cookstoves in Uganda

    E-Print Network [OSTI]

    Levine, David I.; Cotterman, Carolyn

    2012-01-01

    ambitious than our sales offer can achieve. It is important3 years or more? ” N Sales Offer Free Time Trial PaymentsRandomized Variation in Sales Offers for Improved Cookstoves

  17. A comparative study of the scholastic performance of freshmen in the Agricultural and Mechanical College of Texas who offer or do not offer vocational agriculture for entrance credit 

    E-Print Network [OSTI]

    Ross, Henry

    1935-01-01

    A CONPARATIVE STUDY' OF mZ SCHOLASTIC PERFORMANCE OF FRESHMgg4 IN THE AGRICUL&URAL AlG) LiECl. ANICAL COLL GE Oi TEXAS RiO OFFER 0;. DO NOT OFFER VOCATIONAL AGRICULTURE FOR ENTRANCE CREDIT A Thesis By Henry Ross February 1955 Approva1 :s... COHTENTS InVOCQstion ~ ~ ~ ~ ~ ~ o ~ ~ ~ ~ ~ ~ ~ o o ~ ~ ~ ~ ~ s ~ ~ e ~ ~ ~ ~ 1 Developeent of ths Problem . . . . . . . . . . . . . . . . 5 Mstho4 Uee4 . . . Analysis of Data ~ . 10 Sueeat y CO54lklls i ons ~ ~ ~ ~ ~ ~ e ~ ~ ~ ~ 119 . . 154 LIST...

  18. ELECTRICAL ENGINEERING Page 1 of 7 SEMESTER OFFERED COURSE PRE-and/or CO-REQUISITES

    E-Print Network [OSTI]

    ELECTRICAL ENGINEERING Page 1 of 7 1st YEAR SEMESTER OFFERED COURSE PRE- and/or CO-REQUISITES FALLnd Year Electrical Engineering: Regular Program SEMESTER OFFERED COURSE PRE- and/or CO ENEL 300 Electrical and Computer Engineering Professional Skills ENGG 225; ENGG 233; and ENEL 353 Note

  19. INTERNATIONAL SUMMER INSTITUTE (ISI) SNU ISI offers an exceptional opportunity for students to study

    E-Print Network [OSTI]

    Welcome to INTERNATIONAL SUMMER INSTITUTE (ISI) SNU ISI offers an exceptional opportunity-weeksummerprogramledbydistinguished scholars. All lectures are conducted in English, and held from Monday toThursday. SNU ISI also offers in Seoul, experience Korea's dynamic culture with peers and get ahead in academics with a summer at SNU ISI

  20. NASA and Afterschool Programs: Connecting to the Future What NASA Has to Offer

    E-Print Network [OSTI]

    Hammer, David

    NASA and Afterschool Programs: Connecting to the Future What NASA Has to Offer David Hammer and Janet Coffey University of Maryland, College Park When people think of what NASA has to offer science education, one natural starting place is knowledge: NASA scientists have a lot of it, from basic concepts

  1. Web Service Offerings Language (WSOL) and Web Service Composition Management (WSCM)

    E-Print Network [OSTI]

    1 Web Service Offerings Language (WSOL) and Web Service Composition Management (WSCM) Vladimir {vladimir, bernie, babak, kpatel, weima}@sce.carleton.ca ABSTRACT Our research on Web Services is organized into two related projects. First, we develop Web Service Offerings Lan- guage (WSOL) for formal

  2. IEEE Access 2015-000125 1 Abstract--Plug-in hybrid electric vehicles (PHEVs) offer the

    E-Print Network [OSTI]

    Eppstein, Margaret J.

    IEEE Access 2015-000125 1 Abstract-- Plug-in hybrid electric vehicles (PHEVs) offer the potential vehicles (PHEVs); agent-based model; market penetration; electric vehicle adoption; vehicle choice-in hybrid electric vehicles (PHEVs) offer the potential to significantly reduce GHG emissions [2

  3. Special Offer for Indonesian Government DIKTI PhD Scholarship Awardees

    E-Print Network [OSTI]

    Special Offer for Indonesian Government DIKTI PhD Scholarship Awardees Charles Darwin University welcomes applications for PhD degrees from DIKTI scholarship awardees and offers English language must be provided at initial PhD application stage. Tuition fee waiver for a fourth year of study

  4. Letters to Financial Times, June 13, 2014 Iraq crisis offers Iran its chance . . .

    E-Print Network [OSTI]

    Letters to Financial Times, June 13, 2014 Iraq crisis offers Iran its chance . . . From Prof John Ure . Sir, The big story about the current crisis in Iraq surely is the opportunity it offers Iran-Assad in neighbouring Syria. Iran has already sent the Revolutionary Guard to help the government beat back the Islamic

  5. Professional Mentorship Program Application The program offers College of Media juniors, seniors and graduate students the opportunity to be

    E-Print Network [OSTI]

    Mohaghegh, Shahab

    Professional Mentorship Program Application The program offers College of Media juniors, seniors, public relations, broadcasting, print and multimedia journalism. Professionals can offer resume advice

  6. Nucleosynthesis in Supernovae

    E-Print Network [OSTI]

    C. J. Horowitz; Gang Li

    1999-05-19

    Core collapse supernovae are dominated by energy transport from neutrinos. Therefore, some supernova properties could depend on symetries and features of the standard model weak interactions. The cross section for neutrino capture is larger than that for antineutrino capture by one term of order the neutrino energy over the nucleon mass. This reduces the ratio of neutrons to protons in the $\

  7. Fact #718: March 12, 2012 Number of Flex-Fuel Models Offered...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    (GM), Ford, and Chrysler have produced many different models of flex-fuel vehicles (cars and light trucks) over the last five years. In 2011, the number of models offered by...

  8. Need rare-earths know-how? The Critical Materials Institute offers...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Need rare-earths know-how? The Critical Materials Institute offers lower-cost access to experts and research Contacts: For release: Dec. 1, 2015 Alex King, Director, Critical...

  9. FACULTY OF MANAGEMENT The University of Lethbridge's Faculty of Management offers five undergraduate Certificate programs in

    E-Print Network [OSTI]

    Seldin, Jonathan P.

    in Organizations Management 4390 - Leading Organizational Change Management 4901 - Applied Consulting One ofFACULTY OF MANAGEMENT The University of Lethbridge's Faculty of Management offers five undergraduate Certificate programs in · Finance · General Management · Human Resource Management and Labour

  10. SOLICITATION, OFFER, AND AWARD 1. THIS CONTRACT IS A RATED ORDER

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    17. SIGNATURE 18. OFFER DATE AREA CODE NUMBER EXT. ADDRESS IS DIFFERENT FROM ABOVE - ENTER SUCH ADDRESS IN SCHEDULE. AWARD (To be completed by Government) 19. ACCEPTED AS TO...

  11. Fact #718: March 12, 2012 Number of Flex-Fuel Models Offered Increased in 2011

    Broader source: Energy.gov [DOE]

    General Motors (GM), Ford, and Chrysler have produced many different models of flex-fuel vehicles (cars and light trucks) over the last five years. In 2011, the number of models offered by those...

  12. The Impact on the New Mexico Budget of Offering Domestic Partnerships to Same-Sex Couples

    E-Print Network [OSTI]

    Sears, Brad

    2010-01-01

    same-sex couples in New Mexico who choose to celebrate theirThe Impact on the New Mexico Budget of Offering DomesticCommittee of the New Mexico Senate Presented by Professor

  13. Price Competition in Canadian Bought Deal Equity Offerings Nancy D. Ursel

    E-Print Network [OSTI]

    Saskatchewan, University of

    Price Competition in Canadian Bought Deal Equity Offerings Nancy D. Ursel Erdal Gunay Odette School competition may also take place on features of the underwriting contract other than fees, I incorporate non-price

  14. technology offer Vienna University of Technology | Research and Transfer Support | Tanja Sovic

    E-Print Network [OSTI]

    Szmolyan, Peter

    are identical to the existing technology. Benefits Cost reduction during production of master alloy Rawtechnology offer Vienna University of Technology | Research and Transfer Support | Tanja Sovic production without adoption of the common technology. By reduction of melting temperatures the production

  15. technology offer Vienna University of Technology | Research and Transfer Support | Tanja Sovic-Gasser

    E-Print Network [OSTI]

    Szmolyan, Peter

    are identical to the existing technology. Benefits Cost reduction during production of master alloy Rawtechnology offer Vienna University of Technology | Research and Transfer Support | Tanja Sovic production without adoption of the common technology. By reduction of melting temperatures the production

  16. Evolution, nucleosynthesis and yields of AGB stars at different metallicities (III): intermediate mass models, revised low mass models and the ph-FRUITY interface

    E-Print Network [OSTI]

    Cristallo, S; Piersanti, L; Gobrecht, D

    2015-01-01

    We present a new set of models for intermediate mass AGB stars (4.0, 5.0 and, 6.0 Msun) at different metallicities (-2.15database. We describe the physical and chemical evolution of the computed models from the Main Sequence up to the end of the AGB phase. Due to less efficient third dredge up episodes, models with large core masses show modest surface enhancements. The latter is due to the fact that the interpulse phases are short and, then, Thermal Pulses are weak. Moreover, the high temperature at the base of the convective envelope prevents it to deeply penetrate the radiative underlying layers. Depending on the initial stellar mass, the heavy elements nucleosynthesis is dominated by different neutron sources. In particular, the s-process distributions of the more massive models are dominated by the \

  17. "An Offer California Can't Refuse": How an Efficient and Adaptable Framework Can Improve Remedies Under the Talent Agency Act and Correct the Issues With its Interpretation

    E-Print Network [OSTI]

    Warren, Keith; Wechsler, Ryan

    2014-01-01

    An Offer California Can't Refuse": How an Efficient andfinding agents willing to offer representation, they areby illegal procurement offers a fairer outcome for managers,

  18. The information presented here is as of 10/21/2009. For up-to-date course offerings, please return to the pre-vious page and select "Courses Offered."

    E-Print Network [OSTI]

    Aalberts, Daniel P.

    307 The information presented here is as of 10/21/2009. For up-to-date course offerings, please return to the pre- vious page and select "Courses Offered." WILLIAMS-MYSTIC MARITIME STUDIES PROGRAM-Mystic Seaport Maritime Studies Program offers students a unique opportunity to explore the ocean, travel

  19. The information presented here is as of 10/21/2009. For up-to-date course offerings, please return to the pre-vious page and select "Courses Offered."

    E-Print Network [OSTI]

    Aalberts, Daniel P.

    228 The information presented here is as of 10/21/2009. For up-to-date course offerings, please return to the pre- vious page and select "Courses Offered." PHYSICAL EDUCATION, ATHLETICS, AND RECREATION be completed. The following courses are offered at various times during the year. A schedule listing all

  20. The information presented here is as of 10/21/2009. For up-to-date course offerings, please return to the pre-vious page and select "Courses Offered."

    E-Print Network [OSTI]

    Aalberts, Daniel P.

    277 The information presented here is as of 10/21/2009. For up-to-date course offerings, please return to the pre- vious page and select "Courses Offered." WILLIAMS PROGRAM IN TEACHING Director, SUSAN. The program offers a range of opportunities including courses on education, intensive supervised student