57 research outputs found
Masses and lifetimes for r-process nucleosynthesis: FRIB outlook
No full textNuclear masses and lifetimes are key inputs for calculations of rapid neutron capture (r-process) nucleosynthesis. Masses and half-lives for thousands of nuclei from the valley of stability to the neutron drip line are required and only a fraction have been experimentally measured. Here we examine the promise of the Facility for Rare Isotope Beams, now under construction at Michigan State University, to dramatically reduce uncertainties in r-process abundance patterns due to uncertain masses and half-lives
DER URSPRUNG DER RISIKO ABSCHÄTZUNG
No full textOvaj tekst u svojem većem opsegu čini nešto slobodniju obradu jednog dijela studije koju su izradili Covello i Mumpower (1985). Iz njihovog dosta obimnog rada autor je ovoga članka izdvojio i skraćeno opisao samo ona događanja koja smatra iznimno značajnim za raspravu o kronologiji razvoja procjene rizika. Tekst je drugačije strukturiran od izvornog, a uzeti su u obzir i neki Paustenbachovi kritički komentari na njihov rad. Analizirajući dodatnu literaturu autor članka je svoj skroman doprinos istraživanju ove teme dao u poglavljima: Igre na sreću i hazard, Osiguranje i rizici i Tehnološki razvitak, industrijske nezgode i rizici. Naime, autor članka je mišljenja kako u kronološkom pregledu razvoja procjene rizika veće značenje treba pripisati igrama na sreću i njihovom utjecaju na kasniji razvoj teorije kvantitativne procjene rizika nego su to naznačili Covello i Mumpower. Također, analizirajući razvoj osiguranja Covello i Mumpower ispuštaju registrirati utjecaj što ga je na razvoj kvantitativne procjene rizika imao koncept osiguranja koji je uveo stanoviti brodovlasnik iz Genove, o čemi izvješćuju Fullwood i Hall, 1988. Na kraju, čini se očitim kako su na uvođenje i primjenu kvantitativne procjene rizika, kao potpuno strukturirane metode, dominantan utjecaj imale velike nesreće u nuklearnim i drugim industrijskim postro¬jenjima i to zbog posljedica koje su za sobom ostavile kao i zbog izrazito negativnog publiciteta kojeg su izazvale u sredstvima javnog priopćavanja.This text, in its wider range, represents somewhat more liberal elaboration of a part of the study made by Covello and Mumpower, 1985. The author of this paper has isolated and shortly described those happenings of their fairly extensive work that he considers extremely important for the discussion of chronology of the development of risk assessment. The text has been structured in a different way from the original, and some of Paustenbach's critical commentaries on their work have also been taken into account. Analyzing additional literature the author of this article has given his small contribution to the research of this subject in chapters Games of chance and gambling, Insurance and Risks and Technological Development, Industrial Accidents and Risks. Namely, the author of the article thinks that, in the chronological survey of the development of risk assessment, greater significance should be given to games of chance and their influence on later development of the theory of quantitative risk assessment than it was pointed out by Covello and Mumpower. Also, analyzing the development of insurance Covello and Mumpower omit to register the influence that the concept of insurance introduced by a certain shipowner from Geneve had on the development of quantitative risk assessment, which was reported by Fullwood and Hall. Finally, it seems obvious that the introduction and application of the quantitative risk assessment as a completely structured method was dominantly influenced by big disasters in nuclear and other industrial plants, mainly due to consequences they left behind, as well as to explicitly negative publicity they brought about in the media.Dieser Text stellt in seinem breiteren Umfang eine etwas freiere Bearbeitung eines Teils der Studie von Covello und Mumpower aus dem Jahr 1985, dar. Aus ihrer ziemlich umfangreichen Arbeit hat der Autor dieses Artikels nur diejenigen Ereignisse ausgewählt und beschrieben, die er für die Diskussion über die Chronologie der Entwicklung der Risiko–Abschätzung für wichtig hält. Der Text ist anderes strukturiert als der ursprüngliche und berücksichtigt wurden dabei einige kritische Kommentare ihrer Arbeit von Paustenbach. Durch die Analyse der zusätzlichen Literatur hat der Autor dieses Artikels seinen bescheidenen Beitrag zur Erforschung dieses Themas in den Kapiteln "Glücksspiele und Hasard", "die Versicherung und Risiken", "industrielle Unfälle und Risiken" geleistet. Der Autor dieses Artikels vertritt nämlich den Standpunkt, daß im chronologischen Überblick größere Bedeutung den Glücksspielen beigemessen werden sollte und ihren Einfluß auf die spätere Entwicklung der Theorie der quantitativen Risiko–Abschätzung, als Covello und Mumpower das angeführt haben. Auch in der Analyse der Versicherungentwicklung haben es Covello und Mumpower unterlassen den Einfluß des Versicherungskonzepts eines bestimmten Schiffbesitzers aus Genua, auf die Entwicklung der quantitativen Risiko–Abschätzung zu registrieren. Darüber berichten Fullwood und Hall. Am Ende scheint es offensichtlich, daß auf die Einführung und Anwendung der quantitativen Risikio–Abschätzung , als einer völlig strukturierten Methode, den vorherrschenden Einfluß große Unglücksfälle in nuklearen und anderen industriellen Anlagen hatten, und zwar wegen der negativen Publizität, die sie in den öffentlichen Massen–Medien verursacht haben
Precise mass measurements of radioactive nuclides for astrophysics
No full textMuch of astrophysics is fueled by nuclear physics with observables, such as energy output and elements produced, that are heavily dependent on the masses of the nuclides. A mass precision of at least 50 keV/c for many rare nuclides is needed to adequately discriminate models that explain the observables. In recent decades, the development of new facilities and mass-measurement techniques has made available a wealth of precise and accurate mass data. The new data, in combination with novel codes and models, has greatly enhanced the understanding of astrophysical processes in the universe, but much is still to be learned
Systematic and Statistical Uncertainties in Simulated <i>r</i>-Process Abundances due to Uncertain Nuclear Masses
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The Sensitivity of γ-Process Nucleosynthesis to Individual β-Delayed Neutron Emission Probabilities
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Astromers: Status and Prospects
No full textThe extreme temperatures and densities of many astrophysical environments
tends to destabilize nuclear isomers by inducing transitions to higher energy
states. Those states may then cascade to ground. However, not all environments
destabilize all isomers. Nuclear isomers which retain their metastable
character in pertinent astrophysical environments are known as astrophysically
metastable nuclear isomers, or "astromers". Astromers can influence
nucleosynthesis, altering abundances or even creating new pathways that would
otherwise be inaccessible. Astromers may also release energy faster or slower
relative to their associated ground state, acting as heating accelerants or
batteries, respectively. In stable isotopes, they may even simply remain
populated after a cataclysmic event and emit observable x- or -rays.
The variety of behaviors of these nuclear species and the effects they can have
merit careful consideration in nearly every possible astrophysical environment.
Here we provide a brief overview of astromers past and present, and we outline
future work that will help to illuminate their role in the cosmos.Comment: 39 pages(10 of the 16 of them references), 5 figure
Astromers: status and prospects
No full textThe extreme temperatures and densities of many astrophysical environments tend to destabilize nuclear isomers by inducing transitions to higher-energy states which may then cascade to ground. However, not all environments destabilize all isomers. Nuclear isomers which retain their metastable character in pertinent astrophysical environments are known as astrophysically metastable nuclear isomers, or “astromers”. Astromers can influence nucleosynthesis, altering abundances or even creating new pathways that would otherwise be inaccessible. Astromers often release energy faster or slower relative to their associated ground state, acting as heating accelerants or batteries, respectively. In stable isotopes, they may even simply remain populated after a cataclysmic event and emit observable x- or -rays. The variety of behaviors of these nuclear species and the effects they can have merit careful consideration in nearly every possible astrophysical environment. Here, we provide a brief overview of astromers past and present, and we outline future work that will help to illuminate their role in the cosmos
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