3,230 research outputs found

    Computer program FPIP-REV calculates fission product inventory for U-235 fission

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    Computer program calculates fission product inventories and source strengths associated with the operation of U-235 fueled nuclear power reactor. It utilizes a fission-product nuclide library of 254 nuclides, and calculates the time dependent behavior of the fission product nuclides formed by fissioning of U-235

    Status of WANL excursion analysis program

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    Fatigue behavior of materials for the sst - electron fractographic studies final report

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    Electron microscopic fractography to determine fatigue behavior of materials for supersonic transport - titanium, aluminum, molybdenum, and vanadiu

    Feasibility of a full core nuclear poison system for use during RIFT launch operations

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    Structured Decision-Making and Rapid Prototyping to Plan a Management Response to an Invasive Species

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    We developed components of a decision structure that could be used in an adaptive management framework for responding to invasion of hemlock woolly adelgid Adeleges tsugae on the Cumberland Plateau of northern Tennessee. Hemlock woolly adelgid, an invasive forest pest, was first detected in this area in 2007. We used a structured decision-making process to identify and refine the management problem, objectives, and alternative management actions, and to assess consequences and tradeoffs among selected management alternatives. We identified four fundamental objectives: 1) conserve the aquatic and terrestrial riparian conservation targets, 2) protect and preserve hemlock, 3) develop and maintain adequate budget, and 4) address public concerns. We designed two prototype responses using an iterative process. By rapidly prototyping a first solution, insights were gained and shortcomings were identified, and some of these shortcomings were incorporated and corrected in the second prototype. We found that objectives were best met when management focused on early treatment of lightly to moderately infested but relatively healthy hemlock stands with biological control agent predator beetles and insect-killing fungi. Also, depending on the cost constraint, early treatment should be coupled with silvicultural management of moderately to severely infested and declining hemlock stands to accelerate conversion to nonhemlock mature forest cover. The two most valuable contributions of the structured decision-making process were 1) clarification and expansion of our objectives, and 2) application of tools to assess tradeoffs and predict consequences of alternative actions. Predicting consequences allowed us to evaluate the influence of uncertainty on the decision. For example, we found that the expected number of mature forest stands over 30 y would be increased by 4% by resolving the uncertainty regarding predator beetle effectiveness. The adaptive management framework requires further development including identifying and evaluating uncertainty, formalizing other competing predictive models, designing a monitoring program to update the predictive models, developing a process for re-evaluating the predictive models and incorporating new management technologies, and generating support for planning and implementation

    Women\u27s Changing Attitudes Toward Divorce, 1974–2002: Evidence for an Educational Crossover

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    This article examines trends in divorce attitudes of young adult women in the United States by educational attainment from 1974 to 2002. Women with 4‐year college degrees, who previously had the most permissive attitudes toward divorce, have become more restrictive in their attitudes toward divorce than high school graduates and women with some college education, whereas women with no high school diplomas have increasingly permissive attitudes toward divorce. We examine this educational crossover in divorce attitudes in the context of variables correlated with women\u27s educational attainment, including family attitudes and religion, income and occupational prestige, and family structure. We conclude that the educational crossover in divorce attitudes is associated most strongly with work and family structure variables

    Mechanisms and dynamics of the NH<sup>+</sup><sub>2</sub> + H<sup>+</sup> and NH<sup>+</sup> + H<sup>+</sup> + H fragmentation channels upon single-photon double ionization of NH<sub>3</sub>

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    We present state-selective measurements on the NH2+_2^{+} + H+^{+} and NH+^{+} + H+^{+} + H dissociation channels following single-photon double ionization at 61.5 eV of neutral NH3_{3}, where the two photoelectrons and two cations are measured in coincidence using 3-D momentum imaging. Three dication electronic states are identified to contribute to the NH2+_2^{+} + H+^{+} dissociation channel, where the excitation in one of the three states undergoes intersystem crossing prior to dissociation, producing a cold NH2+_2^+ fragment. In contrast, the other two states directly dissociate, producing a ro-vibrationally excited NH2+_2^+ fragment with roughly 1 eV of internal energy. The NH+^{+} + H+^{+} + H channel is fed by direct dissociation from three intermediate dication states, one of which is shared with the NH2+_2^{+} + H+^{+} channel. We find evidence of autoionization contributing to each of the double ionization channels. The distributions of the relative emission angle between the two photoelectrons, as well as the relative angle between the recoil axis of the molecular breakup and the polarization vector of the ionizing field, are also presented to provide insight on both the photoionization and photodissociation mechanisms for the different dication states
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