34,251 research outputs found

    Fragment isospin distributions and the phase diagram of excited nuclear systems

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    Fragment average isospin distributions are investigated within a microcanonical multifragmentation model in different regions of the phase diagram. The results indicate that in the liquid phase versus ZZ is monotonically increasing, in the phase coexistence region it has a rise and fall shape and in the gas phase it is constant. Deviations from this behavior may manifest at low fragment multiplicity as a consequence of mass/charge conservation. Characterization of the "free" and "bound" phases function of fragment charge reconfirms the neutron enrichment of the "free" phase with respect to the "bound" one irrespectively the localization of the multifragmentation event in the phase diagram.Comment: 23 pages, 12 figure

    Improved chlorate candle provides concentrated oxygen source

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    Improved chlorate candle is used as a solid, portable source of oxygen in emergency situations. It contains sodium chlorate, iron, barium peroxide, and glass mixed in powdered form. The oxygen evolves from the decomposition of the sodium chlorate when an ignition pellet is electrically initiated

    A modified proximity approach in the fusion of heavy-ions

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    By using a suitable set of the surface energy coefficient, nuclear radius, and universal function, the original proximity potential 1977 is modified. The overestimate of the data by 4 % reported in the literature is significantly reduced. Our modified proximity potential reproduces the experimental data nicely compared to its older versions.Comment: 9 pages, 5 figures, Chin. Phys. lett.(2010) in pres

    Updated measurements of the dark matter halo masses of obscured quasars with improved WISE and Planck data

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    Using the most recent releases of WISE and Planck data, we perform updated measurements of the bias and typical dark matter halo mass of infrared-selected obscured and unobscured quasars, using the angular autocorrelation function and cosmic microwave background (CMB) lensing cross-correlations. Since our recent work of this kind, the WISE Allwise catalogue was released with improved photometry, and the Planck mission was completed and released improved products. These new data provide a more reliable measurement of the quasar bias and provide an opportunity to explore the role of changing survey pipelines in results downstream. We present a comparison of IR color-selected quasars, split into obscured and unobscured populations based on optical-IR colors, selected from two versions of the WISE data. Which combination of data is used impacts the final results, particularly for obscured quasars, both because of mitigation of some systematics and because the newer catalogue provides a slightly different sample. We show that Allwise data is superior in several ways, though there may be some systematic trends with Moon contamination that were not present in the previous catalogue. We opt currently for the most conservative sample that meet our selection criteria in both the previous and new WISE catalogues. We measure a higher bias and halo mass for obscured quasars (bobsc2.1b_{\textrm{obsc}} \sim 2.1, bunob1.8b_{\textrm{unob}} \sim 1.8) --- at odds with simple orientation models --- but at a reduced significance (\sim1.5σ\sigma) as compared to our work with previous survey data.Comment: 20 pages, 15 figures, accepted for publication in MNRA

    Inventory of wetland habitat using remote sensing for the proposed Oahe irrigation unit in eastern South Dakota

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    An inventory of wetlands for the area included in the proposed Oahe irrigation project was conducted to provide supplemental data for the wildlife mitigation plan. Interpretation techniques for inventoring small wetlands in the low relief terrain of the Lake Dakota Plain were documented and data summaries included. The data were stored and tabulated in a computerized spatial data analysis system

    Nuclear Ground-State Masses and Deformations

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    We tabulate the atomic mass excesses and nuclear ground-state deformations of 8979 nuclei ranging from 16^{16}O to A=339A=339. The calculations are based on the finite-range droplet macroscopic model and the folded-Yukawa single-particle microscopic model. Relative to our 1981 mass table the current results are obtained with an improved macroscopic model, an improved pairing model with a new form for the effective-interaction pairing gap, and minimization of the ground-state energy with respect to additional shape degrees of freedom. The values of only 9 constants are determined directly from a least-squares adjustment to the ground-state masses of 1654 nuclei ranging from 16^{16}O to 263^{263}106 and to 28 fission-barrier heights. The error of the mass model is 0.669~MeV for the entire region of nuclei considered, but is only 0.448~MeV for the region above N=65N=65.Comment: 50 pages plus 20 PostScript figures and 160-page table obtainable by anonymous ftp from t2.lanl.gov in directory masses, LA-UR-93-308

    Remanent magnetization and 3-dimensional density model of the Kentucky anomaly region

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    A three-dimensional model of the Kentucky body was developed to fit surface gravity and long wavelength aeromagnetic data. Magnetization and density parameters for the model are much like those of Mayhew et al (1982). The magnetic anomaly due to the model at satellite altitude is shown to be much too small by itself to account for the anomaly measured by Magsat. It is demonstrated that the source region for the satellite anomaly is considerably more extensive than the Kentucky body sensu stricto. The extended source region is modeled first using prismatic model sources and then using dipole array sources. Magnetization directions for the source region found by inversion of various combinations of scalar and vector data are found to be close to the main field direction, implying the lack of a strong remanent component. It is shown by simulation that in a case (such as this) where the geometry of the source is known, if a strong remanent component is present its direction is readily detectable, but by scalar data as readily as vector data

    A proposed test of the Einstein theory of gravitation by means of an unshielded orbiting gyro using passive telemetry

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    Proposed test of theory of gravitation by an unshielded earth orbiting gyroscope using passive telemetr
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