34,760 research outputs found

    Theoretical analysis of the atmospheres of CP stars. Effects of the individual abundance patterns

    Full text link
    Context. See abstract in the paper. Aims. See abstract in the paper. Methods. See abstract in the paper. Results. We present a homogeneous study of model atmosphere temperature structure, energy distribution, photometric indices in the uvbybeta and Delta_a systems, hydrogen line profiles, and the abundance determination procedure as it applies to CP stars. In particular, we found that Si, Cr and Fe are the main elements to influence model atmospheres of CP stars, and thus to be considered in order to assess the adequacy of model atmospheres with scaled solar abundances in application to CP stars. We provide a theoretical explanation of the robust property of the Delta_a photometric system to recognize CP stars with peculiar Fe content. Also, the results of our numerical tests using model atmospheres with one or several elements overabundant (Si and Fe by +1 dex, Cr by +2 dex) suggest that the uncertainty of abundance analysis in the atmospheres of CP stars using models with scaled abundances is less than plus/minus 0.25 dex. If the same homogeneous models are used for the abundance stratification analysis then we find that the uncertainty of the value of the vertical abundance gradient is within an 0.4 dex error bar. Conclusions. Model atmospheres with individual abundance patterns should be used in order to match the actual anomalies of CP stars and minimize analysis errors.Comment: 18 pages, 9 figure

    Slant and semi-slant submanifolds of a Kenmotsu manifold

    Get PDF

    Characterization of physio-chemical properties of polymeric and electrochemical materials for aerospace flight

    Get PDF
    Sealed nickel cadmium cells having undergone a large number of cycles were discharged using the Hg/HgO reference electrode. The negative electrode exhibited the second plateau. SEM of negative plates of such cells show clusters of large crystals of cadmium hydroxide. These large crystals on the negative plates disappear after continuous overcharging in flooded cells. Atomic Absorption Spectroscopy and standard wet chemical methods are being used to determine the cell materials viz: nickel, cadmium, cobalt, potassum and carbonate. The anodes and cathodes are analyzed after careful examination and the condition of the separator material is evaluated

    A High Phase Advance Damped and Detuned Structure for the Main Linacs of Clic

    Full text link
    The main accelerating structures for the CLIC are designed to operate at an average accelerating gradient of 100 MV/m. The accelerating frequency has been optimised to 11.994 GHz with a phase advance of 2{\pi}/3 of the main accelerating mode. The moderately damped and detuned structure (DDS) design is being studied as an alternative to the strongly damped WDS design. Both these designs are based on the nominal accelerating phase advance. Here we explore high phase advance (HPA) structures in which the group velocity of the rf fields is reduced compared to that of standard (2{\pi}/3) structures. The electrical breakdown strongly depends on the fundamental mode group velocity. Hence it is expected that electrical breakdown is less likely to occur in the HPA structures. We report on a study of both the fundamental and dipole modes in a CLIC_DDS_HPA structure, designed to operate at 5{\pi}/6 phase advance per cell. Higher order dipole modes in both the standard and HPA structures are also studied

    Evaluating Responses of Sugar Beet Cultivars to Fusarium Species in Greenhouse and Field Conditions

    Get PDF
    Fusarium yellows of sugar beet (Beta vulgaris L.) is becoming an important disease in Minnesota and North Dakota in the United States. One of the best ways to manage Fusarium yellows is to develop and use resistant cultivars. Responses of eight sugar beet cultivars to three Fusarium species were determined in the greenhouse and compared to the responses of the same eight cultivars grown in a field already infected by Fusarium yellows. There were significant and appreciable relationships between greenhouse and field studies for responses of eight sugar beet cultivars on Fusarium yellows. The estimated correlation coefficient for area under disease progress curve (AUDPC) between observations in fields and those in greenhouses was 0.987 (p<0.01). The mean AUDPC were significantly different among cultivars (p<0.01) in the greenhouse and in the field studies. Of the cultivars, Van der Have 46177 was the most susceptible, but Crystal R434 the most resistant. Crystal 820, Van der Have 66561, and Beta 4797R were resistant, and Beta 4818R, Seedex Magnum, and Hilleshog 2463Rz were moderately resistant. There was a strong negative relationship between the AUDPC and recoverable sucrose yield in the field experiments and the estimated coefficient of determination was 0.939 (p<0.01). It was concluded that greenhouse screening can act as a useful and reliable means to evaluate and select beet germplasms and/or accessions for resistance to Fusarium yellows.Peer reviewe

    WavePacket: A Matlab package for numerical quantum dynamics. III: Quantum-classical simulations and surface hopping trajectories

    Full text link
    WavePacket is an open-source program package for numerical simulations in quantum dynamics. Building on the previous Part I [Comp. Phys. Comm. 213, 223-234 (2017)] and Part II [Comp. Phys. Comm. 228, 229-244 (2018)] which dealt with quantum dynamics of closed and open systems, respectively, the present Part III adds fully classical and mixed quantum-classical propagations to WavePacket. In those simulations classical phase-space densities are sampled by trajectories which follow (diabatic or adiabatic) potential energy surfaces. In the vicinity of (genuine or avoided) intersections of those surfaces trajectories may switch between surfaces. To model these transitions, two classes of stochastic algorithms have been implemented: (1) J. C. Tully's fewest switches surface hopping and (2) Landau-Zener based single switch surface hopping. The latter one offers the advantage of being based on adiabatic energy gaps only, thus not requiring non-adiabatic coupling information any more. The present work describes the MATLAB version of WavePacket 6.0.2 which is essentially an object-oriented rewrite of previous versions, allowing to perform fully classical, quantum-classical and quantum-mechanical simulations on an equal footing, i.e., for the same physical system described by the same WavePacket input. The software package is hosted and further developed at the Sourceforge platform, where also extensive Wiki-documentation as well as numerous worked-out demonstration examples with animated graphics are available

    An examination of service user satisfaction in forensic mental health settings

    Get PDF
    High levels of service user satisfaction are viewed as a reliable indicator of a service providing good care and treatment. There has been limited research looking into levels of satisfaction in forensic mental health settings with most work focused on staff satisfaction in these settings. This study examined service users' levels of satisfaction with a forensic mental health service in the UK. The service covered two sites; one a purpose-built secure unit and the other based in an old cottage hospital. Thirty-nine in-patients completed a 60-item validated forensic satisfaction scale. The scale measured seven domains of satisfaction as well as reporting an overall satisfaction score. The results indicated the service users were reasonably satisfied with the care and treatment they received. The domains of rehabilitation, safety, staff interaction and overall care showed the highest level of satisfaction. The high rehabilitation satisfaction score demonstrated the importance of meaningful activities for users accessing forensic services and may have been influenced by the security measures on the wards. The high safety domain score indicated respondents felt safe and secure within the wards and likely to be influenced by positive interpersonal interactions. Good staff interaction was also an important factor in helping service users feel safe on the wards. These interactions are likely to be associated with the longer periods of admission in secure services allowing therapeutic relationships to develop. Financial advice/support was the one domain that recorded negative satisfaction levels. Financial literacy training may help develop money management skills

    Enhanced coupling design of a detuned damped structure for clic

    Full text link
    The key feature of the improved coupling design in the Damped Detuned Structure (DDS) is focused on the four manifolds. Rectangular geometry slots and rectangular manifolds are used. This results in a significantly stronger coupling to the manifolds compared to the previous design. We describe the new design together with its wakefield damping properties.Comment: 3 pages, 8 figures, submitted to IPAC1
    • …
    corecore