11,561 research outputs found

    Sustaining and Increasing Participation of Rural Seniors in a Senior Center

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    This case study’s objective was to sustain and increase senior participation in senior center activities by examining the rural senior perception of environmental needs and support of a local senior center. Senior centers assist with aging in place well and aid seniors to be socially active within their communities. Much of the literature around senior centers has focused on urban environments and not on the specific needs of the rural senior. In this study, 24 individuals were interviewed. The questions examined the seniors’ perception about the functionality and accessibility of the senior center to meet their physical and social needs using the person environment fit theory (PE-Fit theory). PE-Fit affects the perceptions and behaviors of the person, which influences whether individuals participate in senior center activities. Transcripts of the interviews were analyzed using NVivo software searching for themes. The main themes were centered around activities expected at a senior center such as meals, games, and discussion groups. Themes around barriers were transportation, time, and health issues. These themes were used to recommend strategies and guidelines for increasing senior participation in senior centers. Documents including the Facebook page, informative emails, flyers, and policies were analyzed for themes, components, accessibility, and functionality. The analysis provided guidelines for senior centers to better fit their environments to the unique needs of rural seniors. Furthermore, understanding how rural seniors feel that they fit into an environment, and what they perceive their needs are, aids in the development of supportive strategies from other community-based organizations to assist older adults to live and function better within their community which leads to positive social change

    Computing Radiation Exchange

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    A computational tool to simulate thermal radiation between surfaces is developed. The output is verified against cases for which the analytical solutions are available. The tool can be used as a stand-alone program, or as an interactive module for CFD. In such an application the module would augment other heat transfer boundary conditions. The tool is demonstrated by post-processing surface temperature field data from a supersonic CFD calculation. The result is a net thermal radiation surface data field - the black body radiative effluxes as functions of temperature, less the integrated influxes multiplied by their geometric view factors from other surface cells. An algorithm to compute blocking, or shadowing of surfaces is presented and demonstrated on a simple geometry. Validations using a geometrically complex experimental case from the literature is performed

    In operando XAS investigation of reduction and oxidation processes in cobalt and iron mixed spinels during the chemical loop reforming of ethanol

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    FeCo2O4 and CoFe2O4 nanoparticles have been studied as oxygen carriers for the Chemical Loop Reforming (CLR) of ethanol. By using in operando X-ray absorption spectroscopy we have followed in real time the chemical and structural changes that take place on the materials as a function of temperature and reactive atmosphere (i.e. ethanol/water streams). During the first step of CLR for both oxides the most active chemical species are the cations in the tetrahedral sites, irrespective of their chemical nature. Quite rapidly the spinel structure is transformed into a mix of wustite-type oxide and metal alloys, but the formation of a metal phase is easier in the case of cobalt, while iron shows a marked preference to form wustite type oxide. Despite the good reducibility of FeCo2O4 imparted by the high amount of cobalt, its performance in the production of hydrogen is quite poor due to an inefficient oxidation by water steam, which is able to oxidize only the outer shell of the nanoparticles. In contrast, CoFe2O4 due to the residual presence of a reducible wustite phase shows a higher hydrogen yield. Moreover, by combining the structural information provided by X-ray absorption spectroscopy with the analysis of the byproducts of ethanol decomposition we could infer that FeCo2O4 is more selective than CoFe2O4 for the selective dehydrogenation of ethanol to acetaldehyde because of the higher amount of Fe(III) ions in tetrahedral sites

    Asteroseismic test of rotational mixing in low-mass white dwarfs

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    We exploit the recent discovery of pulsations in mixed-atmosphere (He/H), extremely low-mass white dwarf precursors (ELM proto-WDs) to test the proposition that rotational mixing is a fundamental process in the formation and evolution of low-mass helium core white dwarfs. Rotational mixing has been shown to be a mechanism able to compete efficiently against gravitational settling, thus accounting naturally for the presence of He, as well as traces of metals such as Mg and Ca, typically found in the atmospheres of ELM proto-WDs. Here we investigate whether rotational mixing can maintain a sufficient amount of He in the deeper driving region of the star, such that it can fuel, through HeII-HeIII ionization, the observed pulsations in this type of stars. Using state-of-the-art evolutionary models computed with MESA, we show that rotational mixing can indeed explain qualitatively the very existence and general properties of the known pulsating, mixed-atmosphere ELM proto-WDs. Moreover, such objects are very likely to pulsate again during their final WD cooling phase.Comment: accepted for publication in A&A Letter

    An asteroseismic test of diffusion theory in white dwarfs

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    The helium-atmosphere (DB) white dwarfs are commonly thought to be the descendants of the hotter PG1159 stars, which initially have uniform He/C/O atmospheres. In this evolutionary scenario, diffusion builds a pure He surface layer which gradually thickens as the star cools. In the temperature range of the pulsating DB white dwarfs (T_eff ~ 25,000 K) this transformation is still taking place, allowing asteroseismic tests of the theory. We have obtained dual-site observations of the pulsating DB star CBS114, to complement existing observations of the slightly cooler star GD358. We recover the 7 independent pulsation modes that were previously known, and we discover 4 new ones to provide additional constraints on the models. We perform objective global fitting of our updated double-layered envelope models to both sets of observations, leading to determinations of the envelope masses and pure He surface layers that qualitatively agree with the expectations of diffusion theory. These results provide new asteroseismic evidence supporting one of the central assumptions of spectral evolution theory, linking the DB white dwarfs to PG1159 stars.Comment: 7 pages, 3 figures, 3 tables, accepted for publication in A&

    RotAB Weed toolbox

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    The toolbox is a handbook of methods for weed monitoring in organic long-term arable experiments. It has been developed based on the expertise of French agronomists in charge of such experiments. The toolbox is composed of an excel file (can be found on Organic Eprints orgprints.org/31937) that provides an overview of the methods and indicators to be calculated and 7 fact sheets detailing different weed monitoring methods. The tool has been developed for organic agriculture but could be used in conventional agriculture. The fact sheets are applicable in all European pedo-climatic conditions
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