2,782 research outputs found

    Solar Brayton engine/alternator set

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    Work on the Mod O solar Brayton engine/alternator set is redirected to utilize solarized components of the automotive advanced gas turbine (AGT). The new configuration is referred to as the Mod I. Commercialization of solar Brayton engines thus should be enhanced not only by relating the design to an engine expected to reach the high quantity, low cost production rates associated with the automotive market, but also by the potential the AGT components provide for growth of efficiency and power rating. This growth would be achieved through use of ceramics in later versions making operation possible at temperatures up to 2500 F. The longer program duration and higher cost of the Mod I is considered

    A hybrid Brayton engine concept

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    A first generation open cycle Brayton engine concept for use in full scale solar module testing was defined. The concept extended to include solar/fossil hybrid capability. The combustion system defined for hybrid operation consists of a wide range combustor liner, a single airblast atomizer, an ignitor and a high-voltage ignition unit. Wide range combustor operation would be achieved through combining pilot and primary zones. The hybrid control mode and the solar only control mode are both based on the concept of maintaining constant turbine inlet temperature and varying the engine speed for part-power operation. In addition, the hybrid control concept will allow the operator to set a minimum thermal power input to the engine by setting a corresponding minimum engine speed. When the solar thermal power input falls below this minimum, fossil fuel would be utilized to augment the solar thermal power input

    Ranges of Atmospheric Mass and Composition of Super Earth Exoplanets

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    Terrestrial-like exoplanets may obtain atmospheres from three primary sources: Capture of nebular gases, degassing during accretion, and degassing from subsequent tectonic activity. Here we model degassing during accretion to estimate the range of atmospheric mass and composition on exoplanets ranging from 1 to 30 Earth masses. We use bulk compositions drawn from primitive and differentiated meteorite compositions. Degassing alone can create a wide range of masses of planetary atmospheres, ranging from less than a percent of the planet's total mass up to ~6 mass% of hydrogen, ~20 mass% of water, and/or ~5 mass% of carbon compounds. Hydrogen-rich atmospheres can be outgassed as a result of oxidizing metallic iron with water, and excess water and carbon can produce atmospheres through simple degassing. As a byproduct of our atmospheric outgassing models we find that modest initial water contents (10 mass% of the planet and above) create planets with deep surface liquid water oceans soon after accretion is complete.Comment: ApJ, in press. 32 pages, 6 figure

    Coreless Terrestrial Exoplanets

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    Differentiation in terrestrial planets is expected to include the formation of a metallic iron core. We predict the existence of terrestrial planets that have differentiated but have no metallic core--planets that are effectively a giant silicate mantle. We discuss two paths to forming a coreless terrestrial planet, whereby the oxidation state during planetary accretion and solidification will determine the size or existence of any metallic core. Under this hypothesis, any metallic iron in the bulk accreting material is oxidized by water, binding the iron in the form of iron oxide into the silicate minerals of the planetary mantle. The existence of such silicate planets has consequences for interpreting the compositions and interior density structures of exoplanets based on their mass and radius measurements.Comment: ApJ, in press. 22 pages, 5 figure

    Job Satisfaction and Work Ethic among Workers in a Japanese Manufacturing Company Located in the United States

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    This correlational and descriptive study synthesizes previous research regarding the impact of work ethic on job satisfaction when moderated by demographics, work dynamics, and occupational choice. Data from a sample of both exempt and non-exempt workers working at a Japanese-owned manufacturing plant was used to explore the relationship between the levels of job-satisfaction and work ethic reported by workers in various job categories and working environments. The sample consisted of 462 individuals who were identified using a stratified sampling of equal size. The study obtained responses from 328 workers through a respondent and non-respondent survey, representing 70% response rate. The researcher concluded that the 66 non-respondents could be included in the statistical analysis without prejudice toward the OWEI instrument; however, special attention should be given to any findings involving the JSS subscale Fringe Benefits due to differences between respondents and non-respondents. Specials examination was also given to the demographic variables of age and country. The researcher employed two robust tests, Wilksā€™s Lambda and Pillaiā€™s Trace, to mitigate differences between respondents and non-respondents. Exempt workers made up 46.6% of the sample, and non-exempt workers represented 53.4%. The researcher used the Pearson r and the Multiple Analysis of Variance (MANOVA) in analyzing data. The OWEI and JSS instruments showed an overall positive, by low though significant correlation. Differences were identified between exempt and non-exempt workers in various job categories. This study should be of value to human resource practitioners interested in improving the level of job satisfaction among varied work groups

    The efficacy of visual telephony as a means of social support in socially isolated nuring home residents

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    Nursing home residents often experience loneliness and social isolation. Research indicates that visitation via the telephone can decrease feelings of social isolation and loneliness. The purpose of this study was to introduce visual images to the telephone conversations of this population. It was hypothesized that the residents receiving this intervention would evidence decreased levels of loneliness and a greater sense of social support. This hypothesis was not supported by the data; however, emotional and social loneliness scores did show positive trends that may have been due to the intervention
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