3,597 research outputs found

    Self-supported aluminum thin films produced by vacuum deposition process

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    Self-supported aluminum thin film is produced by vacuum depositing the film on a polyvinyl formal resin film and then removing the resin by radiant heating in the vacuum. The aluminum film can be used as soon as the resin is eliminated

    Camera shutter is actuated by electric signal

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    Rotary solenoid energized by an electric signal opens a camera shutter, and when the solenoid is de-energized a spring closes it. By the use of a microswitch, the shutter may be opened and closed in one continuous, rapid operation when the solenoid is actuated

    On Chromospheric Variations Modeling for Main-Sequence Stars of G and K Spectral Classes

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    We present a method of chromospheric flux simulation for 13 late-type main-sequence stars. These Sun-like stars have well-determined cyclic flux variations similar to 11 yr solar activity cycle. Our flux prediction is based on chromospheric HK emission time series measurements from Mount Wilson Observatory and comparable solar data. We show that solar three - component modeling explains well the stellar observations. We find that the 10 - 20% of K - stars disc surfaces are occupied by bright active regions.Comment: 8 pages, 2 figure

    Existence theorems in the geometrically non-linear 6-parametric theory of elastic plates

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    In this paper we show the existence of global minimizers for the geometrically exact, non-linear equations of elastic plates, in the framework of the general 6-parametric shell theory. A characteristic feature of this model for shells is the appearance of two independent kinematic fields: the translation vector field and the rotation tensor field (representing in total 6 independent scalar kinematic variables). For isotropic plates, we prove the existence theorem by applying the direct methods of the calculus of variations. Then, we generalize our existence result to the case of anisotropic plates. We also present a detailed comparison with a previously established Cosserat plate model.Comment: 19 pages, 1 figur

    Seasonal Changes in Water Quality and Primary Productivity in Doe Valley Lake

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    Primary productivity and water quality were studied in Doe Valley Lake, a 147-hectare impoundment on Doe Run, a spring-fed stream in Meade County, Kentucky, from 13 June 1969 to 31 July 1972. Doe Valley Lake is monomictic during most winter seasons, but it is dimictic during more severe winters because of its morphometry and location on the borderline climatic region for dimictic lakes (37° N latitude). Oxygen depletion in the hypolimnion is severe, and anaerobic conditions usually prevail by late June. A hypolimnetic areal deficit of 0.038 mg/cm2/day was calculated. Supersaturation of oxygen in the epilimnion was common, and metalimnetic maxima exceeded 150 percent saturation in spring and early summer. Primary productivity ranged from 44 to 1,192 mgC/m2/day and annual rates at Stations I and III were 277 and 255 gC/m2/yr, respectively. Productivity fluctuated considerably at Station I as a result of turbidity, but average daily rates and chlorophyll levels were higher than at Station III. Periodic flooding drastically lowered productivity and phytoplankton standing crops. Negative or low correlations were found between productivity and turbidity, pH, alkalinity, nitrates, and phosphates. The relationship between productivity and standing crop of phytoplankton varied throughout the year but positive correlations were observed on an annual basis. Chlorophyll a levels correlated fairly well with net phytoplankton. Except during summer, nannoplankton contributed more than 50 percent of the total carbon assimilation. The inflowing stream, Doe Run, contributes valuable quantities of nutrients including carbon, nitrogen, phosphorus, and sulfur that enhance the productivity of the lake. Degradation of allochthonous leaf materials introduces significant amounts of carbohydrates, proteins, and lipids into the lake ecosystem, but inflow patterns characteristic of a spring-fed stream greatly influence the fate and availability of these nutrients

    Information Literacy at Augustana: A Programmatic Approach

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    Information literacy programs, and the factors that influence their development and structure, can vary significantly from institution to institution. Credit-bearing discipline-specific information literacy courses are a rare and valuable component of an undergraduate educational experience and form the basis of Augustana\u27s information literacy program. This article provides an overview of the development, implementation, successes, and drawbacks of the credit-bearing discipline-specific information literacy courses at the Augustana Campus of the University of Alberta (Camrose, Alberta, Canada). Additional program components including Augustana\u27s annual information literacy workshop, information literacy awards, information literacy DVD, and marketing/branding, are discussed

    Observation of String Breaking in QCD

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    We numerically investigate the transition of the static quark-antiquark string into a static-light meson-antimeson system. Improving noise reduction techniques, we are able to resolve the signature of string breaking dynamics for n_f=2 lattice QCD at zero temperature. This result can be related to properties of quarkonium systems. We also study short-distance interactions between two static-light mesons.Comment: 27 pages, 22 figures, changed decimal place of errors in 3 entries of Table, corrected reference
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