934 resultados para Vellum printed books.
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Resumen del póster presentado en Symposium on Renewable Energy and Products from Biomass and Waste, CIUDEN (Cubillos de Sil, León, Spain), 12-13 May 2015
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A novel approach is presented to determine mercury in urine samples, employing vortex-assisted ionic liquid dispersive liquid–liquid microextraction and microvolume back-extraction to prepare samples, and screen-printed electrodes modified with gold nanoparticles for voltammetric analysis. Mercury was extracted directly from non-digested urine samples in a water-immiscible ionic liquid, being back-extracted into an acidic aqueous solution. Subsequently, it was determined using gold nanoparticle-modified screen-printed electrodes. Under optimized microextraction conditions, standard addition calibration was applied to urine samples containing 5, 10 and 15 μg L−1 of mercury. Standard addition calibration curves using standards between 0 and 20 μg L−1 gave a high level of linearity with correlation coefficients ranging from 0.990 to 0.999 (N = 5). The limit of detection was empirical and statistically evaluated, obtaining values that ranged from 0.5 to 1.5 μg L−1, and from 1.1 to 1.3 μg L−1, respectively, which are significantly lower than the threshold level established by the World Health Organization for normal mercury content in urine (i.e., 10–20 μg L−1). A certified reference material (REC-8848/Level II) was analyzed to assess method accuracy finding 87% and 3 μg L−1 as the recovery (trueness) and standard deviation values, respectively. Finally, the method was used to analyze spiked urine samples, obtaining good agreement between spiked and found concentrations (recovery ranged from 97 to 100%).
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Schachzabelbuch (ff. 1-87r; incomplete at the beginning) -- Heil- und Segenssprüche (87r-88v) -- Tageszeiten (89r-144v) -- Kalender (145r-159v) -- Heil- und Segenssprüche (160r-v).
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by teachers in Harvard University.
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3
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This broadside contains a proposal for a "System of Mensuration" by William Croswell.
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This folder contains two newspaper clippings with the proposal for Croswell's "System of Mensuration," dated October 1796, as well as a printed recommendation for the work by Professor John Kemp.
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This folder contains two copies of a proposal for publishing the works of Horace.
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Printed broadside and newspaper clipping containing a proposal for the publication of a collection of bibliographic systems.