998 resultados para Glass compositions


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Raman scattering in the region 20 to 100 cm -1 for fused quartz, "pyrex" boro-silicate glass, and soft soda-lime silicate glass was investigated. The Raman spectra for the fused quartz and the pyrex glass were obtained at room temperature using the 488 nm exciting line of a Coherent Radiation argon-ion laser at powers up to 550 mW. For the soft soda-lime glass the 514.5 nm exciting line at powers up to 660 mW was used because of a weak fluorescence which masked the Stokes Raman spectrum. In addition it is demonstrated that the low-frequency Raman coupling constant can be described by a model proposed by Martin and Brenig (MB). By fitting the predicted spectra based on the model with a Gaussian, Poisson, and Lorentzian forms of the correlation function, the structural correlation radius (SCR) was determined for each glass. It was found that to achieve the best possible fit· from each of the three correlation functions a value of the SCR between 0.80 and 0.90 nm was required for both quartz and pyrex glass but for the soft soda-lime silicate glass the required value of the SCR. was between 0.50 and 0.60 nm .. Our results support the claim of Malinovsky and Sokolov (1986) that the MB model based on a Poisson correlation function provides a universal fit to the experimental VH (vertical and horizontal polarizations) spectrum for any glass regardless of its chemical composition. The only deficiency of the MB model is its failure to fit the experimental depolarization spectra.

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Four men (unidentified) walking in tunnel wearing hard hats and carrying flashlights.

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Consulting Engineer drawing of Sections of the Discharge Tunnel. Included in the drawing is the "cross section of tunnel with timbering" and "longitudinal section showing Timber in straight tunnel". Dated October 1902.

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Appears to be an engineer's drawing of the Hydro Station. It is a cross-section view of the interior.

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Plan and profile of discharge tunnel along Niagara River. The horizontal scale is 1 inch = 100 feet, the vertical scale is 1 inch = 40 feet. The drawing is dated November 7, 1902.

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Drawing by consulting engineer dated October 19, 1901. Scale is noted as 1/4 inch = 1 foot.

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Drawing of "Section thru Wheelpit" dated September 1925. Shows unit no.1 through unit no.11, power house floor and water surface.

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Engineer drawing (untitled), some of the labels read "exciter chamber", "fore bay", "power house floor".

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Four men (unknown) standing in the tunnel wearing hard hats.

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A large group of men in hard hats in the tunnel. The names of the men are unknown.

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Four men standing in hydro tunnel.

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Letter to S.D. Woodruff from A. Jeffrey importer of Hardware, Iron, Steel, and Window Glass of St. Catharines, Ont. A. Jeffrey says that he will be able to supply Mr. Woodruff with glass and iron pipe, June 7, 1875.

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Letter to S.D. Woodruff from A. Jeffrey importer of Hardware, Iron, Steel, and Window Glass of St. Catharines, Ont. regarding breakage and freight, June 23, 1875.

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Unsigned letter to A. Jeffrey written on an envelope stating that the glass was free from breakage, therefore there would be a deduction of 10 percent, June 28, 1875.

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Receipt from Chance Brothers and Co. Glass Works near Birmingham, England regarding payment received for glass panes. This is accompanied by an envelope, April 6, 1875.