13 research outputs found

    Application of remote sensor data to geologic analysis of the Bonanza test site Colorado

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    Research activities on geologic remote sensing applications for Colorado are summarized. Projects include: regional and detailed geologic mapping, surficial and engineering geology, fracture studies, uranium exploration, hydrology, and data reduction and enhancement. The acquisition of remote sensor data is also discussed

    I . s/4Au)2f%9&L9 %2? (2 Module 30 Year Life : What does it mean and is it predictable/achievable?

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    ABSTRACT We define what we mean by a 30-year module life and the testing protocol that we believe is involved in achieving such a prediction. However, we do not believe that a universal test (or series of tests) will allow for such a prediction to be made. We can test for a lot of things, but we believe it is impossible to provide a 30-year certification for any PV module submitted for test. We explain our belief in this paper

    Magnetic resonance imaging indicators of blood-brain barrier and brain water changes in young rats with kaolin-induced hydrocephalus

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    <p>Abstract</p> <p>Background</p> <p>Hydrocephalus is associated with enlargement of cerebral ventricles. We hypothesized that magnetic resonance (MR) imaging parameters known to be influenced by tissue water content would change in parallel with ventricle size in young rats and that changes in blood-brain barrier (BBB) permeability would be detected.</p> <p>Methods</p> <p>Hydrocephalus was induced by injection of kaolin into the cisterna magna of 4-week-old rats, which were studied 1 or 3 weeks later. MR was used to measure longitudinal and transverse relaxation times (T1 and T2) and apparent diffusion coefficients in several regions. Brain tissue water content was measured by the wet-dry weight method, and tissue density was measured in Percoll gradient columns. BBB permeability was measured by quantitative imaging of changes on T1-weighted images following injection of gadolinium diethylenetriamine penta-acetate (Gd-DTPA) tracer and microscopically by detection of fluorescent dextran conjugates.</p> <p>Results</p> <p>In nonhydrocephalic rats, water content decreased progressively from age 3 to 7 weeks. T1 and T2 and apparent diffusion coefficients did not exhibit parallel changes and there was no evidence of BBB permeability to tracers. The cerebral ventricles enlarged progressively in the weeks following kaolin injection. In hydrocephalic rats, the dorsal cortex was more dense and the white matter less so, indicating that the increased water content was largely confined to white matter. Hydrocephalus was associated with transient elevation of T1 in gray and white matter and persistent elevation of T2 in white matter. Changes in the apparent diffusion coefficients were significant only in white matter. Ventricle size correlated significantly with dorsal water content, T1, T2, and apparent diffusion coefficients. MR imaging showed evidence of Gd-DTPA leakage in periventricular tissue foci but not diffusely. These correlated with microscopic leak of larger dextran tracers.</p> <p>Conclusions</p> <p>MR characteristics cannot be used as direct surrogates for water content in the immature rat model of hydrocephalus, probably because they are also influenced by other changes in tissue composition that occur during brain maturation. There is no evidence for widespread persistent opening of BBB as a consequence of hydrocephalus in young rats. However, increase in focal BBB permeability suggests that periventricular blood vessels may be disrupted.</p

    Spectral Solar Radiation Data Base At Seri

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    This article describes the results to date of a cooperative project among the Solar Energy Research Institute (SERI), the Electric Power Research Institute, the Florida Solar Energy Center (FSEC), and the Pacific Gas and Electric Company (PG&E) to build a spectral solar radiation data base. The objective is to build a data base representing a range of air masses and atmospheric conditions (or climates) that is applicable to different photovoltaic (PV) collector types and is accessible by the PV and general scientific community. Approximately 1300 spectra and concurrent broadband solar radiation and meteorological data have been collected at FSEC and PG&E and archived at SERI in the data base as of October 1987. © 1989
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