563 research outputs found
Operational applications of satellite snowcover observations in Rio Grande drainage of Colorado
Various mapping techniques were tried and evaluated. There were many problems encountered such as distinquishing clouds from snow and snow under trees. A partial solution to some of the problems involves ground reconnaissance and low air flights. Snow areas, cloud cover, and total areas were planimetered after transferring imagery by use of zoom transfer scope. These determinations were then compared to areas determined by use of a density slicer. Considerable adjustment is required for these two values to compare. NOAA pictures were also utilized in the evaluation. Forest cover is one of the parameters used in the modeling process. The determination of this percentage is being explored
X-ray film holder permits single continuous picture of tubing joint
X ray technique produces a clear continuous picture of a welded brazed tubing joint on a single film with one exposure. A stationary X ray source located in the plane of the joint to be inspected, a means of rotating the tube, and a unique internal film holder and positioning fixture are used
Impacts of Adding Net Worth to the Poverty Definition
This paper estimates changes in the level and composition of poverty that would result from modifying the conventional income-based poverty measure to include the annuity value of household net worth. Under the new income/wealth measure, 13 percent of those currently measured as poor have enough assets to be removed from poverty. Among those more often found to be in poverty under the new measure are young, renters, and large central city residents. Age, home ownership, farm employment, education, retirement status, public assistance participation, and residence in the West are significant factors in explaining the divergence of the alternative poverty measures.
A Laser Ultrasound System to Non-Invasively Measure Compression Waves in Granular Ice Mixes
Accurate knowledge of snow mechanical properties, including Young\u27s modulus, shear modulus, Poisson\u27s ratio, and density, is critical to many areas of snow science and to snow-related engineering problems. To facilitate the assessment of these properties, an innovative non-contacting laser ultrasound system (LUS) has been developed. This system acquires ultrasound waveform data at frequencies ranging from tens to hundreds of kHz in a controlled cold-lab environment. Two different LUS devices were compared in this study to determine which recorded more robust ultrasound in granular ice mix samples. We validated the ultrasound observations with poro-elastic traveltime modeling based on physical and empirical constitutive relationships, comparison to and replication of previous studies, and the use of other accredited snow property measurement systems, i.e., the SnowMicroPen. For ice mixes, we determined that the PSV-400 Scanning Vibrometer (Polytec GmbH) produces higher quality ultrasonic wavefield observations (i.e. has a better signal-to-noise ratio) than the VibroFlex Fiber Vibrometer (Polytec GmbH) in the lab conditions tested here. Using the PSV-400, we then demonstrated the utility of this new LUS to study the relationship between snow compression-wave speed and density during snow compaction experiments
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