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No abstract available at this time...

A simple numerical model for estimating a phreatic surface in an earthen dam is presented. The numerical approach is based upon the Complex Variable Boundary Element Method (CVBEM). By expanding the CVBEM approximation geometric functions into a first order Taylor series, the unknown phreatic surface location geometrics can be approximated...

Summary form only given. A classification error matrix typically contains tabulation results of an accuracy evaluation of a thematic classification, such as that of a land use and land cover map. The diagonal elements of the matrix represent the counts corrected, and the usual designation of classification accuracy has been...

The U.S. Geological Survey has been preparing and maintaining a library of standard reference water samples for inorganic constituents for 19 years. Recently, a pilot study was conducted to see if the reference-sample program could be expanded to include pesticides and other organic materials. Two samples containing organochlorine and organophosphorus...

Soil samples were collected from former radium processing sites in Denver, CO, and East Orange, NJ. Particle-size separations and radiochemical analyses of selected samples showed that while the greatest contents of both 226Ra and U were generally found in the finest (< 45 ??m) fraction, the pattern was not always...

This regional gravity study, based on an irregular 2-km data grid, was conducted during the past few years at Yucca Mountain, southern Nye County, Nevada, as part of a program to locate a suitable repository for high-level nuclear waste. About 100 surface rock samples, three borehole gamma-gamma logs, and one...

Black shales of Devonian age in the Appalachian Basin are a unique rock sequence. The high content of organic matter, which imparts the characteristic lithology, has for years attracted considerable interest in the shales as a possible source of energy. The recent energy shortage prompted the U.S. Department of Energy...

Particulate nitrogen (PN) and chlorophyll a (Chla) were measured in the northern reach of San Francisco Bay throughout 1980. The PN values were calculated as the differences between unfiltered and filtered (0·4 μm) samples analyzed using the UV-catalyzed peroxide digestion method. The Chla values were measured spectrophotometrically, with corrections made for phaeopigments. The...

Rb-Sr isotopic data for anorthosites, charnockites, ferrodioritic to quartz monzonitic plutons, and high-grade gneisses of the Blue Ridge of central Virginia show evidence of post-emplacement metamorphism, but in some cases retain Grenville ages. The Pedlar River Charnockite Suite yields an isochron age of 1021 +/-36 Ma, (initial 87Sr/86Sr ratio of...

No abstract available. ...

Simulated observations of spawning stock size, recruitment, and two random environmental variables were obtained from a density-independent Leslie matrix model. Recruitment to Age 1 was directly proportional to population fecundity but strongly influenced by the effects of the random environmental variables. The simulated observations were subjected to multiple regression analysis...

A series of experiments on drained creep of marine sediment indicates that strength degradation results from the creep process, which implies an associated reduction in slope stability. Furthermore, the highest creep potential of a sediment may be at its preconsolidation stress. Results from the experiments on samples from Georges Bank...

Salt gradient solar collector ponds are economically feasible as a source of heat energy for hatchery rearing water. A pond 3 m deep and covering an area of 5000 m2 will supply approximately 2800 GJ of energy over a three-month period — enough for a one-year smolt program in an Atlantic...

A major explosive eruption occurred 15 May 1981 at Mount Pagan Volcano, the larger of two historic eruptive centers on Pagan Island, Mariana Islands. The eruption was preceded by increased numbers of locally felt earthquakes beginning in late March or early April and by new ground cracks, new sublimates, and...

Studies of secondary mineral distribution, whole-rock chemical compositions, isotopes, and fluid inclusions are being conducted on the core from Newberry Volcano drill hole 2. Rocks from the drill core are divided into 3 major intervals on the basis of their alteration pattern, which is controlled by rock permeabilities, primary lithologies,...

Calibration and testing of aerial mapping cameras includes the measurement of optical constants and the check for proper functioning of a number of complicated mechanical and electrical parts. For this purpose the US Geological Survey performs an operational type photographic calibration. This paper is not strictly a scientific paper but...

[No abstract available]...

[No abstract available]...

A preparative adsorption column chromatographic method is reported for the separation of cis and trans geometrical isomers of two types of N-nitrosamines derived from allylic terpenyl ethanolamines (experimental fish toxicants). Column eluates were monitored by gas chromatography in which a Carbowax 20M stationary phase was used. Further separation of E and Z configurational isomers was achieved by reversed-phase...

For slowly moving freezing fronts in soil, the heat-transport equation may be approximated by the Laplacian of temperature. Consequently, potential theory may be assumed to apply and the temperature state can be approximated by an analytic function. The movement of freezing fronts may be approximated by a time-stepped solution of...

The Jurassic Notch Peak granitic stock, western Utah, discordantly intrudes Cambrian interbedded pure limestones and calcareous argillites. Contact metamorphosed argillite and limestone samples, collected along traverses away from the intrusion, were analyzed for ??18O, ??13C, and ??D. The ??13C and ??18O values for the limestones remain constant at about 0.5...

An assessment of the current status of computer-assisted cartography, in part, is biased by one's view of the cartographic process as a whole. From a traditional viewpoint we are concerned about automating the mapping process; from a progressive viewpoint we are concerned about using the tools of computer science to...

A digital ground-water flow model of the southern High Plains of Texas and New Mexico has been constructed. The calibrated model with the 1980 water level as the initial condition was used to project water levels to 2020. Estimated future pumpage based on the U. S. Economic Development Administration's economic...

Arsenic, antimony, bismuth, cadmium, copper, lead, molybdenum, silver and zinc are very useful elements in geochemical exploration. In the proposed method, geological samples are fused with potassium pyrosulphate and the fusate is dissolved in a solution of hydrochloric acid, ascorbic acid and potassium iodide. When this solution is shaken with...