Showing items related by title, author, creator and subject.

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  Downward Continuation of Bouguer Gravity Anomalies and Residual Aeromagnetic Anomalies by Means of Finite Differences

  Arenson, John Dean; Sturgul, J. R.; Sumner, J. S.; Norton, D. D.; Arenson, John Dean (The University of Arizona., 1975)

  The depths to buried bodies, characterized by anomalous gravity and magnetic properties, are determined by a combination of two numerical techniques. An upward continuation integral is solved by a method by Paul and Nagy using elemental squares and low order polynomials to describe the behavior of the gravity or magnetic data between observed data points. Downward continuation of the magnetic or gravity data is done by a finite difference technique as described by Bullard and Cooper. The applicability of the techniques are determined by comparison to depths determined by other means over the same anomalies and by comparison to various rule-of-thumb methods prevalent in the geophysical literature. The relative speed and cost of the particular computer system used is also considered in the applicability. The results show that although the initial costs of the computer program are high, the combined technique is as good as and at times better than the rule-of-thumb methods in determining the depth to the anomaly-causing body and is useful when more than just an approximate depth is of interest.
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  Measurement of Low 14C Activities in a Liquid Scintillation Counter in the Zagreb Radiocarbon Laboratory

  Horvatinčić, Nada; Barešić, Jadranka; Krajcar Bronić, Ines; Obelić, Bogomil (Department of Geosciences, The University of Arizona, 2004-01-01)

  Two methods of chemical preparation of radiocarbon samples are implemented in the Zagreb Radiocarbon Laboratory for measurement by a new liquid scintillation counter (LSC), Quantulus 1220(TM): a CO2 absorption method (LSC-A) and a benzene synthesis method (LSC-B). For samples prepared by both methods, the optimal counting windows for measurement in LSC were determined. The total efficiency of LSC-A is 65% and that of the LSC-B is 83%, while the corresponding 14C dating limits are 31,800 yr and 52, 160 yr, respectively. 14C activities measured by the LSC-A and LSC-B methods were compared with those measured by the gas proportional counter (GPC) method (efficiency 75%, 14C dating limit 37,500 yr). The results obtained by the LSC-A method have larger errors than those measured by the GPC method, but LSC-A is quick, inexpensive, simple, and requires less carbon than the GPC method. Thus, LSC-A is suitable for 14C measurements of geological, hydrological, and environmental samples. On the other hand, the results obtained by the LSC-B method give smaller errors and a larger 14C dating range. Therefore, LSC-B is more suitable for 14C dating of archaeological samples.
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  Simulation of water reliability on a small scale water harvesting agrisystem

  Dietterick, Brian Craig.; Fogel, Martin M.; Gay, Lloyd W.; Thames, John L. (The University of Arizona., 1982)

  Water harvesting techniques are being studied to determine its potential as an alternative reclamation practice. To assist planners and decision makers in evaluating the water harvesting potential, a procedure is developed by which precipitation and its distribution are simulated and incorporated with a runoff model to forecast the long term availability of harvested water. The output from the stochastic precipitation model and statistically- derived runoff model provide a simulated 100 years of annual precipitation and runoff events. Two reservoirs were designed and evaluated separately using varied seasonal irrigation demands. The sensitivity analysis, of varying the demand, revealed yearly water reliability decreased as the total seasonal irrigation demand approached the mean annual runoff. It was also shown that an appropriate reservoir size could be chosen using the probability distributions of the number of dry reservoir days and the number of days the reservoir overflows.