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Prediction approach to multistage sampling when cluster sizes are unknown

Description: A model for two-stage cluster sampling when sample cluster sizes are unknown is used to derive an optimal (model-based) estimator for the population total and to determine robust sampling strategies. In an empirical study using 1970 and 1980 census data for Los Angeles and surrounding counties, comparisons are made between the model based estimator and conventional estimators. The results favor the new estimator over those derived from randomization theory. In addition, the empirical study shows that the robust sampling strategies suggested by the theory can reduce biases, improve efficiency, and decrease the frequencies of large errors. 7 refs.
Date: January 1, 1985
Creator: Kelly, E.J. & Cumberland, W.G.
Partner: UNT Libraries Government Documents Department

Electrochemical behavior of titanium implanted with platinum

Description: The following conclusions apply to Ti(Pt) near-surface alloys studied. (1) Open-circuit corrosion measurements show that accumulation of platinum may occur at a surface concentration of 0.32 atomic percent Pt while no accumulation occurs at 0.16 atomic percent Pt. However, these results do not allow a distinction as to cause of accumulation to be made between concentration effects and effects due to the presence of an oxide film. (2) Potentiostatic corrosion at -0.450 V (active corrosion) establish that little or no accumulation of platinum occurs at an oxide-free surface for concentrations less than 0.086 atomic percent Pt; whereas, a large amount of accumulation occurs for a distribution with a peak concentration of 0.83 atomic percent Pt. (3) An initial distribution having a peak concentration of 0.32 atomic percent platinum is sufficient to induce natural passivity in titanium and bring a freely corroding sample to a potential of 0.269 V. This is nearly the applicable reversible potential (-0.260 V) for the hydrogen reaction in 1N H/sub 2/SO/sub 4/. (4) Of three samples which showed accumulation, platinum was eventually lost for two of these samples (0.32 atomic percent, open-circuit corrosion; 0.83 atomic percent, potentiostatic corrosion). The remaining sample (9.1 atomic percent, open-circuit corrosion) maintained the maximum possible potential of -0.260 V for the length of the experiment (approx. 30 days). (5) For samples which had been polarized at -0.300 to -0.340 V and which had eventually reverted to the behavior of pure Ti, post corrosion RBS measurements reveal that a substantial fraction of the Pt fluence is retained on the surface in an electrochemically inactive state.
Date: January 1, 1979
Creator: Thompson, N.G.; Lichter, B.D.; Appleton, B.R.; Kelly, E.J. & White, C.W.
Partner: UNT Libraries Government Documents Department

Above and beyond basic public participation

Description: This paper evolved out of a discussion about public participation as it is currently being brought to the fore-front of clean-up activities at hazardous waste sites. There exists much official and unofficial documentation pertaining to the need for public involvement. The purposes for public involvement efforts in Environmental Restoration are: to enable substantive input to the clean-up process; methods for establishing formal, and now informal, mechanisms for public input and awareness of on-going facility activities; and the opening of better channels for communication and conflict resolution between the public and the facility. This presentation will briefly outline the regulatory approach for public outreach because many of these terms are used with such frequency, their meanings tend to get forgotten or misconstrued. Then, the authors will critique the most common methods for conducting public involvement as attempted through advisory boards and public meetings. For illustrative purposes, they will be referring to the site they are most familiar with, which is Los Alamos National Laboratory (LANL).
Date: July 1, 1995
Creator: Mathai, L.P.; Lefkoff, M.S. & Kelly, E.J.
Partner: UNT Libraries Government Documents Department

A Calibration to Predict Concentrations of Impurities in Plutonium Oxide by Prompt Gamma Analysis

Description: Prompt gamma (PG) analysis has been used to identify the presence of certain impurities in plutonium oxide, which has been stored in 3013 containers. A regression analysis was used to evaluate the trends between the count rates obtained from PG analysis and the concentration of the impurities in plutonium oxide samples measured by analytical chemistry techniques. The results of the analysis were used to obtain calibration curves, which may be used to predict the concentration of Al, Be, Cl, F, Mg, and Na in the 3013 containers. The scatter observed in the data resulted from several factors including sample geometry, error in sampling for chemical assay, statistical counting error, and intimacy of mixing of impurities and plutonium. Standards prepared by mixing plutonium oxide with CaF{sub 2}, NaCl, and KCl show that intimacy mixing and sampling error have the largest influence on the results. Although these factors are difficult to control, the calibrations are expected to yield semiquantitative results that are sufficient for the purpose of ordering or ranking.
Date: December 13, 2005
Creator: Narlesky, J.E.; Kelly, E.J. & Foster, L.A.
Partner: UNT Libraries Government Documents Department

Evidence of surface migration and formation of catalytically inactive Pt in corrosion studies of Pt/sup +/ implanted Ti

Description: This investigation is part of an ongoing research project directed at applying the techniques of ion implantation doping and ion scattering analysis to identify the mechanisms associated with the anodic dissolution of Ti-Pt alloys. The Ti-Pt alloys produced by ion implantation were electrochemically examined in hydrogen saturated 1 N H/sub 2/SO/sub 4/ by both potentiostatic polarization and open-circuit potential methods. In this study, Ti samples implanted to relatively high doses (5.4 x 10/sup 15/ to 2.9 x 10/sup 16/ atoms/cm/sup 2/) were examined by ion scattering analysis at various stages in the electrochemical measurements. Quantitative measurements showed that the majority of the implanted Pt accumulated on the surface during anodic dissolution and underwent large scale surface migration. Evidence is also presented for the transition of the Pt on the surface from a catalytically active to inactive state. Possible mechanisms for the observed catalytically inactive Pt are discussed.
Date: August 1, 1980
Creator: Appleton, B.R.; Kelly, E.J.; White, C.W.; Thompson, N.G. & Lichter, B.D.
Partner: UNT Libraries Government Documents Department