Radiological control procedures applicable to radioisotope thermoelectric generator SNAP-27. Volume 1 - Normal operations

Radiological control procedures applicable to transport, handling, and storage of the thermoelectric generator SNAP 27 prior to launch during normal condition

Radiological control procedures applicable to radioisotope thermoelectric generator SNAP-27. Volume 2 - Radiological emergencies

Radiological control procedures for transportation, handling, and storage of SNAP 27 thermoelectric generator in radiological emergencie

Convergence of statistical moments of particle density time series in scrape-off layer plasmas

Particle density fluctuations in the scrape-off layer of magnetically confined plasmas, as measured by gas-puff imaging or Langmuir probes, are modeled as the realization of a stochastic process in which a superposition of pulses with a fixed shape, an exponential distribution of waiting times and amplitudes represents the radial motion of blob-like structures. With an analytic formulation of the process at hand, we derive expressions for the mean-squared error on estimators of sample mean and sample variance as a function of sample length, sampling frequency, and the parameters of the stochastic process. % Employing that the probability distribution function of a particularly relevant shot noise process is given by the gamma distribution, we derive estimators for sample skewness and kurtosis, and expressions for the mean-squared error on these estimators. Numerically generated synthetic time series are used to verify the proposed estimators, the sample length dependency of their mean-squared errors, and their performance. We find that estimators for sample skewness and kurtosis based on the gamma distribution are more precise and more accurate than common estimators based on the method of moments.Comment: 31 pages, 10 figure

The Performance of Chicago Board of Trade Corn, Soybean, and Wheat Futures Contracts after Recent Changes in Speculative Limits

Three attributes of futures contract behavior important for market performanceliquidity, volatility, and convergenceare investigated before and after the 2005 increase in speculative position limits for corn, soybean, and wheat contracts at the Chicago Board of Trade. The analysis of liquidity and market depth reveals a sharp increase in open interest for corn, soybeans and wheat beginning in late 2005. The increase in position limits likely accommodated the increase in speculative interest in corn, soybean and wheat futures, but some of the increase would have occurred without the increase as new market participants received hedge exemptions. The analysis of price volatility revealed no large change in measures of volatility after the change in speculative limits. For corn and soybeans, the picture that unfolds relative to convergence patterns is one of weakness, but not failure. For wheat, the picture that unfolds relative to convergence patterns is not only one of weakness, but failure to accomplish one of the fundamental tasks of a futures market. The persistence and growing magnitude of the delivery location basis in wheat suggests a problem with the contract specifications.corn, futures contract, performance, soybeans, speculation, wheat, Marketing,

EFFICIENCY MEASURES USING THE RAY-HOMOTHETIC FUNCTION: A MULTIPERIOD ANALYSIS

Recent investigations have provided mixed assessments of farm firm efficiency. This analysis examined the efficiency of a homogeneous sample of central Illinois grain farms over a six-year period. A best-practice frontier was constructed using the ray-homothetic function, which allowed optimal farm output to vary with factor intensity. Efficiency measures were found to increase with temporal aggregation. The ray-homothetic approach was found to attribute high scale inefficiencies to larger sample farms in cases where the factor shares did not vary appreciably across farms. The findings suggest that policy recommendations regarding farm efficiency must be made with care.Agribusiness,

Cno Abundances Of Hydrogen-Deficient Carbon And R Coronae Borealis Stars: A View Of The Nucleosynthesis In A White Dwarf Merger

We present high-resolution (R similar to 50,000) observations of near-IR transitions of CO and CN of the five known hydrogen-deficient carbon (HdC) stars and four R Coronae Borealis (RCB) stars. We perform an abundance analysis of these stars by using spectrum synthesis and state-of-the-art MARCS model atmospheres for cool hydrogen-deficient stars. Our analysis confirms reports by Clayton and colleagues that those HdC stars exhibiting CO lines in their spectrum and the cool RCB star SAps are strongly enriched in (18)O(with (16)O/(18)Oratios ranging from 0.3 to 16). Nitrogen and carbon are in the form of (14)N and (12)C, respectively. Elemental abundances for CNO are obtained from C I, Ci2, CN, and CO lines. Difficulties in deriving the carbon abundance are discussed. Abundances of Na from Na I lines and S from S I lines are obtained. Elemental and isotopic CNO abundances suggest that HdC and RCB stars may be related objects, and that they probably formed from a merger of an He white dwarf with a C-O white dwarf.Robert A. Welch Foundation of Houston, TexasSwedish Research CouncilGS-2006A-C-13GS-2007A-DD-1McDonald Observator