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Abstract  

Differential thermal analysis, optical microscopy and ionic conductivity studies have been carried out on polymer electrolyte films prepared by deposition of solutions of neodymium trifluoromethanesulphonate and poly(ethylene oxide). A wide range of electrolyte concentrations were examined and a partial pseudo-equilibrium phase diagram of the system was determined. From the results obtained it is evident that the presence of relatively high concentrations of ionic guest species in the polymer host results in an inhibition of the growth of crystalline material (polymer spherulites or a polymer—salt coordination complex).

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Abstract  

Degradation rates of 14C ring labeled carbofuran and diazinon in selected Sri Lankan soils were studied using 0.1 μCi/10 g soil in Nuwara Eliya (red yellow podzolic), Pugoda (alluvials) Kalpitiya and Negombo (regosols) soils by incubating at 28 °C of temperature for 13 hours light and 11 hours dark conditions and measuring the activity of liberated CO2 using liquid scintillation counter after 0, 1, 3, 5, 7, 14, 28, 36, 42 and 58 days. During the total period the carbofuran mineralization was about 23% in Kalpitiya soils and less than 20% in other three soils and diazinon mineralization was about 25% in Negombo soil and very low in other soils.

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Abstract  

Titrations of Pu(IV) with HNO3 in a series of aqueous HClO4 solutions ranging in ionic strength from 2 to 19 molal were followed using visible and near-infrared absorption spectrophotometry. The Pu 5f-5f spectra in the visible and near IR range change with complex formation. At each ionic strength, a series of spectra were obtained by varying nitrate concentration. Each series was deconvoluted into spectra of Pu4+ (aq), Pu(NO3)3− and Pu(NO3)2 2+ complexes, and simultaneously their formation constants were determined. When corrected for the incomplete dissociation of nitric acid, the ionic strength dependence of each formation constant can be described by two parameters, β0 and Δε using the formulae of specific ion interaction theory.

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Cereal breeding programs are interested in increasing the number of generations per year to reduce the time needed to develop new cultivars. A common method to accomplish this is to extend the photoperiod to speed up plant growth. For oat, this method is problematic because the species responds to changes in light and temperature. Current methods of fast generation cycling in oat require embryo rescue, which is labor intensive and has a low success rate. Recently a method was developed using increased photoperiod and foliar mineral supplement to reduce generation time for wheat and barley. We evaluated this newly published method in oat and found that anthesis occurred 15 ± 3 days faster, however there was a 3-fold reduction in seed count and a 2-fold reduction in inflorescence weight. In addition, we measured endogenous ascorbate to evaluate the physiological status of the plants under fast generation cycling conditions. For oat, fast generation cycling would be effective to more rapidly advance populations using single seed descent, but not as useful when seed yield is important.

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Abstract  

Analytical procedures for measuring various radionuclides in the238U and232Th chains in briney waters are described. Using methods such as mass spectrometry, and alpha, beta and gamma spectrometry, the desired measurement sensitivity required for each of the radionuclides is achieved.233U,228Th,208Po,212Pb, and133Ba are used as tracers for chemical yield recoveries. Typical precision of the results range from 5–20%.

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Abstract

This is the first empirical investigation of blood donations in evolutionary perspective. We examine blood donor and non-donor attitudes about health and injury risks, donor characteristics, and the social value of donor participation. We propose that blood donations may communicate qualities about donors to third parties. Observers may benefit from information about the donor's health, value as a reciprocal partner, and/or ability to endure what is perceived as an anxiety-provoking and risky experience. Donors may benefit from an enhanced reputation, which can lead to greater access to cooperative networks and high-quality partners. We found that participants recognized the need for blood and perceived blood donors as generous and healthy. Study results indicated that anxiety and the perceived risk of a negative health consequence dramatically affected the willingness of donors and non-donors to donate blood in the future. These findings support our hypothesis that the act of blood donation may signal adaptive information about donor quality to third parties.

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Abstract  

Interest in the element selenium with respect to its biological significance has been steadily increasing for the last ten years. Neutron activation analysis has long been used for the accurate determination of selenium in biological samples usually via75Se. More recently activation analysts having access to high flux reactors with rapid delivery pneumatic tube facilities; have successfully employed77mSe. This approach, which is much faster, is particularly well suited to the Missouri University Research Reactor (MURR). The specific interest concerning bulls has to do with the involvement of selenium in the reproductive system. Selenium analysis methodology and data on plasma, semen and 22 tissues from both beef and dairy bulls are presented.

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Abstract  

Radionuclides have been identified as a significant source of contamination at many United States Department of Energy (DOE) sites. As a result, reliable and accurate methods to determine actinide content in environmental samples have become increasingly important. Therefore, an improved analytical scheme using a series of actinide-selective extraction chromatography (Tru-Spec , Teva-Spec ) and ion-exchange (Diphonix ) resins was designed to satisfy the requirements of both alpha spectrometry and inductively coupled plasma mass spectrometry (ICP-MS). Alpha spectrometry required the sequential isolation of the actinides, whereas ICP-MS required only a group separation of the actinides. The separation schemes were designed to allow analysis of the actinides in soil, whether the soils were acid leached or totally dissolved through fusion. For those analytes present as contaminants (239/240Pu,241Am), the laboratory results agreed favorably with the accepted values for several reference soils. However, for the acid digestion procedure, the results for matrix constitutents (238U,234U,232Th) were quite low because the silicate matrix was not decomposed. The sodium hydroxide fusion technique described allowed accurate analysis of both matrix constituents and contaminants because a total dissolution was achieved.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
Rosara Payne
,
J. Drader
,
J. Friese
,
L. Greenwood
,
C. Hines
,
L. Metz
,
J. Kephart
,
M. King
,
B. Pierson
,
J. Smith
, and
D. Wall

Abstract  

Washington State University’s 1 MW TRIGA reactor has a long history of utilization for neutron activation analysis (NAA). TRIGA reactors have the ability to pulse, reach supercritical (k > 1) for short bursts of time (~50 ms). At this high power and fast time the energy spectrum and neutron fluence are largely uncharacterized. The pulse neutron energy spectrum and fluence were determined by the activation of Cu, Au, Co, Fe, and Ti. These analyses were completed with and without Cd shielding to determine reproducibility between pulses. The applications and implications of the neutron energy and fluence reproducibility to the use of pulsed NAA will be discussed.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
A. Aarkrog
,
S. Boelskifte
,
H. Dahlgaard
,
S. Duniec
,
E. Holm
, and
J. Smith

Abstract  

Since the accidental loss of four nuclear weapons by a B-52 at Thule Airbase, Greenland in 1968, the marine environment at Thule has showed enhanced levels of Pu and Am. Most of the activity is confined to the benthic environment within a distance of 50 km from the crash site of the B-52. Samplings of sediments, benthos, seaplants, fish, and water have been carried out in 1968, 1970, 1974, 1979, and in 1984. The study presented herein intends to answer the following questions: What is the mean residence time of these transuranics in the benthic communities? Do Pu and Am behave differently in the environment?

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