Ernest S. Gladney

The use of multivariate analysis to identify sources of selected elements in the Boston urban aerosol

Abstract The concentrations of eighteen elements were determined by instrumental neutron activation analysis for samples of air particulates collected over a five month period in the Boston metropolitan area. This set of data is analyzed for underlying structure by the methods of common factor analysis and hierarchial aggregative cluster analysis. The data can be interpreted on the basis of six common factors accounting for 77.5% of the total variance in the system. These factors are attributed to various sources of particulate material by noting the dependence of the factors on the elements. The cluster analysis assists in the interpretation of the factors.

Elemental concentrations in nbs biological and environmental standard reference materials

Abstract Elemental concentrations reported by 325 investigators in 16 NBS SRMs are summarized. Mean values, standard deviations and comparative data from NBS and other reviews are provided.

Composition and size distribution of in-stack particulate material at a coal-fired power plant

Abstract The particulate material in the stack effluent of a coal-fired power plant was collected and fractionated with an in-stack cascade impactor. Samples of the pulverized coal and process ashes were taken on the same days. These materials were analyzed for 34 elements by instrumental neutron and photon activation analysis. Elements on the in-stack particulates can be separated into three groups by computing enrichment factors relative to the coal for each particle size fraction. These groups are compared to proposed mechanisms for trace element fractionation during combustion.

A revision of the meteorite based cosmic abundance of boron

Abstract Analyses of meteorites for B abundances have shown that many chondrites are contaminated with terrestrial B, producing erroneously high meteoritic abundances of this element. Boron concentrations in freshly prepared interior samples are significantly lower than they are in samples with unknown or unspecified terrestrial histories. An estimate of the cosmic abundance based upon the analyses of 8 interior samples of 2 carbonaceous chondrites and 1 interior sample of each of 8 ordinary chondrites is a factor of 6.7 less than the previous low estimate. Our revised value, 3.0 B/1010H, is in excellent agreement with estimates based on observations of the solar photosphere. There is no longer a need to consider processes that enrich B in carbonaceous chondrites or deplete it in the sun. Relative meteoritic abundances of Li, Be and B are now in general agreement with models of nucleosynthesis of these light elements by galactic cosmic ray induced spallation.

Determination of boron in geological materials by inductively-coupled plasma emission spectrometry

Abstract Determination of boron in international silicate reference materials with an argon plasma is demonstrated. Detection limits are about 5 ppm for rock samples.

Multielement analysis of major and minor elements by thermal neutron induced capture gamma-ray spectrometry

The utility of prompt gamma-rays from thermal neutron capture for the measurement of nine elements (Si, Al, Fe, Na, K, Ca, Ti, Mg and P) in major and minor abundance has been investigated. National Bureau of Standards (NBS) and United States Geological Survey (USGS) standards were used to demonstrate generally good agreement between experimental measurements and certified values. Usually accuracies and precisions of ±10% were observed.

Determination of arsenic and gallium in standard materials by instrumental epithermal neutron activation analysis

Abstract Epithennal neutron activation analysis has been applied to the determination of arsenic and gallium in standard materials at trace concentrations. The reduction of 24Na activity compared to thermal neutron activation is advantageous. Arsenic detection limits (1σ) are 0.04 and 0.015 μg for inorganic and organic materials, respectively. The corresponding gallium detection limits, for the best cases, are 0.13 and 0.29 μg. Gallium determinations with the 834-keV photopeak of 72Ga suffered interferences attributed to the threshold reaction 54Fe(n,p) 54Mn; the less intense 72Ga peaks at 629 and 2200 keV provided quantitative results for all samples tested. Gallium detection limits with the less intense, but more reliable 629-keV peak were 0.9 and 0.1 μg for inorganic and organic materials, respectively. Arsenic determinations are best performed with the more intense 76As 559-keV line, as the 657-keV line has an unknown interference.

Determination of arsenic, antimony, tungsten and molybdenum in silicate materials by epithermal neutron activation and inorganic ion exchange

Abstract Ion exchange on alumina columns was used to determine As, Sb, W and Mo in silicate rock samples. This procedure requires hour-long epithermal neutron irradiations, rapid ion exchange after the rocks have been brought into solution with sodium hydroxide, sodium peroxide fusion and short gamma-ray counts on an intrinsic Ge detector. With this technique the detection limits achieved were 5 ng g −1 for As, 10 ng g −1 for Sb and W and 50 ng g −1 for Mo.

Simultaneous determination of uranium and thorium in ores by instrumental epithermal neutron activation analysis

Abstract Rapid scanning of numerous rock samples when prospecting for uranium and thorium ores can be facilitated by using the shorter-lived nuclides. The samples are activated during short epithermal neutron irradiations and the 20-min activities of 239U and 233Th are observed instrumentally with a small Ge(Li) detector. The detection limits for uranium and thorium are less than 1 ppm and 20 ppm, respectively.

A Comparison Study for Determining Dissolved Boron in Natural Water and Geothermal Fluid

Abstract A comparison study was undertaken to evaluate different analytical methods for measuring boron concentrations in the geothermal fluid from the Los Alamos Hot Dry Rock Geothermal Energy Project and from natural waters collected in the vicinity of the project. Three colorimetric techniques, the carmine method and two azomethine H methods, were compared with two plasma emission spectroscopy methods and with thermal neutron capture-gamma spectroscopy. In general, the analytical results from all the methods were comparable and acceptable; however, each method had its own distinct advantages and disadvantages.