scholarly journals Direct determination of atom and radical concentrations in thermal reactions of hydrocarbons and other gases. Progress report, January 1, 1978--December 31, 1978

1979 ◽  
Author(s):  
G. Skinner ◽  
C. Chiang ◽  
D. Wood
Keyword(s):  
Direct Determination ◽  
Progress Report ◽  
Thermal Reactions

Rock Analysis by X-Ray Fluorescence Spectroscopy

1957 ◽  
Vol 1 ◽  
pp. 315-327 ◽  
Author(s):  
Arthur A. Chodos
Keyword(s):  
Internal Standard ◽  
Direct Determination ◽  
Major Elements ◽  
Tungstic Acid ◽  
Progress Report ◽  
Internal Standard Method ◽  
X Ray ◽  
Rock Types ◽  
Rock Analysis

AbstractOur laboratory has been interested in the use of the X-ray spectragraph for routine rock analysis within limited rock types. This paper is meant as a progress report and to indicate the direction of our work on amphibolites to others interested ill the problem of rock analysis.Even with the use of flow counters and pulse discriminators the intensities of the magnesium, aluminum and silicon peaks are quite low and most dilution techniques may not be used. The direct determination of major elements (except sodium) yields results directly comparable to the chemical results for potassium; manganese and titanium in the range from 0: 1 to 3% as the oxides. For iron (10-20%), calcium (8-12%) and silicon (45-52%) the accuracy is 2-3% but for each element occasional samples will be 5% from the chemical values. Aluminum and magnesium yield erratic results.The use of ratios between elements occurring in. the samples yields slightly improved accuracies. The use of a strong absorber such as tungstic acid (40% by weight) greatly improves the ratios for aluminum and magnesium., without appreciably affecting their intensities. By a combination of the direct and tungstic acid techniques it is possible to attain accuracies of 2-3% with analysis time of two hours. At present we are attempting a combination with an internal standard method to yield greater accuracy.

The Direct Determination of I131 in Heterogeneous Fecal Specimens

1961 ◽  
Vol 41 (4) ◽  
pp. 380-384 ◽  
Author(s):  
Arthur F. Dratz ◽  
James C. Coberly
Keyword(s):  
Direct Determination

A New Method for Direct Determination of the Recoilless Fraction with Application to Magnetic Nanoparticles

2002 ◽  
Vol 721 ◽  
Author(s):  
Monica Sorescu
Keyword(s):  
Room Temperature ◽  
Average Particle Size ◽  
Direct Determination ◽  
Average Particle ◽  
Lattice Method ◽  
Recoilless Fraction ◽  
Single Room ◽  
Magnetite Particles ◽  
Physical Mixtures

AbstractWe propose a two-lattice method for direct determination of the recoilless fraction using a single room-temperature transmission Mössbauer measurement. The method is first demonstrated for the case of iron and metallic glass two-foil system and is next generalized for the case of physical mixtures of two powders. We further apply this method to determine the recoilless fraction of hematite and magnetite particles. Finally, we provide direct measurement of the recoilless fraction in nanohematite and nanomagnetite with an average particle size of 19 nm.

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