Rapid measurement of 241Pu activity at environmental levels using low-level liquid scintillation analysis

A straightforward and rapid method has been developed for the determination of ²⁴¹Pu activities. Pu is chemically separated from the sample, purified and electrodeposited to produce a source for alpha spectrometric determination of ²³⁸Pu and ^239,240Pu. Pu is stripped from the disc with concentrated nitric acid and extracted into tri-octylphosphine oxide (TOPO)/toluene. The organic extract is then mixed directly with commercial liquid scintillation cocktail without any further purification procedures and the sample counted on a Wallac 1220 Quantulus liquid scintillation counter (LSC). ²⁴¹Pu activity is estimated via the ²⁴²Pu yield monitor acquired by alpha spectrometry measurement. Experimental results for the performance testing of a low-level liquid scintillation spectrometer and the data for the evaluation of the method using standard reference materials are presented.     

Stability constants of U(VI) and U(IV)-humic acid complexes

Summary Conditional stability constants have been determined for U(IV) and U(VI) Boom Clay humic acid (BCHA) and Aldrich humic acid (AHA) complexes, under anaerobic and carbonate free conditions. The constants are needed for nuclear waste repository performance assessment purposes. The U(IV) constants were obtained by developing an approach based on the solubility product of amorphous U(OH)₄. The U(VI) constants were obtained by applying the Schubert ion-exchange approach.     

An electronic filter for radioactivity detectors in chromatography systems

A simple low-pass filter system is described for use with chromatographic detectors based on the counting of radioactivity. Typical results are presented which demonstrate that the filter can be used to remove the statistical fluctuations in recorded count rates without the excessive peak broadening which results from using large time constants on conventional ratemeters.     

CirculantGH(p 2; Z p ) exist for all primesp

The only known circulant ordinary Hadamard matrix is developed from the initial row-1, 1, 1, 1. Letp be a prime, and letZ _p denote the cyclic group of orderp. In this paper, we construct circulantGH(p ²;Z _p ) for all primesp. Whenp is odd, this result also extends the earlier result that there exist circulantGH(p;Z _p ) for all odd primesp. Other families ofGH-matrices which are developed modulo a group are discussed.     

The determination of potassium and sodium in coal ash

Methods are described for the rapid determination of sodium and potassium in coal ash. The ash is decomposed by a Lawrence Smith ignition: sodium is determined as sodium zinc uranyl acetate (gravimetncally or titrimctrically) on an aliquot of the aqueous extract, and potassium is determined gravunctrically as potassium tetraphenylboron on a second aliquot.Other methods for completing the determination were examined but were less satisfactory. The flame photometer method although less reproducible than other methods is extremely rapid and is probably accurate enough for routine purposes.     

Submicro methods for the analysis of organic compounds: The determination of sulphide and disulphide groups

Summary Bromination methods are described for determination of sulphide and disulphide groups in organic samples weighing onlyca. 50g. Direct titration with visual end-point indication is suitable in some cases, but a back-titration method is of more general application. The accuracy obtained is of the same order as on much larger scales of working.

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Zusammenfassung Bromierungsverfahren zur Bestimmung von Sulfid- und Disulfidgruppen in Einwaagen von nur etwa 50g organischer Substanz wurden beschrieben. In manchen Fällen eignet sich die direkte Titration mit visueller Endpunktbestimmung, aber die Rücktitration ist allgemeiner anwendbar. Die Genauigkeit ist von der gleichen Größenordnung wie bei wesentlich größeren Einwaagen.

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Résumé On décrit les méthodes de bromation pour le dosage des groupements sulfures et disulfures dans les échantillons organiques, sur environ 50g de prise d'essai. Le titrage avec indication visuelle du point équivalent convient dans certains cas, mais une méthode avec titrage en retour se montre d'une application plus générale. La précision que l'on obtient est du même ordre de grandeur que pour le travail à échelle beaucoup plus grande.

     

The determination of Nickel in Iron and Steel by Atomic absorption spectrophotometry

A procedure is described for the determination of 0.005 to 2% of nickel in low and high alloy irons and steels by atomic absorption spectrophotometry. The sample is dissolved in phosphoric-sulphuric acid and atomised in an atomic absorption spectrophotometer. The method is rapid and free from interferences; preliminary separations are not required and results obtained on standard samples are in good agreement with certificate values.     

The determination of manganese in iron and steel by atomic absorption spectrophotometry

A procedure is described for the determination of 0.001–2% of manganese in low and high alloy irons and steels by atomic absorption spertrophotometry. The sample is dissolved in phosphoric-sulphuric acid and atomised in an atomic absorption spectrophotometer. The method is rapid, free from interferences, preliminary separations are not required and results obtained on standard samples agree closely with stated certificate values.