Coextraction of uranium and radium from ore with ferric chloride

Ferric chloride leaching, at temperatures around 74°C, is found to remove up to remove up to 97% of the uranium from ores occurring in the Elliot Lake area of Canada. Radium removal is poor due to the formation of sulphates from the sulphides present in the ore. However, if the sulphides are removed initially by flotation, then ferric chloride can extract as much as 92% of the radium, giving tailings which are sulphide-free and with radium levels approaching 24 pCi/g. The main steps in a ferric chloride leaching process have been tested at the bench scale. Radium may be removed by adsorption on manganese dioxide and uranium is removed by liquid extraction with D2EHPA (DAPEX process). The ferric chloride may be recirculated for further leaching and the net usage is expected to be in the order of 5 kg/Mg of solids treated. Because of the recycle, it is possible to keep chloride ion levels in the effluent below the prescribed level of 750 mg/L.     

Recent experimental results in near-field antenna measurements

Recent experimental results on determination of antenna pattern and power gain from near-field measurements are described. Two new antenna measurement theorems were applied. Measurements were made on an electrically large horn lens, a standard-gain horn and a nominal duplicate of the measuring antenna. Some comparisons with direct far-field measurement results were made.     

A project management game

This paper deals with the design of a project management game, intended to help project managers and team members acquire some of the necessary understanding for success in this field. The training needs of project managers are contrasted with the training potential of management games in general and some important factors in game desigt are discussed.The game simulates a project which is described in terms of a network. The player is presented with a sequence of ‘project meetings’ at which he must make certain decisions. The outcome of each decision will affect the total cost of the project. The game has been successfully run using a small project designed to test its capabilities. It is concluded that the game, in its working state and with a proved expansion potential, demonstrates that a satisfactory training aid for project managers can be produced.     

Neurobehavioral and life-quality changes after cerebral revascularization.

[Correction Notice: An erratum for this article was reported in Vol 56(4) of Journal of Consulting and Clinical Psychology (see record 2008-10691-001). The authors' names were incorrectly ordered. The correct order is as follows: Anne Dull Baird, Kenneth M. Adams, Mark W. Shatz, James I. Ausman, Fernando G. Diaz, and Manuel Dujovny.] Neuropsychological and life-quality changes were studied 6 months after carotid endarterectomy, superficial temporal artery to middle cerebral artery bypass, multiple revascularization, and vertebrobasilar revascularization procedures. These changes were compared with those in patients with recent severe spinal complaints and in patients for whom revascularization was considered but not elected. Subjects were enrolled prospectively. We did not see statistically significant differences in neurobehavioral gains in patients undergoing cerebral revascularization versus those considered but not selected for surgery and versus patients with spinal complaints. Small sample size, marked intragroup variability, and lack of randomized subject assignments may have obscured modest-to-moderate treatment effects in some individuals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Population Growth Rate Responses of Ceriodaphnia dubia to Ternary Mixtures of Specific Acting Chemicals: Pharmacological versus Ecotoxicological Modes of Action

When considering joint toxic apical effects at higher levels of biological organization, such as the growth of populations, the so-called pharmacological mode of action that relies on toxicological mechanistic effects on molecular target sites may not be relevant. Such effects on population growth rate will depend on the extent to which juvenile and adult survival rates and production rates (juvenile developmental rates and reproduction) are affected by toxic exposure and also by the sensitivity of population growth rates to life-history changes. In such cases, the ecotoxicological mode of action, defined as the crucial life-history trait processes and/or xenobiotic-life-history trait interactions underlying a toxicological effect on population growth rate, should be considered. Life-table response experiments with the crustacean Ceriodaphnia dubia exposed to single and ternary mixtures of nine compounds were conducted to test the hypothesis that joint effects on population growth rates could be predicted from the mixture constituent ecotoxicological mode of action. Joint effects of mixtures containing pharmacologically dissimilar compounds (cadmium, λ-cyhalothrin, and chlorpyrifos) that differentially affected life-history traits contributing to population growth rates were accurately predicted by the independent-action concept. Conversely, the concentration-addition concept accurately predicted joint effects of two different mixtures: one containing pharmacologically similar acting pyrethroids that also affected similarly life-history traits, the other one that included pharmacologically dissimilar compounds (3,4-dichloroaniline, sodium bromide, and fenoxycarb) acting mainly on reproduction rates. These results indicate that when assessing combined effects on population growth rate responses, selection of mixture toxicity conceptual models based on the ecotoxicological mode of action of mixture constituents provided more accurate predictions than those based on the pharmacological mode of action.