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.     

Perceptual awareness of energy requirements of familiar objects.

Conducted 3 experiments to assess undergraduates' perceptual awareness of energy requirements in their immediate surroundings (e.g., refrigerators, automobiles, toasters). In Exp I, 48 Ss sorted 61 energy items (labeled on cards) into categories based on general similarity and similarity in terms of energy consumed in an hour of continuous use. Cluster analysis revealed that items were grouped according to function and size but not by energy requirements. In Exp II, 24 Ss rank ordered 19 household appliances according to energy consumption and volume. The judged order of energy consumption matched the actual order (watts/hour) moderately well, but significant deviations from accuracy occurred for items whose perceived volume appeared to exert an influence on perceived energy consumption. Some large objects were seen to require high energy even though their actual consumption is relatively low. Similarly, small objects were thought to consume small amounts of energy even though the opposite is true. Parallel results were obtained in Exp III (20 Ss) with the method of numerical magnitude estimation. (4 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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)     

Size segregation of spherical nickel pellets in the surface flow of a packed bed: Experiments and Discrete Element Method simulations

The size segregation of binary mixtures of spherical nickel pellets flowing into a packed bed was investigated with Discrete Element Method (DEM) simulations and physical experiments in 30 cm and 60 cm wide rectangular test cells. Each test cell approximates a vertical slice of a cylindrical packed bed, with a rising feed tube on one side of the cell representing the stationary frame of reference in the packed bed. As the feed tube is raised, the pellets flow laterally into the test cell to form a sloping surface inclined to the horizontal by the angle of repose. The lateral flow of pellets is confined near the surface of the packed bed, and was intermittent in character (i.e. surging). Velocity vectors show the detailed flow field in the simulated test cells. The smaller pellets were found to be concentrated near the core of the granular assembly, and the larger pellets segregate to the outer wall farthest from the feed tube. The degree of segregation, or coefficient of variation (variance/mean), is proportional to the diameter ratio α of the pellets and the length of the surface, and inversely proportional to the mass fraction of the smaller pellets within the range of parameters studied. The DEM simulations had an average deviation in mass fraction of 0.07 and maximum deviation of 0.22 from the experimental data.     

Improving the exfoliation of layered silicate in a poly(ethylene terephthalate) matrix using supercritical carbon dioxide

A technique for improving the exfoliation of organically modified layered silicate (OMLS) in a poly(ethylene terephthalate) (PET) matrix using super critical carbon dioxide (scCO₂) is compared to traditional direct melt blending. The process relies on the rapid expansion of a scCO₂/OMLS mixture directly into the second stage of a single screw extruder where the clay and scCO₂ mixture is subsequently melt blended with the PET matrix. The simple, environmentally benign process results in a more highly delaminated system than traditional direct melt compounding. X‐ray diffraction analysis is used to reveal improved clay morphologies and the resulting mechanical properties are examined. Rheology is used as a tool to draw conclusions about the effect that scCO₂ has on reducing PET matrix degradation during processing. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers