Children’s Behavior During Group Storytime in Head Start Pre-Kindergarten

The study examined children's participation, attention, and body movement during group storytime in Head Start pre-kindergarten classrooms. Observers recorded frequencies of participation, looking away, and body movement. Teachers completed questionnaires that included measures of temperament, teacher-child relationship, and literacy skills. A total of sixteen children from four classrooms were observed in storytime at least two different times throughout the semester. Results described children who participate most often in storytime as being extroverted and able to control their attention during activities. Previous studies have shown that children's participation in storytime could positively influence their acquisition of vocabulary and other literacy skills (Sénéchal, Thomas, & Monker, 1995). Teachers in this sample rated nearly all children very highly on the literacy skills measure; no significant correlations were found between the observed variables and scores on the literacy skills measure

Critical Review of Mercury Chemistry in Flue Gas.

Mercury (Hg) and its compounds have long been recognized as potentially hazardous to human health and the environment. Many man-made sources of mercury have been reduced in recent years through process changes and control measures. However, emissions of mercury from coal-fired power plants, while exceedingly dilute by the usual pollution standards, still constitute a major source when considered in the aggregate. Concerns over those emissions and the prospect of impending emissions regulations have led to a wide range of research projects dealing with the measurement and control of mercury in flue gas. This work has made considerable progress in improving the understanding of mercury emissions and their behavior, but inconsistencies and unexpected results have also shown that a better understanding of mercury chemistry is needed. To develop a more complete understanding of where additional research on mercury chemistry is needed, the U.S. Department of Energy (DOE) asked Argonne National Laboratory (Argonne) to conduct a critical review of the available information as reported in the technical literature. The objectives were to summarize the current state of the art of chemistry knowledge, identify significant knowledge gaps, and recommend future research to resolve those gaps. An initial evaluation of potential review topics indicated that the scope of the review would need to be limited and focused on the most important topics relative to mercury control. To aid in this process, Argonne developed a brief survey that was circulated to researchers in the field who could help identify and prioritize the many aspects of the problem. The results of the survey were then used to design and guide a highly focused literature search that identified key papers for analysis. Each paper was reviewed, summarized, and evaluated for the relevance and quality of the information presented. The results of that work provided the basis for conclusions regarding the state of knowledge of mercury chemistry and recommendations for further research. This report begins by summarizing the survey process and describing how the results were used to shape the critical review. Analyses of information obtained from the various publications are presented chronologically, beginning with the earliest relevant publication found and concluding with the end of the review in early 2003. Finally, the conclusions and recommendations for future research are presented. The survey instrument is included in Appendix A, while detailed information on each of the publications reviewed is given in Appendix B

Investigation of modified speciation for enhanced control of mercury

Mercury was identified as a hazardous air pollutant in Title 3 of the 1990 Clean Air Act Amendments. It has been singled out for particular scrutiny because of its behavior in the environment (bioaccumulation) and its potential for deleterious effects on humans and wildlife. After studying the sources of mercury in the environment, the US Environmental Protection Agency has concluded that coal-fired boilers generate a significant fraction of the total anthropogenic emissions. Therefore, the agency is currently considering whether to impose mercury control requirements on coal-fired boilers in the electric utility industry. However, the costs for potential control measures (such as sorbent injection) can be extremely high. Mercury removal with chloric acid solutions was tested. The presence of NO increased Hg removal. It appeared that both gas-gas and gas-liquids reactions were operating, with the gas-phase reactions involving NO becoming increasingly important as the solute concentration was raised. From these studies, it was concluded that even higher Hg{sup 0} removals could be obtained if more of the reagent was made available for reaction in the gas phase. For this reason (and also to simulate a more real-world duct-injection process) a new series of tests was initiated in which an ultrasonic atomizer was used to inject small droplets of the oxidizing solutions into a flowing gas stream containing Hg{sup 0} vapors and other typical flue-gas components. The results of those tests are described in this paper

Enhancement of mercury control in flue-gas cleanup systems

This paper summarizes research at Argonne National Laboratory which is focused on techniques to enhance the capture of elemental mercury and integrate its control into existing flue-gas cleanup (FGC) systems. Both laboratory and field tests have shown that very little elemental mercury is captured in a wet scrubber system due to the low solubility of that species. To enhance the ability of wet scrubbers to capture mercury, Argonne has studied improved mass transfer through both mechanical and chemical means, as well as the conversion of elemental mercury into a more soluble species that can be easily absorbed. Current research is investigating the roles of several halogen species either alone or in combination with typical flue-gas components such as sulfur dioxide and nitric oxide in the oxidation of mercury to form compounds that are easily scrubbed from the flue gas