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We have incorporated an audience response system into our curriculum to increase student interaction in the teaching process. Classroom Performance System (CPS) is a computer-based audience response system that allows students to answer questions posed to the entire class by entering responses on a keypad. The responses are tallied and displayed on the classroom screen for all students to see. The purpose of our study was to determine student accuracy using the system with three different methods of administering questions. A secondary purpose was to assess students' perceptions about using the system. Our hypothesis for the study was that there should be no difference in volunteer accuracy or questionnaire responses to the three methods of gathering responses. Sixty-two dental students volunteered to participate. Using three methods (projected on a screen, verbal, and written), volunteers were given "responses" to enter into the system using CPS wireless remote answering devices. In the projected and verbal formats, the teacher managed the assessment by controlling the pace of input. In the written format, students were given responses on paper to input into the system at their own pace. At the end of the sessions, volunteers completed an anonymous questionnaire regarding their experiences with the system. The accuracy of responses was similar in the teacher-managed assessments (projected and verbal format). There was a statistical difference in the accuracy of responses in the student-managed assessment (p=<0.000001). Questionnaire responses also showed that students preferred teacher-managed assessments. The hypothesis was disproved. The overall response to this audience response system and its methods of gathering information was very positive.

Samples of clean soil from the source used to backfill pits at the Idaho National Engineering and Environmental Laboratory's Radioactive Waste Management Complex were spiked with 239 Pu and 241 Am to evaluate ligand-assisted supercritical fluid extraction as a decontamination method. The actual soil in the pits has been subject to approximately three decades of weathering since it was originally contaminated. No surrogate soil can perfectly simulate the real event, but actual contaminated soil was not available for research purposes. However, fractionation of Am and Pu in the surrogate soil was found to be similar to that previously measured in the real soil using a sequential aqueous extraction procedure. This suggests that Pu and Am behavior are similar in the two soils. The surrogate was subjected to supercritical carbon dioxide extraction, in the presence of the fluorinated beta diketone thenoyltrifluoroacetone (TTA), and tributylphosphate (TBP). As much as 69% of the Pu and 88% of the Am were removed from the soil using 3.2 mol % TTA and 2.7 mol % TBP, in a single 45 minute extraction. Extraction conditions employing a 5 mol % ethanol modifier with 0.33 mol % TTA and 0.27 mol % TBP resulted in 66% Pu and 68% Am extracted. To our knowledge, this is the first report of the use of supercritical fluid extraction (SFE) for the removal of actinides from soil.

The hydroentangling technique uses cone-capillary orifice nozzles to direct high-energy water jets against loose fiber webs. This study simulates the effects of orifice configuration on the water-jet properties. An axisymmetric steady-state model is considered for this two-phase system. The turbulent water jet is simulated using a realizable k -ϵ model, and the behaviors of cone-up and cone-down geometries are investigated. The simulation reveals that the water jet produced by a cone-up orifice keeps contact with the walls all the way through the orifice and may undergo cavitation to reduce the water-jet intact length and damage to the orifice surface. In contrast, the cone-down geometry can form a constricted water jet that is enveloped by an air gap, which separates the water from the orifice surface and therefore prevents cavitation. The results are in excellent agreement with previous experimental studies.Hydroentanglement _as a process for entangling and bonding a web of loose fibers to form a uniform sheet or fabric. The underlying mechanism in hydroentanglement is exposure of fibers to a non-uniform spatial pressure field created by a successive bank of high velocity water jets. The impact of these water jets with the fibers, while they are in contact with their neighbors, displaces and rotates them with respect to their neighbors. During these relative displacements, some of the fibers twist around others and/or interlock with them due to frictional forces.The final outcome is a highly compressed and uniform fabric sheet of entangled fibers. Since its infancy, hydroentangling has shown promise for the textile industry. For a review of hydroentangling history, applications, and operating costs, see references 2, 12, 22, 23, 24, 25.The uniformity of the product and the repeatability of the hydroentangling process require a continuous and locally uniform jet-fabric impact. Water jets are known to break up somewhere downstream of the nozzle due to the interfacial forces between them and the surrounding air. A number of parameters, including nozzle internal flow patterns resulting from cavitation and/or wall friction, influence the behavior of the water jets [ I I ]. Cavitation refers to the condition where bubbles (made of vapor or dissolved gases) form in liquid because of the local pressure drop inside the orifice. Schmidt et al. visualized the cavitation in injection nozzles [ 16], and