Ultrarapid Phase Conversion in β"-Alumina Tubes

β"-Alumina, the electrolyte of choice of sodium/sulfur and sodium/metal chloride batteries and alkali-metal thermal-electric converters, was sintered from precursor phases to high β"-phase purity in less than 15 s from the onset of densification by rapid pass-through rf induction coupled plasma sintering. The maximum instantaneous shrinkage rate was 1.8%/s. The resistivity was measured to be 13.8 ± 1.4 Ω·cm. The rapid conversion found is a significant improvement over conventional processing of β"-alumina, which requires extended postsintering annealing times to obtain high β"-phase purity.     

Contribution of equal-sign instruction beyond word-problem tutoring for third-grade students with mathematics difficulty.

Elementary school students often misinterpret the equal sign (=) as an operational rather than a relational symbol. Such misunderstanding is problematic because solving equations with missing numbers may be important for the development of higher order mathematics skills, including solving word problems. Research indicates equal-sign instruction can alter how typically developing students use the equal sign, but no study has been conducted on the effects of such instruction for students with mathematics difficulty (MD) or how equal-sign instruction contributes to word-problem-solving skill for students with or without MD. In the present study, the authors assessed the efficacy of equal-sign instruction within word-problem tutoring. Third-grade students with MD (n = 80) were assigned to word-problem tutoring, word-problem tutoring plus equal-sign instruction (combined) tutoring, or no-tutoring control. Combined tutoring produced greater improvement on equal sign tasks and open equations than did the other 2 conditions. On certain forms of word problems, combined tutoring, but not word-problem tutoring alone, produced more improvement than did the control condition. When compared at posttest with 3rd-grade students without MD on equal-sign tasks and open equations, only combined tutoring students with MD performed comparably. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Switchgrass selection as a “model” bioenergy crop: A history of the process

A review of several publications of the Oak Ridge National Laboratory's Biofuels Feedstock Development Program and final reports from the herbaceous crop screening trials show that technology, environmental, and funding issues influenced the decision to focus on a single herbaceous “model” crop species. Screening trials funded by the U.S. Department of Energy in the late 1980s to early 1990s assessed thirty-four herbaceous species on a wide range of soil types at thirty-one different sites spread over seven states in crop producing regions of the U.S. Several species, including sorghums, reed canarygrass, wheatgrasses, and other crops, were identified as having merit for further development. Six of the seven institutions performing the screening included switchgrass among the species recommended for further development in their region and all recommended that perennial grasses be given high research priority. Reasons for the selection of switchgrass included demonstration of relatively high, reliable productivity across a wide geographical range, suitability for marginal quality land, low water and nutrient requirements, and other positive environmental attributes. Crop screening results, economic and environmental assessments by the Biofuels Feedstock Development Program staff, and Department of Energy funding limitations all contributed to the decision to further develop only switchgrass as a “model” or “prototype” species in 1991. The following ten year focus on development of switchgrass as a bioenergy crop proved the value of focusing on a single “model” herbaceous crop. The advancements and attention gained were sufficient to give government leaders, policymakers, farmers, and biofuel industry developers the confidence that lignocellulosic crops could support an economically viable and environmentally sustainable biofuel industry in the U.S.     

National structural change and metropolitan specialization in the United States

The national economy is split into four broad sectors. The observed variation in long-term growth among sectors leads to a shift in the composition of aggregate demand. I test Henderson's propositions, namely that secular shifts in the composition of national demand lead to changes in the numbers and sizes of different types of urban places. The numbers and sizes of places specialized in the information sector has increased while the numbers and sizes of places specialized in manufacturing has decreased or has not changed. Metropolitan population growth and per capita earnings growth are enhanced by specialization in the information sector. Received: 29 January 1998 / Accepted: 9 March 1999     

Epidemic Simulation for Training in Public Health Management

Epidemiological simulation models to be used primarily to augment the teaching of epidemiology to medical students and other individuals concerned with public health and control of epidemics are presented. Interactive simulations are used to expose students to ``realistic' epidemic situations and permit them to experiment with various control strategies. Criteria by which simulations for such teaching purposes may be evaluated are proposed and operating simulations, MEASLES and INFLU, are described in detail. Information is provided regarding user experience with the above simulations.     

Applications of in situ magnetic resonance techniques in chemical reaction engineering

NMR spectroscopy is now a well‐established technique for the in situ study of surface chemistry and the chemical processes occurring during catalytic reactions. Developments in probe design are making the sample environments ever closer to the operating conditions of the catalyst in industrial use. In parallel with these advances there is an increasing interest in the application of field gradient magnetic resonance techniques, namely pulsed gradient spin echo (PGSE) NMR and magnetic resonance imaging (MRI), to in situ studies of mass transport processes in catalysts and reactors. An overview of the recent developments in in situ NMR spectroscopy, PGSE NMR and MRI studies in application to catalysis and reaction engineering is presented and the potential of these techniques in the numerical modelling of catalytic processes and reactor design is highlighted. This revised version was published online in August 2006 with corrections to the Cover Date.     

Traits as goal-based categories: The importance of goals in the coherence of dispositional categories.

It is argued that goals are central to the meaning and structure of many traits and help define the prototypicality structure of those traits. Partly on the basis of L. W. Barsalou's (1985) work on goal-derived categories, it was predicted that goals help define the judged prototypicality of many trait-related behaviors and the confidence with which people make trait inferences from those behaviors. Consistent with this hypothesis, ratings of the extent to which behaviors achieved the goal associated with a trait strongly predicted the typicality of the behaviors. Furthermore, the rated goal-relatedness of a behavior also strongly predicted the confidence with which people would make a trait inference from that behavior. It is suggested that goals play a major role in the conceptual coherence of traits and other social categories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison between Y-doped ceria and Ho-doped ceria: Electrical conduction and microstructures

The electrical conduction and microstructure in Y-doped ceria and Ho-doped ceria were investigated. Visible differences between the two doped ceria were observed. The plots of conductivity of Y-doped ceria are well fit to the Arrhenius behavior, while curvature and kinks were observed on the plots of Ho-doped ceria. Such deviation from the Arrhenius behavior could be related to the existence of precipitates in Ho-doped ceria. It indicates that the electrolytic conductivity of doped ceria could be significantly influenced by microstructure features.