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11.
Taking tests enhances learning. But what happens when one cannot answer a test question—does an unsuccessful retrieval attempt impede future learning or enhance it? The authors examined this question using materials that ensured that retrieval attempts would be unsuccessful. In Experiments 1 and 2, participants were asked fictional general-knowledge questions (e.g., “What peace treaty ended the Calumet War?”). In Experiments 3–6, participants were shown a cue word (e.g., whale) and were asked to guess a weak associate (e.g., mammal); the rare trials on which participants guessed the correct response were excluded from the analyses. In the test condition, participants attempted to answer the question before being shown the answer; in the read-only condition, the question and answer were presented together. Unsuccessful retrieval attempts enhanced learning with both types of materials. These results demonstrate that retrieval attempts enhance future learning; they also suggest that taking challenging tests—instead of avoiding errors—may be one key to effective learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
12.
Yuanji Dong Michael D. Hays N. Dean Smith John S. Kinsey 《Journal of aerosol science》2004,35(12):1497-1512
In this paper, the inversion processing of cascade impactor data to construe continuous size distributions within fine particulate matter (PM2.5) is examined for residential oil furnace and fireplace appliance emissions. Impactor data from tests with these emissions sources are selected for the challenges they pose to comprehending the size distributions of aerosol mass and chemical species. In specific, the oil furnace aerosol offers an opportunity to apply data inversion to study a bimodal lognormal distribution in which much of the aerosol mass is impactor-penetrating nanoparticles . The fireplace emissions on the other hand cover the issue of a chemical size distribution, which is subject to particle loss and characterized by a single lognormal, accumulation mode peak. Computational steps relevant to the application of the data inversion are illustrated in detail. Evaluation of correlation coefficients (0.992) indicates that the inversion model predictions fit the impactor data well. Simulations of systematic measurement error (±10%) at each impactor stage are shown to have a negligible impact on the inversion results for test data. It is concluded that data inversion can be effective when (i) source emissions contain a portion of particles that falls outside the measurement range of cascade impactors, (ii) a mass size distribution of an individual species is determined without the knowledge of the total mass concentration for that species, or when (iii) losses in the particle charger system are significant. 相似文献
13.
R. Cocco Y. Arrington R. Hays J. Findlay S.B.R. Karri T.M. Knowlton 《Powder Technology》2010,200(3):224-191
Jet cup attrition testing is a common method for evaluating particle attrition in fixed fluidized beds and circulating fluidized beds. An attrition index, calculated from jet cup data, is used to compare with one or more reference materials. However, this method is far from perfect despite its popularity. Results obtained at Particulate Solid Research, Inc. (PSRI) in different-sized jet cups and a 29-cm (11.5-in.) diameter fluidized bed test unit did not provide the same ranking of catalyst with respect to particle attrition. To obtain a better understanding of attrition in a jet cup, both computational fluid dynamics (CFD) and cold flow studies were performed with a 2.5-cm (1-in.) diameter Davison-type jet cup and PSRI's cylindrical 7.6-cm (3-in.) diameter jet cup. Results showed that a significant amount of material in the Davison and PSRI jet cup remained stagnant. Based on these results and additional CFD modeling, PSRI designed a new jet cup, where most of the material was hydrodynamically active. The new jet cup showed a 25% increase in attrition compared to PSRI's cylindrical jet cup under similar conditions and run times. Results were also compared to cyclone attrition data for several materials at PSRI. The new jet cup provided data that correlated with attrition results from the 29-cm (11.5-in.) diameter fluidized bed unit. 相似文献
14.
During the past decade, 3 major developments in psychotherapy have been converging: the establishment of evidence-based practices in psychology (EBPP); enormous growth in cognitive–behavior therapy and research (CBT); and increasing recognition of the impact of multicultural influences, as highlighted in the field of multicultural therapy (MCT). Cognitive–behavioral research has produced many empirically supported treatments used in the establishment of the scientific research base of EBPP, and MCT research has provided a wealth of qualitative information that balances this scientific emphasis with recognition of the importance of culturally competent clinical judgment, expertise, and experience. This article describes the advantages and potential limitations involved in the integration of CBT and multicultural considerations, with limitations reframed as opportunities to improve the relevance and effectiveness of psychotherapy. Ten suggestions are provided for integrating multicultural considerations into the clinical practice of cognitive–behavior therapy. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
15.
Fisher GM Killeen TL Wu Q Reeves JM Hays PB Gault WA Brown S Shepherd GG 《Applied optics》2000,39(24):4284-4291
Polar cap mesospheric winds observed with a Fabry-Perot interferometer with a circle-to-line interferometer optical (FPI/CLIO) system have been compared with measurements from a field-widened Michelson interferometer optimized for E-region winds (ERWIN). Both instruments observed the Meinel OH emission emanating from the mesopause region (~86 km) at Resolute Bay, Canada (74.9 degrees N, 94.9 degrees W). This is the first time, to our knowledge, that winds measured simultaneously from a ground-based Fabry-Perot interferometer and a ground-based Michelson interferometer have been compared at the same location. The FPI/CLIO and ERWIN instruments both have a capability for high temporal resolution (less than 10 min for a full scan in the four cardinal directions and the zenith). Statistical comparisons of hourly mean winds for both instruments by scatterplots show excellent agreement, indicating that the two optical techniques provide equivalent observations of mesopause winds. Small deviations in the measured wind can be ascribed to the different zenith angles used by the two instruments. The combined measurements illustrate the dominance of the 12-h wave in the mesopause winds at Resolute Bay, with additional evidence for strong gravity wave activity with much shorter periods (tens of minutes). Future operations of the two instruments will focus on observation of complementary emissions, providing a unique passive optical capability for the determination of neutral winds in the geomagnetic polar cap at various altitudes near the mesopause. 相似文献
16.
A set of standards for Australian general practices has been developed through a 4 year project conducted by The Royal Australian College of General Practitioners. An orderly, iterative process was adopted to ensure comprehensive consultation with general practitioners, other health professionals, consumers and governments. The draft standards were field tested in 199 randomly selected urban and rural practices. Results of this field testing showed that the standards have content validity, that they can be measured reliably and that the practice visit protocol is feasible. The standards are calibrated to define the minimum acceptable features of general practices expected for the mid 1990s. The standards have been adopted by Australian General Practice Accreditation Limited as the basis for a voluntary system of practice accreditation. 相似文献
17.
The process of finding optimized fuel reload patterns for boiling water reactors is complicated by a number of factors including the large number of fuel assemblies involved, the three-dimensional neutronic and thermal-hydraulic variations, and the interplay of coolant flow rate with control rod programming. The FORMOSA-B code was developed to provide an automated method for finding fuel loading patterns, control rod programs and coolant flow rate schedules to minimize certain quantitative metrics of core performance while satisfying given operational constraints. One drawback of this code has been the long runtimes required for a complete cycle optimization on a desktop workstation (oftentimes several days or more). To address this shortcoming, a parallel simulated annealing algorithm has been added to the FORMOSA-B code, so that the runtimes may be greatly reduced by using a multiprocessor computer cluster. Tests of the algorithm on a sample problem indicate that it is capable of parallel efficiencies exceeding 80% when using four processors. 相似文献
18.
Ingot quality is characterized by SPC evaluations; meaning Structure (S), Property (P), and Composition (C). Structure-property studies are classified as “sensitive” attributes while composition is considered to be an “insensitive” parameter. For example, it is common to hear the phrase that global composition is “insensitive” to structure and property values. For superalloys, structural analyses are applied using the scanning electron microscope (SEM) to determine both size, shape and distribution effects for the gamma prime phase. Examination of properties requires mechanical tests for strength, hardness, toughness and, so forth. However, for investigations on composition, the scientific community still depends on optical emission spectroscopy (OES) for measurements of global results using arc burns to represent bulk volume. This leads to the obvious question…. What needs to be done to better quantify the OES results? Further…. How can the controlling microconstituents of a superalloy be better related to the overall composition results for an improved qualification of ingots? This article addresses these needs and priorities. And, the said article is offered as a contribution to the sum of total knowledge. 相似文献
19.
20.
Hsin Wang Govindarajan Muralidharan Donovan N. Leonard J. Allen Haynes Wallace D. Porter Roger D. England Michael Hays Gopal Dwivedi Sanjay Sampath 《Journal of Thermal Spray Technology》2018,27(3):371-378
Multilayer, graded ceramic/metal coatings were prepared by an air plasma spray method on Ti-6Al-4V, 4140 steel and graphite substrates. The coatings were designed to provide thermal barriers for diesel engine pistons to operate at higher temperatures with improved thermal efficiency and cleaner emissions. A systematic, progressive variation in the mixture of yttria-stabilized zirconia and bondcoat alloys (NiCoCrAlYHfSi) was designed to provide better thermal expansion match with the substrate and to improve thermal shock resistance and cycle life. Heat transfer through the layers was evaluated by a flash diffusivity technique based on a model of one-dimensional heat flow. The aging effect of the as-sprayed coatings was captured during diffusivity measurements, which included one heating and cooling cycle. The hysteresis of thermal diffusivity due to aging was not observed after 100-h annealing at 800 °C. The measurements of coatings on substrate and freestanding coatings allowed the influence of interface resistance to be evaluated. The microstructure of the multilayer coating was examined using scanning electron microscope and electron probe microanalysis. 相似文献