Preprecipitation Phenomena l Supersaturated Solid Solutions

Guinier, A.

doi:10.1007/bf03377752

Cited by 8 publications

(2 citation statements)

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“…Amongst psychometricians guessing is a technical term that refers to any attempt to answer a question for which the test-taker does not simply know the answer. Critics of testing, such as Guinier and Sturm (2001), have argued that standardized tests reward a ''willingness to guess, conformity, and docility,'' (p.10). Psychometricians are usually more measured, but they often are careful to denote the limits of valid test score interpretations (Messick, 1989;Mislevy, 2009).…”

Section: Multiple-choice Tests and Knowledgementioning

confidence: 99%

Imperfect models, imperfect conclusions: An exploratory study of multiple-choice tests and historical knowledge

Reich

2013

The Journal of Social Studies Research

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This article explores the extent to which multiple-choice history/social studies exams measure student knowledge of social studies content. This article presents descriptive statistics that quantify the findings from a qualitative study. Data for this study were collected from 13 tenth-grade world history students in an urban classroom in New York State. Each participant answered 15 multiple-choice questions that had appeared on previous versions of the Global History and Geography Regents exam, the high-stakes exam they would have to take at the end of the school year. As a small-scale exploratory study, the findings are not what quantitative researchers would call generalizable. Nevertheless, the findings raise questions about what tests measure, their effectiveness, and what constitutes social-studies knowledge.

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Section: Multiple-choice Tests and Knowledgementioning

confidence: 99%

Imperfect models, imperfect conclusions: An exploratory study of multiple-choice tests and historical knowledge

Reich

2013

The Journal of Social Studies Research

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“…1 During precipitation hardening a second phase is precipitated from a supersaturated solid solution. 2 These precipitates are crystallographically coherent with the matrix and their fine dispersion enhances the mechanical properties of the alloy. 3 This age hardening by coherent precipitates in Al-Cu was first observed by Guinier 4 and Preston.…”

Section: Introductionmentioning

confidence: 99%

Billet quenching extrusion process as efficient and reliable replacement for conventional extrusion of Al–Cu alloys

Barbič

Dragojević

Smolej³

2010

Materials Science and Technology

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In order to eliminate the separate solution soaking treatment used for Al–Cu extrudates, the influence of billet heat treatments before the extrusion process on a precipitation hardenable AlCu6PbBi (AA2011) alloy was studied. The hot deformation behaviour of the alloy was studied using compression tests. A comparison of the conventional extrusion process, press quenching and billet quenching (BQ) before extrusion was made in production on a 35 MN press. The transformation kinetics was studied by heat treating homogenised samples in salt baths. The mechanical testing, using tensile tests and the Brinell hardness test, and a microstructural investigation, using light and TEM microscopy, revealed that extrusion using the billet quenching process results in the formation of extrudates with similar mechanical properties, hardness and microstructures as those produced using conventional technology. In the extrudates produced by BQ a supersaturated solid solution is formed directly after cooling in a standing water wave, which makes BQ an efficient and reliable substitute for the conventional extrusion process.

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