1,914 research outputs found

    Nondestructive evaluation of advanced ceramics

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    A review is presented of Lewis Research Center efforts to develop nondestructive evaluation techniques for characterizing advanced ceramic materials. Various approaches involved the use of analytical ultrasonics to characterize monolythic ceramic microstructures, acousto-ultrasonics for characterizing ceramic matrix composites, damage monitoring in impact specimens by microfocus X-ray radiography and scanning ultrasonics, and high resolution computed X-ray tomography to identify structural features in fiber reinforced ceramics

    Search for solid conductors of Na(+) and K(+) ions: Five new conductors

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    Five conductors of three structure types were discovered which, as solids, can transport Na(+) or K(+) ions with conductivities of approximately .00001/(omega cm) at 300 K. These compounds are: (1) the pyrochlores NaTaWO6 and NaTa2O5F, both with an activation energy for conduction delta E of 21 kJ/mole; (2) the bodycentered cubic form of NaSbO3, with delta E = 42 kJ/mole; and (3) the niobates 2Na2O with 3Nb2O5 and 2K2O with 3Nb2O5, with the alkali ions probably in open layers of the incompletely determined structure; delta E = 17 kJ/mole. On the basis of approximately 40 structure types, some generalizations were made regarding the relation between structure and ionic transport

    Conductivity of boules of single crystal sodium beta-alumina

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    The ionic and electrochemical polarization characteristics of two boules of single crystal sodium beta-alumina (Na2O.8Al2O3), 2 cm in diameter, were investigated over the range of 25 to 300 C using 2- and 4-probe ac and dc techniques with reversible and ion-blocking electrodes. Textural (or internal) polarization at 27 C was present only in boule 1 which cleaved easily. Interfacial polarization, using solid sodium electrodes, was present at 27 C in the 2-probe conductivities for both boules. Cleaning with liquid sodium at 300 C reduced its magnitude, but some interfacial polarization was still present in the 2-probe conductivities for boule 2 below about 140 C. Above 140 C, with liquid sodium electrodes, the 2-probe conductivities, essentially polarization-free, were given by KT = 3300 exp(-3650/RT). The conductivity of boule 2 at 180 C remained essentially constant with increasing current density up to about 140 milliamps per square centimeter

    Learning a Manifold of Fonts

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    The design and manipulation of typefaces and fonts is an area requiring substantial expertise; it can take many years of study to become a proficient typographer. At the same time, the use of typefaces is ubiquitous; there are many users who, while not experts, would like to be more involved in tweaking or changing existing fonts without suffering the learning curve of professional typography packages. Given the wealth of fonts that are available today, we would like to exploit the expertise used to produce these fonts, and to enable everyday users to create, explore, and edit fonts. To this end, we build a generative manifold of standard fonts. Every location on the manifold corresponds to a unique and novel typeface, and is obtained by learning a non-linear mapping that intelligently interpolates and extrapolates existing fonts. Using the manifold, we can smoothly interpolate and move between existing fonts. We can also use the manifold as a constraint that makes a variety of new applications possible. For instance, when editing a single character, we can update all the other glyphs in a font simultaneously to keep them compatible with our changes

    Personality Psychology and Economics

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    This paper explores the power of personality traits both as predictors and as causes of academic and economic success, health, and criminal activity. Measured personality is interpreted as a construct derived from an economic model of preferences, constraints, and information. Evidence is reviewed about the "situational specificity" of personality traits and preferences. An extreme version of the situationist view claims that there are no stable personality traits or preference parameters that persons carry across different situations. Those who hold this view claim that personality psychology has little relevance for economics. The biological and evolutionary origins of personality traits are explored. Personality measurement systems and relationships among the measures used by psychologists are examined. The predictive power of personality measures is compared with the predictive power of measures of cognition captured by IQ and achievement tests. For many outcomes, personality measures are just as predictive as cognitive measures, even after controlling for family background and cognition. Moreover, standard measures of cognition are heavily influenced by personality traits and incentives. Measured personality traits are positively correlated over the life cycle. However, they are not fixed and can be altered by experience and investment. Intervention studies, along with studies in biology and neuroscience, establish a causal basis for the observed effect of personality traits on economic and social outcomes. Personality traits are more malleable over the life cycle compared to cognition, which becomes highly rank stable around age 10. Interventions that change personality are promising avenues for addressing poverty and disadvantage.personality, behavioral economics, cognitive traits, wages, economic success, human development, person-situation debate

    Transply crack density detection by acousto-ultrasonics

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    The acousto-ultrasonic method was applied to a PMR-15 8-harness, satin Celion 3000 fabric composite to determine the extent of transply cracking. A six-ply 0/90 laminate was also subjected to mechanical loading, which induced transply cracking. The stress wave factor (SWF) is defined as the energy contained in the received signal from a 2.25-MHz center frequency transducer. The correlation of the SWF with transply crack density is shown

    Hierarchical Subquery Evaluation for Active Learning on a Graph

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    To train good supervised and semi-supervised object classifiers, it is critical that we not waste the time of the human experts who are providing the training labels. Existing active learning strategies can have uneven performance, being efficient on some datasets but wasteful on others, or inconsistent just between runs on the same dataset. We propose perplexity based graph construction and a new hierarchical subquery evaluation algorithm to combat this variability, and to release the potential of Expected Error Reduction. Under some specific circumstances, Expected Error Reduction has been one of the strongest-performing informativeness criteria for active learning. Until now, it has also been prohibitively costly to compute for sizeable datasets. We demonstrate our highly practical algorithm, comparing it to other active learning measures on classification datasets that vary in sparsity, dimensionality, and size. Our algorithm is consistent over multiple runs and achieves high accuracy, while querying the human expert for labels at a frequency that matches their desired time budget.Comment: CVPR 201

    What\u27s in a user story: IS development methods as communication

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    This paper challenges claims made by Scrum proponents when characterising the communicative nature of user stories: including being more \u27authentic\u27 because they comprise spoken language and that they are stories. We argue and decisively demonstrate that neither can be upheld. By incorrectly characterising user stories, we miss opportunities to understand what they are and how they work during development. User stories are better understood by applying a functional theory of communication that emphasises how language is used. By selecting systemic functional linguistics, we can analyse user stories, and have developed a method for factoring unwanted epics into usable user stories

    Fostering and Measuring Skills: Interventions That Improve Character and Cognition

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    This paper reviews the recent literature on measuring and boosting cognitive and noncognitive skills. The literature establishes that achievement tests do not adequately capture character skills personality traits, goals, motivations, and preferences that are valued in the labor market, in school, and in many other domains. Their predictive power rivals that of cognitive skills. Reliable measures of character have been developed. All measures of character and cognition are measures of performance on some task. In order to reliably estimate skills from tasks, it is necessary to standardize for incentives, effort, and other skills when measuring any particular skill. Character is a skill, not a trait. At any age, character skills are stable across different tasks, but skills can change over the life cycle. Character is shaped by families, schools, and social environments. Skill development is a dynamic process, in which the early years lay the foundation for successful investment in later years. High-quality early childhood and elementary school programs improve character skills in a lasting and cost-effective way. Many of them beneficially affect later-life outcomes without improving cognition. There are fewer long-term evaluations of adolescent interventions, but workplace-based programs that teach character skills are promising. The common feature of successful interventions across all stages of the life cycle through adulthood is that they promote attachment and provide a secure base for exploration and learning for the child. Successful interventions emulate the mentoring environments offered by successful families
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