1,329 research outputs found

    Cortical and Subcortical Organization Participating in Tactual Pattern Perception in Man: A PET study

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    Reduction of water content in calcium aluminate cement with/out phosphate modification for alternative cementation technique

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    Cementation of the secondary aqueous wastes from TEPCO Fukushima Daiichi Nuclear Power Plant is challenging due to the significant strontium content and radioactivity, leading to a potential risk of hydrogen gas generation via radiolysis of water content. The present study investigates the reduction of water content in calcium aluminate cement (CAC) with/out phosphate modification by a heat-treatment during the solidification. The reduction of water in the CAC was found restricted by the rapid formation of crystalline hydration phases, whereas the phosphate-modified system allowed the gradual reduction of water, achieving the reduction of 60% water content at 95 °C. Curing at 60–95 °C also eliminated the significant cracks found at 35 °C in the phosphate system. The possible difference in the amorphous products, NaCaPO4∙nH2O type at 35 °C and Ca(HPO4)∙xH2O type at 60–95 °C, may have contributed to the improvement in the microstructure together with the change in the pore size distribution

    SEISMIC RETROFITTING OF EARTHQUAKE-DAMAGED CONCRETE COLUMNS BY LATERAL PRE-TENSIONING OF FRP BELTS

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    ABSTRACT Five square columns with two shear span-to-depth ratios of 1.5 and 2.5 were constructed to model half-scale shear-deficient columns and tested under constant axial compression and reversed cyclic lateral load, simultaneously. After being tested, two of the columns with different shear span-to-depth ratios were subjected to a certain level of damage in terms of crack pattern and also drop in the lateral capacity. Then, these earthquake-damaged columns were retrofitted by pre-tensioned carbon or aramid FRP belts, and once more, were tested under cyclic lateral loading and constant axial compression. As the confining devices, i.e. FRP belts, were pre-tensioned before applying the lateral load to the columns, both active and passive confinements were utilized. As an instant result of pretensioning, the initial cracks of the damaged column were closed. It should be noted that this retrofitting procedure is quick as it is carried out without any repair measures such as removal of damaged concrete or crack injection and so on. Moreover, the prestressing technique is an innovative method and can be applied manually using a simple wrench. According to test results, the lateral capacity of the original columns dropped suddenly, showing a brittle shear failure. When the damaged columns were retrofitted by pre-tensioned FRP belts, the lateral strength could be restored and the drop in shear capacity could be prevented up to large drifts, indicating a better seismic performance

    Poster: Nonverbal Cognitive Assessment for Special-Needs or Non-English ADHD or LD Cases

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    The Cattell-Horn-Carroll Theory (Willis, 2011) posits several components of general intelligence (e.g., fluid reasoning, visual-spatial memory, and processing speed examined in this study). In regards to measures of general intelligence, nonverbal cognitive measures can reduce verbal load and more accurately appraise non-verbal and non-native English speakers (Johnsen, 2017). In the present study, researchers hypothesized participants with ADHD, the most common neuropsychiatric disorder (Thomas et al., 2015) commonly associated with memory difficulties, would score lower on memory and attention tests than LD and no-diagnosis participants

    Assessment of Dopamine Neurotransmission in Dementia Using Positron Emission Tomography

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