2,392 research outputs found

    The integration of storm water flooding and thermal stress potential in Tainan (Taiwan) and Groningen (Netherlands)

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    Stormwater flooding and thermal stresses of citizens are two important phenomena for most of the dense urban area. Due to the climate change, these two phenomena will occur more frequently and cause serious problems. Therefore, the sectors for public health and disaster management should be able to assess the vulnerability to stormwater flooding and thermal stress. To achieve this goal, two cities in different climate regions and with different urban context have been selected as the pilot areas, i.eY., Tainan, Taiwan and Groningen, Netherlands. Stormwater flooding and thermal stress maps will be produced for both cities for further comparison. The flooding map indicates vulnerable low lying areas, where the thermal stress map indicates high Physiological Equivalent Temperature (PET) values (thermal comfort) in open areas without shading. The combined map indicates the problem areas of flooding and thermal stress and can be used by urban planners and other stakeholders to improve the living environment

    Diagrammatic approach to excitonic effects on nonlinear optical response

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    Optical responses of atomically thin 2D materials are greatly influenced by electron-hole interactions. It is by far established that exciton signatures can be well-identified in the optical absorption spectrum of quasi-2D materials. However, the same level of understanding of excitonic effects on nonlinear optical responses and the ability to compute them accurately is still much desired. Based on the functional integral formalisms and working in the velocity gauge, we introduce a convenient Feynman diagram approach for calculating nonlinear responses including excitonic effects. By dressing electron-photon interactions with electron-hole ladder diagrams, we derive an expression for second-order optical responses and provide a comprehensive description of excitonic effects. We apply our approach to a monolayer h-BN model and show qualitative changes in the second harmonic generation spectrum when comparing with results assuming independent particles. Our approach can be readily extended to higher order optical responses and is feasible for first-principles calculations

    Desorption of Cadmium from Porous Chitosan Beads

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    Behavior of a coupled arch system

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    Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2002.Includes bibliographical references (leaves 100-102).by Tzu-Yang Yu.M.Eng

    BIOMECHANICAL DIFFERENCES BETWEEN TAI-CHI PRACTICING AND ACTIVE ELDERLY DURING THE STAIR-TO-FLOOR TRANSITION

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    Long-term Tai-Chi practitioners tend to have similar movement to healthy adults and exhibit movement strategies that reduce fall risk during stair-to-floor transition. We aimed to assess the differences during stair descent to ground in Tai-Chi elderly practitioners and active elderly. Fourteen regular Tai-Chi practitioners and fourteen active elderly participated. Whole-body kinematics and ground reaction forces (GRFs) were recorded synchronously by using motion analysis and a force platform. A t-test was used to test the differences between the groups. Both descent and forward walking step length and center of mass (COM) velocity, both horizontal braking and propulsive force and impulse, ankle range of motion (ROM) and total work in the sagittal plane, and maximum hip moment in the frontal plane had significant differences. Our results appear to support the benefits of long-term Tai-Chi training during the stair-to-floor transition

    The Effect of Lexicality, Frequency, and Markedness on Mandarin Tonal Categorization

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    While the Ganong lexicality effect has been observed for phonemic and tonal categorization, the effects of frequency and markedness are less clear, especially in terms of tonal categorization. In this study, we use Mandarin Chinese to investigate the effects of lexicality, tone frequency and markedness. We examined Mandarin speakers’ tonal categorization of tokens on all possible tonal continua with one end being a word and the other being a tonotactic gap (i.e., an unattested syllable-tone combination). The results of a forced-choice identification experiment showed a general bias against the gap endpoints, with the noted exception of continua involving T4 (X51), the most frequent lexical tone. Specifically, when T4 served as the gap endpoint, no obvious bias against it was observed regardless of its lexical status. Moreover, on the T3–T4 continua, there was an apparent bias against T3 (X214), the tone with the most complex contour, again, regardless of lexicality, suggesting a strong markedness effect. Taken together, the results of this study show the individual effects of lexicality, tone frequency and markedness, as well as their interactions, which contribute to our understanding of tonal categorization in relation to lexical statistics (tone frequency) and phonology (markedness)
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