26 research outputs found

    Mathematical modelling of the liquid atomization process by cocurrent gas flow

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    This paper focuses on the physical-mathematical model of liquid atomization in the spray pattern of an ejection nozzle. A flow field of a gas phase behind the nozzle section is computed using the Ansys Fluent package. Dynamics of molten metal droplets in the gas phase within a trajectory approach is calculated. Using the presented model, numerical calculation results are given

    Artificial limb representation in amputees

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    The human brain contains multiple hand-selective areas, in both the sensorimotor and visual systems. Could our brain repurpose neural resources, originally developed for supporting hand function, to represent and control artificial limbs? We studied individuals with congenital or acquired hand-loss (hereafter one-handers) using functional MRI. We show that the more one-handers use an artificial limb (prosthesis) in their everyday life, the stronger visual hand-selective areas in the lateral occipitotemporal cortex respond to prosthesis images. This was found even when one-handers were presented with images of active prostheses that share the functionality of the hand but not necessarily its visual features (e.g. a \u27hook\u27 prosthesis). Further, we show that daily prosthesis usage determines large-scale inter-network communication across hand-selective areas. This was demonstrated by increased resting state functional connectivity between visual and sensorimotor hand-selective areas, proportional to the intensiveness of everyday prosthesis usage. Further analysis revealed a 3-fold coupling between prosthesis activity, visuomotor connectivity and usage, suggesting a possible role for the motor system in shaping use-dependent representation in visual hand-selective areas, and/or vice versa. Moreover, able-bodied control participants who routinely observe prosthesis usage (albeit less intensively than the prosthesis users) showed significantly weaker associations between degree of prosthesis observation and visual cortex activity or connectivity. Together, our findings suggest that altered daily motor behaviour facilitates prosthesis-related visual processing and shapes communication across hand-selective areas. This neurophysiological substrate for prosthesis embodiment may inspire rehabilitation approaches to improve usage of existing substitutionary devices and aid implementation of future assistive and augmentative technologies

    Overview: Recent advances in the understanding of the northern Eurasian environments and of the urban air quality in China – a Pan-Eurasian Experiment (PEEX) programme perspective

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    The Pan-Eurasian Experiment (PEEX) Science Plan, released in 2015, addressed a need for a holistic system understanding and outlined the most urgent research needs for the rapidly changing Arctic-boreal region. Air quality in China, together with the long-range transport of atmospheric pollutants, was also indicated as one of the most crucial topics of the research agenda. These two geographical regions, the northern Eurasian Arctic-boreal region and China, especially the megacities in China, were identified as a "PEEX region". It is also important to recognize that the PEEX geographical region is an area where science-based policy actions would have significant impacts on the global climate. This paper summarizes results obtained during the last 5 years in the northern Eurasian region, together with recent observations of the air quality in the urban environments in China, in the context of the PEEX programme. The main regions of interest are the Russian Arctic, northern Eurasian boreal forests (Siberia) and peatlands, and the megacities in China. We frame our analysis against research themes introduced in the PEEX Science Plan in 2015. We summarize recent progress towards an enhanced holistic understanding of the land-atmosphere-ocean systems feedbacks. We conclude that although the scientific knowledge in these regions has increased, the new results are in many cases insufficient, and there are still gaps in our understanding of large-scale climate-Earth surface interactions and feedbacks. This arises from limitations in research infrastructures, especially the lack of coordinated, continuous and comprehensive in situ observations of the study region as well as integrative data analyses, hindering a comprehensive system analysis. The fast-changing environment and ecosystem changes driven by climate change, socio-economic activities like the China Silk Road Initiative, and the global trends like urbanization further complicate such analyses. We recognize new topics with an increasing importance in the near future, especially "the enhancing biological sequestration capacity of greenhouse gases into forests and soils to mitigate climate change" and the "socio-economic development to tackle air quality issues".Peer reviewe

    Aristotle’s Solution to Meno’s Paradox

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    Aristotle's Analytics

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    Eugene V. Orlov of the Institute of philosophy and law, Novosibirsk, discusses the basic elements of analysis in Aristotle, including the stages of scientific inquiry, the composition of a valid syllogisms, and applying universal knowledge thus gained to particular inferences

    Internet Penetration and Capacity Utilization in the US Airline Industry,”Working Paper

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    Abstract Airline capacity utilization, or load factors, increased dramatically between 1993 and 2007, after staying fairly level for the first 15 years following deregulation. Improvements in demand forecasting, capacity management, and revenue management are potential explanations, but revenue management systems were widely adopted in the 1980's, significantly before the increase in load factor. We argue that consumers' adoption of the Internet, and their use of the Internet to investigate and purchase airline tickets, explains recent increases in airlines' load factors. Using metropolitan area measures of Internet penetration, we find strong evidence that differences in the rate of change of Internet penetration explain differences in the rate of change of airline airportpair load factors. We argue that these increases, and a significant part of the associated $1 billion reduction in airlines' annual costs, represent a previously unmeasured social welfare benefit of the Internet

    Low temperature stacking fault nucleation and expansion from stress concentrators in 4H-SiC

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    International audienceDespite of intensive studies during the last two decades of nucleation and expansion of Shockley-type single or adjacent stacking faults (double stacking faults) in 4H-SiC, the involved mechanisms are far from being deeply understood. Thus, in this paper, the temperature and carrier injection dependence of nucleation and expansion of these defects from local stress concentrators have been investigated by cathodoluminescence and low energy electron beam irradiation. Their corresponding behavior depends on their multiplicity. Upon annealing, the single stacking faults are found to be nucleated at lower temperature than the double stacking faults and their mobility is lower. Under electron injection at room temperature, only single stacking faults are nucleated. The involved partial dislocations dragging the stacking faults are assumed to have different nature cores. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved
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