2,703 research outputs found

    Experimental study of flashing LNG jet fires following horizontal releases

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    A horizontally oriented jet fire could occur if the leaking liquefied natural gas (LNG) from the side surface of a pipe or storage tank was ignited. Previous work with LNG mostly focused on pool fires. In the present study, horizontally oriented LNG jet fires were studied through 10 open field full scale tests. The flames were visualized by both infrared and video cameras. The recorded flame shapes are compared and analysed. Peak temperatures and heat fluxes at various flow rates were measured and recorded. For relatively low reservoir pressure, a small amount of LNG was found to spray through the fire and rainout onto the ground, forming an LNG pool. A correlation was established to calculate the flame length from the mass flow rate

    Sharp Spectral Gap and Li-Yau's Estimate on Alexandrov Spaces

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    In the previous work [35], the second and third authors established a Bochner type formula on Alexandrov spaces. The purpose of this paper is to give some applications of the Bochner type formula. Firstly, we extend the sharp lower bound estimates of spectral gap, due to Chen-Wang [9, 10] and Bakry-Qian [6], from smooth Riemannian manifolds to Alexandrov spaces. As an application, we get an Obata type theorem for Alexandrov spaces. Secondly, we obtain (sharp) Li-Yau's estimate for positve solutions of heat equations on Alexandrov spaces.Comment: 19 pages, final version, to appear in Math.

    Existence and exponential stability of periodic solution for fuzzy BAM neural networks with periodic coefficient

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    A class of fuzzy bidirectional associated memory (BAM) networks with periodic coefficients is studied. Some sufficient conditions are established for the existence and global exponential stability of a periodic solution of such fuzzy BAM neural networks by using a continuation theorem based on the coincidence degree and the Lyapunov-function method. The sufficient conditions are easy to verify in pattern recognition and automatic control. Finally, an example is given to show the feasibility and efficiency of our results.Вивчено клас нечiтких нейронних мереж Коско з перiодичним коефiцiєнтом. За допомогою теореми про продовження, що базується на ступенi збiгу та методi функцiй Ляпунова, встановлено достатнi умови для iснування та глобальної експоненцiальної стiйкостi перiодичного розв’язку таких нечiтких нейронних мереж Коско. Цi достатнi умови легко перевiряються при розпiзнаваннi образiв та автоматичному керуваннi. Наведено приклад, що демонструє застосовнiсть та ефективнiсть отриманих результатiв

    Multi-Granularity Archaeological Dating of Chinese Bronze Dings Based on a Knowledge-Guided Relation Graph

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    The archaeological dating of bronze dings has played a critical role in the study of ancient Chinese history. Current archaeology depends on trained experts to carry out bronze dating, which is time-consuming and labor-intensive. For such dating, in this study, we propose a learning-based approach to integrate advanced deep learning techniques and archaeological knowledge. To achieve this, we first collect a large-scale image dataset of bronze dings, which contains richer attribute information than other existing fine-grained datasets. Second, we introduce a multihead classifier and a knowledge-guided relation graph to mine the relationship between attributes and the ding era. Third, we conduct comparison experiments with various existing methods, the results of which show that our dating method achieves a state-of-the-art performance. We hope that our data and applied networks will enrich fine-grained classification research relevant to other interdisciplinary areas of expertise. The dataset and source code used are included in our supplementary materials, and will be open after submission owing to the anonymity policy. Source codes and data are available at: https://github.com/zhourixin/bronze-Ding.Comment: CVPR2023 accepte

    The global spatiotemporal distribution of the mid-tropospheric CO2 concentration and analysis of the controlling factors

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    The atmospheric infrared sounder (AIRS) provides a robust and accurate data source to investigate the variability of mid-tropospheric CO2 globally. In this paper, we use the AIRS CO2 product and other auxiliary data to survey the spatiotemporal distribution characteristics of mid-tropospheric CO2 and the controlling factors using linear regression, empirical orthogonal functions (EOFs), geostatistical analysis, and correlation analysis. The results show that areas with low mid-tropospheric CO2 concentrations (20 degrees S-5 degrees N) (384.2 ppm) are formed as a result of subsidence in the atmosphere, the presence of the Amazon rainforest, and the lack of high CO2 emission areas. The areas with high mid-tropospheric CO2 concentrations (30 degrees N-70 degrees N) (382.1 ppm) are formed due to high CO2 emissions. The global mid-tropospheric CO2 concentrations increased gradually (the annual average rate of increase in CO2 concentration is 2.11 ppm/a), with the highest concentration occurring in spring (384.0 ppm) and the lowest value in winter (382.5 ppm). The amplitude of the seasonal variation retrieved from AIRS (average: 1.38 ppm) is consistent with that of comprehensive observation network for trace gases (CONTRAIL), but smaller than the surface ground stations, which is related to altitude and coverage. These results contribute to a comprehensive understanding of the spatiotemporal distribution of mid-tropospheric CO2 and related mechanisms

    Dietary plant soot supplementation improves the intestinal health status of farmed American eels (<em>Anguilla rostrata</em>)

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    The current study evaluated the effect of different dietary plant soot supplementation levels on the intestinal health status of American eels (Anguilla rostrata) cultured in concrete tanks. Nine concrete fish tanks were randomly divided into three groups and fed the diets with plant soot (PS) supplementation levels at 0, 3 g/kg, and 5 g/kg, respectively. After a feeding trial for 60 days, the intestinal tissues were sampled to measure health status parameters. The D-lactate level and DAO activity in the serum of the PS5 group were significantly lower than those of the PS0 group (P <0.05). Compared with the PS0 group, the villi length of the intestine in both PS3 group and PS5 group increased significantly (P<0.05). The muscular thickness of the intestine of the PS5 group was significantly higher than the PS0 group (P<0.05). The microvillus density of the intestine of the American eel was increased obviously in the PS5 group. The intestinal microbiota composition of plant soot groups was beneficially regulated with certain probiotics' higher relative abundances and some pathogenic bacteria' lower relative abundance. In conclusion, dietary 5 g/kg plant soot supplementation could benefit the intestinal health of farmed American eels
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