摘要 :
Experiments were done to research fan water curtain diluting water-insoluble heavy gas (carbon dioxide as an example) dispersion in open space in this paper. In experiments, the influence of water flow pressure, distance between l...
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Experiments were done to research fan water curtain diluting water-insoluble heavy gas (carbon dioxide as an example) dispersion in open space in this paper. In experiments, the influence of water flow pressure, distance between leakage source and water curtain, height of leakage source and squirt angle of fan water curtain on dilution effect were done. Experimental results show that the higher the water pressure of fan water curtain is, the lower the concentration of carbon dioxide behind the water curtain is, and thus, more efficient the dilution effect is. However, when water pressure is no lower than 0.25MPa, the concentration of carbon dioxide behind the water curtain will not continue decreasing. Also, when leakage source height is higher, the concentration of carbon dioxide is higher, and the dilution effect is worse. When water curtain is closer to leakage source, the concentration of carbon dioxide downwind is higher. When the ratio of K, which is leakage source height to the distance of water curtain away from leakage source, is 0.6 and dilution effect is the best. Furthermore, when the squirt angle is 60°, the dilution effect is comparatively good..
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摘要 :
A dynamic analysis model of wind-train-bridge system is established. The wind excitations of the system are the buffeting and self-excited forces simulated in time domain using measured aerodynamic coefficients and flutter derivat...
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A dynamic analysis model of wind-train-bridge system is established. The wind excitations of the system are the buffeting and self-excited forces simulated in time domain using measured aerodynamic coefficients and flutter derivatives. The proposed formulations are then applied to a long suspension bridge. The dynamic responses of the bridge and the train under wind action are analyzed. The results show that the lateral and rotational displacements of the bridge are dominated by wind, while the vertical by running train's gravity loading. The running safety of the train is much affected by wind: Under the wind of 30-40m/s, the offload factors, derail factors and overturn factors of the train vehicles exceed the allowances, to which great attention should be paid.
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摘要 :
A dynamic analysis model of wind-train-bridge system is established. The wind excitations of the system are the buffeting and self-excited forces simulated in time domain using measured aerodynamic coefficients and flutter derivat...
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A dynamic analysis model of wind-train-bridge system is established. The wind excitations of the system are the buffeting and self-excited forces simulated in time domain using measured aerodynamic coefficients and flutter derivatives. The proposed formulations are then applied to a long suspension bridge. The dynamic responses of the bridge and the train under wind action are analyzed. The results show that the lateral and rotational displacements of the bridge are dominated by wind, while the vertical by running train's gravity loading. The running safety of the train is much affected by wind: Under the wind of 30-40m/s, the offload factors, derail factors and overturn factors of the train vehicles exceed the allowances, to which great attention should be paid.
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摘要 :
Traffic time series analysis is important because of its use in traffic control and travel time prediction. In this paper, we discuss how to cluster traffic time series that have similar fluctuation patterns. We use simple average...
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Traffic time series analysis is important because of its use in traffic control and travel time prediction. In this paper, we discuss how to cluster traffic time series that have similar fluctuation patterns. We use simple average detrending method and only study the residual time series. Second, we use principle component analysis (PCA) on raw data and use the weight of the first d-components as the features of the time series. Third, we use k-means algorithm to cluster the traffic time series. Finally, we study the results of the clustering algorithm and discuss the origins of the clusters. In summary, the most important factors of clustering results are urban/rural area, direction and in/not in ramp entrance.
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摘要 :
Traffic time series analysis is important because of its use in traffic control and travel time prediction. In this paper, we discuss how to cluster traffic time series that have similar fluctuation patterns. We use simple average...
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Traffic time series analysis is important because of its use in traffic control and travel time prediction. In this paper, we discuss how to cluster traffic time series that have similar fluctuation patterns. We use simple average detrending method and only study the residual time series. Second, we use principle component analysis (PCA) on raw data and use the weight of the first d-components as the features of the time series. Third, we use k-means algorithm to cluster the traffic time series. Finally, we study the results of the clustering algorithm and discuss the origins of the clusters. In summary, the most important factors of clustering results are urban/rural area, direction and in/not in ramp entrance.
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摘要 :
Traffic time series analysis is important because of its use in traffic control and travel time prediction. In this paper, we discuss how to cluster traffic time series that have similar fluctuation patterns. We use simple average...
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Traffic time series analysis is important because of its use in traffic control and travel time prediction. In this paper, we discuss how to cluster traffic time series that have similar fluctuation patterns. We use simple average detrending method and only study the residual time series. Second, we use principle component analysis (PCA) on raw data and use the weight of the first d-components as the features of the time series. Third, we use k-means algorithm to cluster the traffic time series. Finally, we study the results of the clustering algorithm and discuss the origins of the clusters. In summary, the most important factors of clustering results are urban/rural area, direction and in/not in ramp entrance.
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摘要 :
Water curtain could dilute leaking poisonous gas or obstruct the diffusion of the poisonous gas to the sensitivity regions safely, efficiently and quickly. So it was very important to understand diffusion mechanism of the heavy ga...
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Water curtain could dilute leaking poisonous gas or obstruct the diffusion of the poisonous gas to the sensitivity regions safely, efficiently and quickly. So it was very important to understand diffusion mechanism of the heavy gas diluted by water curtain and explore pattern of the effect of water curtain's setting parameter on the diffusion capacity of heavy gas diluted with water curtain. In this paper, experiments of fan water curtain and cone water curtain diluting CO2 in open space were done. According to experiment results, dilution mechanism of fan water curtain and cone water curtain were obtained. The protective screen formed by fan water curtain could obstruct heavy gas diffusion effectively, and fan water curtain could also disperse heavy gas upwards through the mechanical effect. Cone water curtain would atomize the water and mix the heavy gas and air intensively with the help of air entrainment to dilute the heavy gas clouds. On this basis, it was concluded that when water curtain was opened before heavy gas passed through water curtain and the cone water curtain was installed in front of the fan water curtain, dilution effect was better. When water curtain was opened after heavy gas passed through water curtain and the fan water curtain was installed in front of the cone water curtain, dilution effect was better.
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摘要 :
Water curtain could dilute leaking poisonous gas or obstruct the diffusion of the poisonous gas to the sensitivity regions safely, efficiently and quickly. So it was very important to understand diffusion mechanism of the heavy ga...
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Water curtain could dilute leaking poisonous gas or obstruct the diffusion of the poisonous gas to the sensitivity regions safely, efficiently and quickly. So it was very important to understand diffusion mechanism of the heavy gas diluted by water curtain and explore pattern of the effect of water curtain's setting parameter on the diffusion capacity of heavy gas diluted with water curtain. In this paper, experiments of fan water curtain and cone water curtain diluting CO_2 in open space were done. According to experiment results, dilution mechanism of fan water curtain and cone water curtain were obtained. The protective screen formed by fan water curtain could obstruct heavy gas diffusion effectively, and fan water curtain could also disperse heavy gas upwards through the mechanical effect. Cone water curtain would atomize the water and mix the heavy gas and air intensively with the help of air entrainment to dilute the heavy gas clouds. On this basis, it was concluded that when water curtain was opened before heavy gas passed through water curtain and the cone water curtain was installed in front of the fan water curtain, dilution effect was better. When water curtain was opened after heavy gas passed through water curtain and the fan water curtain was installed in front of the cone water curtain, dilution effect was better.
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摘要 :
Water curtain could dilute leaking poisonous gas or obstruct the diffusion of the poisonous gas to the sensitivity regions safely, efficiently and quickly. So it was very important to understand diffusion mechanism of the heavy ga...
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Water curtain could dilute leaking poisonous gas or obstruct the diffusion of the poisonous gas to the sensitivity regions safely, efficiently and quickly. So it was very important to understand diffusion mechanism of the heavy gas diluted by water curtain and explore pattern of the effect of water curtain's setting parameter on the diffusion capacity of heavy gas diluted with water curtain. In this paper, experiments of fan water curtain and cone water curtain diluting CO_2 in open space were done. According to experiment results, dilution mechanism of fan water curtain and cone water curtain were obtained. The protective screen formed by fan water curtain could obstruct heavy gas diffusion effectively, and fan water curtain could also disperse heavy gas upwards through the mechanical effect. Cone water curtain would atomize the water and mix the heavy gas and air intensively with the help of air entrainment to dilute the heavy gas clouds. On this basis, it was concluded that when water curtain was opened before heavy gas passed through water curtain and the cone water curtain was installed in front of the fan water curtain, dilution effect was better. When water curtain was opened after heavy gas passed through water curtain and the fan water curtain was installed in front of the cone water curtain, dilution effect was better.
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In modern forest measurement situation that lack of good accuracy, in order to meet the needs of precision forestry and realize the precise measurement of every single tree, this paper introduces an automate technology and softwar...
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In modern forest measurement situation that lack of good accuracy, in order to meet the needs of precision forestry and realize the precise measurement of every single tree, this paper introduces an automate technology and software platform of forest measurement in fixed sample. This technology and method can give full play to the precision total station angle measurement range function and PDA data processing and storage function, which are based on the communication system programming development of total station and PDA with WinCE. This automation technology are used to gain 3d coordinate, tree height, DBH and crown of trunks, it can both realize the automation process of testing trees and ensure the accuracy of measurement, improving the work efficiency greatly.
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