Curved steel bridges are commonly used at interchanges in transportation networks and more of these structures continue to be designed and built in the United States. Though the use of these bridges continues to incre...Curved steel bridges are commonly used at interchanges in transportation networks and more of these structures continue to be designed and built in the United States. Though the use of these bridges continues to increase in locations that experience high seismicity, the effects of curvature and other parameters on their seismic behaviors have been neglected in current risk assessment tools. These tools can evaluate the seismic vulnerability of a transportation network using fragility curves. One critical component of fragility curve development for curved steel bridges is the completion of sensitivity analyses that help identify influential parameters related to their seismic response. In this study, an accessible inventory of existing curved steel girder bridges located primarily in the Mid-Atlantic United States （MAUS） was used to establish statistical characteristics used as inputs for a seismic sensitivity study. Critical seismic response quantities were captured using 3D nonlinear finite element models. Influential parameters from these quantities were identified using statistical tools that incorporate experimental Plackett-Burman Design （PBD）, which included Pareto optimal plots and prediction profiler techniques. The findings revealed that the potential variation in the influential parameters included number of spans, radius of curvature, maximum span length, girder spacing, and cross-frame spacing. These parameters showed varying levels of influence on the critical bridge response.展开更多
The fatigue life for components can be predicted by the plot method which is easy and convenient in engineering. Based on the usual fatigue life prediction formula, a new formula for estimating the low stress and hig...The fatigue life for components can be predicted by the plot method which is easy and convenient in engineering. Based on the usual fatigue life prediction formula, a new formula for estimating the low stress and high cycle fatigue life is proposed and deduced, which has adopted more accurate SN curve relationship——WeibullSN curve formula. The solution of the new formula is given, too. In addition, an example has been calculated and proved in practice. The results of the new formula and the old one are given and compared.展开更多
Two systems of additive equations were developed to predict aboveground stand level biomass in log products and harvest residue from routinely measured or predicted stand variables for Pinus radiata plantations in New...Two systems of additive equations were developed to predict aboveground stand level biomass in log products and harvest residue from routinely measured or predicted stand variables for Pinus radiata plantations in New South Wales,Australia.These plantations were managed under three thinning regimes or stand types before clear-felling at rotation age by cut-to-length harvesters to produce sawlogs and pulpwood.The residue material following a clear-fell operation mainly consisted of stumps,branches and treetops,short off-cut and waste sections due to stem deformity,defects,damage and breakage.One system of equations did not include dummy variables for stand types in the model specification and was intended for more general use in plantations where stand density management regimes were not the same as the stand types in our study.The other system that incorporated dummy variables was for stand type-specific applications.Both systems of equations were estimated using 61 plot-based estimates of biomass in commercial logs and residue components that were derived from systems of equations developed in situ for predicting the product and residue biomass of individual trees.To cater for all practical applications,two sets of parameters were estimated for each system of equations for predicting component and total aboveground stand biomass in fresh and dry weight respectively.The two sets of parameters for the system of equations without dummy variables were jointly estimated to improve statistical efficiency in parameter estimation.The predictive performances of the two systems of equations were benchmarked through a leave-one-plot-out cross validation procedure.They were generally superior to the performance of an alternative two-stage approach that combined an additive system for major components with an allocative system for sub-components.As using forest harvest residue biomass for bioenergy has increasingly become an integrated part of forestry,reliable estimates of product and residue biomass will assist harvest and展开更多
With the rapid development of the movie industry, it is vital to evaluate and predict a movie’s quality. In this paper, a movie score prediction model is proposed based on the movie plots. Movie data was processed wi...With the rapid development of the movie industry, it is vital to evaluate and predict a movie’s quality. In this paper, a movie score prediction model is proposed based on the movie plots. Movie data was processed with the word2vec method, and the linear regression model and back propagation neural network algorithm were employed to establish the movie score prediction model. The high-quality classic movie plots of high-scoring movies summed up by big data contributed to a high synthesis of the wonderful content of the film. Experimental results show that it is effective in terms of movie evaluation and prediction, and helpful in understanding people’s preferences for movie plots.展开更多
The Varzaghan district at the northwestern margin of the Urumieh–Dokhtar magmatic arc, is considered a promising area for the exploration of porphyry Cu deposits in Iran. In this study we identified mono-and multi-el...The Varzaghan district at the northwestern margin of the Urumieh–Dokhtar magmatic arc, is considered a promising area for the exploration of porphyry Cu deposits in Iran. In this study we identified mono-and multi-element geochemical anomalies associated with Cu–Au–Mo–Bi mineralization in the central parts of the Varzaghan district by applying the concentration–area fractal method. After mono-element geochemical investigations, principal component analysis was applied to ten selected elements in order to acquire a multi-element geochemical signature based on the mineralization-related component. Quantitative comparisons of the obtained fractal-based populations were carried out in accordance with known Cu occurrences using Student's t-values. Then,significant mono-and multi-element geochemical layers were separately combined with related geologic and structural layers to generate prospectivity models, using the fuzzy GAMMA approach. For quantitative evaluation of the effectiveness of different geochemical signatures in final prospectivity models, a prediction-area plot was adapted. The results show that the multi-element geochemical signature of principal component one(PC1) is more effective than mono-element layers in delimiting exploration targets related to porphyry Cu deposits.展开更多
The gelation behaviours of low molecular weight gelators 1,3：2,5：4.6-tris（3,4-dichlorobenzylidene）-Dmannitol（G1） and 2,4-（3.4-dichlorobenzylidene）-N-（3-aminopropyl）-D-gluconamide（G2） in 34 solvents have be...The gelation behaviours of low molecular weight gelators 1,3：2,5：4.6-tris（3,4-dichlorobenzylidene）-Dmannitol（G1） and 2,4-（3.4-dichlorobenzylidene）-N-（3-aminopropyl）-D-gluconamide（G2） in 34 solvents have been studied.We found that sample dissolved at low concentrations may become a gel or precipitate at higher concentrations.The Hansen solubility parameters（HSPs） and a Teas plot were employed to correlate the gelation behaviours with solvent properties,but with no success if the concentration of the tests was not maintained constant.Instead,on the basis of the gelation results obtained for the G1 and G2 in single solvents,we studied the gelation behaviours of G1 and G2 in23 solvent mixtures and found that the tendency of a gelator to form a gel in mixed solvents is strongly correlated with its gelation behaviours in good solvents.If the gelation occurs in a good solvent at higher concentrations,it will take place as well in a mixed solvent（the good solvent plus a poor solvent） at a certain volume ratio.In contrast,if the gelator forms a precipitate in a good solvent at higher concentrations,no gelation is to be observed in the mixed solvents.A gelation rule for mixed solvents is thus proposed,which may facilitate decision making with regard to solvent selection for gel formation in the solvent mixtures in practical applications.展开更多
基金the Korea Electric Power Infrastructure for funding this work
文摘Curved steel bridges are commonly used at interchanges in transportation networks and more of these structures continue to be designed and built in the United States. Though the use of these bridges continues to increase in locations that experience high seismicity, the effects of curvature and other parameters on their seismic behaviors have been neglected in current risk assessment tools. These tools can evaluate the seismic vulnerability of a transportation network using fragility curves. One critical component of fragility curve development for curved steel bridges is the completion of sensitivity analyses that help identify influential parameters related to their seismic response. In this study, an accessible inventory of existing curved steel girder bridges located primarily in the Mid-Atlantic United States （MAUS） was used to establish statistical characteristics used as inputs for a seismic sensitivity study. Critical seismic response quantities were captured using 3D nonlinear finite element models. Influential parameters from these quantities were identified using statistical tools that incorporate experimental Plackett-Burman Design （PBD）, which included Pareto optimal plots and prediction profiler techniques. The findings revealed that the potential variation in the influential parameters included number of spans, radius of curvature, maximum span length, girder spacing, and cross-frame spacing. These parameters showed varying levels of influence on the critical bridge response.
文摘The fatigue life for components can be predicted by the plot method which is easy and convenient in engineering. Based on the usual fatigue life prediction formula, a new formula for estimating the low stress and high cycle fatigue life is proposed and deduced, which has adopted more accurate SN curve relationship——WeibullSN curve formula. The solution of the new formula is given, too. In addition, an example has been calculated and proved in practice. The results of the new formula and the old one are given and compared.
基金This study was supported by the Australian Government Department of Agriculture,Fisheries and Forestry,the Rural Industries Research and Development Corporation,and Forests NSW.
文摘Two systems of additive equations were developed to predict aboveground stand level biomass in log products and harvest residue from routinely measured or predicted stand variables for Pinus radiata plantations in New South Wales,Australia.These plantations were managed under three thinning regimes or stand types before clear-felling at rotation age by cut-to-length harvesters to produce sawlogs and pulpwood.The residue material following a clear-fell operation mainly consisted of stumps,branches and treetops,short off-cut and waste sections due to stem deformity,defects,damage and breakage.One system of equations did not include dummy variables for stand types in the model specification and was intended for more general use in plantations where stand density management regimes were not the same as the stand types in our study.The other system that incorporated dummy variables was for stand type-specific applications.Both systems of equations were estimated using 61 plot-based estimates of biomass in commercial logs and residue components that were derived from systems of equations developed in situ for predicting the product and residue biomass of individual trees.To cater for all practical applications,two sets of parameters were estimated for each system of equations for predicting component and total aboveground stand biomass in fresh and dry weight respectively.The two sets of parameters for the system of equations without dummy variables were jointly estimated to improve statistical efficiency in parameter estimation.The predictive performances of the two systems of equations were benchmarked through a leave-one-plot-out cross validation procedure.They were generally superior to the performance of an alternative two-stage approach that combined an additive system for major components with an allocative system for sub-components.As using forest harvest residue biomass for bioenergy has increasingly become an integrated part of forestry,reliable estimates of product and residue biomass will assist harvest and
基金Natural Science Foundation of Jilin Provincial Science and Technology Department (20180101016JC)Science and Technology Development Plan of Jilin Province (20180101054JC).
文摘With the rapid development of the movie industry, it is vital to evaluate and predict a movie’s quality. In this paper, a movie score prediction model is proposed based on the movie plots. Movie data was processed with the word2vec method, and the linear regression model and back propagation neural network algorithm were employed to establish the movie score prediction model. The high-quality classic movie plots of high-scoring movies summed up by big data contributed to a high synthesis of the wonderful content of the film. Experimental results show that it is effective in terms of movie evaluation and prediction, and helpful in understanding people’s preferences for movie plots.
文摘The Varzaghan district at the northwestern margin of the Urumieh–Dokhtar magmatic arc, is considered a promising area for the exploration of porphyry Cu deposits in Iran. In this study we identified mono-and multi-element geochemical anomalies associated with Cu–Au–Mo–Bi mineralization in the central parts of the Varzaghan district by applying the concentration–area fractal method. After mono-element geochemical investigations, principal component analysis was applied to ten selected elements in order to acquire a multi-element geochemical signature based on the mineralization-related component. Quantitative comparisons of the obtained fractal-based populations were carried out in accordance with known Cu occurrences using Student's t-values. Then,significant mono-and multi-element geochemical layers were separately combined with related geologic and structural layers to generate prospectivity models, using the fuzzy GAMMA approach. For quantitative evaluation of the effectiveness of different geochemical signatures in final prospectivity models, a prediction-area plot was adapted. The results show that the multi-element geochemical signature of principal component one(PC1) is more effective than mono-element layers in delimiting exploration targets related to porphyry Cu deposits.
基金the financial support of the National Natural Science Foundation of China(Nos.21276188,21476164)Tianjin Science and Technology Innovation Platform Program(No.14TXGCCX00017)
文摘The gelation behaviours of low molecular weight gelators 1,3：2,5：4.6-tris（3,4-dichlorobenzylidene）-Dmannitol（G1） and 2,4-（3.4-dichlorobenzylidene）-N-（3-aminopropyl）-D-gluconamide（G2） in 34 solvents have been studied.We found that sample dissolved at low concentrations may become a gel or precipitate at higher concentrations.The Hansen solubility parameters（HSPs） and a Teas plot were employed to correlate the gelation behaviours with solvent properties,but with no success if the concentration of the tests was not maintained constant.Instead,on the basis of the gelation results obtained for the G1 and G2 in single solvents,we studied the gelation behaviours of G1 and G2 in23 solvent mixtures and found that the tendency of a gelator to form a gel in mixed solvents is strongly correlated with its gelation behaviours in good solvents.If the gelation occurs in a good solvent at higher concentrations,it will take place as well in a mixed solvent（the good solvent plus a poor solvent） at a certain volume ratio.In contrast,if the gelator forms a precipitate in a good solvent at higher concentrations,no gelation is to be observed in the mixed solvents.A gelation rule for mixed solvents is thus proposed,which may facilitate decision making with regard to solvent selection for gel formation in the solvent mixtures in practical applications.
