Various physical parameters, including gas concentrations (O2, CO, CH4, and H2) and temperatures at dif- ferent air velocities, were determined for full scale wood fires in the Chongqing Coal Research Institute fire t...Various physical parameters, including gas concentrations (O2, CO, CH4, and H2) and temperatures at dif- ferent air velocities, were determined for full scale wood fires in the Chongqing Coal Research Institute fire test tunnel. Both experimental measurements and numerical simulations are discussed. The numer- ical analysis was performed with the computational fluid dynamics software package ''FLUENT''. The results show that the experimental data agree with the simulation results. The results verify that Roberts' theory of burning is correct. They also prove that the air velocity is the key factor that determines the type of combustion. Also, it is shown that secondary disasters are unlikely for oxygen rich combustion with a limited fire load.展开更多
In order to analyze the relationship between desert plant growth and precipitation,soil moisture,as well as groundwater in desertification control,a comprehensive desertification prevention and control station was est...In order to analyze the relationship between desert plant growth and precipitation,soil moisture,as well as groundwater in desertification control,a comprehensive desertification prevention and control station was established in the desert area of Hexi Corridor for long-term location monitoring,and data of precipitation,soil moisture,groundwater,coverage,and biomass were obtained.Methods including characteristic parameter algorithm,correlation analysis,and stepwise multiple linear regression analysis were employed to analyze the annual and inter-annual variation characteristics of plant growth and moisture,and related regression models were analyzed.The results showed that:(1) from 2006 to 2014,the inter-annual variation of soil moisture was the most drastic,the precipitation,biomass,and coverage underwent a similarly great variation,and the variation of the groundwater was the most moderate.The coverage showed a significantly fluctuating uptrend,and the biomass increased slightly.The precipitation,soil moisture,and groundwater showed a slight decrease,but it was not obvious.(2) During the plant growing season from March to November,the change of moisture content in each layer of soil was basical y the same,and the changes in biomass and coverage were basically the same,so were the changes in precipitation and groundwater.The order of the change range from large to small within the year was precipitation > groundwater depth > biomass > average coverage > soil moisture content.(3) Both the coverage and biomass models passed the R-fitting test,the F-test,and the t-test.The models predicted the variation of 58.0% and 98.7%,and the accuracy rate reached 52.0% and 86.2%.The research results can provide scientific support and reference data for water resources management in the prevention and control of desertification,as well as the evaluation of the influence of projects such as returning farmland to forest,natural forest protection,and comprehensive management of the Heihe River Basin on water resources.展开更多
基金Financial support for this work provided by the National"Eleventh Five-Year" Key Scientific and Technological Support[Program (No. 2007BAK22B04)2008 independent task (No.SKLCRSM08B12)
文摘Various physical parameters, including gas concentrations (O2, CO, CH4, and H2) and temperatures at dif- ferent air velocities, were determined for full scale wood fires in the Chongqing Coal Research Institute fire test tunnel. Both experimental measurements and numerical simulations are discussed. The numer- ical analysis was performed with the computational fluid dynamics software package ''FLUENT''. The results show that the experimental data agree with the simulation results. The results verify that Roberts' theory of burning is correct. They also prove that the air velocity is the key factor that determines the type of combustion. Also, it is shown that secondary disasters are unlikely for oxygen rich combustion with a limited fire load.
基金Sponsored by National Natural Science Fund of China(41461004)Gansu Provincial Science and Technology Innovation Service Platform Project(144JTCG254)Gansu Provincial Basic Research Innovation Group Project(145RJIG337)
文摘In order to analyze the relationship between desert plant growth and precipitation,soil moisture,as well as groundwater in desertification control,a comprehensive desertification prevention and control station was established in the desert area of Hexi Corridor for long-term location monitoring,and data of precipitation,soil moisture,groundwater,coverage,and biomass were obtained.Methods including characteristic parameter algorithm,correlation analysis,and stepwise multiple linear regression analysis were employed to analyze the annual and inter-annual variation characteristics of plant growth and moisture,and related regression models were analyzed.The results showed that:(1) from 2006 to 2014,the inter-annual variation of soil moisture was the most drastic,the precipitation,biomass,and coverage underwent a similarly great variation,and the variation of the groundwater was the most moderate.The coverage showed a significantly fluctuating uptrend,and the biomass increased slightly.The precipitation,soil moisture,and groundwater showed a slight decrease,but it was not obvious.(2) During the plant growing season from March to November,the change of moisture content in each layer of soil was basical y the same,and the changes in biomass and coverage were basically the same,so were the changes in precipitation and groundwater.The order of the change range from large to small within the year was precipitation > groundwater depth > biomass > average coverage > soil moisture content.(3) Both the coverage and biomass models passed the R-fitting test,the F-test,and the t-test.The models predicted the variation of 58.0% and 98.7%,and the accuracy rate reached 52.0% and 86.2%.The research results can provide scientific support and reference data for water resources management in the prevention and control of desertification,as well as the evaluation of the influence of projects such as returning farmland to forest,natural forest protection,and comprehensive management of the Heihe River Basin on water resources.
