Organic mulch can improve the moisture,chemical composition,dust,and dust suppression of soil,and beautify the environment.In view of the rapid evaporation rate and serious loss of soil water in tropical areas,this pa...Organic mulch can improve the moisture,chemical composition,dust,and dust suppression of soil,and beautify the environment.In view of the rapid evaporation rate and serious loss of soil water in tropical areas,this paper explored the effect of organic mulch materials with different thickness on the increase of soil water retention rate and the improvement of soil water loss caused by evaporation.Rubberwood sawdust(RWS),rubberwood bark(RWB),coconut fiber(CF),and Mulch(MC)were selected as the mulching materials.Field experiment and laboratory experiment were performed,and soil-moisture content and temperature were continuously monitored.However,from the daily measurement of water content at constant conditions(29℃±0.2℃,74%±1%air RH)in the laboratory experiment,the results of variance analysis(ANOVA)showed that there was no significant difference between the soil-water content of covered samples and bare soil(P>0.05).In the field experiments,the analysis of variance indicated significant differences in the soil-moisture content owing to the effect of the covering material(P<0.01).Mulching increased the soil-moisture content with smaller fluctuations in the deep soil compared with bare soil.The most stable soil-moisture content were achieved by RWS,RWB,CF,and MC,with thicknesses of 5,3,7,and 5 cm,respectively,compared with bare soil,and the average water contents of the 0-40 cm soil layer was 0.58%,0.01%,0.82%,and 0.93%,respectively.Vertically,the intensity of the change in soil moisture decreased gradually with increasing depth,and was more stable than that of bare soil and other treatments.Among them,the difference in water content between the adjacent gradient soil layers(the soil layers are graded every 10 cm in depth)M_(3-7)(0.011±0.004)was the smallest.It can be concluded that CF mulching materials with a thickness of 7 cm would be preferable when selecting mulching materials for controlling soil moisture in tropical cities.展开更多
Based on the analysis of the whole process of LNG spill on land,the research methods of LNG pool expansion and heavy gas diffusion are summarized and analyzed.This paper reviews the experimental and analytical work p...Based on the analysis of the whole process of LNG spill on land,the research methods of LNG pool expansion and heavy gas diffusion are summarized and analyzed.This paper reviews the experimental and analytical work performed to data on spill of LNG.Specifically,experiments on the spill of LNG onshore,as well as experiments and numerical study on heavy gas dispersion.Pool boiling and turbulence model are described and discussed,as well as models used to predict dispersion.Although there have been significant progress in understanding the behavior of LNG spills,technical knowledge gaps to improve hazard prediction are still identified.Some of the gaps can be addressed with current modeling and testing capabilities.Finally,a discussion of the state of knowledge,and recommendations to further improvement the understanding of the behavior of LNG spills onshore.展开更多
基金This work was supported by the Scientific Research Start-up Fund Project of Hainan University(KYQD(ZR)1986)the Natural Science Foundation of Hainan Province(319QN168).
文摘Organic mulch can improve the moisture,chemical composition,dust,and dust suppression of soil,and beautify the environment.In view of the rapid evaporation rate and serious loss of soil water in tropical areas,this paper explored the effect of organic mulch materials with different thickness on the increase of soil water retention rate and the improvement of soil water loss caused by evaporation.Rubberwood sawdust(RWS),rubberwood bark(RWB),coconut fiber(CF),and Mulch(MC)were selected as the mulching materials.Field experiment and laboratory experiment were performed,and soil-moisture content and temperature were continuously monitored.However,from the daily measurement of water content at constant conditions(29℃±0.2℃,74%±1%air RH)in the laboratory experiment,the results of variance analysis(ANOVA)showed that there was no significant difference between the soil-water content of covered samples and bare soil(P>0.05).In the field experiments,the analysis of variance indicated significant differences in the soil-moisture content owing to the effect of the covering material(P<0.01).Mulching increased the soil-moisture content with smaller fluctuations in the deep soil compared with bare soil.The most stable soil-moisture content were achieved by RWS,RWB,CF,and MC,with thicknesses of 5,3,7,and 5 cm,respectively,compared with bare soil,and the average water contents of the 0-40 cm soil layer was 0.58%,0.01%,0.82%,and 0.93%,respectively.Vertically,the intensity of the change in soil moisture decreased gradually with increasing depth,and was more stable than that of bare soil and other treatments.Among them,the difference in water content between the adjacent gradient soil layers(the soil layers are graded every 10 cm in depth)M_(3-7)(0.011±0.004)was the smallest.It can be concluded that CF mulching materials with a thickness of 7 cm would be preferable when selecting mulching materials for controlling soil moisture in tropical cities.
基金This work is supported by Nanchong Science and Technology Bureau Project under Grant No.18SXHZ0021.
文摘Based on the analysis of the whole process of LNG spill on land,the research methods of LNG pool expansion and heavy gas diffusion are summarized and analyzed.This paper reviews the experimental and analytical work performed to data on spill of LNG.Specifically,experiments on the spill of LNG onshore,as well as experiments and numerical study on heavy gas dispersion.Pool boiling and turbulence model are described and discussed,as well as models used to predict dispersion.Although there have been significant progress in understanding the behavior of LNG spills,technical knowledge gaps to improve hazard prediction are still identified.Some of the gaps can be addressed with current modeling and testing capabilities.Finally,a discussion of the state of knowledge,and recommendations to further improvement the understanding of the behavior of LNG spills onshore.
