The change and control of nitrogen content in molten steel was investigated through the production process of "LDBAr-LF-RH-CC". Results show that nitrogen content reduces gradually in converter-steelmaking s...The change and control of nitrogen content in molten steel was investigated through the production process of "LDBAr-LF-RH-CC". Results show that nitrogen content reduces gradually in converter-steelmaking stage, rises rapidly from the end of converter process to the end of argon station process, continues to increase in ladle furnace process, and decreases slightly in RH refining stage. Since nitrogen is removed mainly by BOF steelmaking and vacuum refining operations, nitrogen in molten steel should be removed as much as possible in these two operations. However, nitrogen uptake should be minimized in other operations of molten steel production process.展开更多
Objective: The paper aims to analyze the dynamic characteristics of litter production and nutrient return of the forest ecosystems in subtropical areas, and provide a theoretical basis for the nutrient cycling study i...Objective: The paper aims to analyze the dynamic characteristics of litter production and nutrient return of the forest ecosystems in subtropical areas, and provide a theoretical basis for the nutrient cycling study in southwest Hubei Province and carbon sink function of the whole forest ecosystem. Methods: Three typical forest stands (Chinese fir plantation, Cryptomeria fortunei plantation and evergreen and deciduous broad-leaved mixed forest) in Golden Mountain Forest Farm in southwest Hubei Province were investigated and monitored continuously for the litter types and productivity and nutrient return. Results: The annual litter productivity of the three forest stands ranged from 161.77 to 396.26 kg·hm<sup>-2</sup>;Litters of branches, leaves and reproductive organs accounted for 14.14% - 20.85%, 33.26% - 78.33%, 7.52% - 42.18% of the total, respectively;The litter productivity and total litter productivity of each composition in the three forest stands show unimodal or bimodal changes over months, and the total litter productivity reached the highest value in January, April and October respectively. For different nutrient contents of the three forest stands, the common feature is C > N. The order of nutrient return amount from greatest to least is evergreen and deciduous broad-leaved mixed forest, Cryptomeria fortunei plantation and Chinese fir plantation. For different nutrient return amounts, the common feature is C > N, and the nutrient return amounts are 76.51-180.69 kg·hm<sup>-2</sup> and 2.3 - 5.71 kg·hm<sup>-2</sup> respectively. Conclusion: The annual litter productivity and nutrient return amount of the evergreen and deciduous broad-leaved mixed forest are the highest among the three forest stands. Therefore, protecting the evergreen and deciduous broad-leaved mixed forest and studying the litter changes of Chinese fir plantation and Cryptomeria fortunei plantation are of far-reaching significance for the development of sustainable forest management in this region and the further improvement of the carbon sequestration function of the whole forest ecosystem.展开更多
The above-ground biomass and nutrient accumulation by poplar plantations were evaluated for pulpwood production ]n China, Experimental treatments applied in a split-plot design included four planting densities (1111, ...The above-ground biomass and nutrient accumulation by poplar plantations were evaluated for pulpwood production ]n China, Experimental treatments applied in a split-plot design included four planting densities (1111, 833, 625 and 500 stems hm-2), three rotation lengths (4a, 5a and 6a) and three poplar clones (1-69.NL-80351 and 1-72). The highest biomass was achieved in the highest stocked stand (1111 stem hm-2’) at 6 of rotation age for both clone 1-69 and clone 1-72, which is about two times that in the stands of 500 stems hm-2 at 4 ofrotation age. However, the highest occurred in the stand of 833 stems-hm-2 at 6-year rotation for NL-80351. Ranking of the plantation biomass production by component was stem > branches > foliage> stem--bark and the production of the Support components of the plantation was 10-fold that of the productive component, i.e., foliage. Thepattern of accumulation of nutrients by the plantations was similar to the biomass. Nutrient accumulation in theplantations was in the order of Ca>N>K>Mg>P, but some differences existed in annual nutrient accumulationrates for four planting densities and three poplar clones, The mean annual accumulation of N and P in the plantations was 13.2 and 2.8 kg hm-2 in stem, 12.1 and 1 .9 kg hm 2 in branch, and 98.5 and 9.5 kghm’ in foliage. Themean Ca, K and Mg accumulations were 28.2, 1 8.5 and 2.9 kg’hm-2 a-1, 26,9. 11,0 and 2.3 kg-hm-2-a-1 in branch.and 116.5, 81 .3 and 16, 1 kg hm-2 a-1 in foliage, respectively. Biomass utilization standards markedly affected theexport of nutrients from the site, Whole tree utilization yields the most biomass and removes the most nutrients,Removal of stem with 2 10-cm diameter exports about half of the biomass, but N and nutrients removals are only23% and 28% of the total, respectively, Removal of the entire stem provides about tWo--thirds of the total biomassand removes 31,1% total N and 37.5 % total nutrients respectively. Including the branches in the removal increases biomass yield to 92% of the total, and nutrient removal is about 68% of the total,展开更多
Tomatoes are one of the most important specialty crops in United States and tomato products constitute a significant part of the food industry. The quality of tomato paste and juice is evaluated through their viscosit...Tomatoes are one of the most important specialty crops in United States and tomato products constitute a significant part of the food industry. The quality of tomato paste and juice is evaluated through their viscosity, color, flavor and nutritional value. Four processing methods were selected for this study, in-cluding conventional hot break, waring blender with steam, steam injection, and high temperature with shear (HTS) in a twin-screw continuous processor. The HTS method applies high temperature with shear mixer during hot-break tomato processing that improves the efficiency of the extraction process and the resultant tomato products possessed higher consistency, viscosity, and ly-copene content. Lycopene is an excellent antioxidant with cancer-preventing properties. This work showed that HTS method, utilizing whole tomatoes, produced a superior tomato product with a better color, higher viscosity, and improved bioactive properties.展开更多
文摘The change and control of nitrogen content in molten steel was investigated through the production process of "LDBAr-LF-RH-CC". Results show that nitrogen content reduces gradually in converter-steelmaking stage, rises rapidly from the end of converter process to the end of argon station process, continues to increase in ladle furnace process, and decreases slightly in RH refining stage. Since nitrogen is removed mainly by BOF steelmaking and vacuum refining operations, nitrogen in molten steel should be removed as much as possible in these two operations. However, nitrogen uptake should be minimized in other operations of molten steel production process.
文摘Objective: The paper aims to analyze the dynamic characteristics of litter production and nutrient return of the forest ecosystems in subtropical areas, and provide a theoretical basis for the nutrient cycling study in southwest Hubei Province and carbon sink function of the whole forest ecosystem. Methods: Three typical forest stands (Chinese fir plantation, Cryptomeria fortunei plantation and evergreen and deciduous broad-leaved mixed forest) in Golden Mountain Forest Farm in southwest Hubei Province were investigated and monitored continuously for the litter types and productivity and nutrient return. Results: The annual litter productivity of the three forest stands ranged from 161.77 to 396.26 kg·hm<sup>-2</sup>;Litters of branches, leaves and reproductive organs accounted for 14.14% - 20.85%, 33.26% - 78.33%, 7.52% - 42.18% of the total, respectively;The litter productivity and total litter productivity of each composition in the three forest stands show unimodal or bimodal changes over months, and the total litter productivity reached the highest value in January, April and October respectively. For different nutrient contents of the three forest stands, the common feature is C > N. The order of nutrient return amount from greatest to least is evergreen and deciduous broad-leaved mixed forest, Cryptomeria fortunei plantation and Chinese fir plantation. For different nutrient return amounts, the common feature is C > N, and the nutrient return amounts are 76.51-180.69 kg·hm<sup>-2</sup> and 2.3 - 5.71 kg·hm<sup>-2</sup> respectively. Conclusion: The annual litter productivity and nutrient return amount of the evergreen and deciduous broad-leaved mixed forest are the highest among the three forest stands. Therefore, protecting the evergreen and deciduous broad-leaved mixed forest and studying the litter changes of Chinese fir plantation and Cryptomeria fortunei plantation are of far-reaching significance for the development of sustainable forest management in this region and the further improvement of the carbon sequestration function of the whole forest ecosystem.
文摘The above-ground biomass and nutrient accumulation by poplar plantations were evaluated for pulpwood production ]n China, Experimental treatments applied in a split-plot design included four planting densities (1111, 833, 625 and 500 stems hm-2), three rotation lengths (4a, 5a and 6a) and three poplar clones (1-69.NL-80351 and 1-72). The highest biomass was achieved in the highest stocked stand (1111 stem hm-2’) at 6 of rotation age for both clone 1-69 and clone 1-72, which is about two times that in the stands of 500 stems hm-2 at 4 ofrotation age. However, the highest occurred in the stand of 833 stems-hm-2 at 6-year rotation for NL-80351. Ranking of the plantation biomass production by component was stem > branches > foliage> stem--bark and the production of the Support components of the plantation was 10-fold that of the productive component, i.e., foliage. Thepattern of accumulation of nutrients by the plantations was similar to the biomass. Nutrient accumulation in theplantations was in the order of Ca>N>K>Mg>P, but some differences existed in annual nutrient accumulationrates for four planting densities and three poplar clones, The mean annual accumulation of N and P in the plantations was 13.2 and 2.8 kg hm-2 in stem, 12.1 and 1 .9 kg hm 2 in branch, and 98.5 and 9.5 kghm’ in foliage. Themean Ca, K and Mg accumulations were 28.2, 1 8.5 and 2.9 kg’hm-2 a-1, 26,9. 11,0 and 2.3 kg-hm-2-a-1 in branch.and 116.5, 81 .3 and 16, 1 kg hm-2 a-1 in foliage, respectively. Biomass utilization standards markedly affected theexport of nutrients from the site, Whole tree utilization yields the most biomass and removes the most nutrients,Removal of stem with 2 10-cm diameter exports about half of the biomass, but N and nutrients removals are only23% and 28% of the total, respectively, Removal of the entire stem provides about tWo--thirds of the total biomassand removes 31,1% total N and 37.5 % total nutrients respectively. Including the branches in the removal increases biomass yield to 92% of the total, and nutrient removal is about 68% of the total,
文摘Tomatoes are one of the most important specialty crops in United States and tomato products constitute a significant part of the food industry. The quality of tomato paste and juice is evaluated through their viscosity, color, flavor and nutritional value. Four processing methods were selected for this study, in-cluding conventional hot break, waring blender with steam, steam injection, and high temperature with shear (HTS) in a twin-screw continuous processor. The HTS method applies high temperature with shear mixer during hot-break tomato processing that improves the efficiency of the extraction process and the resultant tomato products possessed higher consistency, viscosity, and ly-copene content. Lycopene is an excellent antioxidant with cancer-preventing properties. This work showed that HTS method, utilizing whole tomatoes, produced a superior tomato product with a better color, higher viscosity, and improved bioactive properties.
