Heat and mass transfer through a wustite pellet during converting to sponge iron was investigated. Pellet was reduced by a gaseous mixture containing CO and Hz. The grain model was considered to simulate gas solid rea...Heat and mass transfer through a wustite pellet during converting to sponge iron was investigated. Pellet was reduced by a gaseous mixture containing CO and Hz. The grain model was considered to simulate gas solid reac- tion rate. A finite volume method （FVM） was implemented for solving the governing equations. The heat transfer mechanism around the pellet includes radiation and convection and within the pellet, effective heat transfer is consid- ered as a blend of particles conduction and intraparticle radiation. Heat and mass distribution along the radius of pel- let for two cases of reducing gases composed of pure H2 and pure CO was investigated. Local fractional reduction through the pellet was plotted to examine the heat and mass transfer behavior within the pellet and find their rele- vance with reduction degree. Afterwards, the impacts of pertinent parameters including gas ratio, pellet size and po rosity were studied.展开更多
The reduction of foliar area can cause yield reduction in common bean crops. The objective of this work was to verify which is the effect of different defoliation levels realized in several development stages of commo...The reduction of foliar area can cause yield reduction in common bean crops. The objective of this work was to verify which is the effect of different defoliation levels realized in several development stages of common bean (Phaseolus vulgaris L. cv. Goytacazes) over yield, weight of 100 seeds and number of pods per plant. The experimental design was randomized blocks, in a split-plot arrangement with five replications. The plot corresponded to the five defoliation epochs (first trifoliate leaf, flowering, pods formation, pods filling, and dry pods). In each plot, the split plot was represented by the four defoliation levels (0%, 33%, 67% and 100%). It was observed a decrease of yield for all levels defoliation considering all development stages, except for dried pods. The highest decrease was detected for flowering and pods formation. Through the regression analysis got a greater reduction in yield with 100% defoliation made at 42 days after emergence. The evaluation parameter that showed better relation with yield was a number of pods per plant.展开更多
文摘Heat and mass transfer through a wustite pellet during converting to sponge iron was investigated. Pellet was reduced by a gaseous mixture containing CO and Hz. The grain model was considered to simulate gas solid reac- tion rate. A finite volume method （FVM） was implemented for solving the governing equations. The heat transfer mechanism around the pellet includes radiation and convection and within the pellet, effective heat transfer is consid- ered as a blend of particles conduction and intraparticle radiation. Heat and mass distribution along the radius of pel- let for two cases of reducing gases composed of pure H2 and pure CO was investigated. Local fractional reduction through the pellet was plotted to examine the heat and mass transfer behavior within the pellet and find their rele- vance with reduction degree. Afterwards, the impacts of pertinent parameters including gas ratio, pellet size and po rosity were studied.
文摘The reduction of foliar area can cause yield reduction in common bean crops. The objective of this work was to verify which is the effect of different defoliation levels realized in several development stages of common bean (Phaseolus vulgaris L. cv. Goytacazes) over yield, weight of 100 seeds and number of pods per plant. The experimental design was randomized blocks, in a split-plot arrangement with five replications. The plot corresponded to the five defoliation epochs (first trifoliate leaf, flowering, pods formation, pods filling, and dry pods). In each plot, the split plot was represented by the four defoliation levels (0%, 33%, 67% and 100%). It was observed a decrease of yield for all levels defoliation considering all development stages, except for dried pods. The highest decrease was detected for flowering and pods formation. Through the regression analysis got a greater reduction in yield with 100% defoliation made at 42 days after emergence. The evaluation parameter that showed better relation with yield was a number of pods per plant.
