The objective of this research was to investigate the effect of Malva nut gum （MG） replacement on the pasting characteristics and freeze-thaw stability of wheat, rice or waxy rice flours. Pasting properties and free...The objective of this research was to investigate the effect of Malva nut gum （MG） replacement on the pasting characteristics and freeze-thaw stability of wheat, rice or waxy rice flours. Pasting properties and freeze-thaw stability of different flours incorporated with 0, 0.5%, 1%, 2%, 3% and 5% of MG were investigated. Pasting temperature （60 ℃-87 ℃） of the pastes significantly decreased with increasing of MG content for wheat and rice flours, but had no significant effect for waxy rice flour. Incorporation of MG into all flours significantly elevated the peak viscosity by about 0.9-2.6 folds when compared to non-MG samples. Hot paste viscosity, breakdown and final viscosity for all flour mixtures significantly increased with increasing of MG which ranged from 81-427, 37-559 and 152-463 RVU, respectively. Freeze-thaw stability measurement demonstrated that higher level of MG in wheat and rice gel mixtures could decrease syneresis. However, MG had no effect on syneresis of waxy rice gel. Presence of MG in flours alters the pasting properties and syneresis effect. It is suggested that higher viscosity and lower syneresis of gels could be modified by MG.展开更多
The explosive characteristics of aluminum powder have great significance in preventing and controlling aluminum-dust explosion accidents, especially the nano-aluminum powder. The explosion characteristics of 100 nm an...The explosive characteristics of aluminum powder have great significance in preventing and controlling aluminum-dust explosion accidents, especially the nano-aluminum powder. The explosion characteristics of 100 nm and 75 μm aluminum powders were investigated by using a 20 L spherical explosion cavity and a horizontal pipe whose cross-section area is 80 mm × 80 mm and length is 8 m. The results show that the maximum explosion pressure and its rising rate of 100 nm aluminum powder gradually increase with increasing concentration of aluminum-powder at the beginning. When aluminum-powder concentration is I kg/m3, the maximum explosion pressure reaches its maximum, and then gradually decreases. While when the concentration is 1.25 kg/m3, the maximum rate of pressure rise obtains its maximum, and then decreases. After 100 nm aluminum powder is exploded in pipes, the peak overpressure of blast wave first decreases and then increases to the maximum at a distance of 298 cm from the ignition source, and then gradually decreases. The most violent concentration is about 0.4 kg/m3 which is lower than 0.8 kg/m3 of 75 μm aluminum powder, so 100 nm aluminum powders are more easily exploded. The change laws of maximum explosion pressure, maximum rate of pressure rise and blast-wave peak overpressure of 100 nm aluminum powders with concentration are similar to those of 75 ktm aluminum powders, but these values are much higher than 75 Bm aluminum powders under the same concentration, so the aluminum-powders explosion of 100 nm will produce more harms. In the process of production, storage and transportation of aluminum powder, some relevant preventive measures can be taken to reduce the loss caused by aluminum-dust explosion according to nano-aluminum dust.展开更多
文摘The objective of this research was to investigate the effect of Malva nut gum （MG） replacement on the pasting characteristics and freeze-thaw stability of wheat, rice or waxy rice flours. Pasting properties and freeze-thaw stability of different flours incorporated with 0, 0.5%, 1%, 2%, 3% and 5% of MG were investigated. Pasting temperature （60 ℃-87 ℃） of the pastes significantly decreased with increasing of MG content for wheat and rice flours, but had no significant effect for waxy rice flour. Incorporation of MG into all flours significantly elevated the peak viscosity by about 0.9-2.6 folds when compared to non-MG samples. Hot paste viscosity, breakdown and final viscosity for all flour mixtures significantly increased with increasing of MG which ranged from 81-427, 37-559 and 152-463 RVU, respectively. Freeze-thaw stability measurement demonstrated that higher level of MG in wheat and rice gel mixtures could decrease syneresis. However, MG had no effect on syneresis of waxy rice gel. Presence of MG in flours alters the pasting properties and syneresis effect. It is suggested that higher viscosity and lower syneresis of gels could be modified by MG.
基金supported by the Major State Basic Research Development Program of China (No. 2011CB201205)the Open Fund Program of the State Key Laboratory of Explosion Science and Technology (No. KFJJ10-19M)
文摘The explosive characteristics of aluminum powder have great significance in preventing and controlling aluminum-dust explosion accidents, especially the nano-aluminum powder. The explosion characteristics of 100 nm and 75 μm aluminum powders were investigated by using a 20 L spherical explosion cavity and a horizontal pipe whose cross-section area is 80 mm × 80 mm and length is 8 m. The results show that the maximum explosion pressure and its rising rate of 100 nm aluminum powder gradually increase with increasing concentration of aluminum-powder at the beginning. When aluminum-powder concentration is I kg/m3, the maximum explosion pressure reaches its maximum, and then gradually decreases. While when the concentration is 1.25 kg/m3, the maximum rate of pressure rise obtains its maximum, and then decreases. After 100 nm aluminum powder is exploded in pipes, the peak overpressure of blast wave first decreases and then increases to the maximum at a distance of 298 cm from the ignition source, and then gradually decreases. The most violent concentration is about 0.4 kg/m3 which is lower than 0.8 kg/m3 of 75 μm aluminum powder, so 100 nm aluminum powders are more easily exploded. The change laws of maximum explosion pressure, maximum rate of pressure rise and blast-wave peak overpressure of 100 nm aluminum powders with concentration are similar to those of 75 ktm aluminum powders, but these values are much higher than 75 Bm aluminum powders under the same concentration, so the aluminum-powders explosion of 100 nm will produce more harms. In the process of production, storage and transportation of aluminum powder, some relevant preventive measures can be taken to reduce the loss caused by aluminum-dust explosion according to nano-aluminum dust.
