Occasional irregular initial solidification phenomena,including stickers,deep oscillation marks,depressions,and surface cracks of strand shells in continuous casting molds,are important limitations for developing the ...Occasional irregular initial solidification phenomena,including stickers,deep oscillation marks,depressions,and surface cracks of strand shells in continuous casting molds,are important limitations for developing the high-efficiency continuous casting of steels.The application of mold thermal monitoring(MTM) systems,which use thermocouples to detect and respond to temperature variations in molds,has become an effective method to address irregular initial solidification phenomena.Such systems are widely applied in numerous steel companies for sticker breakout prediction.However,monitoring the surface defects of strands remains immature.Hence,indepth research is necessary to utilize the potential advantages and comprehensive monitoring of MTM systems.This paper summarizes what is included in the irregular initial solidification phenomena and systematically reviews the current state of research on these phenomena by the MTM systems.Furthermore,the influences of mold slag behavior on monitoring these phenomena are analyzed.Finally,the remaining problems of the formation mechanisms and investigations of irregular initial solidification phenomena are discussed,and future research directions are proposed.展开更多
Darcy’s law is widely used to describe the flow in porous media in which there is a linear relationship between fluid velocity and pressure gradient. However, it has been found that for high numbers of Reynolds this ...Darcy’s law is widely used to describe the flow in porous media in which there is a linear relationship between fluid velocity and pressure gradient. However, it has been found that for high numbers of Reynolds this law ceases to be valid. In this work, the Ergun equation is employed to consider the non-linearity of air velocity with the pressure gradient in casting sands. The contribution of non-linearity to the total flow in terms of a variable defined as a non-Darcy flow fraction is numerically quantified. In addition, the influence of the shape factor of the sand grains on the non-linear flow fraction is analyzed. It is found that for values of the Reynolds number less or equal than 1, the contribution of non-linearity for spherical particles is around 1.15%.展开更多
Background: Semi-permanent fillers are among the most favorable fillers on the market. Through their unique mode of action and its associated lasting aesthetic effect, they take an exceptional position. Objective: To ...Background: Semi-permanent fillers are among the most favorable fillers on the market. Through their unique mode of action and its associated lasting aesthetic effect, they take an exceptional position. Objective: To compare the two semi-permanent fillers Poly-L-Lactic Acid (PLLA) and calcium hydroxylapatite (CaHA) in reference to the aesthetic result, patient satisfaction and side effects. Methods: Studies on side effects, patient satisfaction and aesthetic results after augmentation with semi-permanent fillers were analyzed. Results: Semi-permanent fillers seem excellently suited for the augmentation of very deep wrinkles particularly in the lower half of the face. In general, high patient satisfaction can be determined with both fillers. Here, the effect from the polylactic acid can be verified for up to two years while no effect could be verified already after one year in a majority of the patients augmented with CaHA. Short-term side effects such as bleedings or erythema in the region of the augmented area have been observed in both fillers during augmentation. The incidence of nodules and granulomas seems significantly higher in augmentations with PLLA compared to CaHA. Rare side effects such as an embolization of a blood vessel caused by the implant have been described for both fillers in case reports. Conclusion: Semi-permanent fillers are superbly suited for wrinkle augmentation. Which filler is the preferred one in what case depends strongly on the individual needs of the patient and the therapist’s experience.展开更多
基金supported by the National Natural Science Foundation of China(No.52274319)。
文摘Occasional irregular initial solidification phenomena,including stickers,deep oscillation marks,depressions,and surface cracks of strand shells in continuous casting molds,are important limitations for developing the high-efficiency continuous casting of steels.The application of mold thermal monitoring(MTM) systems,which use thermocouples to detect and respond to temperature variations in molds,has become an effective method to address irregular initial solidification phenomena.Such systems are widely applied in numerous steel companies for sticker breakout prediction.However,monitoring the surface defects of strands remains immature.Hence,indepth research is necessary to utilize the potential advantages and comprehensive monitoring of MTM systems.This paper summarizes what is included in the irregular initial solidification phenomena and systematically reviews the current state of research on these phenomena by the MTM systems.Furthermore,the influences of mold slag behavior on monitoring these phenomena are analyzed.Finally,the remaining problems of the formation mechanisms and investigations of irregular initial solidification phenomena are discussed,and future research directions are proposed.
文摘Darcy’s law is widely used to describe the flow in porous media in which there is a linear relationship between fluid velocity and pressure gradient. However, it has been found that for high numbers of Reynolds this law ceases to be valid. In this work, the Ergun equation is employed to consider the non-linearity of air velocity with the pressure gradient in casting sands. The contribution of non-linearity to the total flow in terms of a variable defined as a non-Darcy flow fraction is numerically quantified. In addition, the influence of the shape factor of the sand grains on the non-linear flow fraction is analyzed. It is found that for values of the Reynolds number less or equal than 1, the contribution of non-linearity for spherical particles is around 1.15%.
文摘Background: Semi-permanent fillers are among the most favorable fillers on the market. Through their unique mode of action and its associated lasting aesthetic effect, they take an exceptional position. Objective: To compare the two semi-permanent fillers Poly-L-Lactic Acid (PLLA) and calcium hydroxylapatite (CaHA) in reference to the aesthetic result, patient satisfaction and side effects. Methods: Studies on side effects, patient satisfaction and aesthetic results after augmentation with semi-permanent fillers were analyzed. Results: Semi-permanent fillers seem excellently suited for the augmentation of very deep wrinkles particularly in the lower half of the face. In general, high patient satisfaction can be determined with both fillers. Here, the effect from the polylactic acid can be verified for up to two years while no effect could be verified already after one year in a majority of the patients augmented with CaHA. Short-term side effects such as bleedings or erythema in the region of the augmented area have been observed in both fillers during augmentation. The incidence of nodules and granulomas seems significantly higher in augmentations with PLLA compared to CaHA. Rare side effects such as an embolization of a blood vessel caused by the implant have been described for both fillers in case reports. Conclusion: Semi-permanent fillers are superbly suited for wrinkle augmentation. Which filler is the preferred one in what case depends strongly on the individual needs of the patient and the therapist’s experience.