RESUMO
Objective To investigate the effects of particle size, wind speed and dumping velocity on aerosol concentration distribution during powder dumping in a reprocessing plant. Methods CeO2 powder was selected as the substitute material of PuO2. FLUENT software was used to calculate the pouring process of CeO2 powder under different operation conditions. Then the aerosol concentration distribution under different dumping speeds was measured by particle size spectrometer to verify the accuracy of simulation results. Results The particles with small particle size are more likely to be separated from the mainstream area by the drag force of the surrounding gas, and the radius of the diffusion range also increases with the decrease of the particle size. 2) When the ventilation speed is less than 1 m/s, the dust lifting can be reduced and the concentration of dust particles in the chamber can be reduced to a certain extent. 3) In the process of powder dumping, the spoon is rotated anticlockwise at a speed of 100° in 2～3 s, and less dust aerosol is produced on the right side of the tray. Conclusion When operating the powder particles with smaller particle size, more attention should be paid to the monitoring of aerosol at different positions; the change of air inlet velocity makes the flow field in glove box more complex, and the volume fraction of dust particles is related to the size and location of vortex formed by airflow. The greater the wind speed, the greater the impact on the powder dumping process. The experimental results are basically consistent with the simulation results, and the results show that the lower the dumping speed, the smaller the aerosol concentration near the tray.
RESUMO
Objective To investigate the correlation of glycosylated hemoglobin(HbA1C)levels with carotid atherosclerotic plaque and pulse wave velocity (PWV) in elderly patients with type 2 diabetes mellitus (T2DM).Methods There were 130 cases of elderly patients with T2DM,aged from 60 to 92 years,of whom there were 59 males.All subjects were divided into 3 groups based on the HbA1Clevels:the low level group (HbA1C＜7％,n=49),the middle level group (77％≤HbA1C＜ 8.5 ％,n =58) and the high level group (HbA1C ≥8.5 ％,n=23).Height,body weight,blood pressure,blood glucose,blood lipids,HbA1C and other indexes were collected and compared among groups.In addition,carotid ultrasound and PWV examinations were performed.Results There were significant difference in levels of systolic blood pressure (SBP),fasting blood glucose (FBG),high density lipoprotein cholesterol (HDL-C),carotid intima-media thickness (IMT),plaque score,plaque stability and PWV among groups (all P＜0.05).Correlation analysis showed that IMT levels were correlated with gender (r=0.389),age (r=0.296),FBG (r=0.203),HbA1C(r=0.405) and HDL-C (r =-0.208),all P ＜ 0.05.Carotid artery plaque score correlated with gender (r =0.321),age (r =0.355),HbA1C(r=0.340) and HDL-C (r=-0.249) (all P＜0.01)and there is a correlation between the stability of carotid plaques with body mass index (BMI) (r =-0.286),SBP (r =-0.188),HbA1C(r=-0.368) and HDL-C (r=0.405) (all P＜0.05);PWV was correlated with age (r=0.516),SBP (r=0.521),diastolic blood pressure (r=0.225),FBG (r=0.181),HbA1C(r=0.229),triglyceride (r =-0.253),total cholesterol (r=-0.311) and LDL-C (r=-0.244),all P＜ 0.05.Moreover,there was a correlation between IMT and PWV (r =0.234,P ＜ 0.01).Logistic regression analysis showed that gender,age and HbA1C were independently associated with IMT;gender,age,BMI and HbA1C were independently associated with carotid atherosclerosis plaque score;age,HbA1C and HDL-C were independently associated with the stability of carotid atherosclerotic plaque;age and SBP were independently associated with PWV.Conclusions HbA1C,SBP,HDL-C and BMI are independent risk factors for arteriosclerosis in elderly diabetics.