Diesel particulate matter(DPM) is considered carcinogenic after prolonged exposure. This paper used computational fluid dynamics(CFD) method to study the effect of four auxiliary ventilation systems on DPM distributio...Diesel particulate matter(DPM) is considered carcinogenic after prolonged exposure. This paper used computational fluid dynamics(CFD) method to study the effect of four auxiliary ventilation systems on DPM distribution in a dead-end entry with loading operation. The auxiliary ventilation systems considered include: blower fan and tubing; exhaust fan and tubing, jet fan, and push–pull system. A species transport model with buoyancy effect was used to examine the DPM dispersion pattern with unsteady state analysis. During the 200 s of the loading operation, high DPM levels were identified in the face and dead-end entry regions. This study can be used for mining engineer as guidance to design and setup of local ventilation. It can also be used for selection of DPM control strategies and DPM annual training for underground miners.展开更多
Objective To evaluate the effect of real-world practices for icodextrin peritoneal dialysis solution on patients with end-stage renal disease(ESRD)by Meta-analysis.Methods The PubMed and Embase databases were systemat...Objective To evaluate the effect of real-world practices for icodextrin peritoneal dialysis solution on patients with end-stage renal disease(ESRD)by Meta-analysis.Methods The PubMed and Embase databases were systematically searched for real-world research literature on icodextrin peritoneal dialysate in the treatment of ESRD patients,and RevMan5.4 statistical software was used for Meta-analysis.Results and Conclusion 12 studies with 114656 patients were included.Meta-analysis results showed that icodextrin peritoneal dialysis had good effects on mortality[RR=0.72,95%CI(0.62,0.83),P<0.001],congestive heart failure[RR=0.67,95%CI(0.52,0.87),P=0.003],and risk of new-onset diabetes[RR=0.65,95%CI(0.49,0.86),P=0.003],which was consistent with the Meta-analysis based on clinical trials.Meanwhile,there was no significant difference in PD technical failure rate[RR=0.67,95%CI(0.44,1.00),P=0.05],peritonitis[RR=1.02,95%CI(0.99,1.05),P=0.14],cardiovascular and cerebrovascular diseases[RR=0.79,95%CI(0.59,1.05),P=0.10],coronary artery disease[RR=0.99,95%CI(0.92,1.07),P=0.80],stroke[RR=0.86,95%CI(0.66,1.10),P=0.23],and atrial fibrillation[RR=0.73,95%CI(0.37,1.44),P=0.36].However,it might increase the risk of hypertension[RR=1.05,95%CI(1.03,1.07),P<0.001].Therefore,icodextrin can effectively reduce the risk of mortality,congestive heart failure,and new-onset diabetes,which is beneficial to ESRD patients.展开更多
Hemispherical shell resonator(HSR)is the core component of hemispherical resonator gyro.It is aφ-shaped small-bore complex component with minimum curvature radius less than 3 mm.Thus,traditional polishing methods are...Hemispherical shell resonator(HSR)is the core component of hemispherical resonator gyro.It is aφ-shaped small-bore complex component with minimum curvature radius less than 3 mm.Thus,traditional polishing methods are difficult to polish it.Small ball-end magnetorheological polishing method can polish the small components with complicated three-dimensional surface and obtain non-destructive surface.Therefore,this method is suitable for polishing HSR.However,the material removal rate of the ordinary small ball-end magnetorheological polishing is low,leading to long polishing time and low output of HSR.To solve this problem,a water bath heating assisted small ball-end magnetorheological polishing method is proposed in this research.The influence rule of processing parameters on the material removal rate is studied experimentally.A set of optimal processing parameters is obtained to maximize the material removal rate.Compared with the ordinary method,the material removal rate of the new method can be improved by 143%.Subsequently,an HSR is polished by the new method.The results show that the polishing time can be reduced by 55%,and the polished surface roughness can reach 7.7 nm.The new method has the great potential to be used in actual production to improve the polishing efficiency of HSR.展开更多
In order to improve the performance of the Wells turbine for wave energy conversion, the effect of end plates on the turbine characteristics has been investigated experimentally by model testing under steady flow cond...In order to improve the performance of the Wells turbine for wave energy conversion, the effect of end plates on the turbine characteristics has been investigated experimentally by model testing under steady flow conditions. The end plate attached to the tip of the original rotor blade is slightly larger than the original blade profile. The characteristics of the Wells turbine with end plates have been compared with those of the original Wells turbine, i.e., the turbine without end plate. As a result, it has been concluded that the characteristics of the Wells turbine with end plates are superior to those of the original Wells turbine and the characteristics are dependent on the size and position of end plate. Furthermore, the effect of annular plate on the turbine performance, which encircles the turbine and is attached to the tip, was investigated as an additional experiment. However, its device was not effective in improving the turbine characteristics.展开更多
基金the Western US Mining Safety and Health Training & Translation Center by the National Institute for Occupational Safety and Health (NIOSH) (No. 1R25OH008319)
文摘Diesel particulate matter(DPM) is considered carcinogenic after prolonged exposure. This paper used computational fluid dynamics(CFD) method to study the effect of four auxiliary ventilation systems on DPM distribution in a dead-end entry with loading operation. The auxiliary ventilation systems considered include: blower fan and tubing; exhaust fan and tubing, jet fan, and push–pull system. A species transport model with buoyancy effect was used to examine the DPM dispersion pattern with unsteady state analysis. During the 200 s of the loading operation, high DPM levels were identified in the face and dead-end entry regions. This study can be used for mining engineer as guidance to design and setup of local ventilation. It can also be used for selection of DPM control strategies and DPM annual training for underground miners.
文摘Objective To evaluate the effect of real-world practices for icodextrin peritoneal dialysis solution on patients with end-stage renal disease(ESRD)by Meta-analysis.Methods The PubMed and Embase databases were systematically searched for real-world research literature on icodextrin peritoneal dialysate in the treatment of ESRD patients,and RevMan5.4 statistical software was used for Meta-analysis.Results and Conclusion 12 studies with 114656 patients were included.Meta-analysis results showed that icodextrin peritoneal dialysis had good effects on mortality[RR=0.72,95%CI(0.62,0.83),P<0.001],congestive heart failure[RR=0.67,95%CI(0.52,0.87),P=0.003],and risk of new-onset diabetes[RR=0.65,95%CI(0.49,0.86),P=0.003],which was consistent with the Meta-analysis based on clinical trials.Meanwhile,there was no significant difference in PD technical failure rate[RR=0.67,95%CI(0.44,1.00),P=0.05],peritonitis[RR=1.02,95%CI(0.99,1.05),P=0.14],cardiovascular and cerebrovascular diseases[RR=0.79,95%CI(0.59,1.05),P=0.10],coronary artery disease[RR=0.99,95%CI(0.92,1.07),P=0.80],stroke[RR=0.86,95%CI(0.66,1.10),P=0.23],and atrial fibrillation[RR=0.73,95%CI(0.37,1.44),P=0.36].However,it might increase the risk of hypertension[RR=1.05,95%CI(1.03,1.07),P<0.001].Therefore,icodextrin can effectively reduce the risk of mortality,congestive heart failure,and new-onset diabetes,which is beneficial to ESRD patients.
基金supported by the National Key Research and Development Program of China(No.2022YFB3403600)the National Natural Science Foundation of China(No.52293403)Self-Planned Task of State Key Laboratory of Robotics and System(HIT)(No.SKLRS202204C)。
文摘Hemispherical shell resonator(HSR)is the core component of hemispherical resonator gyro.It is aφ-shaped small-bore complex component with minimum curvature radius less than 3 mm.Thus,traditional polishing methods are difficult to polish it.Small ball-end magnetorheological polishing method can polish the small components with complicated three-dimensional surface and obtain non-destructive surface.Therefore,this method is suitable for polishing HSR.However,the material removal rate of the ordinary small ball-end magnetorheological polishing is low,leading to long polishing time and low output of HSR.To solve this problem,a water bath heating assisted small ball-end magnetorheological polishing method is proposed in this research.The influence rule of processing parameters on the material removal rate is studied experimentally.A set of optimal processing parameters is obtained to maximize the material removal rate.Compared with the ordinary method,the material removal rate of the new method can be improved by 143%.Subsequently,an HSR is polished by the new method.The results show that the polishing time can be reduced by 55%,and the polished surface roughness can reach 7.7 nm.The new method has the great potential to be used in actual production to improve the polishing efficiency of HSR.
文摘In order to improve the performance of the Wells turbine for wave energy conversion, the effect of end plates on the turbine characteristics has been investigated experimentally by model testing under steady flow conditions. The end plate attached to the tip of the original rotor blade is slightly larger than the original blade profile. The characteristics of the Wells turbine with end plates have been compared with those of the original Wells turbine, i.e., the turbine without end plate. As a result, it has been concluded that the characteristics of the Wells turbine with end plates are superior to those of the original Wells turbine and the characteristics are dependent on the size and position of end plate. Furthermore, the effect of annular plate on the turbine performance, which encircles the turbine and is attached to the tip, was investigated as an additional experiment. However, its device was not effective in improving the turbine characteristics.
