Taking the multi-component system as research object, a maintenance optimization model based on the unequal inspection period and imperfect repair is established by considering the requirement of expected availability...Taking the multi-component system as research object, a maintenance optimization model based on the unequal inspection period and imperfect repair is established by considering the requirement of expected availability for improving the system＇s availability. An age reduction factor is used to describe the effect of imperfect repair, and the modelling approach for the unequal inspection period is proposed. Unavailable situations are classified into three kinds of independent cases, and the availability is calculated accordingly. Based on the analysis of the relationship between the unavailable cases and the unequal inspection period, an optimization model under imperfect repair is established to optimize the system＇s expected availability. A case study of a wind turbine is provided, and three key components, i.e. gearbox, generator and spindle, are considered. The optimization results of the unequal inspection period model and the equal inspection period model are compared. The results show that the unequal inspection period model based on availability can update the maintenance plan so as to optimize maintenance activities and improve the system＇s availability.展开更多
Objective:To study the nursing effect of liposuction and volume reduction in the treatment of lymphedema during the perioperative period.Method:A total of 68 patients treated with liposuction volume reduction surgery ...Objective:To study the nursing effect of liposuction and volume reduction in the treatment of lymphedema during the perioperative period.Method:A total of 68 patients treated with liposuction volume reduction surgery for pseudo-lymphedema of lower limbs admitted from May 2019 to May 2020 in a tertiary hospital in Xi’an,Shaanxi Province were selected,and they were divided into observation group and control group by random grouping method.There were 34 cases in each group.The control group took routine care during the perioperative period,while the observation group performed full care during the perioperative period.The complication rate and pain degree of the two groups were compared.Results:The complication rate of the study group was 5.88%,while that of the control group was 26.67%.Compared with the study group,the complication rate was significantly higher than that of the control group,and the gap was statistically significant(P>0.05).The pain scores of patients in the study group were significantly lower than those in the control group at 3 and 6 days after surgery,and the gap was statistically significant(P>0.05).Conclusion:Lymphedema should be taken care of during the perioperative period of liposuction and volume reduction,which can effectively reduce the occurrence of pain and complications.It is worthy of extensive clinical promotion.展开更多
Seismic influence of P-Δ effect is the subject of this study.First,it is pointed out that the elastic static amplification factor shall be isolated in formulating the dynamic inelastic second order effect.An amplific...Seismic influence of P-Δ effect is the subject of this study.First,it is pointed out that the elastic static amplification factor shall be isolated in formulating the dynamic inelastic second order effect.An amplification factor for the static inelastic P-Δ effect is derived.Seismic force reduction factors(SFRF)for given ductility and stability coefficients are computed for one-story,one-span frames.The P-Δ amplification factors for seismic base shears are obtained by dividing SFRFs with and without P-Δ effect.Both P-Δ amplification factors and SFRFs are presented separately with two kinds of period abscissas.The P-Δ amplification factors are dependent on periods with the maximum occurring at about 0.75 s for site type C and approach to the static inelastic counterpart at long periods.Post-yield stiffness cannot fully counteract the adverse impact of the P-Δ effect.Formulas for seismic P-Δ amplification factors are proposed and compared to results of others.Collapse capacity spectra(CCS)are reviewed and their application in codes discussed.Available CCSs are compared with SFRFs with finite ductility computed for two ensembles of seismic records.A comparison reveals that the SFRFs are affected by seismic records,and available CCSs do not always provide upper limits for the SFRFs when stability coefficients are greater than 0.1 for frame models.展开更多
基金The National Natural Science Foundation of China(No.71671035)Open Fund of Jiangsu Wind Power Engineering Technology Center,China(No.ZK15-03-01,ZK16-03-07)
文摘Taking the multi-component system as research object, a maintenance optimization model based on the unequal inspection period and imperfect repair is established by considering the requirement of expected availability for improving the system＇s availability. An age reduction factor is used to describe the effect of imperfect repair, and the modelling approach for the unequal inspection period is proposed. Unavailable situations are classified into three kinds of independent cases, and the availability is calculated accordingly. Based on the analysis of the relationship between the unavailable cases and the unequal inspection period, an optimization model under imperfect repair is established to optimize the system＇s expected availability. A case study of a wind turbine is provided, and three key components, i.e. gearbox, generator and spindle, are considered. The optimization results of the unequal inspection period model and the equal inspection period model are compared. The results show that the unequal inspection period model based on availability can update the maintenance plan so as to optimize maintenance activities and improve the system＇s availability.
文摘Objective:To study the nursing effect of liposuction and volume reduction in the treatment of lymphedema during the perioperative period.Method:A total of 68 patients treated with liposuction volume reduction surgery for pseudo-lymphedema of lower limbs admitted from May 2019 to May 2020 in a tertiary hospital in Xi’an,Shaanxi Province were selected,and they were divided into observation group and control group by random grouping method.There were 34 cases in each group.The control group took routine care during the perioperative period,while the observation group performed full care during the perioperative period.The complication rate and pain degree of the two groups were compared.Results:The complication rate of the study group was 5.88%,while that of the control group was 26.67%.Compared with the study group,the complication rate was significantly higher than that of the control group,and the gap was statistically significant(P>0.05).The pain scores of patients in the study group were significantly lower than those in the control group at 3 and 6 days after surgery,and the gap was statistically significant(P>0.05).Conclusion:Lymphedema should be taken care of during the perioperative period of liposuction and volume reduction,which can effectively reduce the occurrence of pain and complications.It is worthy of extensive clinical promotion.
文摘Seismic influence of P-Δ effect is the subject of this study.First,it is pointed out that the elastic static amplification factor shall be isolated in formulating the dynamic inelastic second order effect.An amplification factor for the static inelastic P-Δ effect is derived.Seismic force reduction factors(SFRF)for given ductility and stability coefficients are computed for one-story,one-span frames.The P-Δ amplification factors for seismic base shears are obtained by dividing SFRFs with and without P-Δ effect.Both P-Δ amplification factors and SFRFs are presented separately with two kinds of period abscissas.The P-Δ amplification factors are dependent on periods with the maximum occurring at about 0.75 s for site type C and approach to the static inelastic counterpart at long periods.Post-yield stiffness cannot fully counteract the adverse impact of the P-Δ effect.Formulas for seismic P-Δ amplification factors are proposed and compared to results of others.Collapse capacity spectra(CCS)are reviewed and their application in codes discussed.Available CCSs are compared with SFRFs with finite ductility computed for two ensembles of seismic records.A comparison reveals that the SFRFs are affected by seismic records,and available CCSs do not always provide upper limits for the SFRFs when stability coefficients are greater than 0.1 for frame models.
