Scientific site selection is the first step in constructing underground water-sealed petroleum storage depots, but no uniform standard and code for such activity has been established. Therefore, the main objective of ...Scientific site selection is the first step in constructing underground water-sealed petroleum storage depots, but no uniform standard and code for such activity has been established. Therefore, the main objective of this study is to propose an evaluation method for the site selection of an underground water-sealed petroleum storage depot. The first large underground water-sealed petroleum storage depot being built in China served as the background of this study. The following 12 indexes were used as evaluation factors based on comprehensive evaluation criteria and specifications for key project site selection: geographic structure development feature, topographic feature, lithostratic formation feature, crustal stress, strength of rock mass, joint development feature, hydrogeological conditions, long-term water sealing conditions, environmental/ecological vulnerability, regional stability, technical and economic conditions, and meteorological and hydrological conditions. The weight back analysis and power coefficient methods were also used to evaluate the site selected for the first underground water-sealed petroleum storage depot project. Petroleum site classification models based on the two aforementioned methods were established and used to verify the feasibility of the evaluation criteria and methods, and the evaluation results show the grade of the site selected for the underground water-sealed petroleum storage depot in Huangdao, China is good. The study results may be used as a reference for the site selection of future underground water-sealed petroleum storage depots.展开更多
Background:The aortic arch replacement and cardiopulmonary bypass(CPB)are both associated with the early mortality after cardiothoracic surgery.This study aimed to investigate the relationship between CPB time and 90-...Background:The aortic arch replacement and cardiopulmonary bypass(CPB)are both associated with the early mortality after cardiothoracic surgery.This study aimed to investigate the relationship between CPB time and 90-day post-operative mortality in patients undergoing aortic arch surgery using the frozen elephant trunk(FET)technique with selective ante-grade cerebral perfusion(SACP).Methods:We retrospectively reviewed data of 377 adult patients undergoing aortic arch surgery via FET with SACP from July 1,2017 to December 31,2018 at Beijing Anzhen Hospital.The baseline characteristics,intra-operative data,and post-operative data were collected.Univariate and multivariate Cox regression analyses were used to determine independent predictors of 90-day postoperative mortality.Results:The 90-day post-operative mortality was 13.53%.The 78.51%of patients were men.There were 318(84.35%)type A aortic dissections and 28(7.43%)aortic aneurysms.Among those,264(70.03%)were emergency operations.Median CPB time was 202.0(176.0,227.0)min.Multivariate Cox regression analysis revealed that CPB time was independently associated with 90-day post-operative mortality after adjusting confounding factors(hazard ratio:1.21/10 min increase in CPB time,95%confidence interval:1.15–1.27,P<0.001).Kaplan-Meier analysis based on CPB time tertiles revealed that the top tertile(median 236.0 min)was associated with reduced survival rate compared with middle and bottom tertiles(P<0.001).Each sub-group analysis based on the complexity of the underlying disease process showed similar associations between CPB time and 90-day post-operative mortality.Conclusions:CPB time remains a significant factor in determining 90-day post-operative mortality in patients undergoing aortic arch surgery using FET with SACP.Surgeons should be aware of the relationship between CPB time and 90-day post-operative mortality during operative procedures and avoid extended CPB time as far as possible.展开更多
This study aims to beneficiate low grade goethitic iron ore fines using a selective flocculation process. Selective flocculation studies were conducted using different polymers such as starch amylopectin(AP), poly acr...This study aims to beneficiate low grade goethitic iron ore fines using a selective flocculation process. Selective flocculation studies were conducted using different polymers such as starch amylopectin(AP), poly acrylic acid(PAA), and a graft copolymer(AP-g-PAA). The obtained results were analyzed; they indicate the enhancement of the iron ore grade from 58.49% to 67.52% using AP-g-PAA with a recovery of 95.08%. In addition, 64.45% Fe with a recovery of 88.79% was obtained using AP. Similarly, using PAA, the grade increased to 63.46% Fe with a recovery of 82.10%. The findings are also supported by characterizing concentrates using X-ray diffraction(XRD) and electron probe microanalysis(EPMA) techniques.展开更多
基金financially supported by a grant from The National Natural Science Foundation of China(Grant Nos.51379112 and 51422904)the National Program on Key Basic Research Project of China(973 Program)(Grant No.2013CB036002)+1 种基金the National Natural Science Foundation of China(Grant No.51309144)the Fundamental Research Funds of Shandong University(Grant No.2015JX003)
文摘Scientific site selection is the first step in constructing underground water-sealed petroleum storage depots, but no uniform standard and code for such activity has been established. Therefore, the main objective of this study is to propose an evaluation method for the site selection of an underground water-sealed petroleum storage depot. The first large underground water-sealed petroleum storage depot being built in China served as the background of this study. The following 12 indexes were used as evaluation factors based on comprehensive evaluation criteria and specifications for key project site selection: geographic structure development feature, topographic feature, lithostratic formation feature, crustal stress, strength of rock mass, joint development feature, hydrogeological conditions, long-term water sealing conditions, environmental/ecological vulnerability, regional stability, technical and economic conditions, and meteorological and hydrological conditions. The weight back analysis and power coefficient methods were also used to evaluate the site selected for the first underground water-sealed petroleum storage depot project. Petroleum site classification models based on the two aforementioned methods were established and used to verify the feasibility of the evaluation criteria and methods, and the evaluation results show the grade of the site selected for the underground water-sealed petroleum storage depot in Huangdao, China is good. The study results may be used as a reference for the site selection of future underground water-sealed petroleum storage depots.
文摘Background:The aortic arch replacement and cardiopulmonary bypass(CPB)are both associated with the early mortality after cardiothoracic surgery.This study aimed to investigate the relationship between CPB time and 90-day post-operative mortality in patients undergoing aortic arch surgery using the frozen elephant trunk(FET)technique with selective ante-grade cerebral perfusion(SACP).Methods:We retrospectively reviewed data of 377 adult patients undergoing aortic arch surgery via FET with SACP from July 1,2017 to December 31,2018 at Beijing Anzhen Hospital.The baseline characteristics,intra-operative data,and post-operative data were collected.Univariate and multivariate Cox regression analyses were used to determine independent predictors of 90-day postoperative mortality.Results:The 90-day post-operative mortality was 13.53%.The 78.51%of patients were men.There were 318(84.35%)type A aortic dissections and 28(7.43%)aortic aneurysms.Among those,264(70.03%)were emergency operations.Median CPB time was 202.0(176.0,227.0)min.Multivariate Cox regression analysis revealed that CPB time was independently associated with 90-day post-operative mortality after adjusting confounding factors(hazard ratio:1.21/10 min increase in CPB time,95%confidence interval:1.15–1.27,P<0.001).Kaplan-Meier analysis based on CPB time tertiles revealed that the top tertile(median 236.0 min)was associated with reduced survival rate compared with middle and bottom tertiles(P<0.001).Each sub-group analysis based on the complexity of the underlying disease process showed similar associations between CPB time and 90-day post-operative mortality.Conclusions:CPB time remains a significant factor in determining 90-day post-operative mortality in patients undergoing aortic arch surgery using FET with SACP.Surgeons should be aware of the relationship between CPB time and 90-day post-operative mortality during operative procedures and avoid extended CPB time as far as possible.
基金the National Metallurgical Laboratory,Jamshedpur for their kind support
文摘This study aims to beneficiate low grade goethitic iron ore fines using a selective flocculation process. Selective flocculation studies were conducted using different polymers such as starch amylopectin(AP), poly acrylic acid(PAA), and a graft copolymer(AP-g-PAA). The obtained results were analyzed; they indicate the enhancement of the iron ore grade from 58.49% to 67.52% using AP-g-PAA with a recovery of 95.08%. In addition, 64.45% Fe with a recovery of 88.79% was obtained using AP. Similarly, using PAA, the grade increased to 63.46% Fe with a recovery of 82.10%. The findings are also supported by characterizing concentrates using X-ray diffraction(XRD) and electron probe microanalysis(EPMA) techniques.
