The heap leaching of oxide copper ores with copper cathode recovery by solvent extraction and electro-winning is now well established as a low-cost method of copper recovery. This technology has recently been applied ...The heap leaching of oxide copper ores with copper cathode recovery by solvent extraction and electro-winning is now well established as a low-cost method of copper recovery. This technology has recently been applied successfully to mixed oxide and chalcocite ores, notably in Chile at Cerro Colorado, Quebrada Blanca and Zaldivar. Currently, there are significant development efforts underway to try to extend heap leaching to chalcopyrite ores. The success of heap leaching/SX/EW has also led to a revival in the development of hydrometallurgical processes to recover copper from chalcopyrite and other copper concentrates. The current status of copper hydrometallurgy is reviewed and the most commercially attractive potential applications are explored. The advantages and disadvantages of the hydrometallurgical treatment of chalcopyrite concentrates and its preliminary economics are compared with those for the current best practices in copper smelting and refining.展开更多
With the scale and cost of geotechnical engineering projects increasing rapidly over the past few decades,there is a clear need for the careful consideration of calculated risks in design.While risk is typically dealt...With the scale and cost of geotechnical engineering projects increasing rapidly over the past few decades,there is a clear need for the careful consideration of calculated risks in design.While risk is typically dealt with subjectively through the use of conservative design parameters,with the advent of reliability-based methods,this no longer needs to be the case.Instead,a quantitative risk approach can be considered that incorporates uncertainty in ground conditions directly into the design process to determine the variable ground response and support loads.This allows for the optimization of support on the basis of both worker safety and economic risk.This paper presents the application of such an approach to review the design of the initial lining system along a section of the Driskos twin tunnels as part of the Egnatia Odos highway in northern Greece.Along this section of tunnel,weak rock masses were encountered as well as high in situ stress conditions,which led to excessive deformations and failure of the as built temporary support.Monitoring data were used to validate the rock mass parameters selected in this area and a risk approach was used to determine,in hindsight,the most appropriate support category with respect to the cost of installation and expected cost of failure.Different construction sequences were also considered in the context of both convenience and risk cost.展开更多
Mechanical cutting provides one of the most flexible and environmentally friendly excavation methods.It has attracted numerous efforts to model the rock chipping and fragmentation process,especially using the explicit...Mechanical cutting provides one of the most flexible and environmentally friendly excavation methods.It has attracted numerous efforts to model the rock chipping and fragmentation process,especially using the explicit finite element method(FEM) and bonded particle model(BPM),in order to improve cutting efficiency.This study investigates the application of a general-purpose graphic-processing-unit parallelised hybrid finite-discrete element method(FDEM) which enjoys the advantages of both explicit FEM and BPM,in modelling the rock chipping and fragmentation process in the rock scratch test of mechanical rock cutting.The input parameters of FDEM are determined through a calibration procedure of modelling conventional Brazilian tensile and uniaxial compressive tests of limestone,A series of scratch tests with various cutting velocities,cutter rake angles and cutting depths is then modelled using FDEM with calibrated input parameters.A few cycles of cutter/rock interactions,including their engagement and detachment process,are modelled for each case,which is conducted for the first time to the best knowledge of the authors,thanks to the general purpose graphic processing units(GPGPU) parallelisation.The failure mechanism,cutting force,chipping morphology and effect of various factors on them are discussed on the basis of the modelled results.Finally,it is concluded that GPGPU-parallelised FDEM provides a powerful tool to further study rock cutting and improve cutting efficiencies since it can explicitly capture different fracture mechanisms contributing to the rock chipping as well as chip formation and the separation process in mechanical cutting.Moreover,it is concluded that chipping is mostly owed to the mix-mode Ⅰ-Ⅱ fracture in all cases although mode Ⅱ cracks and mode Ⅰ cracks are the dominant failures in rock cutting with shallow and deep cutting depths,respectively.The chip morphology is found to be a function of cutter velocdty,cutting depth and cutter rake angle.展开更多
The processing of iron ore to recover the valuable iron oxide minerals is commonly carried out using spiral concentrators that separate valuable minerals from non-valuable ones on the basis of the specific gravity of ...The processing of iron ore to recover the valuable iron oxide minerals is commonly carried out using spiral concentrators that separate valuable minerals from non-valuable ones on the basis of the specific gravity of minerals. This paper shows that the analysis of the operation of spirals should not only focus on the minerals (as it is usually the case), but should also consider the particle size of these minerals. Indeed, the sampling of two industrial iron ore circuits and the data processing of the resulting measurements show that unexpectedly about 10% of the coarse heavy iron oxide minerals are not recovered by the spirals of the two circuits. Tests conducted by an independent research center confirm this plant observation. The pilot plant tests also show that the wash water flowrate addition may adversely affect the recovery of coarse heavy mineral particles. A mathematical model for the spiral was implemented into a simulator for an iron ore gravity concentration circuit. The simulator shows a potential 0.7% increase of iron recovery by simply changing the strategy used to distribute the wash water between the rougher and the cleaner/recleaner spirals of the circuit. The simulator also shows that the introduction of a hydraulic classifier into the gravity concentration circuit yields a marginal improvement to the performances of the circuit.展开更多
. In this analysis, we summarize our experiences with the laparoscopic parametrectomy/upper vaginectomy (LPUV) as a treatment option for patients with an unexpected finding of cervical cancer after simple hysterectomy.... In this analysis, we summarize our experiences with the laparoscopic parametrectomy/upper vaginectomy (LPUV) as a treatment option for patients with an unexpected finding of cervical cancer after simple hysterectomy as well as for patients with cancer of the vaginal cuff. Methods. From 1995- 2004, 6 of our patients underwent LPUV including 5 patients with stage Ib1 cervical cancer and one patient with Ia1 cervical cancer. Prior procedures were TVH (n = 3), TAH (n = 2) or LAVH (n = 1). Charts were reviewed and follow-up data were collected. Results. Mean age was 40.5 (38- 49) years and Quetelet index was 31.5 (25- 40) kg/m2. Average time from hysterectomy to LPUV was 54 (30- 84) days. Retrospective FIGO staging revealed stage Ib1 (n = 5) and stage Ia1 (n = 1) cervical cancer. Mean duration of surgery was 207 (151- 265) min, average blood loss 300 (100- 500)mL. One patient had an intraoperative bladder injury and one patient a bowel injury. Histopathological evaluation found residual adenocarcinoma in situ in one patient and no malignancy in all other specimen. All pelvic (average 22 (10- 36) nodes, n = 6) and paraaortic nodes (9 nodes, n = 1) were negative for malignancy. One patient had postoperative hematocrit drop and required blood transfusion, mean hematocrit difference pre- vs postoperative was 6.4 (0.2- 10.9) % . There were no further postoperative complications during the average hospital stay of 3.5 (2- 5) days. No patient required adjuvant therapy after the operation. There were no recurrences or late complications in an average of 21.5 (350) months of follow-up. Conclusion. LPUV is an alternative to open parametrectomy or radiation therapy in patients with unexpected cervical cancer after simple hysterectomy or cancer of the vaginal stump. Bladder injuries must be considered to be a specific complication of this otherwise safe procedure.展开更多
Accurate influent flow rate prediction is important for operators and managers at wastewater treatment plants(WWTPs),as it is closely related to wastewater characteristics such as biochemical oxygen demand(BOD),total ...Accurate influent flow rate prediction is important for operators and managers at wastewater treatment plants(WWTPs),as it is closely related to wastewater characteristics such as biochemical oxygen demand(BOD),total suspend solids(TSS),and pH.Previous studies have been conducted to predict influent flow rate,and it was proved that data-driven models are effective tools.However,most of these studies have focused on batch learning,which is inadequate for wastewater prediction in the era of COVID-19 as the influent pattern changed significantly.Online learning,which has distinct advantages of dealing with stream data,large data set,and changing data pattern,has a potential to address this issue.In this study,the performance of conventional batch learning models Random Forest(RF),K-Nearest Neighbors(KNN),and Multi-Layer Perceptron(MLP),and their respective online learning models Adaptive Random Forest(aRF),Adaptive K-Nearest Neighbors(aKNN),and Adaptive Multi-Layer Perceptron(aMLP),were compared for predicting influent flow rate at two Canadian WWTPs.Online learning models achieved the highest R2,the lowest MAPE,and the lowest RMSE compared to conventional batch learning models in all scenarios.The R2 values on testing data set for 24-h ahead prediction of the aRF,aKNN,and aMLP at Plant A were 0.90,0.73,and 0.87,respectively;these values at Plant B were 0.75,0.78,and 0.56,respectively.The proposed online learning models are effective in making reliable predictions under changing data patterns,and they are efficient in dealing with continuous and large influent data streams.They can be used to provide robust decision support for wastewater treatment and management in the changing era of COVID-19 and also under other unprecedented emergencies that could change influent patterns.展开更多
Various medicinal ingredients with different tastes are combined according to the theory of compatibility in Chinese materia medica to achieve a better efficacy,while the mechanism was not very clear.Here,the authors ...Various medicinal ingredients with different tastes are combined according to the theory of compatibility in Chinese materia medica to achieve a better efficacy,while the mechanism was not very clear.Here,the authors studied the interaction between ingredients and human transporters such as the kidney transporters OAT1 and OAT3,the liver transporters OATP1 B1 and OATP1 B3,and the intestine transporter OATP2 B1 to discern the compatibility mechanism of ingredients with different tastes in the Yuanhuzhitong preparation(YHP)comprising Corydalis yanhusuo(CYH)and Angelica dahurica(AD),which could relieve pain by restraining the central system.The results show that tetrahydropalmatine(TDE),the major component of CYH,could be transported by OAT3 into kidney,OATP1 B1 and OATP1 B3 into liver,while imperatorin(IPT)and isoimperatorin(ISP),the two key components of AD,and AD extract showed strong inhibition to OAT1 and OAT3.What’s more,AD extract also exerted strongly inhibition to human transporters OATP1 B1 and OATP1 B3.It was also detected that IPT,ISP,and AD extract significantly downregulated the expression of Oatplal,Oafp1 a4,and Oatp1 b2 of liver in mice.The in vivo results show that the concentration of TDE in liver and kidney significantly decreased,while the TDE concentration in blood and brain were both significantly enhanced in the presence of IPT,ISP,and AD extract.These results suggest that the ingredients in AD with pungent taste could enhance the exposure of TDE in blood and brain by inhibiting the uptake of TDE in liver and kidney.That is to say,TDE with bitter taste could"flood up"into the central nervous system to play its therapeutic effect by the cut-off of that into liver and kidney in the presence of ingredients within AD.This paper not only proves the meridian distribution of CYH in liver and kidney with the role of OAT3,OATP1 B1,and OATP1 B3,but also illustrates how to improve the efficacy of CYH by reasonable compatibility with AD.This study may offer a valuable clue to illustrate the mechanism of compatibility theory.展开更多
文摘The heap leaching of oxide copper ores with copper cathode recovery by solvent extraction and electro-winning is now well established as a low-cost method of copper recovery. This technology has recently been applied successfully to mixed oxide and chalcocite ores, notably in Chile at Cerro Colorado, Quebrada Blanca and Zaldivar. Currently, there are significant development efforts underway to try to extend heap leaching to chalcopyrite ores. The success of heap leaching/SX/EW has also led to a revival in the development of hydrometallurgical processes to recover copper from chalcopyrite and other copper concentrates. The current status of copper hydrometallurgy is reviewed and the most commercially attractive potential applications are explored. The advantages and disadvantages of the hydrometallurgical treatment of chalcopyrite concentrates and its preliminary economics are compared with those for the current best practices in copper smelting and refining.
文摘With the scale and cost of geotechnical engineering projects increasing rapidly over the past few decades,there is a clear need for the careful consideration of calculated risks in design.While risk is typically dealt with subjectively through the use of conservative design parameters,with the advent of reliability-based methods,this no longer needs to be the case.Instead,a quantitative risk approach can be considered that incorporates uncertainty in ground conditions directly into the design process to determine the variable ground response and support loads.This allows for the optimization of support on the basis of both worker safety and economic risk.This paper presents the application of such an approach to review the design of the initial lining system along a section of the Driskos twin tunnels as part of the Egnatia Odos highway in northern Greece.Along this section of tunnel,weak rock masses were encountered as well as high in situ stress conditions,which led to excessive deformations and failure of the as built temporary support.Monitoring data were used to validate the rock mass parameters selected in this area and a risk approach was used to determine,in hindsight,the most appropriate support category with respect to the cost of installation and expected cost of failure.Different construction sequences were also considered in the context of both convenience and risk cost.
基金the support of CSIRO and the Australia-Japan Foundation(Grant No.17/20470)supported by the Japan Society for the Promotion of Science KAKENHI(Grant No.JP18K14165)for Grant-in-Aid for Young Scientists。
文摘Mechanical cutting provides one of the most flexible and environmentally friendly excavation methods.It has attracted numerous efforts to model the rock chipping and fragmentation process,especially using the explicit finite element method(FEM) and bonded particle model(BPM),in order to improve cutting efficiency.This study investigates the application of a general-purpose graphic-processing-unit parallelised hybrid finite-discrete element method(FDEM) which enjoys the advantages of both explicit FEM and BPM,in modelling the rock chipping and fragmentation process in the rock scratch test of mechanical rock cutting.The input parameters of FDEM are determined through a calibration procedure of modelling conventional Brazilian tensile and uniaxial compressive tests of limestone,A series of scratch tests with various cutting velocities,cutter rake angles and cutting depths is then modelled using FDEM with calibrated input parameters.A few cycles of cutter/rock interactions,including their engagement and detachment process,are modelled for each case,which is conducted for the first time to the best knowledge of the authors,thanks to the general purpose graphic processing units(GPGPU) parallelisation.The failure mechanism,cutting force,chipping morphology and effect of various factors on them are discussed on the basis of the modelled results.Finally,it is concluded that GPGPU-parallelised FDEM provides a powerful tool to further study rock cutting and improve cutting efficiencies since it can explicitly capture different fracture mechanisms contributing to the rock chipping as well as chip formation and the separation process in mechanical cutting.Moreover,it is concluded that chipping is mostly owed to the mix-mode Ⅰ-Ⅱ fracture in all cases although mode Ⅱ cracks and mode Ⅰ cracks are the dominant failures in rock cutting with shallow and deep cutting depths,respectively.The chip morphology is found to be a function of cutter velocdty,cutting depth and cutter rake angle.
文摘The processing of iron ore to recover the valuable iron oxide minerals is commonly carried out using spiral concentrators that separate valuable minerals from non-valuable ones on the basis of the specific gravity of minerals. This paper shows that the analysis of the operation of spirals should not only focus on the minerals (as it is usually the case), but should also consider the particle size of these minerals. Indeed, the sampling of two industrial iron ore circuits and the data processing of the resulting measurements show that unexpectedly about 10% of the coarse heavy iron oxide minerals are not recovered by the spirals of the two circuits. Tests conducted by an independent research center confirm this plant observation. The pilot plant tests also show that the wash water flowrate addition may adversely affect the recovery of coarse heavy mineral particles. A mathematical model for the spiral was implemented into a simulator for an iron ore gravity concentration circuit. The simulator shows a potential 0.7% increase of iron recovery by simply changing the strategy used to distribute the wash water between the rougher and the cleaner/recleaner spirals of the circuit. The simulator also shows that the introduction of a hydraulic classifier into the gravity concentration circuit yields a marginal improvement to the performances of the circuit.
文摘. In this analysis, we summarize our experiences with the laparoscopic parametrectomy/upper vaginectomy (LPUV) as a treatment option for patients with an unexpected finding of cervical cancer after simple hysterectomy as well as for patients with cancer of the vaginal cuff. Methods. From 1995- 2004, 6 of our patients underwent LPUV including 5 patients with stage Ib1 cervical cancer and one patient with Ia1 cervical cancer. Prior procedures were TVH (n = 3), TAH (n = 2) or LAVH (n = 1). Charts were reviewed and follow-up data were collected. Results. Mean age was 40.5 (38- 49) years and Quetelet index was 31.5 (25- 40) kg/m2. Average time from hysterectomy to LPUV was 54 (30- 84) days. Retrospective FIGO staging revealed stage Ib1 (n = 5) and stage Ia1 (n = 1) cervical cancer. Mean duration of surgery was 207 (151- 265) min, average blood loss 300 (100- 500)mL. One patient had an intraoperative bladder injury and one patient a bowel injury. Histopathological evaluation found residual adenocarcinoma in situ in one patient and no malignancy in all other specimen. All pelvic (average 22 (10- 36) nodes, n = 6) and paraaortic nodes (9 nodes, n = 1) were negative for malignancy. One patient had postoperative hematocrit drop and required blood transfusion, mean hematocrit difference pre- vs postoperative was 6.4 (0.2- 10.9) % . There were no further postoperative complications during the average hospital stay of 3.5 (2- 5) days. No patient required adjuvant therapy after the operation. There were no recurrences or late complications in an average of 21.5 (350) months of follow-up. Conclusion. LPUV is an alternative to open parametrectomy or radiation therapy in patients with unexpected cervical cancer after simple hysterectomy or cancer of the vaginal stump. Bladder injuries must be considered to be a specific complication of this otherwise safe procedure.
文摘Accurate influent flow rate prediction is important for operators and managers at wastewater treatment plants(WWTPs),as it is closely related to wastewater characteristics such as biochemical oxygen demand(BOD),total suspend solids(TSS),and pH.Previous studies have been conducted to predict influent flow rate,and it was proved that data-driven models are effective tools.However,most of these studies have focused on batch learning,which is inadequate for wastewater prediction in the era of COVID-19 as the influent pattern changed significantly.Online learning,which has distinct advantages of dealing with stream data,large data set,and changing data pattern,has a potential to address this issue.In this study,the performance of conventional batch learning models Random Forest(RF),K-Nearest Neighbors(KNN),and Multi-Layer Perceptron(MLP),and their respective online learning models Adaptive Random Forest(aRF),Adaptive K-Nearest Neighbors(aKNN),and Adaptive Multi-Layer Perceptron(aMLP),were compared for predicting influent flow rate at two Canadian WWTPs.Online learning models achieved the highest R2,the lowest MAPE,and the lowest RMSE compared to conventional batch learning models in all scenarios.The R2 values on testing data set for 24-h ahead prediction of the aRF,aKNN,and aMLP at Plant A were 0.90,0.73,and 0.87,respectively;these values at Plant B were 0.75,0.78,and 0.56,respectively.The proposed online learning models are effective in making reliable predictions under changing data patterns,and they are efficient in dealing with continuous and large influent data streams.They can be used to provide robust decision support for wastewater treatment and management in the changing era of COVID-19 and also under other unprecedented emergencies that could change influent patterns.
基金supported by the National Natural Science Foundation of China(grant Nos.81430096 and 81503154)Tianjin Science and Technology Support Key Projects(grant No.17YFZCSY01170,China)Research Unit for Drug Metabolism,Chinese Academy of Medical Sciences(grant No.2019RU009,China)
文摘Various medicinal ingredients with different tastes are combined according to the theory of compatibility in Chinese materia medica to achieve a better efficacy,while the mechanism was not very clear.Here,the authors studied the interaction between ingredients and human transporters such as the kidney transporters OAT1 and OAT3,the liver transporters OATP1 B1 and OATP1 B3,and the intestine transporter OATP2 B1 to discern the compatibility mechanism of ingredients with different tastes in the Yuanhuzhitong preparation(YHP)comprising Corydalis yanhusuo(CYH)and Angelica dahurica(AD),which could relieve pain by restraining the central system.The results show that tetrahydropalmatine(TDE),the major component of CYH,could be transported by OAT3 into kidney,OATP1 B1 and OATP1 B3 into liver,while imperatorin(IPT)and isoimperatorin(ISP),the two key components of AD,and AD extract showed strong inhibition to OAT1 and OAT3.What’s more,AD extract also exerted strongly inhibition to human transporters OATP1 B1 and OATP1 B3.It was also detected that IPT,ISP,and AD extract significantly downregulated the expression of Oatplal,Oafp1 a4,and Oatp1 b2 of liver in mice.The in vivo results show that the concentration of TDE in liver and kidney significantly decreased,while the TDE concentration in blood and brain were both significantly enhanced in the presence of IPT,ISP,and AD extract.These results suggest that the ingredients in AD with pungent taste could enhance the exposure of TDE in blood and brain by inhibiting the uptake of TDE in liver and kidney.That is to say,TDE with bitter taste could"flood up"into the central nervous system to play its therapeutic effect by the cut-off of that into liver and kidney in the presence of ingredients within AD.This paper not only proves the meridian distribution of CYH in liver and kidney with the role of OAT3,OATP1 B1,and OATP1 B3,but also illustrates how to improve the efficacy of CYH by reasonable compatibility with AD.This study may offer a valuable clue to illustrate the mechanism of compatibility theory.
