The cemented tailings backfill(CTB)with initial defects is more prone to destabilization damage under the influence of various unfavorable factors during the mining process.In order to investigate its influence on the...The cemented tailings backfill(CTB)with initial defects is more prone to destabilization damage under the influence of various unfavorable factors during the mining process.In order to investigate its influence on the stability of underground mining engineering,this paper simulates the generation of different degrees of initial defects inside the CTB by adding different contents of air-entraining agent(AEA),investigates the acoustic emission RA/AF eigenvalues of CTB with different contents of AEA under uniaxial compression,and adopts various denoising algorithms(e.g.,moving average smoothing,median filtering,and outlier detection)to improve the accuracy of the data.The variance and autocorrelation coefficients of RA/AF parameters were analyzed in conjunction with the critical slowing down(CSD)theory.The results show that the acoustic emission RA/AF values can be used to characterize the progressive damage evolution of CTB.The denoising algorithm processed the AE signals to reduce the effects of extraneous noise and anomalous spikes.Changes in the variance curves provide clear precursor information,while abrupt changes in the autocorrelation coefficient can be used as an auxiliary localization warning signal.The phenomenon of dramatic increase in the variance and autocorrelation coefficient curves during the compression-tightening stage,which is influenced by the initial defects,can lead to false warnings.As the initial defects of the CTB increase,its instability precursor time and instability time are prolonged,the peak stress decreases,and the time difference between the CTB and the instability damage is smaller.The results provide a new method for real-time monitoring and early warning of CTB instability damage.展开更多
Background:Minimally invasive distal pancreatectomy(MIDP)is increasingly being used,although its oncologic safety for pancreatic ductal adenocarcinoma(PDAC)remains controversial.In Japan,MIDP for PDAC has limited endo...Background:Minimally invasive distal pancreatectomy(MIDP)is increasingly being used,although its oncologic safety for pancreatic ductal adenocarcinoma(PDAC)remains controversial.In Japan,MIDP for PDAC has limited endorsement due to insufficient data.This study aimed to compare the perioperative and long-term outcomes of open distal pancreatectomy(ODP)and MIDP for PDAC.Methods:We retrospectively analyzed patients with resectable pancreatic body and tail cancer treated with ODP or MIDP(laparoscopic or robotic)between January 2007 and July 2022.The surgical procedures(ODP and MIDP)were compared and the patient characteristics,perioperative outcomes,and long-term outcomes were analyzed.We also compared the outcomes of patients with neoadjuvant chemotherapy(NAC)and without NAC.Results:A total of 72 distal pancreatectomies were performed(37 ODPs and 35 MIDPs).In the upfront group,MIDP resulted in significantly less blood loss than ODP(P<0.01),despite similar operative time.There was no statistically significant difference in the 2-year recurrence-free survival(RFS)rates between ODP and MIDP(39.7%vs.57.8%,P=0.60)or in the overall survival(OS)rates(66.7%vs.74.1%,P=0.43).Similarly,in the NAC group,MIDP resulted in significantly less blood loss than ODP(P=0.01);ODP and MIDP had similar 2-year RFS rates(41.7%and 60.0%,P=0.75)and OS rates(50.0%and 70.0%,P=0.36).The interval from surgery to adjuvant chemotherapy initiation did not significantly differ between the ODP and MIDP subgroups in both the upfront group(P=0.13)and the NAC group(P=0.14).The incidence of recurrence was 64.8%for ODP and 42.8%for MIDP(P=0.06).Both procedures showed similar distributions of local and distant recurrence.Conclusions:MIDP caused less blood loss and had similar oncologic safety compared with ODP.MIDP could become a feasible,minimally invasive option with sufficient oncologic safety for pancreatic body and tail cancers.展开更多
Fine particle flotation has been one of the main problems in many mineral processing plants.The bubble particle collision rate is very low for fine particles,which reduces flotation efficiency.Also,the existence of sl...Fine particle flotation has been one of the main problems in many mineral processing plants.The bubble particle collision rate is very low for fine particles,which reduces flotation efficiency.Also,the existence of slimes is,generally,detrimental to the flotation process,affecting the selectivity and the quality of the concentrates.Besides,it causes an increase in reagents consumption.Hence,in most of processing plants,some of these particles are transmitted to the tailing ponds to reduce the effects of these problems and increase the selectivity of the process.Esfordi phosphate plant in Iran loses more than 30%of its capacity as particles with d 80 finer than 30μm.These fine particles with 15.9%P_(2)O_(5)content are transferred to tailing dam.Processing of fine particles is very important for phosphate industry from economic and environmental aspects.This study addressed the processing of fine tailings(slimes)from a phosphate ore concentrator via flotation,despite the traditional view that ultrafine particles do not float.Phosphate flotation performances in the presence and absence of nanobubbles(NBs)in both mechanical and column cells were compared according to the metallurgical results of the process.NBs(generated by hydrodynamic cavitation)have interesting and exclusive properties such as high stability,durability and high surface area per volume,leading to increase of their utilization in mining-metallurgy and environmental areas.The results of this study revealed that,in the absence of NBs,a concentrate containing 26.9%P_(2)O_(5)with a recovery of 29.13%was obtained using mechanical cells in comparison to 31.6%P_(2)O_(5)with a recovery of 32.74%obtained using column flotation.In the presence of NBs,the recoveries of the concentrate of the mechanical and column flotation increased to 40.49%and 41.26%with 28.47%and 30.43%P_(2)O_(5)contents,respectively.Comparative study showed that the column flotation was almost more efficient for processing the phosphate ore in the presence of the NBs,and had thicker froth layer compared to the mechanical flotation.展开更多
The leaching kinetics of selenium from copper anode slimes was studied in a nitric acid?sulfuric acid mixture.The effects of main parameters on selenium leaching showed that the leaching rate of selenium was practical...The leaching kinetics of selenium from copper anode slimes was studied in a nitric acid?sulfuric acid mixture.The effects of main parameters on selenium leaching showed that the leaching rate of selenium was practically independent of stirring speed,while dependent on temperature and the concentrations of HNO3and H2SO4.The leaching of selenium includes two stages.The activation energy in the first stage is103.5kJ/mol,and the chemical reaction is the rate controlling step.It was almost independent of H2SO4concentration and dependent on HNO3concentration since the empirical reaction order with respect to HNO3concentration is0.5613.In the second stage,the activation energy is30.6kJ/mol,and the process is controlled by a mixture of diffusion and chemical reaction.The leaching of selenium was almost independent of HNO3concentration.展开更多
The present investigation examines the viability of dolochar, a sponge iron industry waste material, as a reductant in the reduction roasting of iron ore slimes, which are another waste generated by iron ore beneficia...The present investigation examines the viability of dolochar, a sponge iron industry waste material, as a reductant in the reduction roasting of iron ore slimes, which are another waste generated by iron ore beneficiation plants. Under statistically determined optimum conditions, which include a temperature of 900°C, a reductant-to-feed mass ratio of 0.35, and a reduction time of 30–45 min, the roasted mass, after being subjected to low-intensity magnetic separation, yielded an iron ore concentrate of approximately 64 wt% Fe at a mass recovery of approximately 71% from the feed iron ore slime assaying 56.2 wt% Fe. X-ray diffraction analyses indicated that the magnetic products contain magnetite and hematite as the major phases, whereas the nonmagnetic fractions contain quartz and hematite.展开更多
The steady flow field of a canard missile on different angles of attack and Mach numbers were studied. Based on analysis, a method was proposed to reduce the calculation for the rolling characteristics of the canard m...The steady flow field of a canard missile on different angles of attack and Mach numbers were studied. Based on analysis, a method was proposed to reduce the calculation for the rolling characteristics of the canard missile with free-spinning tails, and was tested to obtain the relations between rolling moment coefficient, Mach number, and angle of attack. All the computed rolling moment coefficients obtained from the proposed method greatly agreed with the experimental results of FD-06 wind tunnel in CAAA, which proved that the method can not only reduce the calculation cost but also keep precision in calculating the rolling characteristics of canard missiles.展开更多
This paper considers the uniform parallel machine scheduling problem with unequal release dates and delivery times to minimize the maximum completion time.For this NP-hard problem,the largest sum of release date,proce...This paper considers the uniform parallel machine scheduling problem with unequal release dates and delivery times to minimize the maximum completion time.For this NP-hard problem,the largest sum of release date,processing time and delivery time first rule is designed to determine a certain machine for each job,and the largest difference between delivery time and release date first rule is designed to sequence the jobs scheduled on the same machine,and then a novel algorithm for the scheduling problem is built.To evaluate the performance of the proposed algorithm,a lower bound for the problem is proposed.The accuracy of the proposed algorithm is tested based on the data with problem size varying from 200 jobs to 600 jobs.The computational results indicate that the average relative error between the proposed algorithm and the lower bound is only 0.667%,therefore the solutions obtained by the proposed algorithm are very accurate.展开更多
There is a pressing need for developing in vivo or ex vivo assays to screen the glucocorticoid（GC） signaling disruption of chemicals. Thus, we aimed to establish an ex vivo assay for screening GC signaling disruptio...There is a pressing need for developing in vivo or ex vivo assays to screen the glucocorticoid（GC） signaling disruption of chemicals. Thus, we aimed to establish an ex vivo assay for screening GC signaling disruption based on the GC-response gene transcription in Xenopus laevis tails cultured ex vivo. Firstly, we investigated effects of corticosterone（CORT, a main GC in frogs） on GC-response gene expression, and determined the six genes as molecular endpoints for assaying the GC signaling disruption. CORT in the range of 1.56–400 nmol/L was found to up-regulate transcription of the six GC-response genes, exhibiting comparable or higher sensitivity than previously reported assays. To validate this ex vivo assay, then, we examined effects of dexamethasone（a known GC signaling agonist） on GC-response gene expression. Dexamethasone displayed an agonistic action in a concentration-dependent manner, further demonstrating the efficiency of the established assay. Finally, we applied the ex vivo assay to evaluate the GC signaling disruption of bisphenol A（BPA）. In accordance with previous reports, we found a concentration-dependent agonistic activity of BPA,showing that the established assay is effective for detecting the GC signaling disrupting activity of environmental chemicals. Correspondingly, the GC signaling agonistic actions of CORT and BPA in ex vivo tails accorded with the observations in vivo, indicating that the ex vivo assay is able to detect the actions of chemicals in vivo. Overall, we established an ex vivo assay that can effectively screen GC signaling disruption of environmental chemicals.展开更多
Numerical study on the unsteady hydrodynamic characteristics of oscillating rigid and flexible tuna-tails in viscous flow-field is performed. Investigations are conducted using Reynolds-Averaged Navier-Stokes （RANS）...Numerical study on the unsteady hydrodynamic characteristics of oscillating rigid and flexible tuna-tails in viscous flow-field is performed. Investigations are conducted using Reynolds-Averaged Navier-Stokes （RANS） equations with a moving adaptive mesh. The effect of swimming speed, flapping amplitude, frequency and flexure amplitude on the propulsion performance of the rigid and flexible tuna-tails are investigated. Computational results reveal that a pair of leading edge vortices develop along the tail surface as it undergoes an oscillating motion. The propulsive efficiency has a strong correlation with various locomotive parameters. Peak propulsive efficiency can be obtained by adjusting these parameters. Particularly, when input power coeffcient is less than 2.8, the rigid tail generates larger thrust force and higher propulsive efficiency than flexible tail. However, when input power coefficient is larger than 2.8, flexible tail is superior to rigid tail.展开更多
In this paper the large deviation results for partial and random sums Sn-ESn=n∑i=1Xi-n∑i=1EXi,n≥1;S（t）-ES（t）=N（t）∑i=1Xi-E（N（t）∑i=1Xi）,t≥0 are proved, where {N（t）;t ≥ 0} is a counting process of non-...In this paper the large deviation results for partial and random sums Sn-ESn=n∑i=1Xi-n∑i=1EXi,n≥1;S（t）-ES（t）=N（t）∑i=1Xi-E（N（t）∑i=1Xi）,t≥0 are proved, where {N（t）;t ≥ 0} is a counting process of non-negative integer-valued random variables, and {Xn; n ≥ 1} are a sequence of independent non-negative random variables independent of {N（t）; t ≥ 0}. These results extend and improve some known conclusions.展开更多
The composite sorbent, including an active inorganic component （alumosilicates derived from clay-salt slimes） in the quantity of more than 80 mas.% and the polymer binder （polyacrylamide） was obtained. The influen...The composite sorbent, including an active inorganic component （alumosilicates derived from clay-salt slimes） in the quantity of more than 80 mas.% and the polymer binder （polyacrylamide） was obtained. The influences of various factors on its sorption and mechanical properties were studied. It is established that the content of polyacrylamide in the composite sorbent should be in the range of 10-15 mas.%. It is shown that quasi-equilibrium of ^137Cs in the system ＂sorbent-solution＂ is reached within 80 rain. The distribution coefficient （Kd） is 2.4× 10^4 cm^3/g. The obtained data of kinetic parameters （diffusion coefficient and sorption during half-time） show that the received sorbent can be referred to sorbents with high rate of ^137Cs sorption.展开更多
In Morocco, the phosphate industry generates by washing during the ore beneficiation in humid way, big quantities of sludge loaded in fine mineral particles （or slimes） with contents of water in the order of 90-95%....In Morocco, the phosphate industry generates by washing during the ore beneficiation in humid way, big quantities of sludge loaded in fine mineral particles （or slimes） with contents of water in the order of 90-95%. The specific consumption in water for the beneficiation of one tone of dry ore is approximately 0.6 m3. The management of this sludge and the recycling of process water are played to a schema of solid-liquid separation by flocculation, settling then stocking in basins of several dozens hectares. Recovered clear waters are recycled into the circuit of washing. The principal motivation of this work which is a part of EL MAA project is dedicated to the study of the impact of the speed of agitation on the flocculation behavior in terms of dewatering of the phosphate slimes and recycling of the process water. Study was driven on sample of slimes taken in entrance of the thickeners of a Moroccan washing plants, before flocculation. The raw slimes have a concentration in solid of 75.5 g·L^-1, a P205 grade of 17.3% and a free settling velocity 9 cm·h^-1. Fine fraction -2 μm, responsible for the poor settling of slimes is composed in practice of nearly 96% of smectite. It represents 9% of the dry solid content in the slimes. Measurements reveal important variations of the granulometric and textural properties of large floes in response to flocculation, opening ways of optimization for the velocity gradient.展开更多
The rare earth elements (REE) include the group of 15 lanthanides, scandium and yttrium and have diverse applications in technological and nuclear areas. The existence of REE in massive solid mining wastes generated i...The rare earth elements (REE) include the group of 15 lanthanides, scandium and yttrium and have diverse applications in technological and nuclear areas. The existence of REE in massive solid mining wastes generated in leaching processes of copper minerals in the Atacama region of Chile generates the possibility of creating added value to the treatment of this type of waste and supporting the development of a circular economy, generating a useful by-product in different industries. In order to know the behavior of these elements present in the solid carrier waste, a leaching process was carried out by using two agents separately, corresponding to hydrochloric and nitric acid. The technical feasibility to recover REE from carrier tail was demonstrated, the best leaching agent for these elements being a hydrochloric solution, obtaining a maximum recovery efficiency of 64.5%, for an acid concentration: 3M, temperature: 40<span style="white-space:nowrap;">°</span>C and (liquid/solid) ratio: 4. Lanthanum and cerium present the best individual recoveries compared to the other REE, with a maximum efficiency for a hydrochloric solution of 75.7% and 70.0%, respectively. The interaction of operational parameters that most influence the REE recovery corresponds to the temperature and the (liquid/solid) ratio. After 4 hours of leaching, REE recovery efficiencies remain practically constant. Acid consumptions correspond to 11 (kg HCl/ton mining tail) and 29 (kg HNO<sub>3</sub>/ton mining tail). The highest amount recovery ratios of these elements correspond to 0.355 and 0.224 (kg REE/ton mining tail), for hydrochloric and nitric solutions, respectively. These results influence the types of reagents and parameters to be studied in the following stages of the global process.展开更多
Utilizing phosphorus tailings as the raw material for foam concrete is a key approach to achieving sustainable and efficient resource utilization.During the preparation of phosphorus tailings-based foam concrete,slurr...Utilizing phosphorus tailings as the raw material for foam concrete is a key approach to achieving sustainable and efficient resource utilization.During the preparation of phosphorus tailings-based foam concrete,slurry performance is critical to the successful production.Phosphorus tailings,cement and microsilica were used to prepare foam concrete slurry in this study.A rheometer was employed as a test tool to measure the variation of linear viscoelastic zone(LVR),viscosity,and yield stress of the slurries with different cement contents.The results indicate that the phosphorus tailings-cement-microsilica slurry exhibits shear-thinning properties,which aligns well with the Herschel-Bulkley model,showing a high degree of correlation.As the cement content increases,the energy storage modulus of the slurry rises,and the LVR length shows a nonlinear trend.The LVR reaches its maximum length of 0.04%when the cement content is 6 mass%or 8 mass%.The increment of the cement content leads to a more intricate internal network structure,which hinders the reconstruction rate of the flocculated structure after high-shear deformation.展开更多
The detection of ash content in coal slime flotation tailings using deep learning can be hindered by various factors such as foam,impurities,and changing lighting conditions that disrupt the collection of tailings ima...The detection of ash content in coal slime flotation tailings using deep learning can be hindered by various factors such as foam,impurities,and changing lighting conditions that disrupt the collection of tailings images.To address this challenge,we present a method for ash content detection in coal slime flotation tailings.This method utilizes chromatographic filter paper sampling and a multi-scale residual network,which we refer to as MRCN.Initially,tailings are sampled using chromatographic filter paper to obtain static tailings images,effectively isolating interference factors at the flotation site.Subsequently,the MRCN,consisting of a multi-scale residual network,is employed to extract image features and compute ash content.Within the MRCN structure,tailings images undergo convolution operations through two parallel branches that utilize convolution kernels of different sizes,enabling the extraction of image features at various scales and capturing a more comprehensive representation of the ash content information.Furthermore,a channel attention mechanism is integrated to enhance the performance of the model.The combination of the multi-scale residual structure and the channel attention mechanism within MRCN results in robust capabilities for image feature extraction and ash content detection.Comparative experiments demonstrate that this proposed approach,based on chromatographic filter paper sampling and the multi-scale residual network,exhibits significantly superior performance in the detection of ash content in coal slime flotation tailings.展开更多
Some equivalent conditions on the classes of lighted-tailed and heavily heavy-tailed and lightly heavy-tailed d.f.s are introduced.The limit behavior of xα(x) and e λx(x) are discussed.Some properties of the subcla...Some equivalent conditions on the classes of lighted-tailed and heavily heavy-tailed and lightly heavy-tailed d.f.s are introduced.The limit behavior of xα(x) and e λx(x) are discussed.Some properties of the subclass DKc and subclass DK 1 are obtained.展开更多
One of the major challenges in the application of microbially induced carbonate precipitation(MICP)is achieving"bacteria freedom",as it necessitates a substantial volume of bacterial solutions.Nevertheless,b...One of the major challenges in the application of microbially induced carbonate precipitation(MICP)is achieving"bacteria freedom",as it necessitates a substantial volume of bacterial solutions.Nevertheless,both insitu bacterial cultivation and transportation of bacterial solutions have proven to be inefficient.In this study,we suggested the utilization of bacteria in the form of dry powder,enabling easy on-site activation and achieving a relatively high urease activity.We conducted MICP curing experiments on gold mine tailings(GMT)using steel slag(SS)as an additive.The results showed that the average unconfined compressive strength(UCS)values of the tailings treated with MICP and MICP+SS reached 0.51 and 0.71 MPa,respectively.In addition,the average leaching reduction rates of Cu,Pb,Cr,Zn,and T-CN in GMT after MICP treatment reached 98.54%,100%,70.94%,59.25%,and 98.02%,respectively,and the average reduction rates after MICP+SS treatment reached 98.77%,100%,88.03%,72.59%,and 98.63%,respectively.SEM,XRD,FT-IR analyses,and ultra-deep field microscopy results confirmed that the MICP treatment produced calcite-based calcium carbonate that filled the inter-tailing pores and cemented them together,and the hydration mechanism was the main reason for the increased curing efficiency of SS.Our research findings demonstrate that bacterial powder can efficiently achieve the objectives of heavy metal removal and tailing solidification.This approach can substantially de-crease the expenses associated with bacterial cultivation and solution transportation,thereby playing a crucial role in advancing the practical implementation of MICP.展开更多
Enhancing soil organic matter characteristics,ameliorating physical structure,mitigating heavy metal toxicity,and hastening mineral weathering processes are crucial approaches to accomplish the transition of tailings ...Enhancing soil organic matter characteristics,ameliorating physical structure,mitigating heavy metal toxicity,and hastening mineral weathering processes are crucial approaches to accomplish the transition of tailings substrate to a soil-like substrate.The incorporation of biomass co-pyrolysis and plant colonization has been established to be a significant factor in soil substrate formation and soil pollutant remediation.Despite this,there is presently an absence of research efforts aimed at synergistically utilizing these two technologies to expedite the process of mining tailings soil substrate formation.The current study aimed to investigate the underlying mechanism of geochemical changes and rapid mineral weathering during the process of transforming tailings substrate into a soil-like substrate,under the combined effects of biomass co-smoldering pyrolysis and plant colonization.The findings of this study suggest that the incorporation of smoldering pyrolysis and plant colonization induces a high-temperature effect and biological effects,which enhance the physical and chemical properties of tailings,while simultaneously accelerating the rate of mineral weathering.Notable improvements include the amelioration of extreme pH levels,nutrient enrichment,the formation of aggregates,and an increase in enzyme activity,all of which collectively demonstrate the successful attainment of tailings substrate reconstruction.Evidence of the acceleratedweathering was verified by phase and surfacemorphology analysis using X-ray diffraction and scanning electron microscopy.Discovered corrosion and fragmentation on the surface ofminerals.The weathering resulted in corrosion and fragmentation of the surface of the treated mineral.This study confirms that co-smoldering pyrolysis of biomass,combined with plant colonization,can effectively promote the transformation of tailings into soil-like substrates.This method has can effectively address the key challenges that have previously hindered sustainable development of the mining industry and provides a novel approach for ecological restoration of tailings deposits.展开更多
基金Projects(52374138,51764013)supported by the National Natural Science Foundation of ChinaProject(20204BCJ22005)supported by the Training Plan for Academic and Technical Leaders of Major Disciplines of Jiangxi Province,China+1 种基金Project(2019M652277)supported by the China Postdoctoral Science FoundationProject(20192ACBL21014)supported by the Natural Science Youth Foundation Key Projects of Jiangxi Province,China。
文摘The cemented tailings backfill(CTB)with initial defects is more prone to destabilization damage under the influence of various unfavorable factors during the mining process.In order to investigate its influence on the stability of underground mining engineering,this paper simulates the generation of different degrees of initial defects inside the CTB by adding different contents of air-entraining agent(AEA),investigates the acoustic emission RA/AF eigenvalues of CTB with different contents of AEA under uniaxial compression,and adopts various denoising algorithms(e.g.,moving average smoothing,median filtering,and outlier detection)to improve the accuracy of the data.The variance and autocorrelation coefficients of RA/AF parameters were analyzed in conjunction with the critical slowing down(CSD)theory.The results show that the acoustic emission RA/AF values can be used to characterize the progressive damage evolution of CTB.The denoising algorithm processed the AE signals to reduce the effects of extraneous noise and anomalous spikes.Changes in the variance curves provide clear precursor information,while abrupt changes in the autocorrelation coefficient can be used as an auxiliary localization warning signal.The phenomenon of dramatic increase in the variance and autocorrelation coefficient curves during the compression-tightening stage,which is influenced by the initial defects,can lead to false warnings.As the initial defects of the CTB increase,its instability precursor time and instability time are prolonged,the peak stress decreases,and the time difference between the CTB and the instability damage is smaller.The results provide a new method for real-time monitoring and early warning of CTB instability damage.
文摘Background:Minimally invasive distal pancreatectomy(MIDP)is increasingly being used,although its oncologic safety for pancreatic ductal adenocarcinoma(PDAC)remains controversial.In Japan,MIDP for PDAC has limited endorsement due to insufficient data.This study aimed to compare the perioperative and long-term outcomes of open distal pancreatectomy(ODP)and MIDP for PDAC.Methods:We retrospectively analyzed patients with resectable pancreatic body and tail cancer treated with ODP or MIDP(laparoscopic or robotic)between January 2007 and July 2022.The surgical procedures(ODP and MIDP)were compared and the patient characteristics,perioperative outcomes,and long-term outcomes were analyzed.We also compared the outcomes of patients with neoadjuvant chemotherapy(NAC)and without NAC.Results:A total of 72 distal pancreatectomies were performed(37 ODPs and 35 MIDPs).In the upfront group,MIDP resulted in significantly less blood loss than ODP(P<0.01),despite similar operative time.There was no statistically significant difference in the 2-year recurrence-free survival(RFS)rates between ODP and MIDP(39.7%vs.57.8%,P=0.60)or in the overall survival(OS)rates(66.7%vs.74.1%,P=0.43).Similarly,in the NAC group,MIDP resulted in significantly less blood loss than ODP(P=0.01);ODP and MIDP had similar 2-year RFS rates(41.7%and 60.0%,P=0.75)and OS rates(50.0%and 70.0%,P=0.36).The interval from surgery to adjuvant chemotherapy initiation did not significantly differ between the ODP and MIDP subgroups in both the upfront group(P=0.13)and the NAC group(P=0.14).The incidence of recurrence was 64.8%for ODP and 42.8%for MIDP(P=0.06).Both procedures showed similar distributions of local and distant recurrence.Conclusions:MIDP caused less blood loss and had similar oncologic safety compared with ODP.MIDP could become a feasible,minimally invasive option with sufficient oncologic safety for pancreatic body and tail cancers.
基金Project supported by Iran Mineral Processing Research Center(IMPRC)。
文摘Fine particle flotation has been one of the main problems in many mineral processing plants.The bubble particle collision rate is very low for fine particles,which reduces flotation efficiency.Also,the existence of slimes is,generally,detrimental to the flotation process,affecting the selectivity and the quality of the concentrates.Besides,it causes an increase in reagents consumption.Hence,in most of processing plants,some of these particles are transmitted to the tailing ponds to reduce the effects of these problems and increase the selectivity of the process.Esfordi phosphate plant in Iran loses more than 30%of its capacity as particles with d 80 finer than 30μm.These fine particles with 15.9%P_(2)O_(5)content are transferred to tailing dam.Processing of fine particles is very important for phosphate industry from economic and environmental aspects.This study addressed the processing of fine tailings(slimes)from a phosphate ore concentrator via flotation,despite the traditional view that ultrafine particles do not float.Phosphate flotation performances in the presence and absence of nanobubbles(NBs)in both mechanical and column cells were compared according to the metallurgical results of the process.NBs(generated by hydrodynamic cavitation)have interesting and exclusive properties such as high stability,durability and high surface area per volume,leading to increase of their utilization in mining-metallurgy and environmental areas.The results of this study revealed that,in the absence of NBs,a concentrate containing 26.9%P_(2)O_(5)with a recovery of 29.13%was obtained using mechanical cells in comparison to 31.6%P_(2)O_(5)with a recovery of 32.74%obtained using column flotation.In the presence of NBs,the recoveries of the concentrate of the mechanical and column flotation increased to 40.49%and 41.26%with 28.47%and 30.43%P_(2)O_(5)contents,respectively.Comparative study showed that the column flotation was almost more efficient for processing the phosphate ore in the presence of the NBs,and had thicker froth layer compared to the mechanical flotation.
基金Projects(51374066,U1608254) supported by the National Natural Science Foundation of ChinaProject(2014BAC03B07) supported by the National Key Technology R&D Program of ChinaProjects(2012223002,2014020037) supported by Industrial Research Projects in Liaoning Province,China
文摘The leaching kinetics of selenium from copper anode slimes was studied in a nitric acid?sulfuric acid mixture.The effects of main parameters on selenium leaching showed that the leaching rate of selenium was practically independent of stirring speed,while dependent on temperature and the concentrations of HNO3and H2SO4.The leaching of selenium includes two stages.The activation energy in the first stage is103.5kJ/mol,and the chemical reaction is the rate controlling step.It was almost independent of H2SO4concentration and dependent on HNO3concentration since the empirical reaction order with respect to HNO3concentration is0.5613.In the second stage,the activation energy is30.6kJ/mol,and the process is controlled by a mixture of diffusion and chemical reaction.The leaching of selenium was almost independent of HNO3concentration.
文摘The present investigation examines the viability of dolochar, a sponge iron industry waste material, as a reductant in the reduction roasting of iron ore slimes, which are another waste generated by iron ore beneficiation plants. Under statistically determined optimum conditions, which include a temperature of 900°C, a reductant-to-feed mass ratio of 0.35, and a reduction time of 30–45 min, the roasted mass, after being subjected to low-intensity magnetic separation, yielded an iron ore concentrate of approximately 64 wt% Fe at a mass recovery of approximately 71% from the feed iron ore slime assaying 56.2 wt% Fe. X-ray diffraction analyses indicated that the magnetic products contain magnetite and hematite as the major phases, whereas the nonmagnetic fractions contain quartz and hematite.
基金Sponsored by the Fundamental Research Funds for the Central Universities(Grant No.HEUCFG201815)
文摘The steady flow field of a canard missile on different angles of attack and Mach numbers were studied. Based on analysis, a method was proposed to reduce the calculation for the rolling characteristics of the canard missile with free-spinning tails, and was tested to obtain the relations between rolling moment coefficient, Mach number, and angle of attack. All the computed rolling moment coefficients obtained from the proposed method greatly agreed with the experimental results of FD-06 wind tunnel in CAAA, which proved that the method can not only reduce the calculation cost but also keep precision in calculating the rolling characteristics of canard missiles.
基金supported by the National Natural Science Foundation of China (7087103290924021+2 种基金70971035)the National High Technology Research and Development Program of China (863 Program) (2008AA042901)Anhui Provincial Natural Science Foundation (11040606Q27)
文摘This paper considers the uniform parallel machine scheduling problem with unequal release dates and delivery times to minimize the maximum completion time.For this NP-hard problem,the largest sum of release date,processing time and delivery time first rule is designed to determine a certain machine for each job,and the largest difference between delivery time and release date first rule is designed to sequence the jobs scheduled on the same machine,and then a novel algorithm for the scheduling problem is built.To evaluate the performance of the proposed algorithm,a lower bound for the problem is proposed.The accuracy of the proposed algorithm is tested based on the data with problem size varying from 200 jobs to 600 jobs.The computational results indicate that the average relative error between the proposed algorithm and the lower bound is only 0.667%,therefore the solutions obtained by the proposed algorithm are very accurate.
基金supported by the National Natural Science Foundation of China (No. 21377153)the Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDB14040102)
文摘There is a pressing need for developing in vivo or ex vivo assays to screen the glucocorticoid（GC） signaling disruption of chemicals. Thus, we aimed to establish an ex vivo assay for screening GC signaling disruption based on the GC-response gene transcription in Xenopus laevis tails cultured ex vivo. Firstly, we investigated effects of corticosterone（CORT, a main GC in frogs） on GC-response gene expression, and determined the six genes as molecular endpoints for assaying the GC signaling disruption. CORT in the range of 1.56–400 nmol/L was found to up-regulate transcription of the six GC-response genes, exhibiting comparable or higher sensitivity than previously reported assays. To validate this ex vivo assay, then, we examined effects of dexamethasone（a known GC signaling agonist） on GC-response gene expression. Dexamethasone displayed an agonistic action in a concentration-dependent manner, further demonstrating the efficiency of the established assay. Finally, we applied the ex vivo assay to evaluate the GC signaling disruption of bisphenol A（BPA）. In accordance with previous reports, we found a concentration-dependent agonistic activity of BPA,showing that the established assay is effective for detecting the GC signaling disrupting activity of environmental chemicals. Correspondingly, the GC signaling agonistic actions of CORT and BPA in ex vivo tails accorded with the observations in vivo, indicating that the ex vivo assay is able to detect the actions of chemicals in vivo. Overall, we established an ex vivo assay that can effectively screen GC signaling disruption of environmental chemicals.
文摘Numerical study on the unsteady hydrodynamic characteristics of oscillating rigid and flexible tuna-tails in viscous flow-field is performed. Investigations are conducted using Reynolds-Averaged Navier-Stokes （RANS） equations with a moving adaptive mesh. The effect of swimming speed, flapping amplitude, frequency and flexure amplitude on the propulsion performance of the rigid and flexible tuna-tails are investigated. Computational results reveal that a pair of leading edge vortices develop along the tail surface as it undergoes an oscillating motion. The propulsive efficiency has a strong correlation with various locomotive parameters. Peak propulsive efficiency can be obtained by adjusting these parameters. Particularly, when input power coeffcient is less than 2.8, the rigid tail generates larger thrust force and higher propulsive efficiency than flexible tail. However, when input power coefficient is larger than 2.8, flexible tail is superior to rigid tail.
基金Supported by the Science Foundation of the Education Committee of Anhui Province(0505101).
文摘In this paper the large deviation results for partial and random sums Sn-ESn=n∑i=1Xi-n∑i=1EXi,n≥1;S（t）-ES（t）=N（t）∑i=1Xi-E（N（t）∑i=1Xi）,t≥0 are proved, where {N（t）;t ≥ 0} is a counting process of non-negative integer-valued random variables, and {Xn; n ≥ 1} are a sequence of independent non-negative random variables independent of {N（t）; t ≥ 0}. These results extend and improve some known conclusions.
文摘The composite sorbent, including an active inorganic component （alumosilicates derived from clay-salt slimes） in the quantity of more than 80 mas.% and the polymer binder （polyacrylamide） was obtained. The influences of various factors on its sorption and mechanical properties were studied. It is established that the content of polyacrylamide in the composite sorbent should be in the range of 10-15 mas.%. It is shown that quasi-equilibrium of ^137Cs in the system ＂sorbent-solution＂ is reached within 80 rain. The distribution coefficient （Kd） is 2.4× 10^4 cm^3/g. The obtained data of kinetic parameters （diffusion coefficient and sorption during half-time） show that the received sorbent can be referred to sorbents with high rate of ^137Cs sorption.
文摘In Morocco, the phosphate industry generates by washing during the ore beneficiation in humid way, big quantities of sludge loaded in fine mineral particles （or slimes） with contents of water in the order of 90-95%. The specific consumption in water for the beneficiation of one tone of dry ore is approximately 0.6 m3. The management of this sludge and the recycling of process water are played to a schema of solid-liquid separation by flocculation, settling then stocking in basins of several dozens hectares. Recovered clear waters are recycled into the circuit of washing. The principal motivation of this work which is a part of EL MAA project is dedicated to the study of the impact of the speed of agitation on the flocculation behavior in terms of dewatering of the phosphate slimes and recycling of the process water. Study was driven on sample of slimes taken in entrance of the thickeners of a Moroccan washing plants, before flocculation. The raw slimes have a concentration in solid of 75.5 g·L^-1, a P205 grade of 17.3% and a free settling velocity 9 cm·h^-1. Fine fraction -2 μm, responsible for the poor settling of slimes is composed in practice of nearly 96% of smectite. It represents 9% of the dry solid content in the slimes. Measurements reveal important variations of the granulometric and textural properties of large floes in response to flocculation, opening ways of optimization for the velocity gradient.
文摘The rare earth elements (REE) include the group of 15 lanthanides, scandium and yttrium and have diverse applications in technological and nuclear areas. The existence of REE in massive solid mining wastes generated in leaching processes of copper minerals in the Atacama region of Chile generates the possibility of creating added value to the treatment of this type of waste and supporting the development of a circular economy, generating a useful by-product in different industries. In order to know the behavior of these elements present in the solid carrier waste, a leaching process was carried out by using two agents separately, corresponding to hydrochloric and nitric acid. The technical feasibility to recover REE from carrier tail was demonstrated, the best leaching agent for these elements being a hydrochloric solution, obtaining a maximum recovery efficiency of 64.5%, for an acid concentration: 3M, temperature: 40<span style="white-space:nowrap;">°</span>C and (liquid/solid) ratio: 4. Lanthanum and cerium present the best individual recoveries compared to the other REE, with a maximum efficiency for a hydrochloric solution of 75.7% and 70.0%, respectively. The interaction of operational parameters that most influence the REE recovery corresponds to the temperature and the (liquid/solid) ratio. After 4 hours of leaching, REE recovery efficiencies remain practically constant. Acid consumptions correspond to 11 (kg HCl/ton mining tail) and 29 (kg HNO<sub>3</sub>/ton mining tail). The highest amount recovery ratios of these elements correspond to 0.355 and 0.224 (kg REE/ton mining tail), for hydrochloric and nitric solutions, respectively. These results influence the types of reagents and parameters to be studied in the following stages of the global process.
基金Hubei Provincial Key Research Program Project(2023BCB099).
文摘Utilizing phosphorus tailings as the raw material for foam concrete is a key approach to achieving sustainable and efficient resource utilization.During the preparation of phosphorus tailings-based foam concrete,slurry performance is critical to the successful production.Phosphorus tailings,cement and microsilica were used to prepare foam concrete slurry in this study.A rheometer was employed as a test tool to measure the variation of linear viscoelastic zone(LVR),viscosity,and yield stress of the slurries with different cement contents.The results indicate that the phosphorus tailings-cement-microsilica slurry exhibits shear-thinning properties,which aligns well with the Herschel-Bulkley model,showing a high degree of correlation.As the cement content increases,the energy storage modulus of the slurry rises,and the LVR length shows a nonlinear trend.The LVR reaches its maximum length of 0.04%when the cement content is 6 mass%or 8 mass%.The increment of the cement content leads to a more intricate internal network structure,which hinders the reconstruction rate of the flocculated structure after high-shear deformation.
基金This work was supported by National Natural Science Foundation of China:Grant No.62106048.
文摘The detection of ash content in coal slime flotation tailings using deep learning can be hindered by various factors such as foam,impurities,and changing lighting conditions that disrupt the collection of tailings images.To address this challenge,we present a method for ash content detection in coal slime flotation tailings.This method utilizes chromatographic filter paper sampling and a multi-scale residual network,which we refer to as MRCN.Initially,tailings are sampled using chromatographic filter paper to obtain static tailings images,effectively isolating interference factors at the flotation site.Subsequently,the MRCN,consisting of a multi-scale residual network,is employed to extract image features and compute ash content.Within the MRCN structure,tailings images undergo convolution operations through two parallel branches that utilize convolution kernels of different sizes,enabling the extraction of image features at various scales and capturing a more comprehensive representation of the ash content information.Furthermore,a channel attention mechanism is integrated to enhance the performance of the model.The combination of the multi-scale residual structure and the channel attention mechanism within MRCN results in robust capabilities for image feature extraction and ash content detection.Comparative experiments demonstrate that this proposed approach,based on chromatographic filter paper sampling and the multi-scale residual network,exhibits significantly superior performance in the detection of ash content in coal slime flotation tailings.
基金Supported by the National Natural Science Foundation of China( 1 0 2 71 0 87)
文摘Some equivalent conditions on the classes of lighted-tailed and heavily heavy-tailed and lightly heavy-tailed d.f.s are introduced.The limit behavior of xα(x) and e λx(x) are discussed.Some properties of the subclass DKc and subclass DK 1 are obtained.
基金supported by the Ordos City Science and Technology Major Project(2021ZD14-16)the National Key Research and Development Program(2018YFC1802904)the Discipline Signature Achievements of the Shanghai Polytechnic University(A10GY23G004-14).
文摘One of the major challenges in the application of microbially induced carbonate precipitation(MICP)is achieving"bacteria freedom",as it necessitates a substantial volume of bacterial solutions.Nevertheless,both insitu bacterial cultivation and transportation of bacterial solutions have proven to be inefficient.In this study,we suggested the utilization of bacteria in the form of dry powder,enabling easy on-site activation and achieving a relatively high urease activity.We conducted MICP curing experiments on gold mine tailings(GMT)using steel slag(SS)as an additive.The results showed that the average unconfined compressive strength(UCS)values of the tailings treated with MICP and MICP+SS reached 0.51 and 0.71 MPa,respectively.In addition,the average leaching reduction rates of Cu,Pb,Cr,Zn,and T-CN in GMT after MICP treatment reached 98.54%,100%,70.94%,59.25%,and 98.02%,respectively,and the average reduction rates after MICP+SS treatment reached 98.77%,100%,88.03%,72.59%,and 98.63%,respectively.SEM,XRD,FT-IR analyses,and ultra-deep field microscopy results confirmed that the MICP treatment produced calcite-based calcium carbonate that filled the inter-tailing pores and cemented them together,and the hydration mechanism was the main reason for the increased curing efficiency of SS.Our research findings demonstrate that bacterial powder can efficiently achieve the objectives of heavy metal removal and tailing solidification.This approach can substantially de-crease the expenses associated with bacterial cultivation and solution transportation,thereby playing a crucial role in advancing the practical implementation of MICP.
基金supported by the National Natural Science Foundation of China(No.52060011).
文摘Enhancing soil organic matter characteristics,ameliorating physical structure,mitigating heavy metal toxicity,and hastening mineral weathering processes are crucial approaches to accomplish the transition of tailings substrate to a soil-like substrate.The incorporation of biomass co-pyrolysis and plant colonization has been established to be a significant factor in soil substrate formation and soil pollutant remediation.Despite this,there is presently an absence of research efforts aimed at synergistically utilizing these two technologies to expedite the process of mining tailings soil substrate formation.The current study aimed to investigate the underlying mechanism of geochemical changes and rapid mineral weathering during the process of transforming tailings substrate into a soil-like substrate,under the combined effects of biomass co-smoldering pyrolysis and plant colonization.The findings of this study suggest that the incorporation of smoldering pyrolysis and plant colonization induces a high-temperature effect and biological effects,which enhance the physical and chemical properties of tailings,while simultaneously accelerating the rate of mineral weathering.Notable improvements include the amelioration of extreme pH levels,nutrient enrichment,the formation of aggregates,and an increase in enzyme activity,all of which collectively demonstrate the successful attainment of tailings substrate reconstruction.Evidence of the acceleratedweathering was verified by phase and surfacemorphology analysis using X-ray diffraction and scanning electron microscopy.Discovered corrosion and fragmentation on the surface ofminerals.The weathering resulted in corrosion and fragmentation of the surface of the treated mineral.This study confirms that co-smoldering pyrolysis of biomass,combined with plant colonization,can effectively promote the transformation of tailings into soil-like substrates.This method has can effectively address the key challenges that have previously hindered sustainable development of the mining industry and provides a novel approach for ecological restoration of tailings deposits.
