Enhancing XRF sensor-based sorting of porphyritic copper ore using particle swarm optimization-support vector machine(PSO-SVM)algorithm

X-ray fluorescence(XRF)sensor-based ore sorting enables efficient beneficiation of heterogeneous ores,while intraparticle heterogeneity can cause significant grade detection errors,leading to misclassifications and hindering widespread technology adoption.Accurate classification models are crucial to determine if actual grade exceeds the sorting threshold using localized XRF signals.Previous studies mainly used linear regression(LR)algorithms including simple linear regression(SLR),multivariable linear regression(MLR),and multivariable linear regression with interaction(MLRI)but often fell short attaining satisfactory results.This study employed the particle swarm optimization support vector machine(PSO-SVM)algorithm for sorting porphyritic copper ore pebble.Lab-scale results showed PSO-SVM out-performed LR and raw data(RD)models and the significant interaction effects among input features was observed.Despite poor input data quality,PSO-SVM demonstrated exceptional capabilities.Lab-scale sorting achieved 93.0%accuracy,0.24%grade increase,84.94%recovery rate,57.02%discard rate,and a remarkable 39.62 yuan/t net smelter return(NSR)increase compared to no sorting.These improvements were achieved by the PSO-SVM model with optimized input combinations and highest data quality(T=10,T is XRF testing times).The unsuitability of LR methods for XRF sensor-based sorting of investigated sample is illustrated.Input element selection and mineral association analysis elucidate element importance and influence mechanisms.

Detecting and monitoring of water inrush in tunnels and coal mines using direct current resistivity method:A review

Detecting, real-time monitoring and early warning of underground water-bearing structures are critically important issues in prevention and mitigation of water inrush hazards in underground engineering. Direct current （DC） resistivity method is a widely used method for routine detection, advanced detection and real-time monitoring of water-bearing structures, due to its high sensitivity to groundwater. In this study, the DC resistivity method applied to underground engineering is reviewed and discussed, including the observation mode, multiple inversions, and real-time monitoring. It is shown that a priori information constrained inversion is desirable to reduce the non-uniqueness of inversion, with which the accuracy of detection can be significantly improved. The focused resistivity method is prospective for advanced detection;with this method, the flanking interference can be reduced and the detection dis-tance is increased subsequently. The time-lapse resistivity inversion method is suitable for the regions with continuous conductivity changes, and it can be used to monitor water inrush in those regions. Based on above-mentioned features of various methods in terms of benefits and limitations, we propose a three-dimensional （3D） induced polarization method characterized with multi-electrode array, and introduce it into tunnels and mines combining with real-time monitoring with time-lapse inversion and cross-hole resistivity method. At last, the prospective applications of DC resistivity method are discussed as follows： （1） available advanced detection technology and instrument in tunnel excavated by tunnel boring machine （TBM）, （2） high-resolution detection method in holes, （3） four-dimensional （4D） monitoring technology for water inrush sources, and （4） estimation of water volume in water-bearing structures.

Implementation of a One-Dimensional Enthalpy Sea-Ice Model in a Simple Pycnocline Prediction Model for Sea-Ice Data Assimilation Studies

To further explore enthalpy-based sea-ice assimilation, a one-dimensional （1D） enthalpy sea-ice model is implemented into a simple pycnocline prediction model. The 1D enthalpy sea-ice model includes the physical processes such as brine expulsion, flushing, and salt diffusion. After being coupled with the atmosphere and ocean components, the enthalpy sea-ice model can be integrated stably and serves as an important modulator of model variability. Results from a twin experiment show that the sea-ice data assimilation in the enthalpy space can produce smaller root-mean-square errors of model variables than the traditional scheme that assimilates the observations of ice concentration, especially for slow-varying states. This study provides some insights into the improvement of sea-ice data assimilation in a coupled general circulation model.

Glacial Thermohaline Circulation and Climate:Forcing from the North or South?

Based on the evidence available from both observations and model simulations, the author proposes a view that may provide a unified interpretation of the North Atlantic thermohaline variability. Because of the slow response time of the Southern Ocean （millennia） and the relatively faster response time of the North Atlantic （centuries）, the North Atlantic thermohaline circulation is controlled predominantly by the climate forcing over the Southern Ocean at the long glacial cycle timescales, but by the North Atlantic climate forcing at the short millennial timescaies.

Impact of the Time Scale of Model Sensitivity Response on Coupled Model Parameter Estimation

That a model has sensitivity responses to parameter uncertainties is a key concept in implementing model parameter es- timation using filtering theory and methodology. Depending on the nature of associated physics and characteristic variability of the fluid in a coupled system, the response time scales of a model to parameters can be different, from hourly to decadal. Unlike state estimation, where the update frequency is usually linked with observational frequency, the update frequency for parameter estimation must be associated with the time scale of the model sensitivity response to the parameter being esti- mated. Here, with a simple coupled model, the impact of model sensitivity response time scales on coupled model parameter estimation is studied. The model includes characteristic synoptic to decadal scales by coupling a long-term varying deep ocean with a slow-varying upper ocean forced by a chaotic atmosphere. Results show that, using the update frequency deter- mined by the model sensitivity response time scale, both the reliability and quality of parameter estimation can be improved significantly, and thus the estimated parameters make the model more consistent with the observation. These simple model results provide a guideline for when real observations are used to optimize the parameters in a coupled general circulation model for improving climate analysis and prediction initialization.

Research and Practice on College Students’Innovation and Entrepreneurship Education

Strengthening the education of innovation and entrepreneurship is one of the important tasks of China’s higher education reform and development.Entrepreneurship Education should focus on setting pioneering genetic code for future generations.Essentially,it is an education innovation-oriented entrepreneurial revolution of human resource development.Technological innovation is strategic support to improve social productivity and comprehensive national strength,which should be placed at the core of national overall development.For China’s higher education,it proposes more new requirements.Serious discussion on the innovation education of college students is needed.Through practice,improvements in the quality of innovation and entrepreneurship education will be achieved.

Influence and mechanism of solar radiation intensity on the interdecadal variability of strong Meiyu events during historical periods

Most recent studies on Meiyu over the middle and lower reaches of the Yangtze River(MLRYR)have focused on its interannual variability or the mechanism of certain abnormal events.The influence and physical mechanism of solar radiation intensity on the interdecadal frequency of strong Meiyu events over the MLRYR during historical periods were investigated using reconstructed precipitation data,reconstructed solar radiation data,and model simulation data.First,according to the solar radiation intensity,the Ming and Qing Dynasties(1470-1850)were divided into three periods of strong solar radiation and three periods of weak solar radiation.It was found that during the periods of strong solar radiation,the frequency of strong Meiyu events was significantly higher than that during the periods of weak solar radiation in the reconstructed precipitation data and model simulations.Mechanism analyses show that during the periods of strong solar radiation,the Western Pacific Subtropical High(WPSH)is stronger,and the blocking highs over the middle-high-latitudes are also stronger,which is conducive to the continuous convergence of the southward cold air and the northward warm and humid air flow at the MLRYR.Therefore,a circulation spatial pattern conducive to the occurrence of strong Meiyu events is then induced.The probability distributions of precipitation also show that,during periods of strong solar radiation,changes in circulation patterns cause the probability distribution of precipitation to shift significantly to the right,increasing the probability of strong Meiyu events occurring on the right side of the probability distribution.

地球倾角驱动的末次冰期期间南亚地区变暖

当前对晚第四纪以来轨道尺度上地球气候变化的认识,主要包括高纬驱动的以~10万年周期为主的冰期-间冰期循环和夏季风影响的以~2.3万年周期为主的低纬水文变化.但是,由于低纬陆地没有较为可靠的温度记录,使得对低纬陆地的长期气候变化仍然缺乏全面的理解.本文通过获取云南腾冲青海的一根湖泊沉积岩芯,分析了沉积物中的支链甘油二烷基甘油四醚酯(brGDGTs)和叶蜡氢同位素,分别重建了~9万年以来南亚地区的年平均温度和季风降水的变化序列.结果表明,夏季风降水与之前的研究一致,表现出明显的2.3万年周期,但是年均温度记录揭示了8.8~7.1万年和4.5~2.2万年存在两个暖期,温度变幅2~3℃,与该记录中的冰期-间冰期变幅接近.通过对比TraCE21ka瞬态模拟结果和相关气候驱动因子,发现这两个暖期很可能受当地的年均太阳轨道辐射影响;而低纬地区的年均太阳辐射由以~4.1万年周期为主的地球倾角变化控制,并与高纬地区的年均太阳轨道辐射呈反向关系.此外,该记录中的两个暖期与古人类活动的年代有较强的相关性,表明末次冰期内温度变化可能对亚洲地区古人类的生存有重要的影响.

Model–proxy comparison for overshoot phenomenon of Atlantic thermohaline circulation at Bφlling–Allerφd

The overshoot phenomenon of the Atlantic thermohaline circulation(THC) is a transient climate response to meltwater forcing and could induce intense climate change by increasing the magnitudes of Atlantic THC changes at the end of meltwater discharges. This phenomenon was formally presented with the successfully simulated Bφlling–Allerφd(BA) event in the first transient simulation of the last deglaciation with fully coupled model NCAR-CCSM3(TraCE-21K). Currently, not all proxy records of Atlantic THC support the occurrence of the THC overshoot at BA. Commonly used THC proxy from Bermuda Rise(GGC5) does not exhibit THC overshoot at BA but other proxies such as TTR-451 at Eirik Drift do. How to interpret this regional discrepancy of proxy records is a key question for the validation of the Atlantic THC overshoot at BA. Here, we show that the vigor of deep circulation varies regionally during the Atlantic THC overshoot at BA in TraCE-21 K simulation, and this regional discrepancy in the simulation is consistent with that in the marine sediment records in North Atlantic. The consistent model–proxy evidence supports the occurrence of Atlantic THC overshoot at BA.

表土花粉范围对现代类比法重建早全新世降水的影响

A long-standing question regarding the Holocene evolution of the East Asian Summer Monsoon(EASM)is whether it peaked during the early Holocene(EH)as inferred from rainfall-related proxy records[1,2],or during the mid-Holocene as inferred from ecoenvironmental records from northern China[3,4].Cheng et al.