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The main task in the production of steel in the basic oxygen furnace (BOF) is dephosphorization Therefore, the prediction and control of the end-point phosphorus content of molten steel is of great significance. Four machine learning regression models (Lasso, Random Forest, Xgboost, and Neural Network) were established to predict the end-point phosphorus content of molten steel in the BOF based on raw and auxiliary material data, process parameters, and production quality data. The prediction effect of the four models was further compared, and their prediction results were interpreted based on the interpretability of the models and the permutation importance method. The results showed that compared with linear regression and neural network regression model, two types of ensemble tree model have higher prediction accuracy, better stability with small data sets, and lower data preprocessing requirements. The factors influencing the end-point phosphorus (P) content in BOF were ranked in order of importance as: Tapping temperature > Turning down times > Steel scrap quantity> Operation habits of different working groups > Amount of oxygen injection> Sulfur and phosphorus content of molten iron > Addition amount of lime, limestone, and lightly burnt dolomite in the slag > Slag-splashing amount.

In hemisphere point temperature (Thp) measurement of continuous casting mold flux, the evaporation of volatiles under high temperature will have a strong impact on the results. Based on the comprehensive analysis of hemisphere point method and its influencing factors, the corresponding volatile-containing mold flux and non-volatile mold flux were selected to get Thp with different heating rates. Combined with the Thp measurement and TG-DSC results, the effect of relevant factors during measuring process were analysed and the way to characterize and evaluate the effects were suggested. Furthermore, an improved method of mold flux melting point test was put forward. The results showed that for non-volatile mold flux, the temperature hysteresis had a greater effect than heat transfer delay and fractional melting. As for the mold flux with volatile, the effect of evaporation was greater than other factors. Traditional hemisphere-point method is no longer suitable for the volatile mold flux. In order to get through this problem, improved methods were proposed. One is measuring Thp traditional way, correcting the composition at the Thp, and corresponding Thp with the corrected composition. Another is taking the initial composition, revising the hemispherical point temperature Thp, and matching the revised Thp with the initial composition.

The physicochemical properties of slag are of great importance in pyrometallurgy. If there is a volatile component in the slag, evaporation will inevitably occur. As a result, the slag composition will change, and the measured results will be inconsistent with the original slag composition. Therefore, the traditional methods can be applied to determine the properties of slag, however, the change in slag composition will lead to the inaccuracy of the results. Two typical kinds of slag ESR slag with higher CaF2 and Pb smelting reduction slag with higher PbO were chosen, and melting point measurements were taken as an example to demonstrate the new method in practice. Weight loss measurements and evaporation test with thermogravimetric (TG) analysis, as well as high-temperature mass spectrometer (MS) tests were carried out to identify the volatiles. It was found that CaF2 and MgF2 is the main volatiles with a small amount of AlF3 to ESR slag and PbO is the main volatile with a small amount of ZnO. Based on these points and the weight loss, the slag melting points measured with traditional method and the slag chemical composition were modified to fit the melting point value. This way is proved to be feasible in theory and practice. Some suggestion for further research are proposed. The work will be of significance for both slag and molten salt with volatiles.

The ability of water mist to mitigate blast loads has been widely recognized. However, the effects of the mean droplet diameter and volume fraction of water mist on the blast mitigation effect and underlying mechanisms have not been comprehensively examined. In this study, a three-dimensional numerical simulation based on the Euler-Lagrangian approach was carried out to study the dissipation process of blast wave energy and momentum by water mist, as well as the impact of varying mean droplet diameters (255-855 μm) and volume fractions (2.4x10-3-5.4x10-3) on blast mitigation. The numerical model incorporates interphase mass, momentum, and energy exchanges, as well as droplet breakup and size distribution. The results showed that the most efficient transfer of momentum and energy between the blast wave and water mist occurred at the air/water mist interface. Subsequently, the efficiency of momentum and energy transfer decreased as the blast wave propagated within the water mist due to the blast wave mitigation. The reduction in the mean droplet diameter and the increase in the volume fraction result in an increase in both the total the surface area and number of water droplets, thereby enhancing the efficiency of energy and momentum absorption by droplets and improving their ability to mitigate blasts. [ABSTRACT FROM AUTHOR]

OBJECTIVE: This study aimed to assess the risks and benefits of reinitiating antiplatelet therapy after spontaneous intracerebral hemorrhage (ICH) through a systematic review and meta-analysis. The reinitiation of antiplatelet therapy is commonly used to reduce major vascular events in patients with occlusive vascular diseases, but its use in ICH patients may increase the risk of bleeding. MATERIALS AND METHODS: A comprehensive search was conducted on databases including MEDLINE, Embase, Cochrane Library, clinicaltrials. gov, and the International Standard Randomized Controlled Trial Number Register (ISRCTN). Randomized controlled trials and cohort studies that investigated the use of reinitiation of antiplatelet therapy after hemorrhagic stroke were included. Data on ICH recurrence, major bleeding events, major occlusive cerebrovascular events, ischemic stroke, and all-cause mortality were extracted and analyzed using R software. RESULTS: The study included a total of 10 studies with 6,340 participants. The control group consisted of 2,964 patients who did not receive antiplatelet therapy, while the study group included 1,285 patients who received antiplatelet therapy without restrictions on the specific drug type. The meta-analysis showed that antiplatelet therapy significantly reduced the risk of ICH recurrence (RR=0.72, 95% CI: 0.59, 0.87), had no significant impact on the risk of severe bleeding events (RR=0.93, 95% CI: 0.80, 1.08), significantly lowered the risk of major occlusive cerebrovascular events (RR=0.59, 95% CI: 0.46, 0.77), had no significant effect on the risk of ischemic stroke (RR=0.77, 95% CI: 0.53, 1.12), and did not significantly influence the risk of all-cause mortality (RR=0.75, 95% CI: 0.45, 1.15). CONCLUSIONS: Based on the findings, reinitiating antiplatelet therapy after spontaneous ICH appears to be generally safe. However, the benefits in terms of reducing the risk of allcause mortality are not evident and require confirmation through large-scale, long-term, prospective, randomized controlled trials. [ABSTRACT FROM AUTHOR]

Over the past decade, a number of speleothem studies have used radiocarbon (14C) to address a range of palaeoclimate problems. These have included the use of the bomb pulse 14C to anchor chronologies over the last 60 years, the combination of U-Th and 14C measurements to improve the radiocarbon age-calibration curve, and linking atmospheric 14C variations with climate change. An issue with a number of these studies is how to constrain, or interpret, variations in the amount of radioactively dead carbon (i.e. the dead carbon fraction, or DCF) that reduces radiocarbon concentrations in speleothems. In this study, we use 14C, stable-isotopes, and trace-elements in a U-Th dated speleothem from Flores, Indonesia, to examine DCF variations and their relationship with above-cave climate over the late Holocene and modern era. A strong association between the DCF and hydrologically-controlled proxy data suggests that more dead carbon was being delivered to the speleothem during periods of higher cave recharge (i.e. lower δ18O, δ13C and Mg/Ca values), and hence stronger summer monsoon. To explore this relationship, we used a geochemical soil-karst model coupled with 14C measurements through the bomb pulse to disentangle the dominant components governing DCF variability in the speleothem. We find that the DCF is primarily controlled by limestone dissolution associated with changes in open- versus closed-system conditions, rather than kinetic fractionation and/or variations in the age spectrum of soil organic matter above the cave. Therefore, we infer that periods of higher rainfall resulted in a higher DCF because the system was in a more closed state, which inhibited carbon isotope exchange between the karst water dissolved inorganic carbon and soil-gas CO2, and ultimately led to a greater contribution of dead carbon from the bedrock. © 2012.

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Author(s): K. E. Westaway (corresponding author) [1]; J. Louys [2]; R. Due Awe [3]; M. J. Morwood [4]; G. J. Price [5]; J.-x. Zhao [5]; M. Aubert [6]; R. Joannes-Boyau [...]

Author(s): M. J. Morwood (corresponding author) [1]; R. P. Soejono [2]; R. G. Roberts (corresponding author) [3]; T. Sutikna [2]; C. S. M. Turney [3]; K. E. Westaway [3]; W. [...]