Search

Stainless-steel slag was used to prepare glass-ceramics, which could solidify chromium (Cr) in the slag. The migration and distribution state of chromium in the slag during the preparation of the glass-ceramics have a great influence on the chromium fixation ability of the glass-ceramics. In this paper, the effects of Al2O3 content in the glass-ceramics on the migration and distribution of chromium during the nucleation and crystallization steps, and on the chromium fixation effect of the glass-ceramics were systematically studied. The results show that in the nucleation stage, with the increase of Al2O3 content, the number of chromium spinel (Cr-spinel) nanocrystals formed in the glass first increases and then decreases, and Cr in the glass phase gradually migrates to Cr-spinel nanocrystals. TEM and XPS analyses show that during crystallization, part of Cr in Cr-spinel diffuses into diopside lattice, and the other part of Cr still exists in Cr-spinel wrapped by diopside. Cr in the glass phase also diffuses and migrates into the diopside lattice with the formation of diopside crystals. The optimal Al2O3 content is 11.8wt.%, which results in 97.94wt.% of the total Cr being fixed in the diopside crystalline phase. The ability of chromium fixation is very high giving a very low Cr leaching concentration of 0.004mg/l. The research results provide theoretical and technical support for increased chromium fixation and realizing harmless and high-value utilization of stainless-steel slag.

BACKGROUND In recent years, the study of rare polymetallic ore tends to be increasingly detailed. As one of the important research methods, electron probe quantitative analysis has made great progress in trace element measurement. During analysis, in addition to increasing the beam size and time to reduce the detection limit, more attention should be paid to removing the interference from other elements, especially the main elements. During the routine testing of rare polymetallic samples, Si, Ta, W interfere with each other. Such interference affects the analytical results of trace elements, and is not easily detected due to its low content, thus affecting the accuracy of the final conclusion. OBJECTIVES To determine the interference relationship among Si, Ta and W under different analytical conditions. METHODS Taking SiO2, metal Ta and W of SPI as the research object, each element was analyzed under different conditions by electron probe microanalyzer. RESULTS In the analysis of silicate, TAP-Kα is used for Si, and LIF-Lα is recommended for Ta and W. In the analysis of niobium tantalum ore, it is suggested to use PET-Kα, PET-Mα and TAP-Mβ for Si, Ta and W, respectively; since 100% Ta will produce about 0.1% Si, therefore, the results are more accurate with the interference correction of Ta on Si. CONCLUSIONS It is important to understand the spectral peak stripping method and the principle of element interference and spectral peak overlap, adjusting the parameters according to the actual situation to ensure the accuracy of data.

China has undergone rapid urbanization and internal migration in the past few years, and its up-to-date gridded population datasets are essential for various applications. Existing datasets for China, however, suffer from either outdatedness or failure to incorporate data from the latest Seventh National Population Census of China, conducted in 2020. In this study, we develop a novel population downscaling approach that leverages stacking ensemble learning and big geospatial data to produce up-to-date population grids at a 100 m resolution for China using seventh census data at both county and town levels. The proposed approach employs stacking ensemble learning to integrate the strengths of random forest, XGBoost, and LightGBM through fusing their predictions in a training mechanism, and it delineates the inhabited areas from big geospatial data to enhance the gridded population estimation. Experimental results demonstrate that the proposed approach exhibits the best-fit performance compared to individual base models. Meanwhile, the out-of-sample town-level test set indicates that the estimated gridded population dataset (R2=0.8936) is more accurate than existing WorldPop (R2=0.7427) and LandScan (R2=0.7165) products for China in 2020. Furthermore, with the inhabited area enhancement, the spatial distribution of population grids is intuitively more reasonable than the two existing products. Hence, the proposed population downscaling approach provides a valuable option for producing gridded population datasets. The estimated 100 m gridded population dataset of China holds great significance for future applications, and it is publicly available at https://doi.org/10.6084/m9.figshare.24916140.v1 (Chen et al., 2024b). [ABSTRACT FROM AUTHOR]

The electrolytic water of oxygen evolution reaction is a four-electron transport process, which results in a slow kinetic process coupled with a high oxygen evolution reaction application potential; therefore, the catalysts have become an urgent bottleneck in the research of hydrolysis reactions. Research on the oxygen evolution reaction is booming with various materials such as noble metals and transition metals. Because of their intrinsically excellent charge transport properties and cost-effective features, transition metal sulfides have attracted much investigation. Herein, we combined the synergistic catalysis of transition metals with the modification of trace noble metal atoms to design and synthesize gold-doped cobalt–nickel sulfide nanosheets (Au-CoNiSx NSs) for oxygen evolution reaction. The cobalt–nickel ratio of electrodeposition and the doping of Au on the millimolar scale were studied. The doping of Au atoms promoted the deposition of sulfur elements and led to the formation of more compact nanostructures, thereby improving the OER performance. The optimal electrochemical performance was obtained with Co/Ni = 3:1 and Au addition of 0.5 mmol/L, with an overpotential of 305.9 mV (vs RHE) at a current density of 10 mA/cm2 and a Tafel slope of 60.98 mV/dec. In the chronopotentiometry measurement, there was no significant difference in electrochemical performance within 12 h, indicating that the nanomaterial has good catalytic stability. [ABSTRACT FROM AUTHOR]

Simple Summary: Relative humidity, as a significant environmental factor, has an important effect on the growth of ducks. This study elucidates the impact of different humidity environments on the production performance and muscle quality of ducks. The research findings demonstrate that ducks exhibit better growth and meat quality at 74% humidity; however, when environmental humidity exceeds 81%, production performance and meat quality plummet sharply. This study aimed to investigate the effects of different humidity levels on the growth performance, slaughter performance, and meat quality of Pekin ducks through the artificial control of humidity, and to identify the suitable environmental humidity for Pekin duck growth. A completely randomized single-factor design was employed, selecting 144 newly hatched male Pekin ducks with healthy and similar BW (body weight) (60.92 g ± 4.38). These ducks were randomly assigned to four groups (A (RH (relative humidity) = 60%), B (RH = 67%), C (RH = 74%), D (RH = 81%)), with 12 ducks and 3 replicates in each group. The ducks were raised in a climate-controlled room for 42 days with ad libitum access to feed and water. BW and feed intake were measured every 3 days, and slaughter performance and meat quality were assessed at 42 days. There was no significant difference in the ADG (average daily gain) from 1 to 21 days (p > 0.05). The ADFI (average daily feed intake) of Group D was significantly lower than that of Groups A, B, and C (p < 0.05), with no significant differences between Groups A, B, and C (p > 0.05). At 42 days, the BW, ADG, and ADFI of Groups A and C were significantly higher than those of Group D (p < 0.05), with no significant differences among Groups A, B, and C (p > 0.05). Group C had a significantly higher breast muscle weight, breast muscle ratio, liver weight, and liver index than Groups B and D (p < 0.05), with no significant differences between Groups A, B, and D (p > 0.05). The meat shear force in Group C was significantly lower than that in Groups A, B, and D (p < 0.05). The L* (brightness) of Group C was significantly lower than that of Group A (p < 0.05), and the a* (redness) value of Group C was significantly higher than that of Groups A and B (p < 0.05), with no significant difference compared to Group D (p > 0.05). Group B had a significantly higher cooking loss than Groups A, C, and D (p < 0.05), with no significant differences among Groups A, C, and D (p > 0.05). Under 26 °C conditions, Pekin ducks perform best in terms of the production performance and feed efficiency, with high-quality meat, especially when reared at 74% humidity. [ABSTRACT FROM AUTHOR]

In recent decades, improvements in thermoelectric material performance have made it more practical to generate electricity from waste heat and to use solid‐state devices for refrigeration. However, despite the development of successful strategies to enhance the figure‐of‐merit zT, optimizing devices for large‐scale applications remains challenging. High zT values do not guarantee excellent device performance, and maintaining high zT over a wide temperature range is difficult. Thus, device‐level structural optimization is crucial for maximizing overall energy conversion efficiency. Proper interfacial and structure design strategies, including contact layer selection, multi‐stage optimization, and size matching for the n‐ and p‐type thermoelectric legs, are necessary for advancing device performance. Additionally, thermal stability issues, device assembly techniques, mechanical properties, and manufacturing costs are crucial considerations for large‐scale applications. To achieve actual applications, the thermoelectric community must look beyond simply aiming for high zT values. This article focuses on modules based on n‐type Mg3(Sb, Bi)2, one of the most promising commercially available thermoelectric materials, and discusses the influence of various parameters on the modules and on the corresponding device‐level optimization strategies. [ABSTRACT FROM AUTHOR]

Stainless steel slag waste can be used to prepare value‐added glass ceramics, which can fix potentially toxic Cr from the slag within the crystalline phase. The occurrence and distribution of Cr during the preparation of glass ceramics has a great influence on the final Cr fixation effect. In this study, the effects of the TiO2 content on the occurrence and distribution of Cr during the nucleation and crystallization steps and on the final properties of the glass ceramics were systematically studied. In the nucleation stage, with increasing TiO2 content, the Cr distributed in the spinel containing chromium nuclei first increases and then decreases. In the crystallization stage, Diopside crystal phase nucleates and grows with spinel containing chromium nanocrystals as heterogeneous nuclei. X‐ray photoelectron spectroscopy analysis showed that the chromium distributed in the diopside crystals first increased and then slightly decreased as the TiO2 content increased. The optimal TiO2 content is 3.4 wt.%, which resulted in 97 wt.% of the total Cr being fixed in the diopside crystalline phase (with a very low Cr leaching concentration of 0.009 mg/L), and a high compressive strength of the final glass ceramic of 267.4 MPa, and a Vickers hardness of 1211.8 HV. The research results provide theoretical and technical support for strengthening Cr fixation to enable harmless and high‐value utilization of stainless steel slag for fabricating glass ceramics. [ABSTRACT FROM AUTHOR]