Accurate prediction of rockburst proneness is one of challenges for assessing the rockburst risk and selecting effective control measures. This study aims to assess rockburst proneness by considering the energy characteristics and qualitative information during rock failure. Several representative rock types in cylindrical and cuboidal sample shapes were tested under uniaxial compression conditions and the failure progress was detected by a high-speed camera. The far-field ejection mass ratio (FEMR) was determined considering the qualitative failure information of the rock samples. The peak-strength energy impact index and the residual elastic energy index were used to quantitatively evaluate the rockburst proneness of both cylindrical and cuboidal samples. Further, the performance of these two indices was analyzed by comparing their estimates with the FEMR. The results show that the accuracy of the residual elastic energy index is significantly higher than that of the peak-strength energy impact index. The residual elastic energy index and the FEMR are in good agreement for both cylindrical and cuboidal rock materials. This is because these two indices can essentially reflect the common energy release mechanism characterized by the mass, ejection velocity, and ejection distance of rock fragments. It suggests that both the FEMR and the residual elastic energy index can be used to accurately measure the rockburst proneness of cylindrical and cuboidal samples based on uniaxial compression test. (c) 2024 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).
Electrolytic manganese residues (EMR) and alkali-activated laterite-based geopolymers were used to prepare slow-release fertilizers (SRFs) and the physicochemical properties and Mn release behavior of EMR-laterite-based SRFs (SRFs-LA) were studied. MnSO4 & sdot;H2O in EMR transforms into CaMnSi2O6, MnO2 and (NH4)(2)Mn(SO4)(2)& sdot;6H(2)O after SRFs-LA synthesis. Geopolymers can slow Mn release through ion exchange and can physically encapsulate Mn-containing minerals. Mn release from the SRFs-LA system was primarily influenced by a combination of nonFick diffusion and skeleton erosion. A comparative pot experiment was also conducted between SRFs-LA and SRFs prepared using alkali/acid-activated geopolymers with EMR (SRFs-alGo/SRFs-acGo) to examine the fertilization efficiency of Guizhou white tea seedlings. Compared with Mg(II), Mn(II) not only played a dominant role in the competitive root absorption process from the soil to the interior of seedlings, but also impeded Fe transportation by regulating the expression of citrate transporters. The slow release of Mn from SRFs-alGo and SRFs-LA could benefit tea seedling growth and protein and photosynthetic pigment synthesis, whereas EMR treatments with Mn burst release damaged the antioxidant system owing to the excessive accumulation of reactive oxygen species in leaves. The Mn released from SRFs-acGo may approach the tolerance limit of tea seedlings growth. The order of fertilizer efficiency for young Guizhou white tea seedlings was as follows: SRFs-LA > SRFs-alGo > SRFs-acGo. Moreover, the cost of SRFs-LA prepared using laterite instead of metakaolin as an active silicon-aluminum source could be reduced by approximately $18.7/t.