Iron Ore Company (Canada)

This investigation analyzes the influence of alkali metal compounds introduced into the firing process through the bentonite binder contained in iron ore pellets on the durability of grate bar assemblies in conveyor-type induration machines. During pellet firing, sodium- and potassium-bearing components inherent to montmorillonitic bentonites transform into reactive forms and interact at high temperatures with the grate bar material. In the presence of chromium in the steel, a complex oxide scale develops at the metal–oxide interface, incorporating low-melting chromate phases. These phases significantly reduce the protective capacity of the oxide film, promote intense scale spalling, and accelerate high-temperature chemical erosion, ultimately resulting in rapid and catastrophic grate bar degradation. To evaluate the degradation mechanisms, laboratory tests were carried out on samples of cast steel 40Kh24N12SL, which were oxidized and exposed to sodium-containing components at 1070 °C for six hours. Scanning electron microscopy and energy-dispersive X-ray spectroscopy revealed the formation of multilayer oxide scales enriched in sodium and chromium and the presence of reaction products characteristic of chromates, confirming the intensification of corrosion processes in the presence of alkali metals. The obtained results clarify the origins of severe grate bar wear under pellet induration conditions when bentonite is used as the binder. Since the alkali metal content is defined by the mineralogical nature of bentonite and is technologically necessary for achieving adequate pellet strength, its reduction is not feasible. Therefore, mitigating the destructive effect of alkali metals must rely on selecting more corrosion-resistant alloys for grate bars and optimizing the temperature–oxidation parameters of the firing process.

Rectangular Spiral Rebar (RSR) is an innovative alternative to conventional ties, offering simplified construction and enhanced performance in reinforced concrete (RC) members. Despite its advantages, a comprehensive evaluation of RSR under multi-behavioral loading conditions (compression, shear, and seismic) remains unexplored. This study integrates numerical, experimental, and theoretical approaches. Numerical models were developed using Abaqus, SAP2000, and VecTor2 to assess RSR performance under static (compression/shear), lateral quasi-static, and seismic loads (five intensity levels). Experimentally, 14 RC short columns with RSR were tested under monotonic compression, varying cross-sectional geometries (rectangular/square) and reinforcement configurations. The Mander confined concrete model was extended to incorporate RSR, refining predictions for longitudinal rebar, cover concrete, and core concrete behavior. RSR increased compressive strength by 8.4% compared to conventional ties, with more uniform stress distribution. Nonlinear finite element analysis (VecTor2) accurately predicted crack patterns, though computational models and standards (e.g., SMCFT, MPLANE, CEB-FIP, CSA, AASHTO) overestimated shear capacity. RSR confinement produced blunter crack patterns. RSR-confined frames exhibited 8% lower drifts under high-intensity ground motions (PGA = 0.52g) and required 12% less transverse reinforcement. The proposed theoretical method showed high accuracy (average experimental-to-theoretical capacity ratio: 1.03 for RSR specimens). This study bridges critical gaps in RSR research, demonstrating its multi-behavior efficacy in improving strength, constructability, and seismic resilience. The validated analytical model provide a foundation for code adoption and practical applications.

ABSTRACTBorehole seismic investigations play a major role for high‐resolution imaging of geological structures at depth. The resulting borehole seismic data enable a direct characterisation of the target units as well as their physical properties along the well and in its direct vicinity. Analysing seismic data acquired at different scales within the borehole provides additional notable insights and allows an improved geological and petrophysical interpretation. In our work, we processed zero offset vertical seismic profiling data and full waveform sonic log data as part of a multiscale borehole seismic imaging workflow to better characterise a mineral exploration target at Ludvika Mines (Blötberget mining area, Central Sweden). Data processing mainly comprised wavefield separation and corridor stacking, followed by migration of the full waveform sonic log data using a diffraction stack approach. Additional borehole data, that is, impedance logs and a lithological borehole profile, were used for the integrated interpretation to provide the basis for an assignment of the reflectors to a specific lithological unit. Besides the existing structural models derived from surface seismic investigations, the new images from borehole seismic data reveal the internal structure of the mineralisation at a significantly higher resolution, complement the geophysical characterisation and can be used for a subsequent reliable mineral resource estimate.

Layered titanium acid (H2TiO3 or HTO) has been extensively utilized as a lithium-ion sieve in studies on lithium extraction from salt lake brines. However, the actual lithium uptake by layered HTO, commonly known through an ion exchange mechanism, is much lower than the theoretical value. The hypothesis is that there is a clear need to further elucidate the mechanism of lithium-ion adsorption for the purpose of guiding the design of a lithium ion sieve (LIS). In this study, lithium adsorption on layered HTO as a function of pH was investigated to gain deeper insight into its underlying adsorption mechanism. Lithium adsorption was found to increase significantly with pH, in particular, at pH 14. To comprehend this strong pH dependency, thermogravimetric analysis-differential scanning calorimetry (TG-DSC) techniques were used to analyze the state of HTO layers before and after lithium adsorption. Surprisingly, HTO surfaces at pH 14 exhibited fewer hydration layers and a higher abundance of hydroxyl groups compared with values at lower pH values. Characterization of HTO before and after lithium adsorption using X-ray diffraction (XRD) and transmission electron microscopy (TEM) revealed an anatase type of TiO2 in HTO at pH 14. Fourier transform infrared spectroscopy (FTIR) and solid-state nuclear magnetic resonance (SSNMR) measurements showed a significant alteration in the configuration of hydroxyl groups within HTO layers after Li+ adsorption at pH 14, distinguishing it from the behavior observed at other pH values. These findings demonstrate that lithium adsorption occurs predominantly through LiOH molecules, which displace interlayer water molecules. The results from density functional theory (DFT) calculations align well with our experimental findings. This research provides a more profound understanding of lithium adsorption in multilayer LIS materials and a scientific basis for the design of innovative multilayer structures for the extraction of lithium from salt lake brines.

The purpose of this study is to evaluate the effectiveness of an artificial intelligence (AI)-assisted review (AAR) system in improving diagnostic accuracy, efficiency, and concordance with expert assessments during the evaluation of donor kidney viability. Sixty H&E-stained frozen-section kidney biopsy slides from explant kidneys obtained for organ donation were evaluated. A board-certified renal pathologist established ground truth (GT) through manual digital evaluation on the Techcyte Fusion Platform. The slides were independently reviewed by an AI algorithm, a board-certified pathologist (Reviewer 2 (R2)), and a board-certified transplant surgeon (Reviewer 1 (R1)). After a washout period, AI-assisted reads were performed. The performance of AARand manual digital review (MDR) was compared to the GTfor total and sclerotic glomeruli (SG) counts, as well as concordance with kidney viability thresholds (using a 20% SG cutoff rate). Secondary outcomes included comparisons of review times and concordance rates for AAR, MDR, and AI analysis alone with the GT. AAR demonstrated concordance with GT across parameters. For R1, coefficient of determination (COD) values for SG counts improved with AAR (0.833) compared to MDR (0.81). Agreement at the 20% SG threshold for kidney viability was 98.33% for both AAR and MDR. AAR reduced mean review times (minutes) by 54.83% compared to MDR, with per-slide review times decreasing from 17:09 (MDR) to 8:35 (AAR). Pearson correlation coefficients (PCC) and concordance correlation coefficients (CCC) for AAR were generally higher than MDR, particularly for the percentage of SG, indicating improved alignment with GT. Analyses revealed no systematic bias, with AAR aligning more closely with GT compared to MDR for both reviewers. The Techcyte algorithm reduces review time while maintaining accuracy and concordance with experts, promoting AI adoption to improve workflow efficiency and expedite transplantation decisions.

West Tasmania has a complex geological history, including a Cambrian tectonic collision and related orogenesis, which formed ore deposits in a volcanic hosted massive sulfide (VHMS) setting. While the topography and dense vegetation covering the area presents challenges for on-ground investigations, the area is relatively well-studied such that 3D geological models are available. This contribution presents results of a broadband magnetotelluric (MT) 2D transect across the area (∼30 stations over a ∼ 80 km line, deployed in early 2016) that enables a combined interpretation of regional-scale geoelectric and geological structures. After accounting for noise, distortion and geoelectric strike; we produce 2D resistivity models using OCCAM2D inversion. We infer low resistivity anomalies in the shallow ( < 3 km ), mid (3–8 km) and deeper crust. Along this MT transect the shallow and mid crust low resistivity zones correspond to major crustal faults. Deep low resistivity features in the east of the transect suggest fluid pathways associated with metamorphism along the western boundary of the Tyennan block during the Cambrian Tyennan Orogeny, while others potentially represent the metasomatism of lower crustal rocks and fluid pathways converging into the mid crust.

In this paper, finding the optimal LR mixed fuzzy random portfolio that is a portfolio that contains some candidate securities with random return rates and some securities with LR fuzzy return rates is investigated. Besides, it is done by a new criterion that as a risk measure provides information about all the likely losses, and at any level of loss, the investor will be able to choose the maximum of her or his tolerable loss. And in the end, a case study of the Tehran stock exchange is presented for the sake of illustration.