Search Results (213)

Vanadium–titanium magnetite is a polymetallic resource in which the low reactivity and complex phase constitution of Ti-bearing smelting slag restrict the coordinated recovery of Fe, V, and Ti. In this study, a coupled route involving laboratory-scale induction-furnace smelting separation, magnetic separation, NaOH activation roasting, and staged leaching was investigated for upgrading ground vanadium–titanium magnetite metallized pellets. At 1690 °C for 20 min with 2.5 wt% coke under natural slag basicity, a vanadium-bearing metallic product containing 92.07 wt% Fe and 1.27 wt% V was obtained, while Ti was concentrated in a slag containing 47.83 wt% TiO₂. Increasing slag basicity improved vanadium partitioning into the metallic phase but decreased the TiO₂ content and subsequent upgrading performance of the slag. Following magnetic separation and NaOH-activated roasting at 900 °C for 90 min with 40 wt% NaOH, staged leaching yielded a rutile-rich product containing 90.70 wt% TiO₂, with a Ti recovery of 88.75%. These results demonstrate that controlling the phase constitution of smelting-derived Ti-bearing slag is important for its subsequent alkali-activation upgrading and Ti enrichment. Full article

Dixie Valley, located in west-central Nevada within the Basin and Range Province, is one of the most important geothermal systems in the western United States and an increasingly attractive target for critical-mineral exploration. The valley combines active extensional tectonics, major range-front and intrabasin fault systems, high heat flow, hydrothermal alteration, and thick sedimentary basins that may provide favorable conditions for the development of geothermal reservoirs and lithium-bearing brines or clays. This paper presents an integrated multiphysics interpretation of gravity, magnetic, helicopter-borne time-domain electromagnetic (HeliTEM), and magnetotelluric (MT) data from Dixie Valley, with emphasis on the Grover Point area investigated by the Basin and Range Investigation for Developing Geothermal Energy (BRIDGE) program. We apply joint Gramian inversion of gravity and magnetic data to recover mutually consistent density and magnetization models, including separate induced and remanent magnetization components. We also perform rigorous 3D inversion of HeliTEM data and cooperative 3D inversion of HeliTEM and MT data to obtain a resistivity model extending from the shallow basin fill to deeper fault-controlled geothermal structures. The integrated interpretation identifies low-density sedimentary basins, induced magnetization highs related to magnetic basement or intrusive rocks, remanent magnetization variations associated with basement architecture and hydrothermal alteration, and conductive corridors interpreted as clay-rich alteration zones and possible hydrothermal pathways. These results demonstrate that integrated gravity, magnetic, HeliTEM, and MT inversion can substantially reduce interpretation ambiguity and improve targeting of concealed geothermal systems and associated lithium resources in extensional terranes. Full article

Anatase-bearing lateritic ores from Qinglong, Guizhou Province, China, are characterized by extremely low TiO₂ grade, high clay content, fine-grained dissemination, and complex intergrowths with iron oxides, which severely hinder efficient beneficiation. In particular, anatase commonly occurs as ultra-fine particles encapsulated by clay minerals or closely associated with iron oxides, and its surface is often covered by nanoscale goethite films, resulting in surface passivation and pseudo-magnetic behavior. These characteristics lead to a pronounced contradiction between mineral liberation and excessive slime generation during conventional grinding processes. To address these challenges, a high-efficiency pre-concentration flowsheet was developed based on selective desliming, stage grinding, intensive scrubbing, flotation, and weak magnetic separation. Selective desliming via hydrocyclones was adopted, which is inferred to preferentially discard true slimes finer than 10 μm while potentially retaining most fine anatase particles within the underflow. Stage grinding was then applied, which may promote the improved liberation of anatase and early rejection of coarse gangue, and may help reduce overgrinding. Intensive scrubbing was introduced, which is expected to weaken or partially remove iron oxide coatings from the anatase surface, thereby potentially restoring surface activity and reducing pseudo-magnetic interference. Subsequent flotation and low-intensity magnetic separation were optimized to increase the concentrate TiO₂ grade and cut iron impurities, which may be associated with improved surface selectivity and weakened pseudo-magnetic responses. Closed-circuit beneficiation tests demonstrated that a TiO₂ concentrate with a grade of 29.62% and a recovery of 65.4% could be obtained from an ore with an initial TiO₂ grade of only 4.39%. Moreover, approximately 40% of the feed mass was rejected at the pre-concentration stage, significantly reducing the load on downstream separation processes. The proposed process demonstrates promising potential as a technical route for the beneficiation of similar refractory anatase-bearing lateritic ores. Full article

Active magnetic bearings (AMBs) require accurate dynamic models for controller design and performance analysis, but their inherent open-loop instability makes modeling difficult under practical operating conditions. This study presents a closed-loop black-box identification method for an AMB system under decentralized control. A pseudo-random binary sequence (PRBS) excitation was injected into the closed-loop system, and the measured input–output data were used to estimate a nonparametric frequency-response model. The effects of excitation amplitude were first examined, and an excitation level of about 10–12% of the saturation current was found to provide a suitable balance among coherence, signal-to-noise ratio, and frequency-response variance. Based on the obtained frequency-domain data, ARX, output-error (OE), and state-space (SS) models were identified and compared. An initial model order range was estimated using the ARX structure and quantitative criteria, including the loss function and Bayesian information criterion. Within this candidate range, different model structures and orders were further evaluated. The 7th-order SS model showed the best overall agreement with the nonparametric frequency response and captured the dominant dynamic features more accurately. Independent time-domain validation and closed-loop reconstruction further confirmed that the selected SS model can represent the practical AMB dynamics with acceptable accuracy. Full article

Background/Objectives: Superparamagnetic iron-oxide nanoparticles (SPIONs) bearing poly(methacrylate) brushes were synthesized via surface-initiated atom-transfer radical polymerization (SI-ATRP) as magnetically responsive nanoplatforms. Three brush architectures, poly(2-hydroxyethyl methacrylate) (PHEMA) and poly(poly(ethylene glycol) methacrylate) with six ethylene-oxide units (PPEGMA6) and ten units (PPEGMA10), were grown from a dopamine-anchored initiator and covalently loaded with methotrexate (MTX). Methods: Physicochemical characterization confirmed successful polymer grafting, tunable hydrodynamic size (185–1320 nm before MTX conjugation and 427–694 nm after), retained superparamagnetic properties (22–69 emu g⁻¹), and high drug payloads, with PPEGMA6 achieving 131 µg mg⁻¹. MTX conjugation induced partial compaction of the polymer shell yet maintained ζ-potentials conducive to colloidal stability. Results: In vitro assays showed negligible toxicity toward primary human fibroblasts, whereas MTX-decorated formulations induced a pronounced concentration-dependent cytotoxic effect in MCF-7 breast cancer cells, reaching 69% loss of viability—significantly higher than free MTX. Structure–activity analysis attributes the superior performance of PPEGMA6-MTX to its balanced brush density, high payload, and favorable surface charge. Conclusions: These findings demonstrate that precise modulation of polymer brush architecture via SI-ATRP yields SPION-based nanocarriers that integrate MRI visibility and the potential for magnetic guidance and targeted chemotherapy. The PPEGMA6-MTX construct is highlighted as a promising platform for future preclinical investigations. Full article

The Qaidam Basin, on the northeastern margin of the Tibetan Plateau, preserves abundant evaporite resources and provides a key archive for investigating basin evolution, climatic change, and brine mineralization. In the Dalangtan area of the northwestern basin, a thick Cenozoic gravelly succession has recently been recognized as the principal host of a newly identified gravel-type potash-bearing brine deposit. Here, we present detailed rock-magnetic and magnetostratigraphic results from borehole CJ-3 to constrain the Late Cenozoic sedimentary evolution of the Altyn Tagh piedmont and its relationship to potash-bearing brine reservoir development. The magnetic polarity sequence consists of 12 pairs of normal and reversed zones, which can be correlated with subchrons C2An.2n–C3r of the geomagnetic polarity timescale (GPTS 2012). A major sedimentary facies shift at 370.75 m yields an age of 3.08 Ma, indicating the onset of a high-energy piedmont alluvial-fan depositional system. This transition was primarily driven by intensified tectonic activity along the Altyn Tagh fault during the Late Pliocene, whereas increasing regional aridity favored the accumulation and preservation of coarse clastic sediments. This age further constrains the initial development of the principal sand–gravel brine reservoir in the Dalangtan area to the latest Pliocene, providing a new chronological basis for understanding sand–gravel-type potash-bearing brine reservoir formation in the northwestern Qaidam Basin. Full article

In order to solve the coupling problem of the six-pole hybrid magnetic bearing (SHMB), an active disturbance rejection control based on modified particle swarm optimization is proposed. Firstly, the active disturbance rejection control (ADRC) for the six-pole hybrid magnetic bearing is introduced, which is a second-order system. Secondly, the modified particle swarm optimization (MPSO) is used for the ADRC, which can decouple the SHMB. Then, simulations of SHMBs are performed under different disturbance signals, and floating simulations and anti-interference simulations of ADRC-MPSO and ADRC are compared. Finally, an experimental platform is established that verifies feasibility and reliability. Full article

Active magnetic levitation bearings incorporate backup bearings that support the rotor during a breakdown, allowing it to maintain its circular movement despite the loss of magnetic force. This safeguards both the stator of the magnetic levitation bearing and the motor stator from harm. Research reveals that ball bearings are susceptible to failure mechanisms, including raceway wear and scoring. The principal cause is the unregulated motion of the rolling parts, which are divided by the cage, once wear manifests, resulting in raceway lag. This leads to significant contact deformation between the rolling elements and the raceway, along with prolonged cumulative impacts between the rolling elements and the cage. Cage-free bearings prevent collisions between the cage and rolling elements; yet, the orbital motion of the rolling elements in these bearings demonstrates a level of independence and randomness relative to traditional caged ball bearings. This presents considerable obstacles to attaining standard orbital motion in cage-free ball bearings. Despite advancements in technology that have largely elucidated the non-linear motion dynamics of ball bearings, several critical hurdles in behavioral characterization persist. This work presents a thorough review of the non-linear motion behavior of ball bearings and the methodologies for their multi-body dynamic characterization. This report proposes future research topics to improve the design of high-performance bearings and augment their reliability. Full article

This study evaluated the efficiency of an scFv antibody-based sex-sorting method using HL magnetic microbeads for the separation of X- and Y-chromosome-bearing sperm in Landrace boar semen, as well as its effects on sperm quality parameters. A dose-dependent plateau in H4L4 antibody coupling efficiency was observed, with 2 mg identified as the optimal concentration, consistently achieving approximately 50% sperm-binding efficiency across boars. Sex ratio analysis confirmed effective discrimination between X- and Y-bearing sperm, with the X-enriched fraction showing a high proportion of X-sperm (77–81%) and the Y-enriched fraction exhibiting high Y-sperm purity (>83%). CASA revealed a significant effect of the sex-sorting process on sperm kinematics (p < 0.001). X-enriched sperm maintained physiological motility, with total and progressive motility comparable to CON, whereas the Y-enriched fraction showed a marked decline in kinematic performance. Flow cytometric analysis demonstrated that membrane integrity remained high in CON and X-enriched semen (>81%), while a significant reduction in viability was observed in the Y-enriched fraction (50.85%; p < 0.001). Consistently, mitochondrial membrane potential analysis indicated pronounced physiological stress in Y-enriched sperm, with significantly reduced mitochondrial activity compared to CON and X-enriched fractions. No significant differences were detected among individual boars (p > 0.05). In conclusion, this study demonstrates that HL magnetic bead-based sperm sexing effectively separates X- and Y-sperm in chilled Landrace boar semen, while preserving the quality of X-enriched sperm. Full article

The technological promise of nonlinear optical (NLO) compounds has stimulated intense interest in optoelectronic devices, data storage, photonics, and anticancer therapy. Thiosemicarbazone ruthenium materials are of growing interest because of their tunable ligand framework and coordination sphere, allowing fine control over geometry, electronics, and functional properties. Here, we report an N-substituted salicylaldehyde thiosemicarbazone ligand and a series of octahedral Ru(III) complexes bearing triphenylphosphine or triphenylarsine and halide (Cl, Br) co-ligands. The complexes were characterized by elemental analysis, FT-IR, UV–Vis, EPR, mass spectrometry, and magnetic susceptibility measurements, which together confirm NS-chelation to a low-spin Ru(III) center in a distorted octahedral environment. Their photophysical and NLO responses were assessed by UV–Vis spectroscopy and powder second-harmonic generation measurements (Kurtz–Perry method), revealing promising NLO behavior. In parallel, antioxidant activity and in vitro anticancer effects against HeLa cells were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cytotoxicity assays. These results provide insight into ligand-controlled structure–activity relationships, in which the halide (Cl/Br) and ancillary triarylphosphine co-ligands regulate electronic interactions and lipophilicity and ultimately increase biological performance, underscoring the dual materials and medicinal potential of these Ru(III) complexes. Full article

Antimicrobial resistance (AMR) remains a major threat to modern medicine, fueled by the excessive use of antibiotics and the spread of multidrug-resistant pathogens such as methicillin-resistant Staphylococcus aureus (MRSA). In this study, we designed and synthesized a series of 2-aryl-4-aminoquinazoline derivatives bearing an aminoalkylimidazole linker, combining two pharmacophoric motifs associated with antimicrobial activity. Starting from anthranilamide, the compounds were prepared in three straightforward steps, affording good yields and high purity. Their structures were confirmed by FT-IR spectroscopy, ¹H and ¹³C nuclear magnetic resonance (NMR), and high-resolution mass spectrometry (HRMS). Biological evaluation showed that series 5 exhibited strong selectivity toward S. aureus, with compounds 5c and 5d displaying minimum inhibitory concentrations (MICs) between 2.2 and 4.4 µM. No significant activity was observed against other tested strains. Cytotoxicity assays in HepG2 cells revealed moderate to low inhibition. Molecular docking indicated preferential binding to dihydrofolate reductase (DHFR) and relevant interactions with topoisomerase IV, resembling reference inhibitors. ADME analysis predicted favourable absorption, blood–brain barrier permeability, and compliance with Lipinski’s rules. Full article

Background/Objectives: Aneurysms develop secondary to progressive weakening of arterial walls and remain a major cause of morbidity and mortality worldwide. Collagen, particularly fibrillar types I and III, is the primary tensile load-bearing component of arteries, yet its specific role in aneurysm formation, progression, and rupture is incompletely defined. This narrative review synthesizes current evidence on collagen structure, regulation, and degradation in aneurysm pathophysiology, highlighting cerebral aneurysms within the broader context of aneurysms as a whole. Methods: Searches of PubMed, MEDLINE, Embase, and Google Scholar were performed to identify all English-language studies published prior to January 2026. Search terms included “cerebral aneurysm”, “collagen”, “extracellular matrix”, “vascular remodeling”, and “aneurysm rupture”. Included studies evaluated collagen structure or content, extracellular matrix remodeling, matrix metalloproteinases, or biomechanical properties of the aneurysm wall in experimental or human models. Results: The literature search identified 348 records, of which 87 studies published between 1999 and 2025 met the inclusion criteria and were synthesized in this review. Collagen types I and III form the primary tensile scaffold of intracranial arteries, while basement membrane and regulatory collagens (e.g., types IV, V, and VI) modulate fibril organization, endothelial stability, and mechanical homeostasis. Research demonstrates that endothelial dysfunction, nitric oxide dysregulation, oxidative stress, and matrix metalloproteinase activation are key pathways driving collagen fragmentation and degradation. Genetic and epigenetic disturbances in collagen and related extracellular matrix pathways further increase aneurysm susceptibility. Conclusions: Collagen dysregulation appears to be a final common pathway through which hemodynamic, inflammatory, hormonal, and genetic insults converge to weaken intracranial arterial walls. However, existing evidence is dominated by animal and aortic models, and in vivo tools, such as Magnetic Resonance Imaging with collagen-sensitive sequences and Positron Emission Tomography Tracers, to quantify collagen integrity in cerebral aneurysms are lacking. Future efforts should prioritize human-focused studies, advanced collagen-sensitive imaging, biomarker development, and targeted strategies to preserve or restore collagen structure as potential means to improve aneurysm risk stratification, prevention, and treatment. Full article

Flywheel energy storage systems exhibit superior performance in electric vehicle regenerative braking, railway traction power supply, and grid frequency regulation due to their high instantaneous power and fast dynamic response. However, systems supported by conventional mechanical bearings face severe radial structural coupling; unbalanced excitation and gyroscopic effects drastically amplify vibrations during critical speed traversal, undermining operational reliability and engineering scalability. To tackle this challenge, this paper proposes a full-speed vibration suppression scheme for active–passive supported flywheel energy storage systems integrated with a damping ring, combined with an inverse system decoupling controller to eliminate structural coupling, unbalance-induced vibration, and gyroscopic effects. A dynamic model of the integrated system is established using Lagrange’s equations, and four-degree of freedom decoupling expressions are derived to achieve complete radial decoupling. A speed-stage-based control strategy is further developed for full-speed adaptation. Comprehensive simulations validate the scheme’s decoupling performance, vibration suppression efficacy, and robustness. Results demonstrate that the proposed controller achieves full radial decoupling, reducing the average steady-state tracking error by 99.86%. The segmented control enables stable operation across 100–20,000 rpm and cuts critical speed resonance peaks by 81.23%. Compared with pure mechanical and magnetic bearing systems, the integrated active–passive support reduces resonance peaks by 94.72% and 42.25%, respectively. Under current perturbation and parameter variation, the scheme reduces the average steady-state error by 75.89% relative to the coupled system, confirming its strong engineering applicability. Full article

To address the issue that current ripple in traditional switching power amplifiers (SPA) for active magnetic bearing (AMB) systems is constrained by the switching frequency, this paper proposes a novel LCL filter-based switching power amplifier (LCL-SPA) along with its parameter design and high-performance control strategy. Without altering the original full-bridge topology or the switching frequency, the proposed scheme achieves superior ripple suppression. To tackle the inherent resonance problem of the LCL filter, a sensorless capacitor current feedback active damping (CCFAD) strategy is proposed. This approach effectively suppresses resonance without additional hardware sensors and ensures system stability under digital control delays. Furthermore, to overcome the limitations of traditional PI controllers in terms of the dynamic performance and parameter tuning of the LCL-SPA, a high-performance LESO-based control algorithm within the Linear Active Disturbance Rejection Control (LADRC) framework is designed. By utilizing a Linear Extended State Observer (LESO) to estimate and compensate for total lumped disturbances in real-time, the algorithm simplifies the parameter tuning process and achieves rapid current tracking with nearly zero overshoot. Experimental results demonstrate that the proposed LCL-SPA achieves extremely low current ripple across various reference currents, with the ripple minimized to 20 mA at a 3 A load. Frequency response tests confirm that the system possesses a closed-loop bandwidth of up to 2 kHz, satisfying the high dynamic requirements of magnetic bearings. Full article

Glioblastoma (GBM) is the most common and most aggressive malignant primary brain tumor in adults with a median survival of 15 months. One of the main factors responsible for the poor prognosis of GBM is resistance to treatment with temozolomide (TMZ), which has been attributed—among other factors—to autophagy. Preclinical studies have shown that the combination of disulfiram (DSF) with copper (Cu) possesses anti-GBM activity, through various mechanisms, including re-sensitization to TMZ. Herein, we tested for the first time the effects of DSF and Cu in combination with TMZ on the survival of Fischer rats bearing F98 glioma, a model characterized by inherent resistance to TMZ. Tumor size evaluation by Magnetic Resonance Imaging as well as immunofluorescence analysis of two autophagy markers, namely microtubule-associated protein 1 light chain 3 (LC3) and sequestosome-1 (SQSTM1)/p62 (p62), were also performed. According to our results, TMZ-DSF-Cu significantly increased mean survival and induced both LC3 and p62 autophagy markers. Interestingly, these results could not be achieved in the absence of Cu, neither in the presence of TMZ alone, suggesting the importance of combining DSF with Cu in order to sensitize glioma to TMZ, presumably via implication of autophagy modulation. Full article