Search Results (865)

Ceramic balls are utilized as grinding media for regrinding of titanomagnetite rougher, owing to its low liberation degree and intricate intergrowth with gangue minerals. Process mineralogy, regrinding experiments and EDEM simulations were adopted to investigate the influencing mechanism of ceramic balls on the regrinding performance of titanomagnetite rougher. The Dv(90) of titanomagnetite rougher is 198.19 μm, and the titanomagnetite is closely intergrown with gangue minerals, including chlorite, serpentine and ilmenite, in the forms of inclusions, interlocks and solid solutions with a liberation degree of 75.54%. The Dv(90) reduces to 39.86 μm, and the liberation degree of titanomagnetite increases to 92.86% after regrinding with ceramic balls. The grade was improved from 53.01% to 58.83% with a recovery of 96.19% after magnetic separation. EDEM simulation results reveal that raising stirrer speed elevated collision energy, increasing pulp density enhanced viscous coupling and particle capture, and improving media filling ratio boosted collision frequency. These findings demonstrate that ceramic balls could effectively refine product size, facilitate mineral liberation and improve concentrate grade, offering a viable pathway toward efficient utilization of titanomagnetite. Full article

This study investigates the effects of different graded crushing durations in a blade crusher on the crushing mechanics of wheat and the properties of the resulting flour. Mechanical models were established for blade–particle collisions, radial sliding of particles along the blade surface, and particle–chamber wall collisions. Under reasonable simplifying assumptions, the models analytically characterize the theoretical relationships of impact force and crushing energy with blade rotational speed, rotational radius, and particle incidence angle. The models were used to provide a qualitative mechanistic interpretation of the experimental trends rather than to quantitatively predict flour particle size distribution or damaged starch content. Two graded crushing processes were evaluated, with crushing durations of 10 s per pass (F10) and 15 s per pass (F15). Observation of particle-size evolution during the crushing of wheat particles showed that as the number of crushing passes increased, the proportion of coarse particles continuously decreased, the proportion of fine particles gradually increased, and the proportion of intermediate-sized particles initially increased and then decreased, demonstrating a progressive coarse-to-fine fragmentation pattern. Particle size analysis of the resulting wheat flour showed that the particle size distribution for the F15 process peaked below 5 μm and shifted toward smaller particle sizes relative to that for the F10 process. Nevertheless, the wheat flour obtained from both processes exhibited relatively concentrated particle size distributions, with Span values ranging from 2.46 to 2.68. Damaged starch content increased significantly with the number of crushing passes and was generally higher for the F15 process than for the F10 process. Moisture content decreased from 14.30% to 12.86% under the F10 process and from 14.25% to 12.73% under the F15 process, whereas ash content ultimately increased to 0.48% under both processes. Protein content initially increased and subsequently decreased under both processes. These findings provide experimental evidence for the effects of graded milling on grain refinement, starch damage, and physicochemical composition of wheat flour. Full article

Granular collapse-induced wave generation is a critical process in coastal engineering and natural hazards, yet its rapid and complex fluid–solid coupling mechanism poses significant challenges for numerical modeling. This paper presents a comprehensive validations and performance benchmarking study of non-spherical granular collapse-induced wave generation using a GPU-accelerated resolved SPH-DEM coupling framework. Through three benchmark cases with increasing complexity, the numerical accuracy and robustness of the model are thoroughly verified with respect to free-surface flows, multi-body collisions, and intense fluid–solid interactions. Subsequently, the influence of SPH resolution and particle shape on computational efficiency is quantitatively assessed. It is found that the total runtime is dominated by the number of SPH particles, while the GPU acceleration advantage becomes more pronounced as the number of DEM faces increases. Furthermore, in the granular collapse-induced wave case, the temporal evolution of the leading wave amplitude and the difference in granular runout distance under dry and wet conditions are analyzed, revealing from the particle scale how fluid resistance modulates the coupling between wave generation and granular motion. This study not only validates the capability of the model to capture complex particle–wave interactions, but also provides quantifiable performance benchmarks and physical insights for its engineering applications. Full article

Addressing the challenges of low environmental modeling accuracy and inadequate obstacle avoidance precision in complex obstacle scenarios in unmanned aerial vehicle (UAV) 3D path planning, this study proposes a UAV 3D path planning method that integrates the truncated signed distance field (TSDF) with an improved particle swarm optimization algorithm (IPSO). A unified planning space integrating a voxel occupancy grid with a truncated signed distance field is constructed offline: the Euclidean distance to obstacle surfaces is truncated and confined within an effective band, whose extent is coordinated with the UAV safety distance threshold determined by physical dimensions and task requirements, thereby preserving the continuous geometric information needed for safety assessment. On this basis, the continuous distance and gradient information provided by the truncated distance field are utilized to formulate a piecewise continuous, distance-based threat cost function, replacing traditional binary collision detection; the distance and gradient are further embedded into the initialization, fitness evaluation, and velocity update procedures of the particle swarm. Moreover, an adaptive inertia weight and a Lévy escape mechanism are introduced to improve search efficiency and global exploration capability. Experimental results demonstrate that under dense discrete safety verification, the proposed method achieves a 100% success rate in complex unstructured environments and that the safety distance threshold can be flexibly adjusted according to task requirements while consistently satisfying the specified safety requirement. The resulting paths achieve a favorable balance among length, smoothness, and controllable safety margin, validating the effectiveness of the proposed method. Full article

Merging galaxy clusters represent one of the most powerful macroscopic laboratories in the Universe for searching for new physics within the dark sector. High-velocity cosmic collisions inherently separate the dark matter and stellar components from the highly collisional, X-ray-emitting intracluster gas. These massive systems provide an ideal environment to probe the fundamental nature of dark matter, specifically testing whether it behaves as a strictly collisionless particle or exhibits non-zero self-interactions. While pioneering systems like the Bullet Cluster historically demonstrated the macroscopic decoupling of dark and ordinary matter, the field has evolved into a sophisticated discipline driven by multi-disciplinary methodologies. This review synthesizes recent theoretical and empirical advances in interpreting post-collision dynamics. It examines how the synergy of combined approaches—integrating multi-wavelength observations from gravitational lensing and X-ray mapping with high-fidelity N-body hydrodynamical simulations—allows the translation of macroscopic spatial observables into stringent constraints on microscopic particle properties. Through this synthesis, the work evaluates how leveraging heterogeneous merger ensembles can reliably advance the ongoing search for physics beyond the standard cosmological model. Full article

Measurements of charge-changing cross-sections were developed as a method for determining proton radii, particularly for unstable, short-lived nuclei. Such cross-sections must be measured with high precision to determine the precise charge radii. However, there are complexities in the experimental method leading to uncertainties in determining precise nuclear radii. Therefore, good models describing the complex physics of charged particle interactions are needed in order to validate the experimental method and to estimate the contribution of systematic uncertainties. GEANT4 is a Monte Carlo simulation code widely used to describe interactions in heavy-ion collisions over a broad energy range, ranging from atomic physics to cosmic-ray energies. Experimental measurements of charge-changing reactions for carbon isotopes ^10,12C on different secondary targets were performed. In the present work, the experimental detector geometry, beam profile, and detector configuration were implemented in GEANT4 simulations in order to reproduce the experimental conditions as closely as possible. The experimentally obtained spectra are compared with the corresponding GEANT4 simulations to validate the interpretation of the measured spectra and assess systematic effects. Also, the secondary particle yield ratio is deduced and compared with GEANT4 results. Full article

Borescope inspection is essential for assessing the airworthiness of aircraft gas turbines. Yet, current procedures remain highly manual, operator-dependent, and inconsistent, which limits the reliability of subsequent image-based damage analysis. This paper introduces a systematic design approach for an ultra-slender continuum robot (CR) tailored to the geometric and operational constraints of aero-engine inspection. We formalize the design space, compare actuation concepts, and select a tendon-driven architecture based on a structured evaluation. Dimensional synthesis is formulated as an optimization problem that maximizes the visible blade surface, yielding segment lengths that ensure high inspection coverage. We detail design, material, and cable choices, the actuation unit, and two variants of the manipulator: A fully actuated (FA) version and a hybrid version with a passive carrier (PC). Evaluation in a high-pressure compressor mock-up reveals distinct strengths in stiffness, controllability, friction, pose observability, and system complexity between the two systems. Based on these findings, future work should focus on advancing a hybrid solution that combines the benefits of both approaches. Moreover, the presented methodology is not limited to high-pressure compressor inspection but can be applied to any section of the engine, significantly broadening its scope of application. Full article

Slender cantilever precision positioning actuators are highly susceptible to ambient low-frequency micro-vibrations, which severely deteriorate dynamic positioning accuracy and operational stability. To address this challenge, this paper proposes a passive vibration attenuation method utilizing a customized partitioned particle damper. A micro-vibration-adapted discrete element method (DEM) coupled dynamic model is established to quantitatively characterize the underlying multi-mechanism energy dissipation driven by micro-slip friction and weak inelastic collisions. Through systematic numerical parametric analysis and physical experimentation, the optimal damper configuration is identified. Experimental results rigorously demonstrate that the optimized particle damper effectively suppresses broadband micro-vibrations (10–100 Hz), achieving a maximum steady-state vibration damping efficiency of 63.24% and a transient peak acceleration attenuation of 67.5% at the cantilever tip. This work provides a highly compact, energy-free, and robust structural vibration suppression strategy, demonstrating significant potential for application in high-precision actuation systems. Full article

Propelled by accelerated technological innovation, the advancement of new material development has become imperative for emerging industries. The finite element method, leveraging multi-scale modeling and interdisciplinary integration, has established itself as one of the pivotal computational tools for significantly boosting research and development efficiency in material science. This study employed a combined approach of ABAQUS simulation and experimentation to efficiently design and synthesize an Al/W energetic composite characterized by concentrated energy release, high reaction enthalpy, and a unique discrete embedded structure. The finite element analysis focused on the stress distribution, equivalent strain, embedding depth, and energy conversion phenomena of heterogeneous particles under varying impact velocities. The results demonstrated that at a collision velocity of 500 m/s, embedded collisions between Al and W particles were achieved, providing effective guidance for synthesizing Al/W energetic composites with embedded structural features via high-speed impacts. TG-DSC analysis revealed that the Al/W energetic composites exhibited a reaction enthalpy change of 8806.0 ± 152 J/g and a maximum heat flow rate of 101.5 ± 2.8 W/g, which were 3.5-fold and 3.1-fold higher than those of pure Al with identical dimensions, respectively, and significantly surpassed the values of the mechanically mixed Al/W energetic composites. This integrated finite element simulation and experimentation provides a new pathway towards the efficient design and synthesis of novel materials with analogous components and structures. Full article

Low-damage plasma processing of atomically thin $\mathrm{M}\mathrm{o}{\mathrm{S}}_2$ requires simultaneous control of ion species, energy, and incident angle, yet the discharge mechanisms governing $\mathrm{A}\mathrm{r}/{\mathrm{O}}_2$ plasma and their connection to surface damage remain insufficiently understood. Here, we investigate the effect of the $\mathrm{A}\mathrm{r}/{\mathrm{O}}_2$ mixing ratio on the spatial distributions of charged particles, the plasma potential, and the substrate-incident ion energy and angular distributions in a low-voltage, single-frequency capacitively coupled plasma using a two-dimensional particle-in-cell Monte Carlo collision (PIC-MCC) simulation. At a fixed pressure of 50 mTorr with the $\mathrm{A}\mathrm{r}/{\mathrm{O}}_2$ ratio varied from 9:1 to 2:8, the ion energy and angular distributions were collected at the center and edge of the powered electrode. Increasing the oxygen fraction reduced the electron density while enhancing the ${\mathrm{O}}^{-}$ density and electronegativity, driving an electropositive-to-electronegative transition near 8:2, and shifted the dominant positive ion from $\mathrm{A}{\mathrm{r}}^{+}$ to ${\mathrm{O}}_2^{+}$, with ${\mathrm{O}}^{+}$ remaining minor owing to charge-exchange loss. The plasma potential and ion-energy peaks generally increased with the oxygen fraction but showed nonmonotonic dependence, while radial edge fields tilted and broadened the angular distributions. To link the ion and oxygen-radical fluxes to $\mathrm{M}\mathrm{o}{\mathrm{S}}_2$ processing without assuming uncertain surface-response coefficients, we interpreted the ion and oxygen-radical fluxes through a phenomenological two-channel surface-reaction scheme, introducing a damaging ion fraction and a radical-to-ion flux ratio. Their opposing trends reveal an intrinsic trade-off, indicating that an intermediate ${\mathrm{O}}_2$ fraction offers a more favorable low-damage window than either $\mathrm{A}\mathrm{r}$-rich or strongly oxygen-rich conditions. Full article

This paper addresses the multi-objective optimization of cooperative dual-arm robotic manipulation, focusing on the reduction and balancing of interaction forces during the coordinated transport of a shared payload. The manipulation task is formulated from an object-centric perspective, where candidate trajectories are defined through intermediate object poses that are simultaneously mapped to both robotic manipulators under rigid grasping assumptions. Within this framework, the optimization problem is posed as a constrained multi-objective search in which the force demands associated with each robot are minimized while preserving kinematic feasibility and collision-free cooperative motion. Two representative population-based multi-objective algorithms, Multi-Objective Particle Swarm Optimization (MOPSO) and Non-dominated Sorting Genetic Algorithm II (NSGA-II), are evaluated under equivalent trajectory bounds and objective definitions. The results provide a set of non-dominated cooperative trajectories that support the selection of force-efficient motions with lower peak demands and improved load-sharing behavior. The comparative analysis demonstrates the potential of multi-objective metaheuristic optimization for force-aware dual-arm manipulation and highlights the different convergence and solution-distribution behaviors of MOPSO and NSGA-II in a constrained robotic manipulation scenario. Full article

In deep-space exploration and remote sensing, characterizing radiative transfer in complex planetary atmospheres is fundamental for robust target detection and optical navigation. On the Martian surface, intense scattering and attenuation by dust aerosols pose severe environmental interference, challenging star sensors used for high-precision navigation. To address this, this study develops a spectral radiative transfer model based on the Null Collision Monte Carlo Method to characterize the optical background of the dusty Martian atmosphere. Mie scattering theory is employed for dust particles, while gas molecular absorption is modeled via line-by-line integration. The simulated sky radiance is validated against Mars rover Navcam observations, yielding an average relative error of 7.83% between the modeled and observed radiance values across scattering angles greater than 5°. Building on this, an imaging link model evaluates surface-based detection performance, including signal-to-noise ratio, detection success probability, and star count. Optical parameters—aperture, field of view, and integration time—are optimized for nighttime and dawn-dusk modes. Spatio-temporal assessments are conducted globally across Martian years, focusing on the Zhurong landing site and Tianwen-3 candidates. Finally, an Earth-environment equivalence experiment using a 60% transmittance filter verifies the design’s robustness. This work confirms the feasibility of star-sensor-based attitude determination on Mars. Full article

Guided by the objectives of sustainable coal utilization and resource efficiency improvement, this study investigated the recovery of fine, high-ash coal slime using a Reflux Flotation Cell (RFC). Particle size analysis showed that the −0.074 mm fraction accounted for approximately 33.3% of the feed and exhibited poor flotation performance in conventional classification flotation, resulting in substantial combustible matter losses. To improve the recovery of this fine fraction, flotation experiments were conducted using the RFC. Under the optimum operating conditions, combustible matter recovery of the −0.074 mm fraction reached 89.92%, approximately 10 percentage points higher than that achieved by conventional flotation. The improved performance enhances the utilization of low-grade coal resources while reducing combustible matter losses to tailings. The superior separation performance of the RFC is attributed to its unique hydrodynamic characteristics. High-shear flow in the downcomer generates abundant microbubbles and promotes particle–bubble collisions, whereas the inclined channels accelerate gangue settling through the Boycott effect, improving the separation efficiency of fine particles. These results demonstrate that the RFC provides an effective approach for the sustainable recovery of fine coal slime and offers theoretical support for improving resource utilization and reducing solid waste generation in coal preparation. Full article

To improve the accuracy of discrete element method (DEM) simulation parameters for American ginseng precision seeding and to overcome the reliance of metering device design on empirical trial-and-error—a consequence of the scarcity of physical property data for specialised medicinal seeds and the low transferability of generic parameters—this study focuses on germination-induced American ginseng seeds from the Jilin Baishan production region. Intrinsic parameters, including triaxial dimensions, density, elastic modulus, and Poisson’s ratio, were determined through physical experiments. The free-fall collision method, inclined plane sliding method, and rolling method were employed to measure the contact parameters between seeds and the ABS plastic material. Based on the measured results, a Plackett–Burman design was used to screen for three inter-particle contact parameters that significantly affect the angle of repose (AOR), and the steepest ascent test was subsequently applied to determine their optimal value intervals. A Box–Behnken design was further adopted to construct a second-order regression model and perform parameter optimisation. The calibrated seed–seed static friction coefficient was 0.759, the seed–seed rolling friction coefficient was 0.089, and the seed–seed coefficient of restitution was 0.17. The simulated static and dynamic AORs deviated from the physical test values by only 0.33% and 0.67%, respectively. In the bench validation using a pneumatic scoop-type seed metering device, a DEM–CFD coupling model was established to simulate the seeding process; the relative errors of the multiple rate and missing rate between simulation and bench tests were both below 8%, meeting the requirements of the relevant national standards. The calibrated parameters showed acceptable reliability under the tested conditions and can provide a theoretical basis for the selection of working parameters and the design optimisation of American ginseng precision seed metering devices. Full article

In this manuscript, we present the results of our studies on the exclusive photoproduction of quarkonium-photon pairs with large invariant mass. In our analysis, we focus on the production of the ${\eta }_c\gamma$ and ${\chi }_{cJ}\gamma$ pairs in high energy kinematics. We use the Color Glass Condensate (CGC) framework for analysis and demonstrate that at leading order in ${\alpha }_s$ the cross-sections of these processes are determined by the forward dipole scattering amplitude. The kinematic distributions of the produced particles allow us to study the dipole amplitude in detail, making this process a very clean probe for studies of saturation physics. Using phenomenological parametrizations of the dipole amplitudes, we estimate numerically the differential production cross-sections for ${\eta }_c\gamma$ and ${\chi }_c\gamma$ in the kinematics of ultraperipheral collisions at the LHC and the future Electron-Ion Collider (EIC). Furthermore, we assess the role of this process as a possible background to the exclusive photoproduction of C-even quarkonia, which is frequently considered as a tool for odderon searches. Full article