This study adopted a novel high-speed stirring and crushing device (HSD) for flotation feed pretreatment. Systematic flotation tests, particle size analysis, floc microscopic observation, and a first order flotation kinetic model were used to comprehensively analyze the effects of HSD output energy (1500–12000 J) on coal slime flotation performance, particle size distribution, coarse particle crushing efficiency, and floc structure. The results demonstrate that the HSD effectively crushes +0.5 mm coarse coal slime and enhances clean coal yield. Optimal performance was achieved at 4000 J, with clean coal yield reaching 85.5% (compared to 75.23% in conventional flotation) and the +0.5 mm particle content in tailings reduced to 0.79% (compared with 6.65% in the conventional process). Moreover, within a relatively low energy range of 1500–4000 J, the HSD induces shear flocculation of fine slurry particles to boost the flotation rate. This study clarifies the regulation mechanism of HSD output energy for coal slime flotation, provides a new technical solution to the “coarse particle run-off” issue in coal preparation plants, and is vital for improving flotation separation efficiency and coal resource recovery.

A numerical model is established using the Discrete Element Method (DEM) to simulate flows of flexible, elongated tobacco particles in a rotating drum, which is used to add flavor to the tobacco products. Similar rotating drum experiments are performed to validate the DEM model by comparing mixing results of the tobacco particles that flow out of the drum and settle on a receiver belt. Subsequently, effects of some critical operating parameters (drum rotational speed, feeder belt speed, and mass flow rate) and material properties (particle aspect ratio and flexibility) on the particle mixing and flavor spray uniformity are examined. It is found that an increase in the drum rotational speed and a decrease in feeder belt speed can increase the particle residence time in the spray zone and improve the spray uniformity. Non-monotonic effects of the mass flow rate on the particle residence time and spray uniformity are observed. The tobacco particles with larger aspect ratios and higher flexibility have longer residence time in the spray zone and thus better spray uniformity.

Real-time detection of particle size distribution (PSD) in a ball mill is essential for optimizing grinding efficiency and reducing energy consumption. This study proposes a vibration-signal-based method for soft sensing of PSD during milling. First, the influence of particle size on the impact energy of media was studied based on particle breakage mechanism and the motion law of grinding media; Second, a Discrete Element Model (DEM) was conducted to verify the relationship between particle size and the throwing height of the media; Finally, vibration signals were mined to determine the proportion of particles with different sizes in the mixed particles based on “white box” characteristics of dendritic neural network. The experimental results show that when some parameters, such as: Ball Charge Volume Ratio (BCVR), total particle mass and rotational speed, remain constant, the larger the particle size in ball mill, the smaller the amplitude of vibration signal collected; Meanwhile, the dendrite neural network can effectively achieve soft measurement of PSD in ball mill.

Spiral jet milling is a prevalent powder production apparatus, frequently selected in the powder metallurgy sector due to its narrow particle size distribution, mechanical simplicity, ease of cleaning, and minimal pollution levels. Current numerical simulations of spiral jet milling do not provide an analysis that concurrently examines the interactions between gas and solids. In this work, a novel two-way coupled CFD-DEM model was developed to simulate the gas-solid interactions and particle classification behavior of NdFeB powder in a spiral jet mill, representing an advance over previous one-phase and one-way coupled studies. Initially, we used the single-factor test method to individually examine the impact of each grading parameter on performance, which led to the identification of key variables. Subsequently, the orthogonal test method was employed to explore the interactions systematically among multiple parameters, and optimal parameter combinations were established through analysis of the polar deviation. Nozzle deflection angle and nozzle inlet pressure emerged as the most influential factors on grading performance; the former greatly affects classification performance, while the latter predominantly affects grading accuracy. The efficiency of grading and grading accuracy significantly influence the nozzle deflection angle and nozzle air inlet; the material inlet primarily affects classification performance; the nozzle air inlet predominantly impacts grading accuracy; and outlet pressure and the number of blades on the grading wheel exert a relatively minor influence on both indicators. This work presents a theoretical foundation for optimizing spiral jet milling parameters and introduces a new idea for the advancement of powder metallurgy materials and technology.

To address the poor sedimentation of low-concentration fine mineral slurries (1% concentration, over 90% of particles finer than 0.038 mm) in thickeners, a novel turbo centrifugal separator was designed for rapid solid–liquid separation. Single-factor experiments and Response Surface Methodology (RSM) were used to investigate the effects of blade height, number, and inclination angle on separation performance and flow field characteristics. The results demonstrated that increasing blade height and inclination angle improved underflow yield, whereas the effect of blade number on yield followed an initial increase followed by a decrease, with a minimum cut size d50 of 8.24 μm. Optimization via RSM identified the optimal parameter combination as a blade height of 200 mm, 27 blades, and a 50° inclination angle, achieving a simulated underflow yield of 78.83%. In the optimized impeller experiments with a feed concentration of 1.67%, the underflow concentration reached 19.69% with a yield of 77.52%. The optimized design enhances separation efficiency through multiple mechanisms: generating strong centrifugal forces, creating organized spiral flow patterns, dissipating turbulent energy, and suppressing circulating flows. This study provides a theoretical basis and optimization methodology for the design of solid–liquid separation equipment for low-concentration fine mineral slurries.

This study investigates the production of environmentally friendly lightweight geopolymer concretes utilizing fly ash (FA) as the primary precursor with calcined calcium bentonite (CCB), ferrochrome slag (SG), and expanded polystyrene (EPS) as supplementary components. A Box–Behnken design was employed to investigate the combined effects of CCB and SG additions, along with the solid-to-liquid ratio, on the compressive strength. Moderate CCB incorporation, particularly around 10%, improved mechanical performance, achieving strengths above 48 MPa, with a maximum of 51.33 MPa at 90 °C for a mix containing 5% CCB and 5% SG. Higher CCB dosages (>20%) reduced strength due to matrix dilution, while SG showed limited contribution at elevated levels. Incorporation of EPS granules reduced density to as low as 1292 kg/m³, yet compressive strengths between 25 and 30 MPa were maintained in mixes with 10% CCB and 0.3% EPS. SEM-EDX analysis confirmed dense geopolymer matrices in FA–CCB composites, whereas SG particles appeared less integrated. These results confirm the potential for producing high-strength, lightweight geopolymer concretes through the effective valorization of waste. The combined use of FA, CCB, SG, and EPS offers a sustainable pathway for resource-efficient construction that supports circular resource utilization.

Coal cutting in fully mechanized excavation faces produces high dust concentrations, which can be effectively controlled using a combined ventilation system with long forcing and short exhaust ducts. This study investigates the generation, transport, and diffusion of cutting-induced dust through integrated theoretical, experimental, and numerical approaches. A PFC2D model was developed based on particle size distribution, uniaxial compression, and Brazilian splitting tests to simulate pick penetration into coal, revealing how cutting parameters influence dust production. An ANSYS Fluent-based model was also established to analyze dust behavior under the ventilation system, clarifying airflow dynamics and dust dispersion patterns. Results show that dust generation is minimized with a tip angle of 87°, an attack angle of 90°, and a pick spacing of 6 mm. Optimal dust control is achieved when the exhaust inlet is 3 m from the face and the forcing duct outlet is 25 m away. During the first 20 sec of cutting, the average dust concentration in the roadway first increases and then decreases, while dust removal efficiency gradually rises to 38.75%. Model validation with field data confirms the reliability of the simulations, providing theoretical guidance for dust management in fully mechanized excavation environments.

This study aimed to evaluate the real-time performance of an Electrostatic Mass Monitor (EDM) against the reference-grade Tapered Element Oscillating Microbalance (TEOM) for measuring PM2.5 mass concentrations emitted from a simulated oil/gas furnace. PM2.5 was sampled from the furnace exhaust using a dilution system under varying operating conditions, including a wide range of Air-to-Fuel Ratios (AFR) (2.5, 5.0, 7.5) and flue gas temperature setpoints (75 °C–150 °C). Experimental results confirmed that PM2.5 emission rates were overwhelmingly controlled by the AFR, with the fuel-rich condition (AFR = 2.5) generating concentrations up to 1400 g/m3 and exhibiting high temporal volatility. A linear regression analysis performed on the paired real-time data established a strong positive correlation between the two instruments (Pearson’s r = 0.962; Adj. R2= 0.963). The resulting regression slope of 0.909 suggests the EDM systematically reports mass concentrations approximately 9% lower than the TEOM for these combustion aerosols. However, the EDM demonstrated superior temporal resolution, capturing greater short-term fluctuations in the PM2.5 concentration compared to the TEOM. The high level of correlation validates the EDM as a reliable and cost-effective instrument for continuous, real-time PM2.5 emission monitoring in combustion source applications, contingent upon the application of a site-specific calibration factor derived from the TEOM.

Extensive efforts have enhanced flat plate solar collectors through active and passive strategies to advance clean energy adoption aligned with SDG7. In this context, a compact domestic solar hot water system was developed using a rifled riser tube flat plate collector and CuO/La2O3 nanofluids under forced circulation. A 1 m2 collector coupled with a 50 L day − 1 storage tank was experimentally evaluated using deionized water, CuO, La2O3 mono nanofluids, and an 80:20 CuO/La2O3 hybrid nanofluid at 0.5 wt% concentration and flow rates of 1, 2, and 3 LPM. At 3 LPM, maximum thermal efficiencies of 70.24%, 75.73%, 79.95%, and 81.96% were achieved for deionized water, La2O3, hybrid, and CuO nanofluids, respectively. The rifled tube produced heat transfer coefficients of 8836 W m − 2 K − 1 for the hybrid and 9027 W m − 2 K − 1 for CuO nanofluids. La2O3 improved colloidal stability, while CuO enhanced thermal conductivity, yielding synergistic performance. Compared with a plain tube collector using deionized water, average efficiency improved by 30.56% and 32.36% for hybrid and CuO nanofluids. Enhanced heat transfer increased exergy efficiency to 22.54% and 25.45% for hybrid and CuO nanofluids, respectively. The combined use of rifled tubes and hybrid nanofluid enabled a 24.86% reduction in collector area domestically.

Heart failure is increasingly prevalent in terms of mortality and morbidity worldwide, with myocardial infarction (MI) being a significant contributor. This work presents lisinopril (LN) and tannic acid (TA)-loaded nanoparticles (LNTA NPs), tailored for the pathological features of acute MI. The particle diameter of TA NPs was 325 nm with a polydispersity index of 0.002. Consequently, a fucoidan (Fu)/collagen (Col) hydrogel (HGL) exhibiting favorable mechanical and biological properties has been developed, with LNTA NPs integrated into the HGL-LNTA, resulting in several synergistic therapeutic effects. The incorporation of Fu enhanced the injectability and mechanical strength of the HGL, while endowing the Col material with anticoagulant characteristics vital for prospective clinical applications as cardiovascular biomaterials. LNTA NPs decreased the production of reactive oxygen species (ROS) and enhanced the activities of superoxide dismutase (SOD), glutathione (GSH), and glutathione peroxidase (GPx). The LNTA NPs, administered directly to the infarct site, not only provide mechanical support but also significantly restore cardiac function (***p < 0.001) and protect myocardial tissue by scavenging ROS and alleviating inflammation. Collectively, our results have validated the superior therapeutic efficacy of HGL-LNTA in treating MI patients, positioning it as a promising strategy for MI management.