Search Results (625)

The new type of gold cone filter cartridge has dual functions of increasing filter area and enhancing pulsed-jet cleaning, but the issue of patchy cleaning remains to be addressed. This study further enhances the pulsed-jet cleaning performance of cone filter cartridges by employing a porous diffusion nozzle. The temporal and spatial distributions of pulse jet velocity and pressure under the condition of porous nozzles were investigated through numerical modeling. The variation law of pressure on the side wall of the filter cartridge was analyzed. The influence of jet distance of porous nozzles on pulsed-jet pressure and pulsed-jet uniformity was experimentally investigated. Dust filtration and cleaning experiments were conducted, and the filtration pressure drop, dust emission concentration, and comprehensive filtration performance were compared. It was found that the airflow jetted by the porous diffusion nozzle is more divergent than that of the common round nozzle. This results in a larger entrainment of the jet stream, a milder collision of the jet stream with the cartridge cone, and a slower overall velocity reduction. More airflow is generated into the filter cartridge and accumulated; the accumulated static pressure covers a larger range of the upper section of the filter cartridge, with a longer duration of static pressure. In the online dust filtration and cleaning experiment, compared with the condition of the common round nozzle, the porous nozzle can reduce the residual pressure drop by 27.0%, increase the filtration cleaning interval by a factor of 3.80, reduce the average dust emission concentration by 45.2%, and increase the comprehensive performance index Q_F by 5.2%. The research conclusions can provide references for the design and optimization of industrial filter cartridge dust collectors. Full article

The erosion mechanism of hydrocyclones under air column conditions is still unclear. In this paper, Computational Fluid Dynamics–Discrete Phase Model (CFD-DPM) technology is adopted to perform transient simulations of the three-phase flow (liquid–gas–solid) within a hydrocyclone. The Reynolds Stress Model (RSM) and Volume of Fluid (VOF) model are adopted to simulate the continuous phase flow field within the hydrocyclone, while the DPM coupled with the Oka erosion model is used to predict the particle flow and erosion mechanisms on each wall within the hydrocyclone. The particle sizes considered are 15 μm, 30 μm, 60 μm, 100 μm, 150 μm, and 200 μm, respectively, with a density of 2600 kg/m³. The particle velocity is consistent with the fluid velocity at 5 m/s, the total mass flow rate is 6 g/s, and the volume fraction is less than 10%. The results indicate that the cone section suffers the severest erosion, followed by the overflow pipe, column section, infeed section, and roof section. The erosion in the cone section reaches its maximum value near the underflow port, with an erosion rate approximately 6.8 times that of the upper cone section. The erosion distribution in the overflow pipe is uneven. The erosion of the column section exhibits a spiral banded distribution with a relatively large pitch. The erosion rate in the infeed section is approximately 1.47 times that of the roof section. Full article

Micro-combustion-powered thermoelectric generators (μ-CPTEGs) combine the high energy density of hydrocarbons with solid-state conversion, offering compact and refuelable power for long-endurance electronics. Such characteristics make μ-CPTEGs particularly promising for aerospace systems, where conventional batteries face serious limitations. Their achievable performance hinges on how a swirl-stabilized flame transfers heat into the hot ends of thermoelectric modules. This study uses a conjugate CFD framework coupled with a lumped parameter model to examine how input power and equivalence ratio shape the flame/flow structure, temperature fields, and hot-end heating in a swirl combustor-powered TEG. Three-dimensional numerical simulations were performed for the swirl combustor-powered TEG, varying the input power from 1269 to 1854 W and the equivalence ratio from φ = 0.6 to 1.1. Results indicate that the combustor exit forms a robust “annular jet with central recirculation” structure that organizes a V-shaped region of high modeled heat release responsible for flame stabilization and preheating. At φ = 1.0, increasing Q_in from 1269 to 1854 W strengthens the V-shaped hot band and warms the wall-attached recirculation. Heating penetrates deeper into the finned cavity, and the central-plane peak temperature rises from 2281 to 2339 K (≈2.5%). Consistent with these field changes, the lower TEM pair near the outlet heats more strongly than the upper module (517 K to 629 K vs. 451 K to 543 K); the inter-row gap widens from 66 K to 86 K, and the incremental temperature gains taper at the highest power, while the axial organization of the field remains essentially unchanged. At fixed Q_in = 1854 W, raising φ from 0.6 to 1.0 compacts and retracts the reaction band toward the exit and weakens axial penetration; the main-zone temperature increases up to φ = 0.9 and then declines for richer mixtures (peak 2482 K at φ = 0.9 to 2289 K at φ = 1.1), cooling the fin section due to reduced transport, thereby identifying φ = 0.9 as the operating point that best balances axial penetration against dilution/convective-cooling losses and maximizes the TEM hot-end temperature at the fixed power. Full article

Cotton is a vital economic crop, and cotton fiber serves as the primary raw material for the textile industry. Lignin in cotton fiber is closely associated with fiber quality. Lignin is synthesized through the phenylpropanoid metabolic pathway, where the cinnamyl alcohol dehydrogenase gene CAD6 plays a significant role. In this study, we obtained successfully transformed overexpression plants by constructing an overexpression vector and performing genetic transformation and tissue culture. To verify the function of the GhCAD6 gene in upland cotton, we analyzed the agronomic traits, fiber quality, cell wall structure, and lignin content of GhCAD6-overexpressing plants. Our results indicate that the GhCAD6 gene is predominantly expressed during the stages of fiber elongation and secondary wall synthesis. Overexpression of the GhCAD6 gene resulted in increased plant lignin content and fiber upper half mean length, boll number per plant, fiber uniformity index, strength, and lint were improved. The fiber surface was smoother, and the fiber cell wall was more compact. These findings demonstrate that the GhCAD6 gene positively regulates lignin synthesis and fiber quality formation, contributing to the enhancement of cotton fiber quality. Full article

Near-wall flow around circular cylinders is commonly encountered in various engineering applications, such as submarine pipelines and river-crossing conduits. The wake structure significantly influences local flow stability and has become a critical focus in fluid dynamics research. Specifically, when the gap ratio (G/D) ranges from 0.1 to 1.0, the interaction mechanism between the wall and the wake structure remains poorly understood. Moreover, the combined effects of the Reynolds number (Re) and gap ratio on the flow field require further investigation. In this study, a series of experimental measurements were conducted using two-dimensional, two-component particle image velocimetry (2D–2C PIV) to examine the influence of G/D and Re on the near-wall wake characteristics. The results indicate that, at a gap ratio of G/D = 0.1, the gap flow exhibits pronounced curling into the recirculation region, where the lower vortex is entrained and actively participates in wake evolution. When G/D ≥ 0.3, an increase in Re leads to a reduction in the lengths of both the upper and lower shear layers, a delayed attenuation of the wall-side shear layer, and a gradual symmetrization and contraction of the recirculation region behind the cylinder. Further analysis reveals that the evolution of the secondary vortex is strongly influenced by the combined effects of Re and G/D. Specifically, at Re = 3300 and G/D ≤ 0.3, the secondary vortex migrates away from the wall toward the upper shear layer, where it merges with the upper vortex. For 0.5 ≤ G/D ≤ 0.7, it interacts with the lower vortex, while at G/D = 1.0, it evolves independently downstream along the wall. At G/D = 0.5, the secondary vortex merges with the upper vortex at Re = 1100, whereas at Re = 5500, it interacts with the lower vortex instead. These findings contribute to a deeper understanding of the complex flow structures associated with near-wall cylinder wakes and offer valuable theoretical insights for engineering applications involving submarine pipelines in bottom-mounted or partially suspended configurations. Full article

For the possible damage to overhead pipelines caused by gas explosions in utility tunnels, an overall three-dimensional finite-element model of utility tunnel–soil–pipeline is established, the overpressure loads are applied to the inner wall of the gas chamber in the utility tunnel, the dynamic response laws of the utility tunnel and the pipeline are calculated and analyzed, and anti-explosion protection measures are proposed. The results show that the degree of damage to the pipe wall is determined by both the explosion-impacted area and the soil constraint. Under the same explosion-impacted area, the peak horizontal displacement of the monitoring point without soil constraint is 1.64 times that with soil constraint, and 1.29 times for the peak vertical displacement. The damage to the lower part of the pipeline is significantly greater than that to the upper part of the pipeline, and the damage to the pipeline decreases with an increase in the horizontal angle between the utility tunnel and the pipeline. The diameter deformation rates were 49% at α = 0° and 84% at α = 45°, with α = 90° showing the least damage. Therefore, it is suggested that the overhead pipeline is perpendicular to the utility tunnel. As the vertical distance between the utility tunnel and the pipeline increases, the diameter deformation rate and displacement of the pipeline both decrease, and when this distance is greater than 3 m, the influence on the pipeline significantly decreases. Therefore, it is recommended that the distance between the pipeline and the utility tunnel should be at least 3 m. In addition, the damage caused by gas explosions to the overhead pipeline can be reduced by reinforcing the gas chamber, using energy-absorbing materials around the utility tunnel, and setting up hollow piles between the utility tunnel and pipelines. Full article

Background and Objectives: The clinical significance of gastrointestinal (GI) tract wall thickening incidentally detected on abdominal imaging remains unclear. This study aimed to examine the relationship between GI tract wall thickening seen in imaging and what is found during endoscopy, as well as to explore how hemoglobin, C-reactive protein (CRP), and albumin levels can help predict the presence of malignancy. Materials and Methods: In this retrospectively designed study, 209 patients were included who were found to have GI tract wall thickening on radiological imaging and underwent endoscopy within 90 days. Endoscopic findings and laboratory data were recorded. Patients were compared based on the presence or absence of malignancy, and a receiver operating characteristic analysis was performed. Results: Malignancy was detected in 8.5% and 10.9% of the upper and lower GI tract cases, respectively. In patients with upper GI tract malignancy, hemoglobin levels were significantly lower and CRP levels were higher (p < 0.001 and p = 0.015, respectively). Similarly, in lower GI tract malignancy, hemoglobin levels were lower (p = 0.033), whereas CRP did not show a significant difference (p = 0.115). Cut-off values were determined as 11.8 g/dL for hemoglobin and 40.75 g/L for albumin, and both were found to have high negative predictive values. Conclusions: GI tract wall thickening detected radiologically is clinically significant and should be further investigated endoscopically. Certain biochemical parameters may aid in ruling out malignancy; however, endoscopy remains essential for definitive diagnosis. Full article

In this paper, the electromagnetohydrodynamic (EMHD) flow and heat transfer of a fluid are analytically investigated. The flow and heat transfer occur in a horizontal channel filled with a porous medium, where the permeabilities of the upper and lower halves of the channel are different. The lower half of the channel is saturated with a hybrid nanofluid, while the upper half is saturated with a nanofluid. The base fluids of the nanofluid and the hybrid nanofluid are different. The channel walls are impermeable. The channel is subjected to external magnetic and electric fields. The problem is analyzed under the inductionless approximation. By introducing dimensionless variables and physical parameters that characterize the flow and heat transfer, the governing equations are transformed into their dimensionless forms. These equations are solved analytically, and the velocity and temperature distributions of the fluid in the channel are obtained. The distributions are graphically illustrated for the case in which the upper half of the channel contains the Al₂O₃/oil nanofluid and the lower half contains the Cu–TiO₂/water hybrid nanofluid, considering various values of the Hartmann number, the external electric load factor, the porosity factor, and the nanoparticle volume fractions. The numerical values of the dimensionless shear stresses and Nusselt numbers at the channel walls are presented in a table. The analysis of the results indicates that an increase in the Hartmann number leads to higher temperatures within the channel. The findings also demonstrate that, in this case, the flow velocities are lower and the temperatures decrease, while the shear stresses and Nusselt numbers at the channel walls are higher compared to those observed for pure fluid (oil and water) flow through the channel. This indicates the advantage of employing the model investigated here over the classical model (water and oil) in engineering practice. Full article

This work aimed to address the severe deformation and uncontrollable instability of surrounding rocks in gob-side roadways of ultra-thick coal seams under intense mining disturbances. Theoretical analysis, numerical simulation, and field practice were used to investigate the reasonable width of deteriorated coal pillars and surrounding rock control technology. The following items were clarified, including the structural characteristics of the overlying strata, the fracture location of main roof, and the stress, failure, and deformation patterns of surrounding rocks based on coal pillar width. In terms of the load-bearing characteristics of coal pillars, the reasonable width of deteriorated coal pillars in roadways was determined. According to the differential deformation characteristics of roadway roof and sides, an adaptive and targeted asymmetric control scheme was proposed for surrounding rocks. Key strata above the ultra-thick coal seam working face formed a structure of low-level cantilever beam and high-level articulated rock beam. The fracture position of the main roof cantilever beam was located 15.4 m from the coal wall of the goaf. When the pillar width reached 8 m during roadway excavation, the internal stress exceeded the original rock stress. The lateral deterioration range of the coal seam extended to 25 m from the coal wall after mining the upper working face. The protective coal pillars within the reasonable width range were all in a fully plastic failure state. The plastic-bearing zone within the deteriorated coal pillar occupied a high proportion when the coal pillar width ranged from 8 to 10 m, demonstrating convenient load-bearing capacity. Considering economic and safety factors, the reasonable width for deteriorated coal pillars was determined to be 8 m. The deformation of roof and side on the coal pillar side of the roadway was greater than that on the solid coal side, showing obvious asymmetric characteristics. A targeted asymmetric support scheme using truss anchor cables was proposed for surrounding rocks. This scheme formed an effective prestress field in the surrounding rocks, enabling enhanced control of severely deformed areas. Field practice has verified the rationality of the designed deteriorated coal pillar width and support system, ensuring safe production in the working face. This provides reference and inspiration for the reasonable width and surrounding rock control technology of deteriorated coal pillars under similar geological conditions. Full article

In this study, we discuss the water masses and their transport in the Chain fracture zone (CFZ), which is a poorly studied part of the Equatorial Atlantic. Our study is based on measurements carried out during the 63rd cruise of R/V “Akademik Ioffe” in 2022. We identified water masses in the CFZ, determined their physical and chemical properties, localized their boundaries and components of the North Atlantic Deep Water (NADW), and calculated the transport of water masses. A four-layer structure of the NADW was identified with two components of middle NADW, which are defined by minimal and maximal oxygen concentrations. The upper boundary of the Antarctic Bottom Water (AABW) corresponds approximately to the isotherm θ = 1.5 °C. The assessed proportion of AABW in the bottom layer at the western entrance to the CFZ is 50%, and not higher than 33% at the eastern exit from the CFZ. For the first time, instrumental observations were carried out at the exit of the CFZ and in its western part. They showed that the AABW flux has an intensity of about 0.02–0.5 Sv depending on the upper boundary of AABW and moves through a passage in the northern wall (at 13° W), and not through the main sill. Full article

This study presents a three-dimensional numerical analysis of natural convection during the postharvest storage of corn and wheat in a galvanized steel silo with a conical roof and floor, measuring 3 m in radius and 18.7 m in height, located in the Bajío region of Mexico. Simulations were carried out specifically for December, a period characterized by cold ambient temperatures (10–20 °C) and comparatively lower solar radiation than in warmer months, yet still sufficient to induce significant heating of the silo’s metallic surfaces. The governing conservation equations of mass, momentum, energy, and species were solved using the finite volume method under the Boussinesq approximation. The model included grain–air sorption equilibrium via sorption isotherms, as well as metabolic heat generation: for wheat, a constant respiration rate was assumed due to limited biochemical data, whereas for corn, respiration heat was modeled as a function of grain temperature and moisture, thereby more realistically representing metabolic activity. The results, obtained for December storage conditions, reveal distinct thermal and hygroscopic responses between the two grains. Corn, with higher thermal diffusivity, developed a central thermal core reaching 32 °C, whereas wheat, with lower diffusivity, retained heat in the upper region, peaking at 29 °C. Radial temperature profiles showed progressive transitions: the silo core exhibited a delayed response relative to ambient temperature fluctuations, reflecting the insulating effect of grain. In contrast, grain at 1 m from the wall displayed intermediate amplitudes. In contrast, zones adjacent to the wall reached 40–41 °C during solar exposure. In comparison, shaded regions exhibited minimum temperatures close to 15 °C, confirming that wall heating is governed primarily by solar radiation and metal conductivity. Axial gradients further emphasized critical zones, as roof-adjacent grain heated rapidly to 38–40 °C during midday before cooling sharply at night. Relative humidity levels exceeded 70% along roof and wall surfaces, leading to condensation risks, while core moisture remained stable (~14.0% for corn and ~13.9% for wheat). Despite the cold ambient temperatures typical of December, neither temperature nor relative humidity remained within recommended safe storage ranges (10–15 °C; 65–75%). These findings demonstrate that external climatic conditions and solar radiation, even at reduced levels in December, dominate the thermal and hygroscopic behavior of the silo, independent of grain type. The identification of unstable zones near the roof and walls underscores the need for passive conservation strategies, such as grain redistribution and selective ventilation, to mitigate fungal proliferation and storage losses under non-aerated conditions. Full article

Flexible pressure sensors have shown promise applications in scenarios such as robotic tactile sensing due to their excellent sensitivity and linearity. However, the realization of flexible pressure sensors with both static and dynamic response capabilities still face significant challenges due to the properties of the sensing materials themselves. In this study, we propose a flexible pressure sensor that integrates piezoelectric and ionic capacitance mechanisms for full-domain response detection of dynamic and static forces: a “sandwich” sensing structure is constructed by printing a mixture of multi-walled carbon nanotubes (MWCNTs) onto the surface of the upper and lower electrodes, and sandwiching a polyvinylidene fluoride (PVDF) thin film between the electrodes. The device exhibits a sensitivity of 0.13 kPa⁻¹ in the pressure range of 0–150 kPa. The sensor has a rapid dynamic response (response time 19 ms/12 ms) with a sensitivity of 0.49 mV kPa⁻¹ based on the piezoelectric mechanism and a linearity of 0.9981 based on the ionic capacitance mechanism. The device maintains good response stability under the ball impact test, further validating its potential application in static/dynamic composite force monitoring scenarios. Full article

This study investigates the formation mechanism and stress response characteristics of normal faults in coal-bearing strata through large-scale physical simulation experiments. A multi-layer heterogeneous model with a geometric similarity ratio of 1:300 was constructed using similar materials that were tailored to match the mechanical properties of real strata. Real-time monitoring techniques, including fiber Bragg grating strain sensors and a DH3816 static strain system, were employed to record the evolution of deformation, strain, and displacement fields during the fault development. The results show that the normal fault formation process includes five distinct stages: initial compaction, fault initiation, crack propagation, fault slip, and structural stabilization. Quantitatively, the vertical displacement of the hanging wall reached up to 5.6 cm, equivalent to a prototype value of 16.8 m, and peak horizontal stress increments near the fault exceeded 0.07 MPa. The experimental data reveal that stress concentration during the fault slip stage causes severe damage to the upper coal seam roof, with localized vertical stress fluctuations exceeding 35%. Structural planes were found to control crack nucleation and slip paths, conforming to the Mohr–Coulomb shear failure criterion. This research provides new insights into the dynamic coupling of tectonic stress and fault mechanics, offering novel experimental evidence for understanding fault-induced disasters. The findings contribute to the predictive modeling of stress redistribution in fault zones and support safer deep mining practices in structurally complex coalfields, which has potential implications for petroleum geomechanics and energy resource extraction in similar tectonic settings. Full article

Objectives: This study assesses the efficacy of tracheotomy-primed sclerotherapy in craniofacial venous malformations (VMs), establishes evidence-based airway intervention criteria, and develops site-specific safety protocols to optimize treatment timing and safety in cases with upper airway compromise. Methods: We retrospectively collected the clinical data of 35 patients treated by our center between January 2008 and November 2024, who were diagnosed with cervicofacial VMs involving the upper respiratory tract. All patients underwent direct tracheotomy or tracheotomy after sclerotherapy for lesions located in the anterior cervical area. Sclerotherapy was performed under fluoroscopy or laryngoscopy after tracheotomy. Results: 35 patients underwent 225 sclerotherapy sessions. Nineteen patients underwent tracheotomy directly, and sixteen patients received sclerotherapy at the anterior cervical area before tracheotomy. All patients presented improvement according to magnetic resonance imaging (MRI) findings, and 94.29% (33/35) of patients reported improvement in clinical presentations. All patients experienced improvement in quality of life (QoL). No major complications occurred. Decannulation was successfully performed in all 35 patients after finishing sclerotherapy. Conclusions: Tracheotomy followed by sclerotherapy is safe and effective for VMs involving the upper respiratory tract. This is necessary for patients with lesions involving the laryngopharyngeal region, tongue base, and bilateral pharyngeal walls. In high-risk prophylactic tracheostomy candidates, anterior cervical sclerotherapy–tracheostomy–sclerotherapy (ACSTS) is an effective strategy for managing airway obstruction. Full article

A rise in the water level may result in different vertical rebound levels of the ground surface, adversely affecting buildings. Ground rebound occurred in the Xi’an Yuhuazhai area from 2018 to 2019, but the soil’s deformation characteristics remain unclear. Drilling and water level data and FLAC3D 6.0 were used to simulate water level recovery. The deformation characteristics of different soil layers were examined, their future development was predicted, and the influences of various parameters on ground rebound were analyzed. The rebound amount of the hanging wall in the second confined aquifer was 38.32 mm, accounting for 61.12% of the total rebound amount. The rebound amount of the footwall in the second confined aquifer was 22.14 mm, accounting for 79.63% of the total rebound amount. The predicted maximum rebound of the upper and lower soil layers in the next 5 years was 2.8 mm and 2.6 mm, respectively, representing a vertical difference of 0.2 mm, which has no significant effect on building safety. The results provide a scientific basis for groundwater management and settlement prevention and control in Xi’an. Full article