Search Results (2,882)

Full-duplex acoustic telemetry is important for real-time bidirectional measurement and control in intelligent coiled-tubing operations, but its reliability in deep horizontal wells is limited by long-range dispersion, asymmetric flow-induced noise, and severe near-end self-interference. This study proposes an orthogonal frequency-band planning and synergistic interference suppression method for full-duplex acoustic communication in coiled tubing. A dispersion model and an asymmetric attenuation model were first established for a fluid-filled coiled-tubing cylindrical-shell waveguide to characterize the physical transmission constraints. A multiphysics multi-objective cost function was then formulated by considering dispersion flatness, channel attenuation, asymmetric noise adaptability, and spectral isolation, and an improved simulated annealing algorithm was used to optimize the uplink and downlink frequency bands. In addition, a three-stage suppression architecture integrating mechanical decoupling, physical-layer frequency isolation, and CEEMDAN–wavelet denoising was developed to reduce self-interference and residual nonstationary noise. Full-scale experiments on a 457.2 m coiled-tubing surface circulation system showed that the proposed method improved the output signal-to-interference-plus-noise ratio from −15 dB to 18.5 dB and maintained a bit error rate below 1.2 × 10⁻⁴ at 400 L/min. These results indicate that the proposed approach can enhance the robustness of full-duplex acoustic telemetry under strong flow-induced noise. Full article

The Huainan Mining Area features extensively developed, fragmented-soft and low-permeability coal seams, characterized by low porosity and permeability, complex geological structures, and significant difficulty in coalbed methane (CBM) drainage. Horizontal wells with staged fracturing in the coal seam roof have become a key method for regional gas control. To further enhance the volume fracturing stimulation effect and single-well gas production, this study targets the horizontal well group in the roof of the No. 8 coal seam in the Huainan Mining Area as the research object. A saturated volume fracturing technology for horizontal wells in the coal seam roof, centered on the concept of a high pump rate (18–20 m³/min) and a high proppant volume (>250 m³/stage), is proposed. This study investigates the fracture propagation mechanisms and fracturing parameter optimization of this technology, and conducts engineering application to verify its stimulation effect. Increasing the fracturing pump rate improves the proppant-carrying capacity of the fracturing fluid, successfully enabling high-rate and high-volume proppant placement. Optimization of the perforation parameters—12 holes per m per cluster and a cluster spacing of 15–25 m—utilizes high perforation friction and moderate stress interference to promote balanced initiation and propagation of multiple fractures within a stage. The optimized ‘saturated’ injection mode, with a single-stage fluid volume exceeding 2400 m³, a single-stage proppant volume exceeding 250 m³, and a maximum sand ratio exceeding 20%, combined with a multi-size proppant mixture, enables full propping of both main and branch fractures. Microseismic monitoring shows that the hydraulic fracture extension length increased by approximately 50% compared to conventional wells, significantly enlarging the stimulated reservoir volume (SRV). Saturated fracturing achieved stable gas production of 2000 to 3000 m³/d, with average production ramp-up rates of 21.47–26.40 m³/d (five times higher than the 5.34 m³/d of the conventional well), and the stable plateau period was notably extended from 36 days to over 150 days. The saturated volume fracturing technology proposed in this study provides an important reference for efficient CBM extraction and surface gas control in mining areas with similar geological conditions. Full article

Variable-amplitude vibrating screens are widely adopted for screening frozen sea buckthorn berry particles. Investigating their motion characteristics and particle behaviors on the screen surface is essential for optimizing the screening process and improving equipment performance and screening efficiency. In this work, a variable-amplitude vibrating screen is taken as the research subject. Its structural composition and working principle are elaborated, and kinematic simulations are conducted via RecurDyn. The results reveal that the vertical amplitude and velocity of the screen surface increase gradually from the feed end to the discharge end, which facilitates rapid particle penetration. Meanwhile, the horizontal velocity remains stable across all sections of the screen. Specifically, crank length governs the screen amplitude, while crank rotational speed determines the vibration frequency. A dynamic model of particles and the screen surface is established by combining EDEM 2024 and RecurDyn V9R4, and two-way coupling of the discrete element model is realized. Coupled simulation results indicate that the dynamic screening efficiency rises with increasing crank length and rotational speed, reaching the maximum at a crank length of 20 mm and a rotational speed of 208 r/min. Crank parameters exert remarkable effects on the thickness of the particle layer and the quantity of penetrated particles: a thicker particle layer leads to a longer residence time of materials on the screen. Field tests are carried out to verify the model accuracy. It turns out that the simulation results are basically consistent with experimental data. In conclusion, crank length and rotational speed are critical influencing factors for variable-amplitude vibrating screens. Research on the screen’s motion characteristics and particle behaviors can provide a theoretical reference for its efficient operation and optimal design. Full article

The growing need for sustainable wastewater treatment highlights the importance of low-energy solutions such as horizontal subsurface flow constructed wetlands (HSSF CWs). While effective, these systems often face clogging issues that reduce performance and lifespan. This study investigates clogging dynamics in a Water Treatment Plant (Lleida, Spain) using a multidisciplinary approach. Non-invasive geophysical methods such as Electrical Resistivity Tomography (ERT) and Induced Polarization (IP) were combined with high-resolution drone imagery to characterize surface and subsurface indicators of clogging. Drone data captured surface anomalies, while geophysical measurements revealed subsurface obstructions. The integrated analysis identifies clogged zones and shows a strong spatial correlation between surface features and geophysical anomalies. These results validate the use of drone imagery as a rapid, non-invasive diagnostic tool and demonstrate the effectiveness of combining remote sensing with geophysical techniques for wetland assessment. This approach supports improved monitoring, targeted maintenance, and optimized long-term performance of HSSF CWs. Full article

Fast, convergent local-mode expansions of nonlinear water waves are discussed for the representation of the velocity and stream function. Subsequently, the representations are used to derive and study a novel nonlinear coupled-mode system of differential equations on the horizontal plane, with respect to unknown horizontal velocity modal amplitudes and free-surface elevation. The coupled-mode system, in conjunction with the convergence properties of the local-mode series, facilitates the numerical solution of the water wave propagation problem over general bottom topography. The efficiency of the present method is demonstrated through various examples, including the simulation of periodic waves in a constant depth and over trapezoidal bar test cases. The results show the robustness and accuracy of the coupled-mode system in capturing the complexities of wave transformations over non-uniform bathymetric features. Moreover, truncating the modal expansions of the wave velocity field by keeping only the first mode leads to a low-cost, single-mode nonlinear wave model with enhanced dispersion characteristics that is useful for engineering applications. Full article

Background/Objectives: The maxillary lateral incisor (U2) root has been proposed to influence the eruption pathway of the maxillary canine. This retrospective study aimed to evaluate the association between mesial root tipping of the U2 and the eruption of impacted maxillary canine (IPU3), and to identify radiographic predictors of eruptive movement. Methods: Orthopantomograms of 37 IPU3 from 29 patients aged 10–12 years were analyzed in this retrospective responder study; all included cases showed initiation of IPU3 eruption following U2 mesial root tipping, and this design was considered when interpreting potential selection bias and overestimation of effect. U2 and canine (U3) positions were measured at treatment initiation (T0) and at the 1-year follow-up (T1). Positional changes were analyzed using paired t-tests, Pearson’s correlation, and multiple linear regression. Results: Significant positional changes were observed for both U2 and U3 (all p < 0.001). The blockage point on the distal U2 root (2DBlock) shifted mesially by 2.0 mm, and U2 root angulation increased by 5.6° at the distal surface and 6.3° along its long axis. The U3 cusp tip (3Cusp) moved vertically by 3.7 mm, distally by 2.1 mm, and tipped distally by 7.5°. A strong correlation (r = 0.697) was observed between mesial root movement (2DHorz) and vertical cusp displacement (3Vert). Regression analysis identified 2DHorz as the only significant predictor of 3Vert (p < 0.001), explaining 51% of the variance; this indicates moderate explanatory power, while the remaining 49% suggests that additional biological, developmental, and three-dimensional spatial factors may also influence eruptive movement. Conclusions: Mesial root tipping of the U2 facilitates IPU3 eruption in early adolescents (10–12 years), specifically in cases with non-palpable IPU3 in sector II and fully developed U2 roots. Horizontal repositioning of the U2 root may serve as a clinically relevant radiographic indicator for guiding interceptive treatment; however, these findings should be interpreted as associations rather than evidence of causality. Full article

Optimizing the structural stability of foundations is challenging in modern geotechnical engineering. This study investigated the mechanism of geocell-reinforced foundations through discrete element modeling based on transparent soil model tests. A three-dimensional particle flow code (PFC^3D) model was developed to investigate the micromechanical soil–geocell interactions in both unreinforced and geocell-reinforced foundations under strip loading. Particle displacement, contact force distribution, and structural deformation within the foundation system were analyzed to quantify the performance of geocell reinforcement. The results show that geocell inclusion enhances structural performance by 2.1 times compared to an unreinforced foundation, increasing the bearing capacity from 60.6 to 126.8 kPa at a defined bearing capacity criterion. The geocell walls act as rigid physical boundaries that microscopically intercept the lateral migration and horizontal extrusion of soil particles. The kinematic trajectories of soil particles beneath the loading plate are forced into a downward realignment, decreasing the displacement vector rotation angle from 42° in the unreinforced soil to 27° in the reinforced soil and effectively mitigating the heave of adjacent surfaces. Furthermore, the quasi-rigid three-dimensional network completely interrupts the continuous steep contact force chains inherent in unreinforced foundations. Concentrated vertical stresses are converted into horizontal components through interfacial friction and mechanical interlocking, resulting in the lateral redistribution of the applied load by a distance of approximately 0.06 m. The geocell–soil composite considered as a flexible raft foundation extends load dispersion and reduces average subsoil pressure. A coupled tension and compression stress state in the horizontal plane is developed within the geocell structure. Forces are channeled along rigid paths by elevated bending moments and stress concentrations at the cell junctions. These findings provide micromechanical insights into the performance of geocell-reinforced-foundation systems. Full article

This study was conducted to investigate a novel quaternary hybrid nanocomposite (QHNC) that can successfully remove Mn(VII) ions from contaminated water. The nanocomposite was analyzed using FTIR, XRD, BET, TGA/DTG and FESEM/EDX techniques to investigate whether the synthesis led to an outcome with optimal properties that will enable it to effectively remove Mn ions from aqueous solutions. Optimal results have been achieved by conducting the analysis at a pH level of 2, using 25 mg of the adsorbent material, an interaction time of 60 min and a concentration of 500 mg/L. The Freundlich isotherm best described the adsorption equilibrium. Further analysis through advanced computational simulations indicated that a sorption process underpins the phenomenon based upon a complex geometry mechanism with a preferential horizontal to inclined orientation of the adsorbate upon the surface. The techno-economic assessment reveals the biosorbent’s viability—with a production cost that is highly competitive at USD 9.95/kg, yet with a stable removal efficiency of nearly 60% over five cycles. Such factors lead to a treatment cost of around USD 7.3 for 1 m³ of 500 mg/L Mn(VII)—confirming both the economic viability and scalability for advanced tertiary wastewater remediation applications. Full article

Hydraulic fracturing is the core technology for stimulation and reform of low-permeability and unconventional oil and gas reservoirs. Reservoir fracability directly determines fracture morphology, complexity, and stimulated reservoir volume. To address the shortcomings of existing fracability evaluation models, such as poor applicability, subjective weighting and insufficient accuracy, five key indicators are selected, including brittleness index, brittle mineral index, stress difference coefficient, minimum horizontal principal stress and porosity. First, the three-dimensional discrete lattice method is used to clarify the influence of each parameter on fracture complexity. Then, the Analytic Hierarchy Process (AHP) and Entropy Weight Method (EWM) are combined to determine the indicator weights, a continuous fracability evaluation model is constructed, and a classification standard for fracturing applicability is established. The results show that the brittleness index has the greatest influence on fracture complexity with a weight of 0.3559, followed by brittle mineral index (0.2986), minimum principal stress (0.1994), stress difference coefficient (0.0993) and porosity (0.0467). The reservoir fracability indices of 0.37 and 0.59 are the mutation points of fracture complexity. Based on microseismic evaluation of stimulated reservoir volume (SRV) using an envelope surface method, it is found that reservoirs with low fracability are more suitable for fracturing designs characterized by large cluster spacing, fewer clusters, and smaller stage spacing. In contrast, reservoirs with medium and high fracability can develop more complex fracture networks by reducing cluster spacing, increasing the number of clusters, and adopting higher pumping rates. The research results can provide theoretical basis and technical support for hydraulic fracturing operation design. Full article

To improve the efficiency of jet-based fire suppression for high-rise building façade fires, this study experimentally investigates the liquid film formation characteristics and fire suppression behavior of water jets impinging on insulated vertical surfaces. The effects of operating pressure (flow rate), nozzle-to-wall distance, and jet inclination angle on liquid film spreading morphology, wetted area, and effective water supply rate are systematically analyzed. The results show that increasing the flow rate significantly enlarges the wetted area, while reducing the effective water supply rate. As the nozzle-to-wall distance increases, the liquid film gradually develops a “top-wide and bottom-narrow” morphology. Although increasing the jet inclination angle decreases the wetted area, it enhances the continuity and stability of wall-adhering liquid film flow, thereby improving cooling efficiency near the flame root region. During the fire suppression experiments, low-flow-rate jets exhibit insufficient suppression stability, whereas high-flow-rate horizontal jets are capable of suppressing the flame to a residual burning state near the bottom of the façade. Further increasing the jet inclination angle enables complete flame extinguishment. This study reveals the relationship between jet parameters, liquid film behavior, and fire suppression performance, providing experimental evidence for the optimization of jet-based façade fire suppression strategies. Full article

The deployment of wall-climbing robotic systems plays an important role for executing inspection and maintenance tasks in high-risk environments and minimizing the risk to operators tasked with the inspection. Conventional adhesion techniques, such as magnetic, suction, and dry adhesives, encounter significant challenges when applied to diverse surface types. This study presents a four-wheeled robotic platform utilizing dual electric ducted fans (EDFs) to produce adjustable adhesion forces, facilitating uninterrupted movement from horizontal to vertical planes. A comprehensive multibody dynamics model constructed using MSC Adams analyzed wheel–surface interaction, thrust forces, and system stability during transitional phases, revealing essential force parameters for stable vertical operation and determining minimum thrust levels required to sustain four-point contact during orthogonal transitions. These findings informed thrust distribution optimization between the two EDF units to reduce rotational effects while ensuring sufficient safety margins during the ground to vertical wall transition. The findings also allowed for appropriate thrust application ensuring the generation of the required normal force distribution at wheel contact interfaces during vertical movement. A physical prototype was developed and experimentally validated, demonstrating dependable adhesion and maneuverability across a spectrum of orientations and highlighting the efficacy of simulation-driven design for thrust-based adhesion systems. Full article

Taking a small long-endurance unmanned surface vehicle (USV) with a trapezoidal cross-section deck structure as the research object, this study investigates the power generation characteristics of a heterogeneous photovoltaic (PV) system consisting of two symmetrically arranged PV arrays with different orientations, under various electrical connection schemes, tilt angles, and heading angles. A PV power prediction model that accounts for dynamic USV attitude changes was established, and the simulation model was validated based on a trapezoidal deck test setup with a tilt angle of 26.6°. Using this model, the daily cumulative energy yields of the independent and parallel configurations were simulated and analyzed under different tilt and heading angles, focusing on the power generation efficiency of the heterogeneous PV system under seakeeping hull constraints. The results show that at a tilt angle of 24°, the daily cumulative energy yield of the heterogeneous system is approximately 95% of that of the horizontal layout, indicating that the trapezoidal frame structure maintains high power generation efficiency while improving wave resistance. The heading angle has only a minor effect on the daily cumulative energy yield, suggesting that variations in course during marine navigation have little impact on power generation. Nevertheless, a significant coupling effect exists between heading angle and tilt angle. Taking a tilt angle of 60° as an example, when the heading increases from 0° to 90°, the energy yield deficit increases from 26.5% to 30.5%. The parallel configuration exhibits slightly lower energy loss at non-south headings and offers a simplified system structure, although its absolute energy yield is marginally lower at large tilt angles. These findings provide practical design guidance for heterogeneous PV systems in sustained ocean observation, climate research, and other long-duration marine missions. Future work will focus on sea trials, hybrid energy integration, and durability studies to further validate and extend these findings. Full article

Bacterial outer membrane vesicles (OMVs) are spherical structures made up of a double layer, they are each nanostructured (20–300 nm), and they are released from all populations of Gram-negative bacteria. The purpose of this review is to synthesize a comprehensive summary of the current state of knowledge about OMV biogenesis, function in biology, and application to biomedical engineering. Using these three known biogenesis mechanisms as a basis for this review, we discuss the mechanisms of OMV biogenesis that have been described as conserved: (1) disruption of outer membrane–peptidoglycan links. (2) periplasmic stress-driven adaptive release is associated with bilayer lipid asymmetry and the use of signaling molecules. OMVs are considered to be “public goods” for the microbe, allowing for nutrient acquisition, resistance to antibiotics, and the potential for horizontal gene transfer between microbes. OMVs exhibit a different duality at the interface of the pathogen host, where the pathogenic OMV is the delivery vehicle for virulence factors and pathogen-associated molecular patterns (PAMPs) leading to host immune response, while the symbiotic OMV (e.g., those produced by Bacteroides fragilis (Bact. fragilis)) promote regulatory T cell differentiation and mucosal tolerance. The review also addresses the various techniques currently available to isolate OMVs (e.g., ultracentrifugation and size-exclusion chromatographic techniques) and presents engineered/alloying strategies (e.g., genetic modifications to tolR/msbB and surface functionalization) to enhance the viability, safety, and specificity of OMVs for biomedical delivery. Finally, the review addresses significant obstacles related to standardization, batch variation, and in vivo safety associated with synthetic or personalized therapeutics based on OMVs, providing some recommendations for future research in this area. Full article

Aluminum electrolysis is an energy-intensive process in which the cathode voltage drop (CVD) and horizontal current in the molten aluminum layer directly affect energy consumption and cell stability. In this study, a three-dimensional electro-thermal model of a 400 kA prebaked aluminum electrolysis cell was established to optimize copper-embedded cathode collector bars. Using a staged parameter-screening and integrated optimization strategy, the effects of copper rod longitudinal position, diameter, and embedded length on CVD, horizontal current density, cathode surface current uniformity, and thermal response were systematically evaluated. Under the present modeling conditions, the configuration with a longitudinal position of 1.0 m, diameter of 0.05 m, and embedded length of 1.0 m provided a favorable balance between electrical performance and copper consumption. This design reduced the equivalent voltage drop by 142.7 mV and decreased the average horizontal current density in the molten aluminum layer to approximately 4900 A/m². The peak cathode surface current density was also reduced, corresponding to a predicted cathode service-life increase of approximately 13.2% based on a relative wear model. A preliminary economic analysis indicated that an initial investment of CNY 424,000 could yield conservative annual electricity cost savings of approximately CNY 114,000, with a simple payback period of about 3.7 years. These results provide quantitative guidance for the structural design and industrial evaluation of copper-embedded cathode collector bars. Full article

Background: The rising prevalence of Extended-spectrum β-lactamase-producing (ESBL) Escherichia coli poses a significant threat to human and animal health. Methods: To address this, we conducted a longitudinal two-year One Health study to assess ESBL E. coli occurrence and distribution across dairy farms, surrounding environments, and urban wastewater in a peri-urban region of Western Canada. Results: A total of 546 presumptive ESBL E. coli were recovered, with the highest occurrence in wastewater influent (75.9%) and calf feces (73.6%), and lowest in soil (6.3%) and surface water (18.8%). Seasonal analysis showed a significantly higher occurrence in summer compared to spring. The bla_CTX-M-15 gene predominated (79%), followed by bla_TEM (28%) and bla_SHV (9%), with most isolates harboring multiple ESBL genes. Whole-genome sequencing of 387 isolates identified 75 resistance determinants spanning nine antimicrobial classes, including 24 β-lactamase genes and 10 CTX-M variants. Ninety-four sequence types (STs), including nine novel STs, were detected. The most common STs were ST648, ST69, and ST10, with distinct distributions across sources. Plasmid analysis revealed extensive diversity, with approximately half of the plasmid types shared across multiple sample types, indicating potential horizontal gene transfer. Over 200 virulence factors were identified, including toxin genes and Shiga toxin-associated genes, primarily in calf and surface water isolates. Phylogroups A and B1 dominated samples from dairy farms, and phylogroup B2 was restricted to wastewater and surface water. Conclusions: These findings identify the environment as a reservoir for ESBL E. coli and reveal the unexpected predominance of the emerging MDR ST648 lineage, rather than ST131, and reinforce the need for comprehensive integrated One Health surveillance. Full article