Search Results (1,497)

As high-speed railway systems continue to develop toward intelligent operation, axle box bearings integrated with sensors have become key components for real-time condition monitoring. However, introducing sensor-embedded slots disrupts the structural continuity and thermal conduction paths of traditional bearing rings. This results in localized stress concentrations and thermal distortion, which compromise the bearing’s overall performance and service life. This study focuses on a double-row tapered roller bearing used in axle boxes and develops a multi-physics finite element model incorporating the effects of sensor-embedded grooves, based on Hertzian contact theory and the Palmgren frictional heat model. Both contact load verification and thermo-mechanical coupling analysis were performed to evaluate the influence of two key design parameters—groove depth and arc length—on equivalent stress, temperature distribution, and thermo-mechanical coupling deformation. The results show that the embedded slot structure significantly alters the local thermodynamic response. Especially when the slot depth reaches a certain value, both stress and deformation due to thermo-mechanical effects exhibit obvious nonlinear escalation. During the design process, the length and depth of the arc-shaped embedded slot, among other parameters, should be strictly controlled. The study of the stress and temperature characteristics under the thermos-mechanical coupling effect of the axle box bearing is of crucial importance for the design of the intelligent bearing body structure and safety assessment. Full article

Most existing carbon fiber composite materials are formed by high-temperature molding of multiple layers of fiber cloth. During the manufacturing and usage processes, materials are prone to defects such as voids, delamination, and inclusions, which seriously threaten their service life and safety performance. Ultrasonic testing is currently a widely adopted method for detecting defects in carbon fiber composite materials. However, existing narrow-pulse ultrasonic transducers often have to sacrifice emission energy to achieve narrow-pulse emission, which results in their limited ability to penetrate thicker carbon fiber composite materials. To address this issue, this paper proposes the design of a focused laminated transducer. By stacking and bonding lead titanate piezoelectric wafers and using a concave lens made of organic glass to focus ultrasonic waves, the emission sound intensity of the ultrasonic transducer is enhanced. The simulation results show that the designed focused double-stack transducer has a directivity gain that is 4.49 dB higher than that of the traditional single-piezoelectric-wafer transducer. The transducer fabricated based on this design has successfully achieved effective detection of internal defects in carbon fiber composite materials. Full article

This article presents an original experimental and numerical approach to examining the pull-out behavior of fastening systems made of steel bars simultaneously embedded in both ends of concrete samples. This double-embedded configuration simulates a connection between the existing concrete structure and a new external exoskeleton, promoting seismic strengthening. Pull-out tests were performed across six specimen configurations combining different concrete strength classes in order to compare the adhesive solution against traditional monolithic cast-in rebar embedments. The adhesive-anchored bars achieved a peak pull-out force of ~28.6 kN, which is about 18% higher than with mixed anchorage (one end adhesive, one end cast-in). All specimens failed in concrete cracking and pull-out cone formation, with no steel bar yielding, indicating that failure was governed by concrete strength. Finite element simulations in ANSYS Explicit Dynamics were validated against these experiments, confirming the observed behavior and enabling the extension of our analysis to broader concrete strength ranges. Overall, the results demonstrate that double-ended adhesive anchorage significantly increases the connection’s load-bearing capacity and ductility compared to mixed configurations. Full article

This study aims to address the problem that traditional helical gears generate significant axial forces during transmission and innovatively proposes a design scheme of double helical face gears (DHFG). An accurate mathematical model of the tooth surface is established using spatial meshing theory and coordinate transformation. A systematic investigation using the orthogonal test method is then conducted to analyze the influence of key parameters, such as the pinion tooth number, transmission ratio, and helix angle, on gear performance. The finite element analysis results show that the overlap degree of this double helical tooth surface gear pair in actual transmission can reach 2–3, demonstrating excellent transmission smoothness. More importantly, its unique symmetrical tooth surface structure successfully achieves the self-balancing effect of axial force. Simulation verification shows that the axial force is reduced by approximately 70% compared to traditional helical tooth surface gears, significantly reducing the load on the bearing. Finally, the prototype gear is successfully trial-produced through a five-axis machining center. Experimental tests confirmed that the contact impressions are highly consistent with the simulation results, verifying the feasibility of the design theory and manufacturing process. Full article

Staphylococcus aureus is a major pathogen responsible for staphylococcal food poisoning (SFP), with its pathogenicity primarily dependent on staphylococcal enterotoxins (SEs). Among these, staphylococcal enterotoxin A (SEA) is a critical risk factor due to its high toxicity, high detection rate (accounting for 80% of SFP cases), strong thermal stability, and resistance to hydrolysis. Traditional SEA immunoassays, such as enzyme-linked immunosorbent assay (ELISA), are prone to false-positive results caused by nonspecific binding interference from S. aureus surface protein A (SpA). In recent years, nanobodies (single-domain heavy-chain antibodies) have emerged as an ideal alternative to address SpA interference owing to their small molecular weight (15 kDa), high affinity, robust stability, and lack of Fc regions. In this study, based on a previously developed highly specific monoclonal antibody against SEA (mAb-4C6), four anti-SEA nanobodies paired with mAb-4C6 were obtained through two-part (four-round) of biopanning from a naive nanobody phage display library. Among these, SEA-4-20 and SEA-4-31 were selected as optimal candidates and paired with mAb-4C6 to construct double-antibody sandwich ELISAs. The detection limits for SEA were 0.135 ng/mL and 0.137 ng/mL, respectively, with effective elimination of SpA interference. This approach provides a reliable tool for rapid and accurate detection of SEA in food, clinical, and environmental samples. Full article

To meet gas turbines’ growing demand for high-performance thermal barrier coatings (TBCs), this study addresses the limitations of traditional single-layer 8% Y₂O₃-stabilized ZrO₂ (YSZ) coatings in high-temperature corrosive environments. Atmospheric plasma spraying (APS) was used to fabricate the double-ceramic TBCs with (Sm_0.2Gd_0.2Dy_0.2Er_0.2Yb_0.2)₂(Zr_0.7Hf_0.3)₂O₇ (RHZ) as the outer layer and YSZ as the inner layer; thermal cycling corrosion tests (1000 °C, Na₂SO₄ + V₂O₅ molten salt) were conducted to compare its performance with traditional single-layer YSZ. The results showed that the YSZ corrosion products were m-ZrO₂ and YVO₄, while RHZ/YSZ produced rare-earth vanadates, m-(Zr,Hf)O₂, and t′-(Zr,Hf)O₂, and corrosion degree was positively correlated with salt concentration (which was more impactful) and the number of cycles. Both coatings failed via molten salt penetration, thermochemical reaction, and crack-induced spallation. The corrosion mechanism between the RHZ/YSZ coating and the mixed salt can be explained based on the Lewis acid–base theory and the optical basicity. The RHZ layer on the surface of RHZ/YSZ coatings indeed hinders the penetration of corrosive molten salts into the underlying YSZ layer to some extent. Full article

Multisensory behavioral research is increasingly aiming to move beyond traditional laboratories and into real-world settings. Smartphones offer a promising platform for this purpose, but their use in psychophysical experiments requires rigorous validation of their ability to precisely present multisensory stimuli and record reaction times (RTs). To date, no study has systematically assessed the feasibility of conducting RT-based multisensory paradigms on smartphones. In this study, we developed a reproducible validation method to quantify smartphones’ temporal precision in synchronized auditory–tactile stimulus delivery and RT logging. Applying this method to five Android devices, we identified two with sufficient precision. We also introduced a technique to enhance RT measurement by combining touchscreen and accelerometer data, effectively doubling the measure resolution—from 8.33 ms (limited by a 120 Hz refresh rate) to 4 ms. Using a top-performing device identified through our validation, we conducted an audio–tactile RT experiment with 20 healthy participants. Looming sounds were presented through headphones during a tactile detection task. Results showed that looming sounds reduced tactile RTs by 20–25 ms compared to static sounds, replicating a well-established multisensory effect linked to peripersonal space. These findings present a robust method for validating smartphones for cognitive research and demonstrate that high-precision audio–tactile paradigms can be reliably implemented on mobile devices. This work lays the groundwork for rigorous, scalable, and ecologically valid multisensory behavioral studies in naturalistic environments, expanding participant reach and enhancing the relevance of multisensory research. Full article

Underactuated systems, such as rotary and double inverted pendulums, challenge traditional control due to nonlinear dynamics and limited actuation. Classical methods like state-feedback and Linear Quadratic Regulators (LQRs) are commonly used but often require high gains, leading to excessive control effort, poor energy efficiency, and reduced robustness. This article proposes a generalized state-feedback controller with its own internal dynamics, offering greater design flexibility. To automate tuning and avoid manual calibration, we apply Bayesian Optimization (BO), a data-efficient strategy for optimizing closed-loop performance. The proposed method is evaluated on two benchmark underactuated systems, including one in simulation and one in a physical setup. Compared with standard LQR designs, the BO-tuned state-feedback controller achieves a reduction of approximately 20% in control signal amplitude while maintaining comparable settling times. These results highlight the advantages of combining model-based control with automatic hyperparameter optimization, achieving efficient regulation of underactuated systems without increasing design complexity. Full article

In multidisciplinary design optimization (MDO) of high-end equipment, parameter uncertainty significantly undermines performance robustness. Existing methods are limited in convergence efficiency and in controlling uncertainty propagation. To address this gap, we propose a multidisciplinary robust collaborative optimization method under parameter uncertainty (MRCO-PU). The approach augments traditional Collaborative Optimization (CO) with a collaborative optimization method based on weight distribution difference information (CO-WDDI) to accelerate cross-disciplinary convergence. It also integrates a double-layer EI–Kriging robust optimization model to enhance robustness under complex coupling and small-sample conditions. The MRCO-PU method targets single-objective, strongly coupled, multi-constraint MDO problems with high per-evaluation cost. The method was validated on a mathematical case and on a cantilever roadheader cutting-head case. In the mathematical case, the robust feasibility of the constraints increased from 0.49 to 1.00. In the engineering case, the specific energy consumption decreased by 6.3% under the premise of fully satisfying the robust feasibility of the constraints, leading to operational cost minimization under uncertainty. This work provides an effective approach to multidisciplinary robust optimization for high-end equipment. Full article

Pea protein yogurt (PPY), as an alternative to traditional dairy yoghurt, has the advantages of being a green raw material, lactose cholesterol-free, and adaptable to the needs of lactose-intolerant people. PPY was prepared by fermenting a mixture of pea protein and water (1:10, w/v) supplemented with 5% fructose for 10 h after heat sterilisation. During fermentation, lactic acid bacteria metabolise pea protein to produce aldehydes and other aromatic compounds, imparting a unique sweet–sour balance and mellow flavour. However, issues such as weak gel formation and prominent soybean-like off-flavours severely restrict the development and consumer acceptance of PPY. In this study, five fermentation systems were systematically investigated to elucidate the fermentation mechanisms of pea yoghurt and explore effective methods for eliminating undesirable soy flavours. The results indicated that hydrophobic interactions and disulfide bonds are the predominant forces driving gel formation in PPY. Additionally, the protein content increased by 0.81 g/100 g following fermentation. A total of 43 volatile flavour compounds—including aldehydes, alcohols, acids, ketones, and furans—were identified, among which the concentrations of hexanal and 2-pentylfuran, known markers for soybean off-flavour, significantly decreased. Furthermore, high-temperature and high-pressure treatments (121 °C, 3 min) demonstrated superior effectiveness in reducing soybean-like flavours. Although the high-temperature and high-pressure treatment, double-enzyme hydrolysis, and flavour-masking methods operate through distinct mechanisms, their flavour profiles converged, displaying substantial deodorisation effects and synergistic interactions. These findings provide a theoretical basis and processing parameters for flavour modulation in PPY; however, further formulation optimisation is required to enhance its nutritional and textural properties. PPY shows promise as a potential alternative to conventional dairy products in the future. Full article

In order to solve the problem of the efficiency reduction and complex manufacturing of traditional grating couplers under environmental temperature fluctuations, a Si₃N₄ high-efficiency grating coupler integrating a distributed Bragg reflector (DBR) and thermo-optical tuning layer is proposed. In this paper, the double-layer DBR is used to make the down-scattered light interfere with other light and reflect it back into the waveguide. The finite difference time domain (FDTD) method is used to simulate and optimize the key parameters such as grating period, duty cycle, incident angle and cladding thickness, achieving a coupling efficiency of −1.59 dB and a 3 dB bandwidth of 106 nm. In order to further enhance the temperature stability, the amorphous silicon (a-Si) thermo-optical material layer and titanium metal serpentine heater are embedded in the DBR. The reduction in coupling efficiency caused by fluctuations in environmental temperature is compensated via local temperature control. The simulation results show that within the wide temperature range from −55 °C to 150 °C, the compensated coupling efficiency fluctuation is less than 0.02 dB, and the center wavelength undergoes a blue shift. This design is compatible with complementary metal-oxide-semiconductor (CMOS) processes, which not only simplifies the fabrication process but also significantly improves device stability over a wide temperature range. This provides a feasible and efficient coupling solution for photonic integrated chips in non-temperature-controlled environments, such as optical communications, data centers, and automotive systems. Full article

Background and Objectives: Lupus nephritis (LN) is a major cause of mortality and morbidity in patients with systemic lupus erythematosus (SLE). Biomarkers derived from blood, urine, and multi-omics techniques are essential for enabling access to less invasive methods for LN evaluation and personalized precision medicine. Materials and Methods: The purpose of this work was to review the studies that addressed the potential role of urinary and serological biomarkers for the diagnosis, disease activity, response to treatment, and renal outcome of adult patients with LN, published over the past decade, and summarize their results with a particular emphasis being directed towards the available traditional tools. Results: Traditional biomarkers used for the diagnosis and surveillance of LN are proteinuria, urinary sediment, estimated glomerular filtration rate (eGFR), anti-double-stranded deoxyribonucleic acid (anti-dsDNA), anti-C1q, and serum complement levels. Anti-dsDNA, serum C3, and proteinuria are the conventional biomarkers with the strongest clinical evidence, with overall moderate ability in predicting LN from non-renal SLE, disease activity, renal flares, response to therapy, and prognosis. The last decade has brought significant progress in our understanding regarding the pathogenesis of LN and, consequently, several molecules, either alone or in combination panels, have emerged as potential novel biomarkers, some of them outperforming conventional biomarkers. Promising results have been suggested for urinary activated leukocyte cell adhesion molecule (ALCAM), soluble cluster of differentiation 163 (CD163), C-X-C motif chemokine ligand 10 (CXCL10), monocyte chemoattractant protein 1 (MCP-1), neutrophil gelatinase-associated lipocalin (NGAL), tumor necrosis factor-like weak inducer of apoptosis (TWEAK), and vascular cell adhesion molecule 1 (VCAM-1). Conclusions: Despite the intensive research of the last decade, no novel biomarker has entered clinical practice, and we continue to rely on traditional biomarkers to assess non-invasively LN and guide its treatment. Novel biomarkers should be validated in multiple longitudinal independent cohorts, compared with conventional biomarkers, and integrated with renal histology information in order to optimize the management of LN patients. Full article

Advancements in material technologies and increasingly stringent thermal insulation requirements are driving the search for innovative solutions to serve as an alternative to traditional insulating materials. Using 3D printing techniques to produce thermal insulation opens up new possibilities for creating structures, geometries, and shapes from a variety of raw materials, ranging from synthetic polymers to biodegradable composites. This study aimed to develop a modern thermal insulation barrier with a comparable thermal conductivity to conventional materials to enhance the energy efficiency of buildings. Cellular materials based on the Kelvin cell were fabricated using additive manufacturing via 3D SLS printing from a composite consisting of a biodegradable material (TPS) and a recyclable polymer (PA12). The printed cellular structural partitions were tested for their thermal insulation properties, including thermal conductivity coefficient, thermal transmittance (U-value), and thermal resistance. The best thermal insulation performance was demonstrated by a double-layer partition made from TPS + PA12 at a mass ratio of 5:5 and with a thickness of 60 mm. This sample achieved a thermal conductivity of λ = 0.026 W/(m·K), a thermal resistance of R = 2.4 (m²·K)/W, and a thermal transmittance of U = 0.42 W/(m²·K). Cellular partition variants with the most favorable properties were incorporated into building thermal balance software and an energy simulation was conducted for a single-family house using prototype insulating materials. This enabled an assessment of their energy efficiency and cost-effectiveness. Full article

The traditional vertical-shaft-impact sand-making machine has the problems of uneven discharge particles and discharge port wear. To solve these problems, the influence of the main structural parameters (number of impact rotors, angle of impact plates, angle of anvil, and number of teeth on the anvil) on sand production is researched through orthogonal testing and polar analysis. The results show that the parameters’ degrees of influence on the sand production rate are as follows: the angle of impact plates, the number of impact plates, the angle of the anvil, and the number of teeth on the anvil. The double rotor exhibits the best crushing effect when the number of impact rotors is six, the angle of the impact plate is 0°, the angle of the anvil plate is 0°, and the number of teeth on the anvil plate is 89. By taking the working speed of the double rotors as a factor, an equal-level uniform design table is constructed for the double-rotor crushing system. Polynomial regression analysis shows that the best crushing effect occurs when the accelerating rotor speed is 1200 r/min and the impact rotor speed is 585 r/min. Finally, the crushing characteristics of the double-rotor vertical-shaft-impact sand-making machine are simulated and analyzed to obtain the kinetic energy distribution of particles in the crushing chamber. The kinetic energy of particles in the main crushing area is determined, and the wear pattern of the discharge port and parts is identified. Full article

To address the poor trajectory tracking of mining trucks in narrow, high-curvature paths, this study explores the impact of four-wheel steering (4WS) and direct yaw moment control (DYC) on vehicle stability. A validated two-degree-of-freedom 4WS vehicle model was developed. A fuzzy logic controller with dual inputs (yaw rate and yaw angular acceleration) and a single output (compensatory yaw moment) was designed, alongside an optimal torque distribution controller based on tire friction circle theory to allocate the resultant yaw moment. A co-simulation platform integrating TruckSim and MATLAB/Simulink was established, and experiments were conducted under steady-state and double-lane-change conditions. Comparative analysis with traditional front-wheel steering and alternative control methods reveals that the 4WS mining truck with fuzzy-controlled optimal torque distribution achieves a reduced turning radius, enhancing maneuverability and stability. Hardware-in-the-loop (HIL) testing further validates the controller’s effectiveness in real-time applications. Full article