Search Results (72)

Reliable and energy-efficient capacity control in high-pressure single-rotor screw compressors requires precise regulation of adjustable ring mechanisms operating under combined gas and thermal loading. Thermo-mechanical deformation, friction-induced torque demand, and stress concentration near discharge windows significantly influence structural integrity, clearance stability, and actuation performance. This study presents an integrated thermo-structural and analytical investigation of a regulating ring system with a hydraulic wedge-groove drive concept. Three groups of geometric variants (nine configurations total) were analyzed using coupled Steady-State Thermal and Static Structural finite element modeling in ANSYS 19.2. Thermal asymmetry between suction (22 °C) and discharge (120 °C) regions produced peak thermally induced deformation of 0.17–0.18 mm, consuming up to 60–70% of nominal operating clearance. Neglecting thermal effects underestimated peak thermally induced structural deformation of the regulating ring by 12–15%. Among the configurations, variant 2b provided the most balanced response, reducing peak equivalent stress by 12–15% and required actuation torque by 8–11%. An analytical model for friction torque and driving force was derived based on distributed contact pressure. The results reveal quadratic sensitivity of torque to contact radius and strong dependence on groove geometry. The proposed framework supports reliable clearance design and efficient actuation in heavy-duty rotating machinery. Full article

The pile–bucket foundation, comprising a bucket attached to a single pile, represents an innovative offshore solution for supporting wind turbines. Previous studies on laterally loaded foundations have primarily focused on single piles and pile–bucket systems; however, the effects of bucket size and loading eccentricity on lateral capacity and soil failure mechanisms remain insufficiently understood. This study investigates the lateral performance of pile–bucket foundations in silty sand under static loading conditions. Seven three-dimensional numerical simulations were conducted to evaluate the influence of bucket diameter, embedment depth, and loading eccentricity. Results indicate that pile–bucket foundations achieve 37–60% higher lateral capacity than single piles and 3–4 times the capacity of standalone buckets. Increasing bucket diameter produces more significant improvements than increasing embedment depth, whereas higher loading eccentricity reduces lateral capacity, ranging from an 8% increase to a 10% decrease relative to a single pile. Increases in loading eccentricity, bucket diameter, and embedment depth shift the rotation center upward by approximately 3–9%, compared with a single pile. At the mudline, the bucket resists up to 75% of the lateral load, while the pile carries up to 92% of the moment. Failure mechanisms are dominated by excessive rotation, including wedge-type failure near the mudline and deep rotational soil flow. Increasing bucket diameter or embedment depth raises bending moments by 5–9%, while higher eccentricity amplifies them by 32–50%. A modified analytical formulation incorporating a correction factor of 1.16 improves the prediction of the rotation center position. These findings provide quantitative guidance for the design and optimization of pile–bucket foundations supporting offshore wind turbines. Full article

Medial opening-wedge supramalleolar osteotomy (MOWSMO) is a joint-preserving surgical option for varus ankle osteoarthritis (OA); however, its ability to correct large varus talar tilt (TT), particularly in advanced diseases like Takakura stage IIIB, remains limited. Varus TT represents a complex three-dimensional deformity characterized by coronal malalignment and internal rotation, which cannot be reliably corrected by isolated supramalleolar realignment. Building on our previous work, we propose a new treatment algorithm for large varus TT based on preoperative tibial plafond inclination (TPI) and arthritis type, categorized as translational and rotational. While MOWSMO primarily addresses TPI, effective correction of talar inclination requires a balanced, multilevel approach. This includes using an oblique sliding fibular osteotomy to facilitate rotational realignment with fibular shortening and, critically, prioritizing inframalleolar correction (IMC). IMC is implemented through an “all-in-one” strategy involving lateral ligament repair, deltoid ligament release, calcaneal osteotomy, and posterior tibial tendon lengthening. Furthermore, we discuss critical intraoperative considerations, such as avoiding excessive TPI valgization to prevent a “paradoxical increase” in TT. Collectively, this framework provides clinically relevant insights and a reproducible algorithm for achieving satisfactory outcomes in the joint-preserving management of severe varus ankle OA. Full article

This study establishes a direct and quantitative link between field-scale monopile behavior, three-dimensional finite element (FE) modeling, and practical p-y curve formulations for large-diameter offshore monopiles. A validated three-dimensional FE model, benchmarked against a full-scale monopile field test, was employed to derive depth-dependent p-y curves under monotonic lateral loading and to evaluate the applicability of classical formulations proposed by Matlock and Reese. A systematic parametric analysis was performed to investigate the influence of pile diameter, embedment depth, and undrained shear strength of the surrounding soil. The results demonstrate that pile diameter and soil shear strength exert a dominant control on lateral stiffness and ultimate soil reaction, whereas embedment depth has only a minor influence on near-surface p-y behavior within the deep embedment range considered. Increasing the pile diameter leads to a transition from bending-dominated response to rigid-body rotation accompanied by three-dimensional soil wedge formation. Quantitative comparisons show that, at depths of 1–4 m and for working displacement levels of approximately 5–10 mm, FE-derived soil reactions are typically 3.0–4.8 times higher than those predicted by the Matlock formulation, as well as Reese curves. These findings demonstrate that classical p-y methods can significantly underestimate lateral soil resistance for modern large-diameter monopiles and highlight the necessity of calibrated three-dimensional FE analyses or FE-informed p-y modifications for reliable offshore wind turbine foundation design. Full article

Conventional tunnel face stability models are constrained by idealized steady-state seepage assumptions, one-dimensional formulations for inherently three-dimensional flow, and the neglect of transient filter-cake effects. To address these limitations, this study focuses on blowout failure triggered by excess slurry pressure in slurry pressure balance shield tunneling. We establish a limit-analysis framework that couples slurry infiltration with transient seepage, developing a work rate-balance formulation and a three-dimensional rotational failure mechanism. This framework incorporates heterogeneous, time-dependent filter-cake pressure transfer and the spatiotemporal evolution of pore pressure—key factors overlooked in traditional models. Transient seepage simulations demonstrate that the spatiotemporal heterogeneity of the dynamic filter cake provides the fundamental pressure basis for blowout failure. A prominent hydraulic gradient within the potential core failure zone (Z/R ≤ 2.0, Y/R ≤ 2.0) drives failure initiation and propagation, with the vertical hydraulic gradient in the high-risk subregion (Z/R < 0.5) reaching values as high as 12. Results indicate that passive failure risk increases markedly when excess slurry pressure exceeds 200 kPa, accompanied by a sharp decline in the safety factor. Validation against the Heinenoord No. 2 Tunnel case confirms that the proposed three-dimensional model more accurately captures 3D seepage characteristics and critical failure pressures compared to traditional wedge–prism approaches. By overcoming steady-state and one-dimensional simplifications, this framework deepens the understanding of blowout evolution and provides theoretical guidance for the rational control of slurry pressure and improved tunnel-face stability assessment under complex transient conditions. Full article

To improve the seismic performance of semi-rigid steel frame beam–column joints connected by T-stubs, reinforced T-stubs formed via wedge-shaped and thickening modifications are proposed. Taking the middle column joints in steel frames as the research objects, three types of beam–column joints are designed by adopting ordinary, wedge-shaped, and thickened wedge-shaped T-stubs. To conduct a comparative analysis of the seismic performance of the test specimens, this study imposes low-cycle cyclic loads on the column ends of each specimen along their major-axis and minor-axis in-planes. This loading protocol is adopted to simulate the dynamic responses of the specimens under bidirectional seismic action. Comparing the macroscopic failure phenomena of the specimens, the influence of reinforced T-stubs on the plastic development mode of the joints is analyzed. Based on seismic indicators such as hysteresis characteristics, skeleton curves, stiffness degradation, and energy dissipation capacity, the energy dissipation capacity of the specimens along the major-axis is greater than that along the minor-axis, but their deformation capacity is slightly reduced. The bearing capacity, energy dissipation, and rotational stiffness could be improved by reinforced T-stubs, but the deformation capacity is reduced to varying degrees. The stiffness degradation rate of the specimen adopting wedge-shaped T-stubs shows a more obvious accelerating trend. Through the comparative analysis of the three specimens based on the energy damage index, the results indicate that wedge-shaped T-stubs significantly increase the damage degree of the specimens, but thickened wedge-shaped T-stubs have a relatively small impact on the evolution of joint damage. Full article

Research on the Mesozoic–Cenozoic magmatism and the tectonic framework within the Lhasa Terrane is voluminous. However, the sparse documentation of Early Cretaceous magmatism in this region fuels ongoing debate over the prevailing tectonic regime during this time period (i.e., normal subduction vs. flat subduction). The present study investigates the Luerma pyroxenite and Boyun granitoid in the Western Lhasa Terrane through zircon U-Pb dating, whole-rock geochemistry, mineral chemistry, and Sr-Nd-Hf isotopes. The findings date the formation of Luerma pyroxenite at 115 Ma and Boyun granites at 113 Ma to the Early Cretaceous period (115–113 Ma). SiO₂ content of pyroxenite is relatively low (34.27–44.16 wt.%), characterized by an enrichment in large ion lithophile elements (LILEs), light rare earth elements (LREEs), and a depletion in heavy field strength elements (HSFEs), indicative of a metasomatic origin. The εNd (t) and εHf (t) values of the Early Cretaceous ultrabasic rocks range from +2.1 to +2.7 and −0.8 to +10.1, respectively, suggesting their derivation from an enriched mantle source with asthenospheric material incorporation. The Early Cretaceous granodiorites and their mafic enclaves belong to the high-K calc-alkaline series, and show enrichment in LILEs (e.g., Rb, Ba, U, and Th) and depletion in HFSEs (e.g., Nb, Ta, Ti, and Zr). The acidic rocks and their developed mafic enclaves exhibit the geochemical characteristics of trace elements found in island arc magmas. Their εNd (t) values are (−6.0–−5.0), while their εHf (t) values are (−11.7–−1.8); the MMEs εHf (t) values are (−4.1–+0.9). In summary, the Early Cretaceous pyroxenite in the Gangdese Belt originated from a combination of asthenospheric and enriched lithospheric mantle melts, while the granitoids were generated by partial melting of the mantle wedge, a process driven by metasomatism resulting from the slab-derived fluids. At the same time, heat from upwelling mantle-derived melts induced the partial melting of lower crustal materials, leading to the formation of acidic magmas through varying degrees of mixing with basic magmas. This study suggests that Early Cretaceous magmatic activity occurred within a northward subduction setting, characterized by the rotation and fragmentation of the Neo-Tethys oceanic crust. Full article

Orthognathic surgery, particularly maxillomandibular advancement (MMA), has emerged as an effective therapeutic option for patients with moderate to severe OSA who are refractory to conventional treatments. The wedge osteotomy of the maxilla, often performed in combination with mandibular surgery, can be a surgical treatment for obstructive sleep apnea (OSA). This case series report describes 6 OSA patients without anteroposterior maxillary deficiency who were treated with wedge osteotomy of the maxilla. Material and Methods: We conducted a retrospective analysis of 6 patients who underwent maxillomandibular advancement (MMA) for obstructive sleep apnea (OSA), all operated on consecutively by the same surgeon between 2018 and 2024 at the Maxillofacial Surgery of San Camillo-Forlanini Hospital, in Rome, Italy. Patients were evaluated using a CAD/CAM-assisted approach. A pre- and postoperative comparative analysis was conducted to assess the effectiveness of the surgical treatment in improving OSA-related parameters. Maxillary wedge osteotomy and bilateral sagittal split osteotomies (BSSO) of the mandibular ramus were digitally planned. Results: The comparison between preoperative and postoperative CT scans, along with 3D reconstructions generated using dedicated software, revealed a counterclockwise rotation of the occlusal plane, resulting in a mandibular advancement of approximately 13 mm. The CT shows a significant increase in airway volume following the skeletal repositioning. The airway volume increased from 20.665 ± 546 mm³ to 27.177 ± 446 mm³. Conclusions: Counterclockwise rotational orthognathic surgery without maxillary advancement has been shown to effectively enlarge the posterior pharyngeal space while also delivering excellent esthetic outcomes. Full article

This study addresses two critical challenges in biprism-based laser scanning systems: the lack of a comprehensive mathematical framework linking prism parameters to scanning performance, and unresolved theoretical gaps regarding parameter effects on point cloud quality. We propose a multi-parameter optimization method for point cloud generation using dual-prism scanning. By establishing a beam pointing mathematical model, we systematically analyze how prism wedge angles, refractive indices, rotation speed ratios, and placement configurations influence scanning performance, revealing their coupled effects on deflection angles, azimuth control, and coverage. The non-paraxial ray tracing method combined with the Möller–Trumbore algorithm enables efficient point cloud simulation. Experimental results demonstrate that our optimized parameters significantly enhance point cloud density, uniformity, and target feature integrity while overcoming limitations of traditional database construction methods. This work provides both theoretical foundations and practical solutions for high-precision 3D reconstruction in high-speed rendezvous scenarios such as missile-borne laser fuzes, offering advantages in cost-effectiveness and operational reliability. Full article

Span-wise homogeneous supersonic cavity flows display complicated structures due to shear layer breakdown, flow acoustic resonance, and even non-linear hydrodynamic-acoustic interactions. In practical applications, such as aircraft bays, the cavity is of finite width and has doors, both of which introduce distinctive phenomena that couple with the shear layer at the cavity lip, further modulating shear layer bifurcations and tonal mechanisms. In particular, asymmetric states manifest as ‘tornado’ vortices with significant practical consequences on the design and operation. Both inward- and outward-facing leading-wedge doors, resulting in leading edge shocks directed into and away from the cavity, are examined at select opening angles ranging from $22.5°$ to $90°$ (fully open) at Mach 1.6. The computational approach utilizes the Reynolds-Averaged Navier–Stokes equations with a one-equation model and is augmented by experimental observations of cavity floor pressure and surface oil-flow patterns. For the no-doors configuration, the asymmetric results are consistent with a long-time series DDES simulation, previously validated with two experimental databases. When fully open, outer wedge doors (OWD) yield an asymmetric flow, while inner wedge doors (IWD) display only mildly asymmetric behavior. At lower door angles (partially closed cavity), both types of doors display a successive bifurcation of the shear layer, ultimately resulting in a symmetric flow. IWD tend to promote symmetry for all angles observed, with the shear layer experiencing a pitchfork bifurcation at the ‘critical angle’ ($67.5°$). This is also true for the OWD at the ‘critical angle’ ($45°$), though an entirely different symmetric flow field is established. The first observation of pitchfork bifurcations (‘critical angle’) for the IWD is at $67.5°$ and for the OWD, $45°$, complementing experimental observations. The back wall signature of the bifurcated shear layer (impingement preference) was found to be indicative of the 3D cavity dynamics and may be used to establish a correspondence between 3D cavity dynamics and the shear layer. Below the critical angle, the symmetric flow field is comprised of counter-rotating vortex pairs at the front and back wall corners. The existence of a critical angle and the process of door opening versus closing indicate the possibility of hysteresis, a preliminary discussion of which is presented. Full article

This study presents an innovative wedge-shaped inlet weir-type microfluidic chip designed to address common issues of clogging and inefficiency in microfiltration processes. Driven solely by centrifugal force, the chip integrates a crossflow separation mechanism and enables selective droplet sorting based on size, without the need for external pumps. Fabricated from PMMA, the device features a central elliptical chamber, a wedge-shaped inlet, and spiral microchannels. These structures leverage shear stress and Dean vortices under centrifugal fields to achieve high-throughput separation of droplets with different diameters. Using water-in-oil emulsions as a model system, we systematically investigated the effects of geometric parameters and rotational speed on separation performance. A theoretical model was developed to derive the critical droplet size based on force balance, accounting for centrifugal force, viscous drag, pressure differentials, and surface tension. Experimental results demonstrate that the chip can effectively separate droplets ranging from 0 to 400 μm in diameter at 200 rpm, achieving a sorting efficiency of up to 72% and a separation threshold (cutoff accuracy) of 98.2%. Fluorescence analysis confirmed the absence of cross-contamination during single-chip operation. This work offers a structure-guided, efficient, and contamination-free droplet sorting strategy with broad potential applications in biomedical diagnostics and drug screening. Full article

Numerous studies exist on medial opening wedge supramalleolar osteotomy (SMO), ever since its introduction by Takakura et al., as a joint-preserving surgical option for treating varus ankle osteoarthritis (OA). Although SMO can induce lateral translation of the talus—which is medially translated in varus ankle OA—it has only minimal effects on the correction of the varus tilt of the talus. Particularly, SMO alone does not effectively neutralize the talar position. The primary reason for this limitation is that varus tilting of the talus is not merely a two-dimensional deformity in the coronal plane, but rather a three-dimensional deformity involving internal rotation and anterior subluxation. Therefore, this study aimed to explore the key considerations for achieving effective correction of varus talar tilt in joint-preserving surgery for treating degenerative varus ankle OA with large talar tilting. Further, we have discussed the relevant studies and included the lessons learned from our clinical experience, categorizing the key surgical considerations into preoperative, intraoperative, and postoperative phases. Full article

Aiming at the problem of abnormal wear caused by the poor dynamic characteristics of aeroengine segmented annular seals, according to the hydrodynamic lubrication theory, based on the conventional structure featuring the Rayleigh step profile rectangular pocket (RP), novel structures with the circumferential linear convergent pocket (CLCP) and the circumferential parabolic convergent pocket (CPCP) were proposed. A model was developed to analyze both the static and dynamic characteristics of three types of segmented annular seals, utilizing the local differential quadrature (LDQ) method. Once the accuracy of the solution model was confirmed, the effects of working conditions and design features on both static and dynamic characteristics were analyzed. Results indicate that the circumferential wedge convergent pockets can effectively improve the dynamic characteristics of the seal system. Under different rotational speeds, compared with the RP seal, the CLCP seal’s stiffness coefficient and damping coefficient increases by an average of 60.76% and 65.27%, respectively. As the rotational speed increases, the RP seal damping ratio decreases, and the seal system transitions from an overdamped state to an underdamped state, resulting in reduced stability. Nevertheless, under different rotational speeds and pressure ratios, the CLCP and the CPCP seals are both in an overdamped state. Taking into account the static and dynamic characteristics, the CLCP seal is the optimal structure in this study. Full article

A composite diaphragm wall anchor foundation (CDWAF) is a novel type of anchor foundation, but research on its bearing performance remains limited. In this study, the horizontal bearing characteristics of a CDWAF and the interaction mechanism between the foundation and surrounding soil using finite element analysis were investigated. The foundation’s displacement behavior under external loads, the distribution of resistance from various soil components, and the failure mechanisms of the foundation were also studied. The results reveal that under external loads, the CDWAF experiences both rigid-body translation and rotational displacement, with the rotation center shifting dynamically to the upper right with the increase in load. At the failure state, a passive failure wedge forms on the outer side of the front wall of the foundation due to soil compression, while an active failure wedge develops on the outer side of the back wall, and both the displacement and rotation of the foundation increase nonlinearly with the applied load. As the load increases, the passive earth pressure on the front wall’s outer side rises, while the active earth pressure on the back wall’s outer side decreases. The distribution of soil resistance and side friction resistance of the CDWAF with depth is influenced by the critical depth, which increases with the load. The soil resistance at the bottom of the foundation shows an overall increase in the direction of the applied load, peaking at the bottom of the front wall. The plastic zone in the surrounding soil progressively develops, starting at the base and the outer sides of the front and back walls. Notably, the embedded end of the CDWAF significantly reduces the plastic failure at the bottom of the foundation. In comparison with traditional gravity caissons, the embedded end and internal compartments of the CDWAF effectively enhance its horizontal bearing capacity by 30% and 6%, respectively. At the same time, the mechanism of soil resistance is changed with the foundation type. The load-sharing ability of the cabinet foundation reaches 23% at the bottom and 45% outside the front and rear walls, respectively, while the load-sharing ratio of the composite diaphragm wall anchorage foundation is transferred from the base to the outer sides of the front and back walls, which is 5% and 58%, respectively. These findings contribute valuable insights to the design and application of underground diaphragm wall foundations in anchor foundation engineering. Full article

It is suggested that the occurrence of tectonic activity in the northern Nubian belts (Tell-Rif and Atlas systems) since the Late Pliocene can be interpreted as one of the processes that were produced in the central and western Mediterranean zones by the collision of the Adriatic continental promontory with the Anatolian–Aegean Tethyan system. Since then, the consumption of the residual low-buoyancy domains in the Mediterranean area was allowed by a major change in the plate mosaic and the related kinematics. The new tectonic setting started with the decoupling of a large portion of the Adriatic domain (Adria plate) from Nubia, through the formation of a long discontinuity crossing the Ionian domain (Victor Hensen–Medina fault) and the Hyblean–Pelagian domain (Sicily channel fault system). Once decoupled, the Adria plate underwent a clockwise rotation, at the expense of E–W shortening in the Hyblean–Pelagian domain and in the northern Nubian margin. The shortening in the Pelagian domain was accommodated by the northward escape of the Adventure wedge, which in turn caused the northward displacement of the eastern Maghrebian sector. The indentation of these structures into the Alpine–Apennine material lying east of the Corsica–Sardinia block induced an east to southeastward escape of wedges (southern Apennines and Calabria). This occured at the expense of the remnant Ionian Tethys oceanic domain and the thinned Adriatic margin. The extensional regime that developed in the wake of the migrating wedges led to the formation of the central and southern Tyrrhenian basins. In the northern Nubian belts, the westward push of the Adria–Hyblean–Pelagian domain has been accommodated by oroclinal bending, thrusting and uplifting across the Tell and Atlas belts. This geodynamic context might explain some features of the seismicity time pattern observed in the Tell system. Full article