Search Results (53)

Background/Objectives: Indirect decompression through restoration of disc and foraminal height with a large lateral interbody cage has been advocated for selected patients, but its efficacy in a large series remains unproven. In this retrospective study, we evaluated the clinical and radiographic results of indirect decompression achieved by posterior longitudinal ligament (PLL) ligamentotaxis in minimally invasive oblique lateral interbody fusion (MIS-OLIF) performed without posterior decompression. Methods: We retrospectively reviewed 236 consecutive patients treated for single- or two-level degenerative lumbar disease (November 2019–May 2025); clinical follow-up of at least 24 months was available in 181 patients. Visual analogue scale (VAS) scores and radiographic parameters—disc height, foraminal height, foraminal area, spinal canal diameter and cross-sectional area (CSA) of the thecal sac—were compared before and after surgery, and extension ratios were correlated with preoperative values. Results: Clinical scores improved significantly. All radiographic parameters increased substantially: disc height +49.1%, foraminal height +33.7%, foraminal area +44.5%, canal diameter +37.4% and CSA +36.2%. Extension ratios were inversely correlated with preoperative values. Six patients (2.5%) required additional posterior decompression. The slippage subgroup showed greater radiographic gains than the stenosis subgroup. Conclusions: MIS-OLIF without posterior decompression significantly enlarged the foramen and spinal canal; reduction in disc bulging and PLL ligamentotaxis may contribute to this effect, with greater improvement in more severely degenerated, overtly slipped segments. Careful patient selection remains essential, and prospective comparative studies with longer follow-up are needed. Full article

Replication slippage at repetitive DNA sequences generates insertions and deletions that drive genomic instability. Although magnesium ions are essential cofactors for DNA polymerase activity, their role in modulating slippage fidelity remains unclear. Using an in vitro primer extension assay on a single-stranded template carrying direct repeats flanking a hairpin-forming inverted repeat, we investigated the effect of Mg²⁺ concentration on slippage produced by mesophilic (T4 Pol, T7 Pol, E. coli pol I Klenow fragment, pol I KF exo⁻, and pol III holoenzyme) and thermophilic (Taq pol and Pfu pol) DNA polymerases. We show that Mg²⁺ modulates slippage frequency in a polymerase-dependent manner, as follows: low concentrations suppress slippage in T7 Pol, pol I KF, pol III HE, and Taq Pol, whereas T4 Pol and Pfu Pol slip at all productive concentrations. Mechanistically, Mg²⁺ modulates strand displacement activity, and polymerases that acquire enhanced strand displacement at intermediate concentrations show a corresponding reduction in slippage. Proofreading activity had no detectable effect on slippage frequency. These findings reinforce the inverse correlation between strand displacement activity and slippage propensity and suggest that physiological free Mg²⁺ levels may help suppress slippage in vivo. Full article

The micro-vibration of overhead transmission lines often leads to conductor fatigue and damage to hardware, and the reliability of the connection of vibration dampers is of vital importance. To prevent loosening and detachment during operation, this study investigated the slippage mechanism of vibration dampers’ wire clamps under dynamic loads. The static friction coefficient was measured through the pull-off force experiment, and the dynamic sliding characteristics of the two types of clamp covers (pressure block type and hinge type) under different vibration conditions were systematically tested. The experiments showed that vibration significantly reduces the dynamic friction force, resulting in a “friction reduction effect”. The pressure block type structure is prone to slip under low tightening torque, while the hinge type structure has excellent anti-loosening performance due to its lever amplification design. The study clarified that the tightening torque, vibration parameters, and structural form are the key influencing factors, providing a basis for the optimization design and installation of anti-vibration dampers. Full article

While traditional frameworks often simplify fluid dynamics, non-ideal thermodynamic characteristics, driven by intermolecular forces and spatial confinement, significantly alter bulk flow at the nanometer scale. To address this gap, we propose a novel transport model that rigorously couples nanoscale gas slippage with dynamic fluid properties. This approach uniquely integrates varying molecular interactions, seamlessly transitioning from attractive to repulsive regimes, alongside confinement-induced shifts in critical parameters. Taking the deep shale formation in the Sichuan Basin, China, as a representative geological context, accurately modeling methane transport is essential. Our analytical results reveal that incorporating non-ideal thermodynamics profoundly amplifies the predicted boundary slip. Specifically, the corrected mean free path is amplified by a factor of up to 4.7 relative to standard ideal gas assumptions. This enhancement scales strongly with elevated pressure but remains negligible near 1 MPa. Furthermore, we demonstrate that relying on ideal gas laws can inflate nanopore flow capacity estimates by more than 75%, an error primarily driven by density reductions and viscosity increases under high-pressure regimes. We also identify a specific thermodynamic window, sub-10 MPa pressures combined with temperatures below 290 K, where corrected transport metrics actually surpass conventional predictions, an anomaly governed predominantly by intensified slip dynamics. Ultimately, these findings highlight widespread inaccuracies in current permeability estimations, providing a more robust physical foundation for forecasting production and conducting numerical reservoir simulations. Full article

The foot structure plays a decisive role in the trafficability of legged robots on granular media. Traditional foot-ends (spherical, cylindrical, flat-bottomed) are prone to sinkage and slippage, resulting in unstable locomotion. To solve this problem, a novel bionic-inspired reconfigurable foot with active opening and closing adjustment capability is designed based on bionics, combining the stable phalangeal contour of goat hoof capsules and the high-adhesion feature of beetle foot-end spines. A coupled EDEM–Adams simulation model is established, and physical experiments combined with simulation inversion are used to calibrate contact parameters between particles and between particles and the foot, including the coefficient of restitution, static friction and rolling friction. A high-fidelity numerical platform for foot–ground dynamic interaction is thus constructed. By comparing and analyzing the differences in anti-sinkage and traction performance between the bionic-inspired foot and traditional foot-ends, this study systematically revealed the influence law of bionic morphology on the mechanical behavior of the foot, and clarified the intrinsic mechanism through which bionic design improves foot–ground interaction. The results demonstrate that the spine structures of the bionic-inspired foot reshape the mechanical constitutive relationship of granular media. By expanding the ground contact area and optimizing contact pressure distribution, the maximum reduction in foot sinkage depth reaches 70.11%, and the traction coefficient is increased by up to 37.13%. Full article

This paper proposes a decentralized data trading approach based on the Automated Market Maker (AMM) mechanism, aiming to address the bottlenecks in data trading efficiency and fairness via the collaborative innovation of market-oriented pricing mechanisms and automated trading processes. We focus on constructing an automatic pricing and matching mechanism based on liquidity pools. Subsequently, mathematical modeling and simulations reveal the slippage generation mechanism in data liquidity pools under trading shocks and imbalances. To address these issues, a novel dual slippage optimization mechanism integrating dynamic trade splitting and alternating order sorting is proposed, which decomposes orders into sub-orders and reorganizes their timing, establishing a dynamic equilibrium model. Experiments show that the method reduces the average slippage amplitude from 2.1% to 0.5%, representing a 76.2% reduction, and significantly enhances price stability and market efficiency. This research explores the mechanism of applying AMM to data asset trading and mitigates the limitations of AMM in this scenario, providing a theoretical and empirical foundation for building low-cost, high-fairness data trading systems through mechanism innovation and technical optimization. Full article

This paper proposes a robust navigation method based on a robust square-root cubature Kalman filter (RSRCKF) to address the accuracy divergence of integrated navigation systems caused by drilling-induced slippage and the mismatch between the tail-cable encoder and the robot motion during operations of a seafloor drilling robot in deep-sea soft sedimentary layers. Considering the large-deformation mechanical characteristics of the seabed under drilling conditions, a unified state-space model incorporating a time-varying odometer scale-factor error is first established. To alleviate the numerical instability of the nonlinear system in the presence of non-Gaussian noise, a square-root cubature Kalman filter (SRCKF) framework is employed, in which the positive definiteness of the error covariance matrix is dynamically preserved via QR decomposition. Subsequently, an online fault detection mechanism based on a modified chi-square test is developed. By introducing a two-segment IGG (a classical robust weighting scheme) weighting function, an adaptive variance inflation factor is constructed to enable real-time identification and down-weighting of abnormal observations induced by slippage. Field experiments, including drilling and turning tests conducted on tidal mudflats off the coast of Zhoushan, demonstrate that the proposed method can effectively mitigate the impact of “false displacement” disturbances caused by typical soft clay slippage conditions through enhanced statistical robustness. Taking the conventional SINS/OD integration scheme as the baseline, the proposed method achieves an approximate 82.4% reduction in positioning error. These results verify the robustness and engineering applicability of the proposed algorithm in complex seabed environments. Full article

The integration of glass fibre-reinforced polymer (GFRP) and steel reinforcement in hybrid RC beams offers durability benefits, yet the specific influence of GFRP surface treatments on bond mechanics remains critical. This study experimentally investigates the performance of hybrid GFRP-steel-reinforced beams under three-point bending, comparing sand-coated and ribbed GFRP bars, while maintaining a constant total reinforcement ratio of 1.4% to isolate interface mechanics. Due to the exploratory nature of the study and the specific specimen matrix, the results are interpreted as observed experimental trends rather than statistically generalised performance metrics. The results indicate that ribbed GFRP bars provide enhance mechanical interlocking; in this specific experimental program, the ribbed GFRP hybrid beam exhibits an observed load capacity approximately 11% greater than the sand-coated specimen in this study and surpassing comparable steel-only beams. Additionally, ribbed configurations demonstrated an observed 15% higher toughness. In contrast, sand-coated hybrid beams exhibited signs of premature bond degradation, quantitatively captured by strain gauge monitoring; sand-coated bars plateaued at 14,000 µε, reaching only 79% of their theoretical rupture capacity. This strain limitation indicates failure by internal slippage rather than material rupture, further evidenced by a 50% reduction in crack propagation compared to ribbed beams. While energy-based ductility indices suggest a marginal 6% advantage for sand-coated bars, both hybrid systems exhibited relatively low energy-based ductility indices (μ < 2), reflecting the linear-elastic nature of GFRP reinforcement. These findings suggest that the mechanical interlock of ribbed surface treatments is more resilient under the combined stress states typical of hybrid configurations, providing a foundational baseline for the development of future numerical models and reliability-based design frameworks for hybrid GFRP-steel-RC systems. Full article

A sucker rod pump is an artificial lift system widely used in oil wells to extract crude oil from deep underground. Due to the clearance between the barrel and the pump plunger, a phenomenon termed slippage occurs in which the annulus column of oil returns to the pump chamber due to the plunger motion and the pressure difference at the two ends of the plunger. Although it is important to maintain the clearance for lubrication between the plunger and the pump barrel in order to prevent excessive wear and tear along with galling, excessive clearance can also be a primary factor in the reduction of oil well production and must be managed. In this research, after briefly reviewing the Couette and Poiseuille flows within the annulus region, the relaxation time for the transients, and the eccentricity effects, we focus on the derivation of important system parameters such the effective mass, stiffness, and damping ratio based on the measurements of the sucker rod displacement and the pressures or loads. Analysis of experimental measurement data can provide better understanding of the sucker rod pump system parameters, helping to quantify and manage the so-called slippage issues. Full article

The reinforcement mechanism of functionalized graphene nanosheets (GNS) on the mechanical properties of polyetheretherketone (PEEK)/polytetrafluoroethylene (PTFE) composites was investigated. Composite specimens were fabricated using PGNS, as well as GNS grafted with hydroxyl, carboxyl (-COOH) and amino functional groups, and mechanical characterizations were conducted on the prepared specimens. The results demonstrated that carboxyl-functionalized GNS (COOH-GNS) exhibited the most remarkable reinforcing effect on PEEK/PTFE composites, with its elastic modulus, tensile strength, yield strength and compressive modulus increased by 47.09%, 31.1%, 45.16% and 20.91%, respectively, compared with PGNS-reinforced composites. Combined with experimental measurements and molecular dynamics simulations, the reinforcement mechanism of this composite system was elucidated. The functional groups on the surface of GNS can induce interfacial interactions with the PEEK/PTFE matrix, by which the mobility of polymer molecular chains is restricted, the deformation and slippage of molecular chains are suppressed, and the interfacial bonding between GNS and the polymer matrix is simultaneously strengthened. The enhancement of interfacial binding energy, the reduction in free volume in the composite system, and the restriction of polymer molecular chain mobility were identified as the critical atomic-scale mechanisms responsible for the improvement of the macroscopic mechanical properties of the composites. Full article

Improving the energy efficiency of rolling bearings requires a component-resolved understanding of loss mechanisms. While analytical models capture load-dependent losses, load-independent hydraulic losses demand a physics-based approach. This paper presents a computational fluid dynamics (CFD) methodology for the qualification of individual hydraulic loss contributions and to assess their sensitivity to operating conditions. The approach decomposes the total hydraulic loss of the spherical roller bearing 22320 into component-level shares and is benchmarked against dedicated experiments. The simulated results show good agreement with experimental measurements, supporting the validity of the methodology. The discrepancy between the measured and simulated friction torque values averaged at 2–7%, with a single outlier. Furthermore, CFD methods have been demonstrated to be capable of predicting trends in hydraulic losses resulting from variations in speed and temperature. A consistent finding across all investigated conditions is that the rolling elements dominate the hydraulic losses. Churning-induced losses of the rolling elements contribute for more than 50% of the hydraulic losses of the hole bearing in every test. The proposed methodology offers a reproducible way to assign losses individually, compare operating scenarios and guide targeted design measures for loss reduction in rolling bearings. Furthermore, dynamic kinematic simulations of rolling bearings can be equipped with component-resolved hydraulic losses. This is enabling more accurate predictive modelling of the bearing kinematics and detecting effects such as slippage. Full article

Sport horse feeding robots face significant challenges in achieving precise navigation within complex stable environments. Uneven terrain and frequently moist ground often cause drive wheel slippage, resulting in path deviation and cumulative pose errors that compromise feeding accuracy and operational efficiency. To address this challenge, an enhanced Dynamic Window Approach (DWA) path planning framework, which integrates an automatic drift correction module based on an Inertial Measurement Unit (IMU) and a two-stage cascade proportional–integral–derivative (PID) controller, is proposed in this paper. This enhanced DWA enables precise yaw adjustment while preserving the native velocity sampling and trajectory evaluation framework of conventional DWA. Field validations were conducted through ten independent trials along a fixed 28 m feeding route in an actual sport horse feeding environment to quantitatively evaluate the robot’s path deviation and yaw angle stability. The results demonstrated that the enhanced algorithm reduced the standard deviation of path deviation from 0.161 m to 0.144 m (10.56% improvement) and decreased yaw angle standard deviation from 2.19° to 1.74° (20.55% reduction in angular oscillation). These improvements validated the effectiveness of the proposed algorithm in mitigating slippage-induced pose drift and significantly improving the locomotion capability of robots for sport horse feeding within stable environments. Full article

Background: Winch-assisted harvesting is an alternative to traditional cable yarding on steep slopes, offering improved operational efficiency and fewer limitations. Knowledge on the effects of winch-assisted harvesting on soil disturbance are limited. This study aimed to assess the effects of winch-assisted and conventional tracked harvester operations on soil compaction and machine slippage in a clear-cut stand with sandy loam soil. Methods: We evaluated changes in soil physical properties, in depth and extent, along machine operating corridors with and without winch-assist across slope gradients ranging from 30% to 52% and up to three machine passes. Results: The relative increase in bulk density differed between treatments. In the non-assisted corridors, the bulk density increased by 18%, 12%, and 11% at depths of 0–10, 10–20, and 20–30 cm, respectively; the winch-assisted corridors showed smaller increases of 12%, 5%, and 3% at the corresponding depths. The winch-assisted plots did not show a significant reduction in rut depth compared with the non-assisted plots, a result likely influenced by site-specific dry soil conditions. Conclusions: These results highlight the potential of winch-assisted systems to reduce horizontal soil disturbance, though their effectiveness in limiting rutting remains variable under dry conditions. Full article

In modern robotics, actuator performance is fundamental to achieving efficient and durable motion, with compactness and torque density being especially critical. Compact actuators enable integration in space-constrained systems without compromising functionality, while high torque density ensures powerful output relative to size, enhancing efficiency and versatility. Harmonic gearboxes embody these qualities, offering lightweight design, zero backlash, and excellent torque density, which have made them a standard choice in robotics. However, their widespread adoption is limited by high manufacturing costs due to the precision machining required. To address this challenge, the authors previously introduced RM-Act, a Radial Modular Actuator employing two synchronous belts as harmonic speed reducers. Building on this concept, RM-Act 2.0 is introduced as an improved version that employs a single synchronous belt. This design reduces transmission slippage, improves torque density, and offers greater modularity with a wider range of reduction ratios. The work details the development and validation of RM-Act 2.0 through a functional prototype and performance model, highlighting its advancements over the original RM-Act in compactness and torque density. Full article

This paper investigates the use of reinforcement learning (RL) algorithms to learn adaptive hedging strategies for derivatives under realistic market conditions, incorporating permanent market impact, execution slippage, and transaction costs. Market frictions arising from trading have been explored in the optimal trade execution literature; however, their influence on derivative hedging strategies remains comparatively understudied within RL contexts. Traditional hedging methods have typically assumed frictionless markets with only transaction costs. We illustrate that the dynamic decision problem posed by hedging with frictions can be modelled effectively with RL, demonstrating efficacy across various market frictions to minimize hedging losses. The results include a comparative analysis of the performance of three RL models across simulated price paths, demonstrating their varying effectiveness and adaptability in these friction-intensive environments. We find that RL agents, specifically TD3 and SAC, can outperform traditional delta hedging strategies in both simplistic and complex, illiquid environments highlighted by 2/3rd reductions in expected hedging losses and over 50% reductions in 5th percentile conditional value at risk (CVaR). These findings demonstrate that DRL agents can serve as a valuable risk management tool for financial institutions, especially given their adaptability to different market conditions and securities. Full article