Mechanical response and damage evolution of surrounding rock in shallow-buried twin-arch tunnel under asymmetric loading with variable slope topography

Abstract A fundamental challenge in star formation is understanding how a protostar accretes mass from its circumstellar disk while removing excess angular momentum. Protostellar jets are widely invoked as the primary channels for angular-momentum removal, yet the mechanism by which they are launched and extract angular momentum remains poorly constrained. Here, we report high-resolution Atacama Large Millimeter/submillimeter Array Band 7 (345 GHz) and Band 6 (230 GHz) observations of 12 CO (3–2), 12 CO (2–1), and SiO (5–4) emission from the protostar HOPS 10 (G209.55−19.68S2). The combined data trace both the entrained outflow and the collimated jet with excellent spatial and velocity resolution, revealing a uniquely monopolar protostellar jet—the clearest example reported to date. The system exhibits a distinctly unipolar high-velocity jet (velocity offset, V HV , off = V observed − V systemic = +44 to +66 km s −1 ), unlike the predominantly bipolar morphology characteristic of most protostellar jets. While the low-velocity outflow (velocity offset, V LV,off = V observed − V systemic = −20 to +30 km s −1 ) is detected in both directions, the high-velocity jet appears only on one side, and this monopolarity is consistent across all tracers. Given the nearly edge-on geometry and low submillimeter extinction, comparable emission would normally be expected from both lobes. The shock tracer SiO emission confirms a genuine, highly collimated jet rather than cloud contamination, and no ambient structure is capable of obscuring a counterjet. We argue that intrinsically asymmetric mass loading along the disk’s magnetic field lines provides the most plausible explanation for the observed monopolarity.

Problem statement. For conditions of asymmetric loads on underground structures caused by uneven weakening of rocks due to flooding and other natural and man-made factors, issues of substantiating rational forms and sizes of injection hardening zones require further comprehensive studies combining geomechanics, materials science and optimization methods. Purpose of the study. Justification of the parameters of injection rock hardening zones to improve the safety level of underground workings and buried structures under conditions of asymmetric loads on the support. Methods. Generalization of data on the asymmetry of loads on the support of underground structures; methodology for assessing the rock massif destruction; mathematical modeling using the finite element method. Research results. Hardening of rocks around underground workings and buried structures allows to reduce the probability of cracks, prevent the development of deformations and increase the overall resistance of objects to the impact of operational and natural loads. The issue of substantiation of rational forms and sizes of injection hardening zones for conditions of asymmetric loads on underground structures which are caused by uneven weakening of rocks due to flooding and other natural and man-made factors requires further research. The features of the formation process of loads asymmetry on the support of the underground structures are determined. The method of assessing the state of the polymer-saturated rock massif and forecasting its changes under the influence of certain measures to strengthen the rocks around the underground structure is substantiated. It has been established that rock hardening by means of injection and other hardening technologies allows for effective compensation of supporting deficiencies without a significant increase in capital expenditures. In addition, the use of various configurations and arrangement schemes of hardening zones allows for flexible adaptation to specific geological conditions, redistribution of stresses in rocks, reduction of their concentrations in potentially hazardous zones, prevention of local collapses, deformations and water inflows, which ensures long-term safe use of underground structures. For conditions of uneven loads on the supports, an asymmetric shape of the hard-ened zone is proposed, which can be used as a reserve for increasing the stability of the underground structure. It is established that the nearly elliptical shape of the hardened zone as an element of rock pressure control ensures an in-crease in the stability of the underground structure due to a 10‒35 % reduction in the inelastic deformation zone and a 0,5‒3,0 m deep displacement of the asymmetric support pressure zone. The displacement of the roof of the underground workings is reduced by 6‒13 % of the total displacements, and the workings floor by 7‒23 %. Scientific novelty. For the first time, in order to increase the level of safety in the operation of underground workings and buried structures under conditions of asymmetric loads on the support, patterns of changes in maximum principal stresses have been established when using various nearly elliptical shape of injection rock hardening zones. Practical significance. The proposed configurations of injection hardening zones reduce stress concentrations in rocks, which helps prevent sudden deformations of supports and ensure long-term safe use of underground structures.

Superior glenoid inclination in shoulder arthroplasty: a comparison of standard to superiorly augmented glenoid implants.

Experimental study on dynamic response of offshore wind turbine structures under asymmetric wave and wind loads

This study examines CMOS ring oscillators that are used as converters of capacitive sensor parameters. The issue with most analytical models is their assumption of symmetric stage loading, making them inaccurate for the topology where a sensor connection to a single node introduces asymmetry. The lack of a validated model for 45-nm technology complicates the design of sensitivity and energy efficiency. An analytical model for the capacity to frequency converter that accounts for asymmetric loading has been built and verified. The model is based on the physical principle of summing asymmetric stage delays and a linear approximation of inverter delay versus load capacitance. A parametric analysis was performed in LTspice (sensor capacitance Csensor is from 0 to 2.5 pF) to verify the model. It was determined that the oscillation period has a quasi-linear dependence on capacitance; therefore, the frequency dependence is hyperbolic. The proposed model predicts the frequency with a maximum relative error of no more than 1.55% over the entire simulation range (21.17–29.96 MHz) compared to SPICE data. Key metrics have been analyzed: the average sensitivity is 3.52 MHz/pF, while the instantaneous sensitivity is non-linear, decreasing from 5.57 MHz/pF to 2.15 MHz/pF. Power consumption increases slightly (151.3–155.7 µW), as the capacitance growth is compensated by the frequency drop. Energy per cycle (Ecycle), conversely, increases almost linearly (5.05–7.35 pJ) with a slope of 0.92 pJ/pF. This closely matches the theoretical value of VDD2 = 1.0 pJ/pF, confirming the dominance of dynamic power consumption. The proposed model allows engineers to accurately predict and design the capacity-to-frequency characteristics, sensitivity, as well as power consumption of compact integrated sensor interfaces.

Interlimb asymmetries may influence contralateral knee osteoarthritis (OA) progression, yet research remains unclear. This study examined whether patient-reported outcomes and knee biomechanics differ between individuals with knee OA exhibiting symmetrical versus asymmetrical knee loading. Forty-three individuals with knee OA were dichotomized into symmetrical (≤14% asymmetry; n = 19) and asymmetrical (>14% asymmetry; n = 24) groups based on total joint moment symmetry indices. Participants completed the Knee Injury and Osteoarthritis Outcome Score and Intermittent and Constant Osteoarthritis Pain questionnaires. Three-dimensional kinematics and kinetics were collected during walking at a self-selected speed. Independent t tests and statistical parametric mapping examined between-group differences in patient-reported outcomes and biomechanical measures. Individuals with symmetrical knee loading had worse Knee Injury and Osteoarthritis Outcome Score activities of daily living scores (P = .041) than those with asymmetrical loading. Individuals with symmetrical knee loading exhibited less knee extension moment during late stance (P = .031) and lower knee adduction moment range in their affected knee compared with asymmetrical loaders. Individuals with symmetrical knee loading walked with lower knee flexion angles (P = .011), less midstance unloading (P = .011), and lower peak knee flexion moment (P < .001) in their contralateral knee compared with asymmetrical loaders. Symmetrical knee loading was associated with affected and contralateral knee biomechanics that were consistent with more severe knee OA and worse functional outcomes.

This study examined how hand dominance influences lower-limb biomechanics during single-leg landing in bilateral lay-ups. Because the lay-up is a high-frequency basketball skill that imposes substantial impact loading and requires rapid neuromuscular control, side-dependent landing strategies may contribute to asymmetrical joint loading and elevate injury risk, particularly at the knee and ankle. However, empirical evidence clarifying how hand dominance interacts with lay-up side to shape landing biomechanics remains limited. Thirty male collegiate basketball players (15 left-hand dominant, 15 right-hand dominant) performed standardized right-hand lay-ups with left-leg landing and left-hand lay-ups with right-leg landing on force plates under 3D motion capture. Vertical ground reaction force (VGRF) and sagittal-plane knee and ankle kinematics and kinetics were analyzed using 2 × 2 mixed ANOVA and SnPM1D over the normalized stance phase. Left-hand–dominant players exhibited higher VGRF first peaks (p = 0.001), second peaks (p = 0.012) and total impulse (p &lt; 0.001), with pronounced side-to-side asymmetry, whereas right-hand–dominant players showed more symmetrical loading between lay-up directions. At the joint level, significant Handedness and Side interactions were found for sagittal ROM, peak flexion, joint moments and power. Left-hand–dominant athletes relied on greater knee flexion, higher knee extensor moments and larger ankle and knee power on their preferred support leg. SnPM1D revealed time-dependent differences clustered in early–mid stance (impact attenuation) and late stance (push-off).These findings indicate that hand dominance systematically reorganizes proximal–distal coordination and load distribution during lay-up landings, and that monitoring asymmetry, particularly in left-hand–dominant athletes, may be important for targeted training and injury prevention.

**Background:** Prosthetic gait asymmetry is commonly treated as a functional limitation; however, its long-term orthopedic consequences on the intact limb remain under-recognized. This study investigates how chronic asymmetrical loading patterns influence degenerative risk in unilateral lower-limb amputees. **Methods:** Nineteen individuals with unilateral transtibial amputation (16 male, 3 female; age 49.5 ± 11.3 years) participated in a 12-month longitudinal study. Gait analysis was performed at baseline, 6 months, and 12 months using force plates and 3D motion capture. We analyzed temporal symmetry (stance time ratio), force symmetry (vertical ground reaction force [vGRF] ratio), intact limb joint moments, and clinical outcomes (WOMAC pain scores, radiographic Kellgren-Lawrence [KL] osteoarthritis grade). **Results:** Over 12 months, significant deleterious changes were observed despite some participants improving temporal symmetry. Force symmetry significantly worsened (0.701 to 0.663; p &lt; 0.001), while intact limb knee flexion and adduction moments significantly increased by 6.6% and 7.7%, respectively (p &lt; 0.001). WOMAC pain scores increased by 26.4% (p = 0.0001). Baseline force symmetry was significantly correlated with baseline knee flexion moment (r = 0.479, p = 0.038). Notably, subjects with improved inter-limb temporal symmetry but unresolved force asymmetry continued to demonstrate elevated intact-limb tissue stress. **Conclusion:** These findings emphasize that restoring visual or temporal gait symmetry is insufficient without addressing underlying mechanical load distribution. Compensatory strategies—particularly increased intact-side stance time, vertical loading rate, and frontal-plane knee moments—are more predictive of osteoarthritic progression than prosthetic design alone. The study supports biomechanically informed prosthetic tuning and neuromuscular retraining strategies aimed at protecting the intact limb over the lifespan.

ABSTRACTBackgroundRecent advancements in next‐generation bioreactors have substantially improved the simulation of complex, detrimental spinal mechanics in ex vivo intervertebral disc models. This study investigated intervertebral disc responses to combined flexion, torsion, and static compression. A range of loading frequencies, magnitudes, and patterns was applied to identify conditions that contribute to disc degeneration under complex motion.MethodsTwelve bovine coccygeal intervertebral discs (mean age 9 months) were subjected to three distinct loading regimes, with four samples per condition. Static compression of 0.1 MPa was combined with: (1) symmetrical 3° flexion/extension and 2° torsion, (2) symmetrical 6° flexion/extension and 4° torsion, and (3) asymmetrical 6° flexion and 4° torsion. Loading frequencies and durations ranged from 0.2 Hz for 1 h in symmetrical loading to 1 Hz for 2 h in asymmetrical loading over a 14‐day period. Structural integrity, cell viability, tissue composition, and molecular responses were evaluated using histology, biochemical assays, and gene expression analysis.ResultsLower‐cycle symmetrical flexion/extension and torsion, regardless of magnitude, preserved disc structure and maintained a high cell viability (88% ± 14%) across all disc regions. Higher cycle numbers and asymmetrical loading induced significant fissures in the outer annulus fibrosus (AF) on the tensed side (p < 0.01) and delamination on the compressed side. This structural damage occurred in AF regions with high cell viability (81% ± 17%), whereas significantly reduced cell viability was observed in the inner AF (30% ± 33%) and nucleus pulposus (28% ± 35%).ConclusionsUnder conditions of asymmetrical and more frequent loading, complex motion involving flexion, torsion, and compression led to structural damage in the outer disc regions and promoted cell death in inner regions. These region‐specific responses suggest the independent development of distinct failure mechanisms contributing to disc degeneration. They also underscore the importance of developing targeted strategies that address both structural integrity and cellular resilience in degeneration models and therapeutic interventions.

ABSTRACT Context The highest incidences of musculoskeletal (MSK) injuries within the military occur at anatomical regions most impacted by jumping and landing, including the knee. Military personnel assigned to Special Operations Forces (SOF) are at particularly high risk of MSK injury due to occupational demands. Objective To characterize changes in limb loading symmetry during walking gait from 6 to 12 months after ACLR in patients with extensor mechanism autografts using force-sensing insoles, and to compare the change in limb loading metrics between patients with bone-patellar tendon-bone (BPTB) and quadriceps tendon (QT) autograft. Design Cross-Sectional Study Setting Laboratory Patients or Other Participants Two hundred twenty-four uninjured active-duty male SOF personnel (age = 27.7 ± 5.0 years; mass = 83.1 ± 9.1 kg; height = 176.5 ± 5.7 cm) completed biomechanical analyses of two different drop landing tasks (double leg (DLDL) and single leg (SLDL)) and isokinetic strength testing of the quadriceps and hamstrings. Main Outcome Measure(s) Peak hip, knee, and ankle angles; hip, knee, and ankle angles at initial ground contact (@IC); and peak vertical ground reaction (VGRF) forces were identified during landing tasks. Maximum voluntary isokinetic knee extension strength (KES) and knee flexion strength (KFS) were also assessed. Results Participants demonstrated greater KES with their dominant limb by an average of 0.06 Nm/kg (p=0.001, d=0.219) and landed with greater force on the dominant limb during DLDL by an average of 20% bodyweight (p&lt;0.001, d=0.377). No asymmetries involving knee kinematics were identified. During DLDL, both limbs demonstrated similar significant correlations between knee (peak) and ankle (@IC and peak) kinematics and peak VGRF. During nondominant SLDL, knee@IC, peak knee flexion, and peak dorsiflexion significantly correlated to peak VGRF. Peak knee flexion during non-dominant SLDL correlated to non-dominant KES. Conclusions Knee mechanics are important components for shock attenuation, but for this population, factors other than strength likely play a more significant role in controlling the mechanics about the knee during landing tasks.

Bipolar direct current (DC) microgrids have emerged as a promising alternative for efficiently integrating of renewable energy sources. However, these systems are susceptible to voltage imbalance between the positive and negative poles, especially with asymmetric loads. This paper presents the modeling and control of a non-isolated DC–DC Boost converter with a symmetric bipolar output suitable for photovoltaic applications. The proposed topology eliminates issues related to voltage imbalance and leakage currents while providing continuous low-ripple input current, a reduced number of components, simplified operation, and common grounding with the output neutral point. The operating principle, modeling, and control strategy of the converter are discussed, and its performance is validated through simulations and experimental results from a 1500 W prototype. The results demonstrate stable operation under both balanced and unbalanced conditions.

Patellofemoral joint loading after anterior cruciate ligament reconstruction (ACLR) remains poorly understood, despite the high prevalence of patellofemoral joint complications following surgery. With an observational cohort design, we compared patellofemoral joint stress (PFJS) and reaction force (PFJRF) between surgical and nonsurgical limbs during a double-limb squat at 12weeks postsurgery and return to sport (RTS), with sex-based comparisons. Forty-seven athletes (21 males and 26 females) aged 12-25years performed a body weight double-limb squatting task at 12weeks postoperatively and RTS. Maximal knee extensor strength was assessed at both time points with isokinetic dynamometry. Ground reaction forces and kinematic data were used to compute patellofemoral loading. Mixed factorial analyses of variance compared patellofemoral loading and knee extension strength, and Pearson correlations examined associations between patellofemoral loading and knee extensor strength. The surgical limb demonstrated lower PFJS (P < .001, ηp2=.439) and PFJRF (P < .001, ηp2=.423) at both time points, though these measures increased over time without significant changes in the nonsurgical limb. Females exhibited lower PFJS (P < .001, d = 0.73) and PFJRF (P = .032, d = 0.52) than males across limbs and time points. Knee extensor strength was positively associated with PFJS (r = .697; r = .616) and PFJRF (r = .605; r = .531, all P < .01) at both 12 weeks postsurgery and RTS, respectively. Athletes demonstrate decreased patellofemoral joint loading in the surgical versus the nonsurgical limb through RTS. Females exhibit lower patellofemoral loading after ACL reconstruction, which may be linked to their higher prevalence of posttraumatic osteoarthritis and patellar abnormalities-supporting the paradoxical hypothesis that underloading, rather than overloading, may promote osteoarthritis development.

Introduction: Knee Osteoarthritis (KOA) plays a substantial role in the global burden of musculoskeletal disorders. Biomechanical factors such as leg dominance are hypothesised to contribute to the onset and progression of KOA; however, the relationship between dominant limb use and symptom development remains unclear. Aim: To investigate the association between leg dominance and the onset and side of symptoms in KOA, utilising both a validated questionnaire and standardised functional task assessments. Materials and Methods: A cross-sectional study was conducted at the Department of Sports Physiotherapy, KLE Institute of Physiotherapy, Belagavi, Karnataka, India, over 11 months, from May 2024 to March 2025. It involved 131 individuals aged between 45 and 70 years with radiologically confirmed Grade I or II KOA. Leg dominance was assessed through a standardised questionnaire and six motor tasks. The data collected were compiled in Microsoft Excel and analysed using IBM Statistical Package for the Social Sciences (SPSS) Statistics version 29.0. Chi-square tests and t-tests were used to analyse associations. Results: A total of 131 participants (55 males and 76 females) were included in the final analysis. Right leg dominance was identified in 124 (94.7%) of the participants across all motor tasks, with a high concordance noted in the ball-kicking task between self-report and observation. Right knee pain was more common, reported by 111 (84.7%) participants, and the majority noted a gradual onset of symptoms, with 110 (84%) indicating this pattern. All left-leg dominant individuals were female and exhibited left-sided KOA (p-value &lt;0.001). Sudden onset of symptoms was significantly associated with left-leg dominance, observed in 5 (71.4%) participants (p-value=0.001). Conclusion: The study identified a significant association between leg dominance and both the side and onset of KOA symptoms. Dominant limb mechanics may play a role in asymmetric joint loading and early symptom manifestation. Assessing leg dominance through both self-report and task observation may aid in the early identification of at-risk individuals and support targeted rehabilitation planning.

Asymmetric loading effects and reinforcement strategies for double-arch tunnels in probabilistic jointed rock masses

A Thermo–Hydro–Mechanical (T–H–M) coupled analytical solution for an open-hole under 3D asymmetric loads

Cervical disc replacement aims to preserve cervical spine motion and reduce the risk of adjacent segment disease. The Rhine cervical disc is a non-articulating, viscoelastic implant designed to replicate the natural biomechanics of the cervical spine. To date, no explant analyses of this device have been published. This study presents the explant analysis of two Rhine cervical discs retrieved from a 41-year-old female patient who had undergone two-level cervical total disc replacement, C4-C5 and C6-C7, for myeloradiculopathy. The implants were removed approximately one year after the surgery due to increasing neck discomfort, recurrent neurological symptoms, and radiographic evidence of osteolysis. Explant analysis was performed on both implants to assess their physical condition and any associated tissue reactions. Both explants were intact, however, notable findings included plastic deformation of the viscoelastic cores, particularly in the upper disc. The direction of shear deformation differed between the explants, anterior in the upper disc and posterior in the lower disc, suggesting asymmetric loading conditions. In addition, osteolysis was observed predominantly at the posterior aspect of the lower disc one year after implantation. These observations highlight deformation of the viscoelastic core in Rhine cervical discs. Whether this finding relates to surgical factors such as implant sizing and positioning, or to implant design itself, improper sizing and malpositioning may contribute to excessive shear forces, core deformation, and poor clinical outcomes. These factors are all important in implant survival and should be carefully considered. The deformation observed in the cores of the explants is consistent with viscoelastic polymer limitations reported in the literature for other viscoelastic cervical discs.

The relationship between the stomatognathic system and postural control, including gait, is a growing area of interdisciplinary research. While some studies suggest a connection between malocclusion and postural imbalances, the effect of occlusal correction on plantar pressure remains underexplored. This study investigates the changes in static and dynamic plantar pressure distribution following the correction of Class II malocclusion. A clinical study was conducted on 100 participants (50 women and 50 men, mean age 24.5 ± 3.2 years) with diagnosed anteroposterior malocclusion (Angle Class II ). Plantar pressure distribution was assessed using a baropodometric platform under static conditions (bipedal stance) and dynamic conditions (gait) both before and after achieving Angle Class I occlusion. Parameters analyzed included the centre of pressure (CoP) path, forefoot/hindfoot weight distribution (%), and pressure symmetry. Following malocclusion correction, a statistically significant improvement in plantar pressure balance was observed. The CoP path length and sway area decreased significantly during static posturography (p &lt; 0.01). The forefoot/hindfoot load distribution became more symmetrical, approaching a physiologically optimal ratio. During gait, pressure analysis revealed a more harmonious and symmetrical pressure distribution across both feet, with a reduction in asymmetrical loading patterns that were present pre-treatment. The correction of Class II malocclusion has a significant positive effect on normalizing both static and dynamic plantar pressure distribution. These findings underscore the existence of a stomatognathic-podal relationship and highlight the importance of a multidisciplinary approach involving dentists and physiotherapists for the comprehensive management of patients with malocclusion.

Abstract Belt conveyors are widely used in bulk material handling, yet system-level observability remains limited. Existing monitoring solutions are typically localized and component-specific, while comprehensive monitoring of distributed components is often impractical. This article presents a belt-integrated monitoring concept that measures tensile loads during operation by instrumenting a belt section with multiple strain-based sensing elements across the belt width. The resulting measurements aim to detect asymmetric load states and load peaks associated with, for example, eccentric bulk material loading, belt mis-tracking, or localized increases in idler rolling resistance. The concept includes an in-belt measurement chain with signal conditioning, data acquisition, and wireless transmission to an external base station for processing and evaluation. Splice-compatible integration using a hot-vulcanized step splice in a fabric conveyor belt was investigated; representative vulcanization temperature and pressure profiles were recorded during splicing of an 11 mm thick belt segment, and the strain-based sensing elements remained functional after curing. Operational validation on an in-house test stand is ongoing.

The increased demand for clean renewable energy requires innovative technology designs. A dual-rotor wind turbine system is presented and modelled using Blade Element Momentum Theory. Four different rotor configurations were analysed in both structural loading and vibrational impact. A key advantage of the dual-rotor approach is its ability to maintain partial operation even if one rotor fails, a feature that could significantly increase wind farm reliability. The study explores contra-rotation as a strategy to mitigate asymmetric lateral loads, thereby reducing torsional and rolling stresses at the tower and beam locations – a critical factor for structural longevity. This investigation analysed the impact of rotor phasing, an area previously unaddressed in the literature, by focussing on system dynamics in both frequency and time domains. Our findings reveal that operating the rotors out of phase can reduce fore-aft vibrations in the connecting beam by up to 86%, without increasing overall structural loads.