This study investigates the effects of an arch rib inclination angle and loading scenario on the elasto-plastic stability of steel basket-handle arches to support bridge design. A parametric finite element analysis was performed on 48 models, with inclination angles ranging from 0° to 15° under three vertical loading conditions: uniformly distributed (V), transversely eccentric (V1), and longitudinally eccentric (V2). A nonlinear analysis was conducted using the arc-length method. The results indicate that the ultimate bearing capacity is highest under loading V, followed by V1 and V2, irrespective of the inclination angle. The initial stiffness increases monotonically with inclination in all cases. Under V, the capacity peaks at a 10° inclination before declining, with a corresponding transition from out-of-plane to in-plane buckling at this critical angle. Under V1, out-of-plane buckling dominates, and the capacity fluctuates slightly before increasing with the inclination. Under V2, in-plane antisymmetric buckling prevails, and the capacity decreases gradually as the inclination increases. Eccentric loading induces severe stress concentration and local buckling at the arch feet, accelerating global failure. It is concluded that an inclination angle up to 10° enhances elasto-plastic stability under symmetric vertical loading, whereas eccentric loading substantially reduces the capacity; therefore, symmetric and simultaneous loading on both arches is recommended during construction.

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.

This study investigates processes related to the occurrence, acceptance, and redistribution of loads in the modernized supporting structure of a railroad open wagon. The task addressed is to improve the efficiency of transporting long-length cargo by rail. The work proposes that the bearing structure of an open wagon should be modernized by dismantling the end walls or doors. This makes it possible to reduce the sprung mass of the bearing structure of the open wagon by more than 1 t and, accordingly, to increase the load capacity by the same amount. To substantiate the proposed modernization, the strength of the bearing structure of an open wagon moving in a train was calculated. The longitudinal loads acting on the bearing structure of the open wagon were determined by mathematical modeling. The calculated acceleration value was taken into account when studying the stress state of the bearing structure of the open wagon. It was established that its strength is maintained as the calculated stresses are 14.5% lower than the permissible ones. In addition, as part of the study, a modal analysis of the bearing structure of the open wagon was conducted. The calculation results showed that traffic safety from the point of view of modal analysis is observed. A feature of the proposed modernization is that, if necessary, the bearing structure of the open wagon can be returned to the original version. The scope of practical application of the reported results is the transportation industry, in particular railroad transport. A condition for practical use of the results is symmetrical loading of the bearing structure of the open wagon with cargo. This study could contribute to compiling recommendations for increasing the efficiency of transportation of long-length cargo by rail.

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.

Dual-drug releasing PEG-PLA hydrogels with tunable degradation for sustained local analgesia and anti-inflammatory therapy in a rat fracture/osteotomy model.

This paper aims to determine the surface patterns of corneal diseases under the effects of swelling, such as in keratoconus (KC). Swelling is a mechanism that responds to changes in pressure within a medium. The cornea allows aqueous humor to flow from the stroma into the anterior chamber, following the laws of mechanics to reach mechanical equilibrium. The geometry of the cornea is altered to change its curvature, and it is reformed through the process of inflating and shearing. The theory of shells is divided into two theories: membrane theory and bending theory. These theories are used to determine stress and its corresponding shell deformation, providing solutions for bending, changes in shell thickness, and axially symmetrical load deformation, respectively. The change in corneal shape due to swelling is calculated and demonstrated under constant intraocular pressure (IOP) and the corneal load. This estimates the potential deformations of the corneal structure in response to the pressure and load imposed by the equilibrium equations. Moreover, the model can estimate the tensile properties of corneal tissue, such as its elastic modulus and stiffness. This model helps understand the mechanical stress–strain relations, permanent structural changes, and surface patterns of corneal deformations.

Recent advances in design, manufacturing and development techniques have been very relevant to making solar collectors feasible for production in a variety of applications. In the field of concentrated solar thermal technologies, several techniques have been developed to achieve high levels of radiation concentration. The generation of concave curvature geometry through the polishing of the reflective surface or through specialized machining is one of the most common methods. However, the way in which these bends are obtained can vary significantly, depending on the required quality of optical concentration for the application. This study presents a simple parametric technique to achieve a parabolic curvature for solar concentration applications. To do this, a controlled bending deformation was applied to a metal hollow profile beam supported by a pin and roller at each of the ends, and only two symmetric point loads were applied to generate a bending moment to induce a bending of a curved shape. It was found that, for a given load configuration, a parabolic geometry was generated along a partial center section of the beam. The analysis carried out showed that under the load configuration analyzed, up to 66% of the beam length adopted a fully parabolic geometry. The technique proposed in this work allows for the creation of parabolas with variable focal distances, offering versatility in the design of solar concentrating systems. It also allows corrective adjustments to be made during the assembly of the complete solar concentrator system.

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 In conventional structural design, columns are typically placed at the center of footings to ensure symmetrical load distribution and structural stability. However, architectural constraints often require eccentric placement along the edge mid-length, mid-breadth, or corner resulting in biaxial loading and non-uniform stress distribution. This study investigates the seismic behavior of a G + 7 framed structure (an eight-storey reinforced concrete frame comprising ground plus seven floors) simulated in ABAQUS, analyzing 250 mm × 250 mm columns positioned on 900 mm × 900 mm footings in four locations. Inclined knee bracings at 0°, 30°, 45°, and 60° were implemented to enhance lateral and rotational resistance. The number of bracings varied by column position: four for centrally placed columns, three for edge-mid, and two for corner placements. Fracture mechanics methods stress intensity factor and fatigue life analysis were used to evaluate crack propagation and failure modes. While central columns demonstrated better uniaxial load performance, inclined bracing significantly enhanced the seismic resilience of eccentric layouts, increasing critical rocking angles by up to 12%. Nonlinear dynamic analyses and fragility curves quantified the probability of exceedance, offering probabilistic insights into the vulnerability of 16 column–footing configurations.

Tyrannosaurus is viewed as a model organism in vertebrate paleontology, with numerous studies analyzing its feeding biomechanics. Nonetheless, the evolution of this feeding performance has been under-addressed in Tyrannosauroidea, especially in basal tyrannosauroids. Here we used muscle-force reconstruction and finite element analysis (FEA) to quantify the cranial performance of tyrannosauroids and outgroup theropod clades. 2D (planar) cranial models, set to standardized skull lengths and jaw adductor forces, were used to analyze the evolution of feeding behavior in a large sample size of Tyrannosauroidea and other theropods. Sampled stresses matched well between planar and 3D analyses of three disparately shaped crania, suggesting valid interpretations from 2D models along the lateral sides of theropod crania if symmetrical bite loadings are assumed. We traced cranial evolution by sampling stresses at homologous points of theropod crania and input their average stress values into a maximum likelihood ancestral character state estimation. Our results show tyrannosauroids having moderate-to-low cranial stresses. We further tested whether the average stress value correlates with head size through phylogenetic generalized least square regressions. We found that 2D FEA provides significant information on the evolution of feeding performance in a major dinosaur clade. Along internal branches of Tyrannosauroidea, hypothetical common ancestors exhibit low cranial stress values owing to a combination of robust skulls and cranial protuberances. These traits may have been passed down to later tyrannosauroids, enabling them to handle high forces. Our results additionally demonstrate a possible correlation between cranial shape (brevirostrine versus longirostrine) and inferred cranial performance in non-tyrannosauroid clades.

Purpose This study aims to evaluate the dynamic pedobarographic profiles of additional load in a backpack on the shoulder during daily stair activities by examining the foot pressure distribution in foot segmentation. Methods Twelve healthy male individuals with age of 25±2 years were chosen to participate the experiment. Each participant was tasked with six stair walking tasks including stair ascending, stair ascending with symmetrical load, stair ascending with asymmetrical load, stair descending, stair descending with symmetrical load, and stair descending with asymmetrical load. The plantar pressure pattern was measured using a force platform placed adjacent to the initial landing stairs, with pressure and contact time analysed as the average of three passes for each task. Results The additional load had a marginal impact on the change in peak pressure, which was clearly visible for the heel and the big toe than other areas in the same time reveals differences between stair ascending and descending. Conclusions The study shows a difference in strategy of stair ascending and descending, but the presence of a backpack on the shoulder resulted only in a slight increase in peak pressure in each foot area. Additionally, the study revealed a minor impact of the load on the contact time analysis compared to normal stair walking.

Aim: This study examined how load size and symmetry affect trunk muscle activation patterns, vertical ground reaction forces, and estimated lumbar spine compression during overground walking in individuals with chronic low back pain (CLBP) and those without symptoms. Methods: Thirty male participants (15 with CLBP, 15 controls; ages 23–28 years) performed walking tests under four load conditions: symmetric and asymmetric carriage at 10% and 20% of body weight. Bilateral surface electromyography measured activation from seven trunk muscles (rectus abdominis, external oblique, internal oblique, latissimus dorsi, lumbar erector spinae, multifidus) and the thoracolumbar fascia region, normalized to maximum voluntary isometric contractions (%MVIC). Force plates recorded vertical ground reaction forces synchronized with heel-strike events. A repeated-measures ANOVA with Bonferroni corrections was used to analyze the effects of load configuration and magnitude. Results: Asymmetric loading at 20% body weight caused significantly higher peak vertical ground reaction forces compared to symmetric loading (mean difference = 47.3 N, p < 0.001), with a significant interaction between load magnitude and configuration (p = 0.004, ηp2 = 0.26). Participants with CLBP showed consistently higher trunk muscle activation throughout the gait cycle (peak: 37% MVIC vs. 30% MVIC in controls; p < 0.001, d = 1.68), with maximum recruitment at shorter muscle lengths and 24% less activation at optimal length (95% CI: 18.2–29.8%). The lumbar erector spinae and multifidus muscles exhibited the highest activation during asymmetric 20% loading in CLBP participants (0.282 and 0.263%MVIC, respectively), indicating compensatory neuromuscular strategies. Conclusion: Asymmetric load carriage creates disproportionately high mechanical and neuromuscular demands, effects that are greatly amplified in individuals with CLBP. These findings support rehabilitation strategies that improve load distribution and restore motor control, thereby reducing compensatory strain and enhancing trunk stability.

This study analyzes a hybrid computational framework that combines peridynamics (PD) and the finite element (FE) method to model wave propagation in a one-dimensional bar, focusing on their integration for enhanced accuracy and efficiency. The analysis investigates PD’s ability to capture non-local interactions in regions near loading points, with computationally efficient coarse discretization in other areas through finite element methods. The dynamic response to symmetric and asymmetric axial loading, including loading and unloading phases, is analyzed through time-dependent external forces, solving displacement, velocity, and acceleration fields at each time step. The effects of PD-specific parameters, such as the horizon size, and the FE–PD node spacing size ratios on the performance of the hybrid model in wave propagation are investigated. Additionally, the study examines the von Neumann stability for PD to ensure stability and reliability, offering a robust framework for integrating PD and FE in dynamic analyses.

Semi-analytical solution for ground vibrations of a finite soil layer induced by symmetrical vertical distributed loads

A technique for monitoring the kinetics of micro-, meso-, and macrodamage development in elements of structure and assessing their load-bearing capacity under mechanical impact using acoustic emission, developed at the A. A. Blagonravov Institute of Mechanical Engineering of the Russian Academy of Sciences, was applied in fatigue testing of VT5-1 titanium alloy specimens under conditions of a symmetrical loading cycle by bend with a frequency of 10 Hz and an amplitude of 6 mm. The effect of the depth of a bilateral lateral notch in the zone of maximum stress (along the clamped end) on the load-bearing capacity of the specimen was determined. For notch depths of 0, 1, and 3 mm, the number of cycles to failure was 56,642, 52,261, and 30,884, respectively. It is shown that the proposed method reliably reflects the kinetics of micro-, meso-, macrodamage and the reduction in the level of bearing capacity of samples, and their durability correlates with the total number of accumulated AE locational pulses.

Symmetry and asymmetry jointly govern the dynamics and surface integrity of thin-wall AA7075 end milling. In this work, a symmetry-aware simulation and experimental framework is developed to connect process parameters with milling forces, dynamic response, surface quality, and through-thickness residual stress. A mechanistic milling-force model is first established for multi-tooth end milling, where the periodically repeated tooth-order excitation provides a nominally symmetric load pattern along the tool path. The predicted forces are then used as input for finite-element modal and harmonic-response analysis of a thin-walled component, revealing how symmetric and anti-symmetric mode shapes interact with the tooth-order excitation to generate locally amplified, asymmetric vibration of the compliant wall. Orthogonal and single-factor milling experiments on AA7075 thin-wall specimens are performed to calibrate and validate the force model, and to quantify the influence of feed per tooth, axial depth of cut, spindle speed, and radial width of cut on deformation, surface roughness, and geometric accuracy. Finally, a thermo-mechanically coupled finite-element model is employed to evaluate the residual-stress field, showing a characteristic pattern in which an initially symmetric thermal–mechanical loading produces depth-wise symmetry breaking between tensile surface layers and compressive subsurface zones. The proposed symmetry-aware framework, which combines milling-force theory, finite-element simulation, and systematic experiments, provides practical guidance for selecting parameter windows that suppress vibration, control residual stress, and improve the machining quality of thin-wall AA7075 components.

Background: Sitting and standing with conventional hip-knee-ankle-foot (HKAF) prostheses are demanding tasks for hip disarticulation (HD) amputees due to the passive nature of current prosthetic hip joints that cannot assist with moment generation. This study developed a sitting and standing control strategy for a motorized hip joint and evaluated whether providing active assistance reduces the intact side demand of these activities. Methods: A dedicated control strategy was developed and implemented for a motorized hip prosthesis (Power Hip) compatible with existing prosthetic knees, feet, and sockets. One HD participant was trained to perform sitting and standing tasks using the Power Hip. Its performance was compared with the participant's prescribed passive HKAF prosthesis through measurements of ground reaction forces (GRFs), joint moments, and activity durations. GRFs were collected using force plates, kinematics were captured via Theia3D markerless motion capture, and joint moments were computed in Visual3D. Results: The Power Hip enabled more symmetric limb loading and faster stand-to-sit transitions (1.22 ± 0.08 s vs. 2.62 ± 0.41 s), while slightly prolonging sit-to-stand (1.69 ± 0.49 s vs. 1.22 ± 0.40 s) compared to the passive HKAF. The participant exhibited reduced intact-side loading impulses during stand-to-sit (4.97 ± 0.78 N∙s/kg vs. 15.06 ± 2.90 N∙s/kg) and decreased reliance on upper-limb support. Hip moment asymmetries between the intact and prosthetic sides were also reduced during both sit-to-stand (-0.18 ± 0.09 N/kg vs. -0.69 ± 0.67 N/kg) and stand-to-sit transitions (0.77 ± 0.20 N/kg vs. 2.03 ± 0.58 N/kg). Conclusions: The prototype and control strategy demonstrated promising improvements in sitting and standing performance compared to conventional passive prostheses, reducing the physical demand on the intact limb and upper body.

Accurate estimation of support moments in continuous beams is essential for ensuring structural safety, serviceability, and material efficiency in modern reinforced concrete design. Despite advancements in computational modeling, inconsistencies persist between classical analytical predictions and finite element (FE) simulations, particularly at internal supports where stress concentrations and boundary idealizations strongly influence results. This study addresses this gap by conducting a comparative analysis of support moment variability in double-span continuous beams under symmetric loading, using classical analytical methods the Slope Deflection Method, Moment Distribution Method, and Clapeyron’s Three-Moment Theorem alongside finite element modeling (FEM) in STAADPro. The beams were modeled as linearly elastic, isotropic elements with uniform stiffness, subjected to both point and uniformly distributed loads. Analytical and numerical results were compared using percentage deviation analysis to evaluate consistency and accuracy. The results revealed a strong correlation between analytical and finite element outcomes, with an average deviation of approximately 9.7%, confirming that both approaches yield reliable support moment predictions within acceptable engineering tolerances. Minor discrepancies were attributed to mesh discretization, stiffness distribution, and boundary flexibility inherent in FEM modeling. The study found that analytical methods provided transparent and computationally efficient solutions, while finite element analysis offered refined accuracy and visualization of structural responses. These findings highlight the complementary roles of analytical and numerical approaches in structural analysis, reinforcing the continued relevance of classical theory for design verification and educational application. The research provides a harmonized framework for integrating analytical and computational techniques in beam design, offering practical guidance for engineers and educators while promoting accuracy, efficiency, and compliance with performance-based structural design standards.

Objective: To examine the biomechanical effects of load carriage on gait patterns, joint kinematics, and muscle activity during walking in older adults. Methods: A systematic literature search was conducted across five databases (CNKI, Wanfang, VIP, PubMed, and Web of Science) through June 2025. Eight studies met the inclusion criteria. The methodological quality of included studies was assessed using the ROBINS-I Version 2 tool. Results: Asymmetrical load carriage during walking increases step frequency and step width, shortens step length and the gait cycle, induces lateral trunk tilt, and leads to asymmetric muscle activation between body sides. With increasing load, adverse effects on trunk posture and muscle activation become more pronounced, including a significant increase in contralateral hip joint torque. Symmetrical load carriage up to 5% of body weight has no significant effect on gait and may improve static postural stability in older adults. Conclusion: Both asymmetrical and heavier load carriage impose greater biomechanical demands on gait in older adults. Older adults are advised to carry loads symmetrically and keep the weight below 5% of body mass to maintain gait stability and reduce fall risk.

Technical losses of electricity are losses in the distribution of electricity from transformers to consumers in electrical distribution equipment. Majority of the losses are in low-voltage overhead lines. Solar panels installed by consumers can affect the reduction of losses by reducing the flow of electric current, i.e. electricity through low-voltage lines until the moment when the power of the solar panels is equal to the power of the consumer. Further increases in the power of solar panels lead to an increase in losses. The presentation of the assumed daily diagram of the symmetrical load of the low-voltage line with the calculation of losses per hour without the influence of solar panels and with different degrees of influence of solar panels without electricity storage and example with electricity storage is given. The impacts of solar panels without and with electricity storage are also shown in a daily diagram, as well as the voltage values at the end of the low-voltage line. In the calculation, an equivalent line with half the length and full hourly load is used for the low-voltage line. Possible negative impacts are considered if the power of the solar panels exceeds the consumption.