Search Results (1,276)

Parallel operations by multiple trades on constrained workfaces pit safety against schedule. Static schedulers, scalar fatigue models, and standard evolutionary algorithms all struggle to reconcile the two. Simulation tackles the Parallel Task Matching Problem (PTMP). A Spatial Conflict Graph quantifies workspace interference, with edge weights combining a 3D Jaccard overlap and a process-coupling coefficient. The Cross-Task Fatigue Transfer Model (CTFTM) governs whole-body, localized, and cognitive fatigue. Task-specific accumulation, recovery, and crosstalk parameters in this coupled ODE system capture fatigue carryover across heterogeneous activities. Minimizing schedule delay and OHS risk then follows from a bi-objective model under spatial-conflict, fatigue, skill, crew-size, and precedence constraints. An NSGA-III extension uses integer worker–task encoding, a Conflict Repair Operator that modifies fewer than 7% of genes and removes penalty calibration, and TOPSIS-based Pareto selection. Hybrid re-scheduling pairs persistent event triggers with structural state updates and a periodic trigger. The test campaign used three parallel tasks, eight heterogeneous workers, five ablative baselines, four empirical sensitivity analyses, and a design-level threshold assessment. Standalone calibration produced comparable, trade-off-dependent multi-objective performance for NSGA-III, NSGA-II, and MOEA/D; NSGA-III with conflict repair was retained for the full dynamic experiments. Over-threshold-fatigue workers fell from 5.789 to 0.020 relative to the scalar-fatigue baseline. Fatigue-efficiency index (FEI) improved by 43.5% relative to the scalar-fatigue baseline, alongside robust real-time disruption handling. Taken together, these results establish a simulation-based foundation for intelligent, safety-aware workforce scheduling. Full article

In the fields of signal processing and applied mathematics, the uncertainty principle plays a significant role. Motivated by the theoretical significance of the octonion quadratic-phase Fourier transform (OQPFT), we present a systematic investigation of uncertainty relations for this transform. Firstly, we derive the differential properties of the OQPFT. Secondly, we systematically derive four corresponding uncertainty principles for the OQPFT, covering both deterministic and random octonion signal scenarios. Finally, three sets of simulation experiments using 3D octonion chirped signals are performed, including two Gaussian-modulated cases with different complexity and a constant-coefficient rectangular-window non-Gaussian case for comparative verification. Full three-dimensional spectral observation shows that the OQPFT achieves superior frequency-domain aggregation compared with the octonion Fourier transform (OFT). Further comparative analysis demonstrates that this spectral aggregation advantage is not limited to Gaussian signals, but also holds for non-Gaussian windowed signals. This paper enriches the uncertainty theory in the hypercomplex domain and provides theoretical support for the frequency-domain analysis of high-dimensional quadratic-phase signals. Full article

The three triad sheets of the face-centered cubic (FCC) lattice, at even lattice size L, are edge-disjoint but share their vertex and octahedral-void ancilla positions. Running the three sheet codes in a three-round time-multiplexed cycle on one chip needs $4L^3$ physical qubits against $6L^3$ for three separate blocks, a saving of exactly one third at every L, for instance, 864 qubits instead of 1296 at $L=6$. The schedule is implemented explicitly, with all three sheets on one shared ancilla set; comparing it against the effective single-sheet model used for the parameter sweeps shows agreement to within $5\%$ at $L=4$ and $2.2\%$ at $L=6$. The cost of the saving is that each sheet idles for two of every three sub-rounds, and the finite-size crossing estimate of the circuit-level threshold falls from $1.13\pm 0.08\%$ to $0.86\pm 0.06\%$: a factor of $1.3$, that is a $24\%$ relative reduction, or $0.27$ percentage points. Sweeping the idle-to-gate noise ratio r over $0,1,2,4$ gives estimates decreasing monotonically from $1.13\%$ to $0.71\%$. The dual X-basis memory gives $0.78\pm 0.05\%$, overlapping the Z value. All values are finite-size crossings at $L=4,6,8$ from the full FCC circuit, not asymptotic thresholds, and the quoted spreads are dominated by finite-size drift rather than statistical error. Each sheet decomposes exactly into L independent rotated 2D toric codes (Proposition 1), so the memory is the toric code’s and no encoding-rate advantage is claimed; at $d=4$, the rate equals the rotated toric code’s. In the simulated noise model, where no channel couples two sheets, the sheets fail independently. Sub-threshold suppression survives the sharing at $\mathsf{\Lambda }(4\to 6)=12.3\pm 1.1$ and $\mathsf{\Lambda }(6\to 8)=5.6\pm 1.2$ at $p={10}^{-3}$, on a memory carrying 24 to 48 logical qubits. Block-level failure probabilities are reported alongside, since they grow with the logical count: at $L=6$ and $p={10}^{-3}$, the 36-logical chip loses at least one logical qubit in about one experiment in sixty. The $L=6$ instance, $\left[\right[648,36,6\left]\right]$, needs 864 physical qubits, within the nominal atom count of current neutral-atom processors; no implementability claim is made beyond that count. Full article

This study develops an integrated electromechanical model of a seed-removing device used in a saw-type cotton gin. The modeled machine unit comprises a squirrel-cage induction motor, an elastic-dissipative belt transmission, a seed-removing tube rigidly connected to a ring gear, planet gears mounted on a fixed carrier, and an auger rigidly connected to the sun gear. The equations of motion were derived using Lagrange’s equations of the second kind. The induction motor was represented by the dynamic characteristic proposed by A.E. Levin, which was selected as a reduced-order model that captures the transient electromagnetic torque response during start-up without requiring the additional electrical parameters of a full direct–quadrature (d–q) axis model, while providing a more realistic transient representation than a static torque–speed characteristic. The moments of inertia of the rotating components were identified experimentally by the acceleration method, and the resulting nonlinear ordinary differential equations were solved by a fourth-order Runge-Kutta scheme. The model reproduces the start-up, transient, and steady-state stages and enables the evaluation of angular velocities, torques, angular accelerations, power demand, and rotational irregularity. Experimental validation was performed for the steady-state rotational speeds of the seed-removing tube and auger and for motor power, whereas the reported transient peak torque and angular acceleration were obtained from the numerical simulation. For the 3 kW, 735 rpm induction motor, the rated torque was 38.98 $\mathrm{N}·\mathrm{m}$, whereas the calculated peak starting torque reached 101.63 $\mathrm{N}·\mathrm{m}$, corresponding to a starting-torque ratio of 2.61. The transient process lasted approximately 3.5 s, and the maximum motor angular acceleration reached 2988.6 $\mathrm{rad}/{\mathrm{s}}^2$ at t = 2.25 s. Within the investigated parameter ranges, the OFAT sensitivity analysis showed that the resistance moment of the seed-removing tube and the inertia of the auger exert the strongest influence on rotational irregularity, whereas the inertia and resistance of the planet gears have a comparatively weak effect. A reduction in the effective torsional stiffness of the belt drive from 17.2 to approximately 10.3 $\mathrm{N}·\mathrm{m}$/rad reduced the start-up rotational irregularity of the auger, evaluated over t = 2–4 s, from 0.435 to 0.420 and decreased motor power consumption from about 2.55 to 2.50 kW. The proposed model provides a system-level framework for selecting drive parameters and limiting torsional oscillations in planetary-driven cotton-processing machinery. Full article

During service, conformal load-bearing antennas (CLBAs) are subjected to the coupled effects of aerodynamic and aerothermal loads. The resulting geometric distortion of the array surface, deflection of element pointing, and temperature drift of the material electromagnetic parameters lead to the degradation of radar cross-section (RCS) characteristics. To overcome the limitation of existing scattering models in uniformly describing the aforementioned multi-physics coupling effects, this paper proposes a comprehensive electromechanical–thermal coupled modeling method for the scattering field of CLBAs. This method establishes a complete mapping from flight conditions to the array RCS by incorporating geometric corrections for element-level pointing deflection and bending deformation, material corrections accounting for the temperature-dependent antenna efficiency, and phase corrections induced by aerodynamic displacements. Verification using a 9 × 9 cylindrical conformal array shows that, within a scanning range of ±30°, the model calculations agree with HFSS full-wave simulations with an absolute error of less than 1 dB, and the broadside RCS is reduced by 14.97 dB compared with that of a planar array. Furthermore, a BP neural network surrogate model is constructed to achieve accurate prediction of the array physical fields. Analyses across the Mach regime of 0.20–0.65 Ma indicate that structural deformation is the dominant cause of RCS distortion, with the trailing-edge array experiencing a rapid nonlinear increase in RCS peak increment, reaching up to 7 dB at 0.65 Ma. The proposed model provides an effective theoretical tool for the rapid evaluation of stealth performance for conformal antennas operating in complex environments. Full article

A high-aperture-efficiency Fabry–Perot (FP) antenna with broadband out-of-band radar cross-section (RCS) reduction enabled by a partially reflective absorptive frequency-selective surface (PRAFSS) is proposed. Unlike conventional absorptive frequency-selective surfaces that emphasize high in-band transmission, the PRAFSS is designed specifically for FP cavity operation. It provides controlled reflection and transmission near 1 GHz to sustain cavity resonance, while providing broadband absorption at higher frequencies for out-of-band scattering suppression. A prototype is designed, fabricated, and measured. The measured −10 dB impedance bandwidth is 965–1009 MHz (4.46%), and the measured gain reaches approximately 13.0 dBi near 985 MHz, with a gain enhancement greater than 2.2 dB relative to the reference antenna. Using the measured gain and the exact 416 mm × 416 mm physical aperture, the measured gain-based aperture efficiency is approximately 85.1%. Full-wave far-field simulations predict a continuous 10 dB monostatic RCS reduction band of 3.05–6.47 GHz. The finite-range measurement shows a consistent reference-normalized backscattering reduction band of 3.15–6.32 GHz. The results demonstrate a cavity-oriented design strategy in which high aperture utilization in the antenna operating band and broadband out-of-band scattering suppression are implemented by different electromagnetic responses of the same PRAFSS. Full article

LLM-based conversational agents generate fluent responses but remain limited in adapting their supportive style to individual personality and emotional needs. We present a Detect–Regulate–Evaluate (D–R–E) architecture that performs turn-by-turn Big Five detection and applies Zurich Model-inspired behavioural regulation, orchestrated with PROMISE. The novelty is this integrated, reproducible detection→regulation→evaluation architecture for controlled simulation—not a claim of clinical effectiveness. In a GPT-4 simulation comparing personality-adapted (regulated) and standard (non-adaptive) assistants, scored by a structured LLM-based evaluator with author review retained as an internal audit, the main finding is the mixed-personality comparison with identical user text (input replay; outcome-scoring protocol not independently archived in full): dimension-level accuracy fell to 58.1%, yet three cross-family LLM judges retained a Personality Needs advantage, locating the extreme-profile result as an upper bound. Under extreme boundary-condition profiles, strict all-five-trait recovery was 21/60 (35.0%) and dimension-level accuracy was 83.3%; regulation adherence was 100%, and the Personality Needs Yes rate rose from 8.3% (5/60) to 100% (60/60) as an upper-bound selective-enhancement check. A two-rater verify-and-revise audit on an $n=66$ overlap showed substantial agreement on detection labels (mean linear $\kappa =0.731$) but covered detection labels only; outcome rubrics remain LLM-rated. Safety behaviours (crisis handling, unsafe advice, hallucination, escalation) were not evaluated. The Zurich mapping is implemented as a design choice rather than validated as psychological theory; the system is not evaluated as a therapeutic or clinical intervention. Full article

This study numerically investigated the applicability of the Forchheimer and Izbash equations for describing non-Darcian flow in three-dimensional (3D) rough-walled rock fractures. High-precision flow simulations were conducted on 52 synthetic 3D rough-walled fractures with varied apertures and surface roughness, generated from 56 combinations after excluding four cases with surface contact, under different hydraulic gradients. The simulation results captured transverse flow, back flow, and non-uniform streamlines on horizontal planes, which cannot be observed in conventional two-dimensional (2D) fracture models. The total eddy volume ratio negatively correlated with the aperture and positively correlated with roughness, and the 3D fractures exhibited a much smaller eddy volume ratio than the 2D fractures. Both equations provided excellent fits to the simulated data, with coefficients of determination R² > 0.996. Notably, the Forchheimer coefficients showed strong and monotonic correlations with the aperture and roughness and are therefore predictable and characterizable, whereas the Izbash coefficients showed weak and non-monotonic correlations. Since non-negligible prediction errors occurred at low Reynolds numbers when the equations were fitted over the entire flow range, a piecewise fitting strategy was proposed, which reduced the prediction errors of both equations to within 5% across the full range and quantitatively divided the flow into the Darcy, weak inertial, and strong inertial regimes. Double-parameter equations relating the critical Reynolds numbers to the aperture and roughness were then established, allowing the flow regime to be predicted directly from the geometric parameters without additional simulation. These findings facilitate reasonable flow regime division and accurate full-range flow characterization in rock fractures. Full article

Background: Endovascular exclusion of popliteal artery aneurysms (PAAs) with long covered stent-grafts is valuable for patients unfit for open surgery but is undermined by late stent thrombosis, even in fully scaffolded segments without kinking, a failure best clarified by computational fluid dynamics (CFD), which requires anatomically accurate 3D models—difficult to obtain in the mobile knee. Methods: In this prospective, single-centre study, consecutive patients undergoing endovascular PAA repair over 24 months (≥20 patients) underwent CT angiography in three knee positions (full extension, 45° and 90° flexion). Every treated limb was included, with limb as the unit of analysis. Images undergo a geometric pipeline: segmentation in 3D Slicer, then refinement in MeshLab, Meshmixer and VMTK. Meshes are converted to hexahedral volumes (ANSA Cadense) and simulated under pulsatile flow (ANSYS Fluent). Primary endpoints are time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI) and relative residence time (RRT) over the stented segment, plus the surface proportion meeting thrombogenic criteria; positions are compared via linear mixed-effects models with limb nested within patient. Results: The protocol reproducibly yields watertight, artefact-free models preserving physiological morphology and supporting TAWSS, OSI and RRT quantification across knee positions. Conclusions: This protocol standardizes generation of CFD-ready popliteal geometries, enabling positional analysis of stent thrombosis. Full article

Microplastics (MPs) in long-distance trains remain undercharacterized despite prolonged exposure of passengers and staff in confined environments. In this study, settled dust was collected from four distinct coach classes on an Indian railway to establish baseline MPs occurrence, morphology, polymer composition, relative load, and exposure-relevant particle intake. Samples were processed via oxidative digestion, density separation, and stereomicroscopy for particle quantification and morphological characterization. Polymer identity was assessed using micro-Raman spectroscopy, and human exposure was evaluated using estimated trip (${EDI}_{Trip}$) and annual (EAI) intake models. MPs were detected in all four sampled coach composites, with coach-level concentrations ranging from 925 to 3755 MPs/g. Among the four sampled coaches, the 1AC (first-class sleeper air-conditioned) coach had the highest measured concentration. Fibers (72%), transparent particles (61%), and polyester dominated, suggesting mixed textile and interior sources. The Relative Load Ratio (RLR) reached 4.06 in 1AC, compared to the lowest-abundance general unreserved coach (GL). Deterministic ${\mathrm{E}\mathrm{D}\mathrm{I}}_{\mathrm{T}\mathrm{r}\mathrm{i}\mathrm{p}}$ ranged from 5.78 to 388.35 particles/trip, with maximum intake observed for toddlers on full-route 1AC journeys. Monte Carlo simulations confirmed intake increases with travel duration and frequency. These findings highlight long-distance railway coaches as overlooked MPs reservoirs, emphasize the need for improved dust control, ventilation management, and lower-shedding interior materials. Full article

The structural integrity of precast concrete composite beams heavily relies on the new-to-old concrete interface. Existing numerical models and traditional analytical methods struggle to capture the complex, multi-variable interfacial degradation mechanisms. This study proposes an integrated framework combining high-fidelity 3D nonlinear finite element (FE) simulations with explainable machine learning (XML). A mixed interface constitutive model, seamlessly coupling surface-based cohesive behavior with residual Coulomb friction, was established and validated to accurately replicate the full-range progressive damage and frictional slip. Using an orthogonal experimental design, a 53-sample database was generated to evaluate key design variables, including material strengths and interfacial roughness. An eXtreme Gradient Boosting (XGBoost)-based surrogate model successfully mapped the nonlinear relationships between these features and core flexural indicators, achieving an R² exceeding 0.965. The SHapley Additive exPlanations (SHAP) framework was subsequently introduced to decode the algorithmic black box, providing transparent traceability of feature importance. Results reveal that cast-in-place concrete strength dominates initial flexural stiffness, whereas tensile reinforcement dictates yield and ultimate capacities. Crucially, interfacial roughness governs the post-peak response, enhancing energy dissipation by over 400%. This data-driven strategy validates that rationally matching material strengths with optimal interfacial friction maximizes the comprehensive flexural potential of composite members. Full article

This study presents a rapid design-and-validation framework incorporating resistance optimization for 3D-printed bridge pier geometries. A full-factorial experimental campaign comprising 16 reduced-scale solid pier sections is first conducted by systematically varying upstream fairing length and downstream fishtail length while maintaining constant maximum transverse width and cross-sectional area. The specimens are fabricated using fused deposition modeling (FDM) 3D printing with polyethylene terephthalate glycol-modified (PETG) material and tested in controlled towing experiments driven by a field-oriented control (FOC) motor, with motor torque signals recorded as a proxy for hydrodynamic resistance. The raw data are processed through steady-state trimming, null-test bias correction, and one-dimensional Kalman filtering, after which a root-mean-square (RMS) resistance metric is computed for each geometry. A key finding from the two-way analysis of variance (ANOVA) analysis reveals that fairing length exerts the dominant influence on resistance, followed by the fairing-fishtail interaction, whereas fishtail length alone plays a secondary role. The experimental ranking identifies S13, combining a short fairing with a long fishtail, as the optimal geometry, achieving a 33.6% reduction in RMS torque relative to the circular baseline. Bootstrap resampling confirms that the low-resistance cluster is a robust geometry family rather than a statistically fragile optimum. Then, independent COMSOL Multiphysics 6.3 (COMSOL) topology optimization and transient flow-field simulations are employed as morphology-level validation tools, with the optimized outline converging toward a streamlined profile qualitatively consistent with the experimental findings. The drag decomposition further indicates that pressure drag constitutes the dominant component, suggesting that shape-induced pressure redistribution is the primary mechanism underlying resistance reduction. The proposed framework thus provides a physically grounded, low-cost intermediate step between computational shape generation and detailed engineering validation for resistance-optimized bridge-pier sections, and it can be readily extended to a broader range of pier cross-sections or other hydraulic structures. Full article

Tunnel lining concrete exposed to groundwater rich in carbonate species can deteriorate under the combined action of CO₂, HCO₃⁻, and CO₃²⁻. An L₉(3³) orthogonal experiment evaluated the effects of the water-to-binder ratio (FA), slag powder content (FB), and composite formulation level (FC) on concrete resistance to carbonate attack using compressive strength, the rebound value, and carbonation depth as response indicators. During 56 d of simulated CO₂–HCO₃⁻ corrosion, compressive strength generally increased initially and then decreased, whereas the rebound value increased or fluctuated upward because of its sensitivity to surface carbonation. Carbonation depth increased continuously, with fitted carbonation coefficients ranging from 0.236 to 0.417 $\mathrm{mm}/\sqrt{\mathrm{d}}$. Range analysis showed the largest response ranges of compressive strength and carbonation depth for FA, while FC produced relatively larger ranges for the rebound value and carbonation depth at later ages. However, none of the three factors reached statistical significance in analysis of variance (ANOVA) at α = 0.10. Among the nine directly tested mixtures, mixture 3# (A1B3C3) exhibited the most favorable mean response over the full corrosion period, with a mean compressive strength, rebound value, and carbonation depth of 67.4 MPa, 40.7, and 1.37 mm, respectively. Averaging the responses at each factor level over the full corrosion period identified A1 and C3 as the most consistently favorable levels for FA and FC, respectively. Differences among the FB levels were comparatively small; B1 was retained as the balanced level because it exhibited the highest mean compressive strength and rebound value, together with a lower mean carbonation depth. The results provide separate mixture level and factor level evidence for evaluating tunnel lining concrete under carbonate corrosion conditions. Full article

The adoption of carbon fiber-reinforced polymer (CFRP) composites in aircraft structures has significantly reduced structural weight but compromised mid-frequency sound insulation performance. To address this issue, this study develops a lightweight membrane-type acoustic metamaterial design targeting the 2000 Hz sound insulation valley of aeronautical composite panels. An impedance tube test platform was constructed to characterize the full-frequency sound transmission loss (STL) of CFRP specimens, and a structure–acoustic coupled finite element model incorporating equivalent boundary stiffness was established and validated. The mean absolute error (MAE) of the simulation above 1000 Hz is within 3 dB, with a maximum single-point error of 3.9 dB, satisfying the engineering accuracy requirement for most frequency points. Under the constraint of no more than 5% weight increase, a forward-design methodology for membrane metamaterials is proposed based on modal analysis and local resonance tuning. Experimental results show that the proposed design achieves a 16.5 dB STL enhancement at 2000 Hz with a 2.29% weight increase under normal incidence conditions at the unit-cell level, exceeding the 3 dB technical requirement. This work provides a practical engineering reference for lightweight mid-frequency noise control in aircraft cabin applications. Full article

The spectral line density of an optical frequency comb (OFC) generated in a microring resonator is fixed by the free spectral range (FSR), and hence by the resonator size: the dense combs required for spectroscopy, optical clocks, and high-capacity communications conventionally demand centimeter-scale cavities, in direct conflict with photonic integration. Here, we propose a route around this FSR–footprint trade-off using topological ring resonators (TRRs) built on a silicon valley photonic crystal (VPC) platform. Evanescently coupling two identical TRRs, an optical analog of quantum tunneling in a double-well potential, deterministically splits each resonance into a doublet of supermodes (Rabi splitting), doubling the spectral line density within a fixed bandwidth while the parallel two-ring layout occupies orders of magnitude less chip area than a single conventional ring of equivalent effective FSR. A coupled-mode-theory model quantitatively captures the splitting observed in full-wave 3D finite-difference time-domain (FDTD) simulations, and the topological protection of the valley edge states preserves the doublet against lattice disorder; a fabrication-tolerance analysis shows the splitting varies by only a few percent for nanometer-scale gap errors. Nonlinear simulations based on the coupled nonlinear Schrödinger equation indicate that the doubled supermode grid translates directly into a denser comb, increasing the generated line count from 48 to 122 under identical Kerr-only pumping conditions. An explicit nonlinear-loss budget, including two-photon and free-carrier absorption, bounds these results for silicon at 1550 nm and identifies mid-infrared silicon and TPA-free platforms such as silicon nitride as physically realistic implementations. This design study establishes coupled topological resonators as a compact, disorder-tolerant architecture for high-density comb generation, which can potentially be experimentally demonstrated. Full article