Search Results (212)

The performance of ultra-high-performance fiber-reinforced concrete (UHPFRC) under repeated low-velocity impacts, particularly in the context of nominally fixed boundaries relevant to protective structures, remains underexplored. In practice, protective components made of UHPFRC, such as falling object barriers and vehicle parapet systems, are exposed to foreseeable repeated low-velocity impacts; however, no standardized design provisions or residual capacity assessment methods exist for such members, particularly under nominally fixed boundary conditions. This study presents an integrated experimental and numerical investigation into the progressive damage and failure mechanisms of a 50 mm thick UHPFRC plate with nominally fixed (bolted clamping) boundaries subjected to sequential low-velocity impacts. A custom drop-weight test setup was used for impact loading, while high-speed 3D digital image correlation (3D-DIC) captured the quarter-field transient kinematics, which were reconstructed back to the full field based on verified test symmetry and complemented by traditional accelerometer and strain gauge measurements. The results demonstrate a distinct progression of damage. Initial low-energy impacts (196 J/drop) caused negligible damage, highlighting the material’s tolerance. Subsequent higher-energy impacts induced a transition from flexural cracking to a combined flexural–punching shear failure mode. The model-assisted nominal secant stiffness indicator decreased by 5.3% over the repeated 0.5 m drops and fell by 50.8% after the 2.0 m drop, quantifying the transition in structural behavior. A finite element (FE) model, incorporating the concrete damaged plasticity (CDP) model with an energy-based degradation law, was developed and evaluated against the experimental data. This model replicated both the quantitative dynamic responses (with model-to-test ratios of peak acceleration, strain, and displacement between 0.86 and 1.30 across three energy levels) and the qualitative damage evolution. The model thus evaluated enabled a model-derived reconstruction of the critical impact force–time history, revealing the evolution of structural degradation toward the exhaustion of the plate’s global flexural resistance and the transition to a punching shear mechanism. Full article

Civilian communication systems often fail during armed conflicts, political unrest, and large-scale Internet disruptions—precisely when reliable communication is most needed. This paper presents HERMES, a resilient hybrid communication architecture that integrates HTTP/IP networking, Bluetooth Low Energy (BLE) mesh communication, and Delay-Tolerant Networking (DTN) within a unified adaptive routing framework. Unlike conventional approaches that treat alternative transports as backup solutions, HERMES dynamically selects the most efficient transport path based on current network conditions using a transport-aware forwarding policy whose cost function combines round-trip time, transport preference, and observed link risk. The architecture is built on distributed microservices that support topology discovery, shortest-path routing, and fault-tolerant message delivery. Reliability is enhanced through acknowledgments, bounded retransmissions, duplicate suppression, and graceful degradation mechanisms, while end-to-end authenticated encryption (Noise XX with a Double Ratchet) ensures secure communication across transport changes. A prototype implementation developed in C# on .NET 9 was evaluated on a five-node testbed, and a custom Network Simulator 3 (NS-3) module was used to extend the evaluation to networks of up to 500 nodes, under multiple failure scenarios, including node crashes, network partitioning, and complete Internet outages. Experimental results show that HERMES maintains perfect or near-perfect delivery in static topologies, including during a complete Internet blackout that disables IP-only messaging. Compared with the published Delay-Tolerant Networking protocols Epidemic and PRoPHET at one hundred nodes, HERMES exceeds their delivery ratio in static and failure scenarios and remains within 0.06 of them under pedestrian mobility during blackout, while transmitting roughly 35× fewer bytes– and about 21× fewer even relative to the more bandwidth-efficient MaxProp baseline. Under coordinated drop attacks by adversarial relays, HERMES degrades gracefully where flooding-based baselines collapse. This approach demonstrates that resilient civilian communication can be effectively achieved through metric-driven adaptive multi-transport routing, making it suitable for disaster recovery, contested environments, and connectivity-limited regions. Full article

Modern manufacturing is currently shifting toward highly flexible, high-mix, and low-volume production cycles, requiring small and medium-sized enterprises (SMEs) to adopt reconfigurable automation to remain competitive. However, the adoption of such technologies is often slowed down by the high cost and rigidity of commercial solutions, which typically rely on proprietary toolchains and necessitate specialized expert knowledge for reconfiguration. This study proposes a methodological framework for a modular robotic cell based on an open-architecture approach using ROS2 middleware, designed to be maintained by personnel without deep robotics expertise. The methodology emphasizes the replacement of fixed mechanical fixtures with an AI-driven perception pipeline, utilizing YOLO-based image segmentation to enable the autonomous localization of heterogeneous components. A rigorous tolerance chain analysis defines the design requirements of custom 3D-printed self-aligning fingertips, providing a mathematical and mechanical basis for ensuring assembly feasibility under tight geometric constraints. By adopting a node-based software topology, the framework facilitates rapid task reconfiguration and hardware interoperability. Experimental validation in an industrial-like environment confirms that this integrated approach provides a scalable pathway with the potential to improve cost-effectiveness in high-mix low-volume production scenarios to overcome manual production bottlenecks through intelligent, reconfigurable automation. Full article

Additive manufacturing, particularly Fused Deposition Modeling (FDM), has emerged as a promising technology for construction applications due to its ability to fabricate complex geometries, optimize material usage, and enable customized designs. This study investigates the effects of different infill patterns and densities on the compressive behavior of polylactic acid (PLA) specimens to identify suitable configurations for industrial applications. Cubic specimens (50 mm × 50 mm × 50 mm) were designed in SolidWorks, sliced with PrusaSlicer using various conventional and bio-inspired infill patterns, and manufactured using a Prusa i3 MK3S printer. Compression tests were conducted to evaluate stiffness, strength, toughness, and deformation capacity. In addition, finite element method (FEM) simulations were carried out to predict the mechanical response under compressive loading. The results showed that the honeycomb infill pattern provided the best overall performance, combining moderate stiffness with high deformation capacity, reaching strains of approximately 40% before failure, and exhibiting superior energy absorption. Among the tested configurations, an infill density of 20% offered the best balance between mechanical performance, material consumption, and printing time. These findings demonstrate that honeycomb-based structures with moderate infill densities are promising candidates for lightweight engineering applications requiring high energy dissipation and damage tolerance. Full article

Background/Objectives: Compression therapy serves as first-line conservative management for low-flow vascular malformations and Klippel–Trénaunay syndrome (KTS). However, ready-made garments are frequently ill-fitting for patients with limb overgrowth, asymmetry, deformity, or heterogeneous body habitus. Custom-made compression elastic garments offer an individualized solution, yet systematic data across diverse clinical entities remain scarce. This study evaluated objective and subjective outcomes of custom-made compression garments across vascular anomalies and edematous disorders in a multi-institutional real-world setting. Methods: A retrospective observational case series was conducted between May 2023 and September 2025 at four institutions: a tertiary medical center, a pediatric specialty hospital, a corporate hospital, and a corporate clinic. Patients who received custom-made compression elastic garments for vascular anomalies, edema, varicose veins, post-traumatic or post-burn venous stasis, or postoperative conditions were included. Objective outcome (limb circumference change) and subjective outcome (patient satisfaction) were analyzed. Results: A total of 191 patients who received custom-made garments were described (117 females, 61.3%; 74 males, 38.7%; mean age 36.3 years; median 22 years; range 1–96 years). The age distribution was bimodal, with 91 patients (47.6%) aged 0–19 years and 50 patients (26.2%) aged ≥70 years. The tertiary center and pediatric hospital treated vascular anomaly patients exclusively (n = 102), while the corporate hospital and clinic primarily served adult and elderly edematous disorder patients (n = 88; one additional vascular anomaly case was managed at the corporate hospital). Quantitative paired outcome analysis was feasible in the subgroups with complete paired data: 20 vascular anomaly patients (objective outcome) and 20 edematous disorder patients (subjective outcome). In the vascular anomaly subgroup (n = 20), the affected limb showed a significantly greater circumference reduction at the ankle’s narrowest point (median −2 mm, IQR −4.2 to 0.0) compared with the unaffected contralateral limb (median +0.5 mm, IQR −0.2 to +1.0; Wilcoxon signed-rank test T = 4; p < 0.001; effect size r = 0.83). In the edematous disorder subgroup (n = 20), patient satisfaction scores improved significantly from a median of 3 (IQR 2.0–4.0) to 4 (IQR 3.0–6.0) after garment use (Wilcoxon signed-rank test T = 0; p < 0.001; effect size r = 0.83). Representative cases illustrated pediatric vascular anomaly (Case A, vascular malformation; Case C, KTS) and adult edematous disorder (Case B, chronic lower limb edema) presentations and outcomes. Conclusions: Custom-made compression elastic garments were feasible and well tolerated across a broad real-world spectrum of vascular anomalies and edematous disorders. In the analyzed subgroups, a measurable reduction in affected-limb circumference was observed in pediatric vascular anomaly patients, and patient satisfaction improved in adult and elderly edematous disorder patients. Because each subgroup was evaluated with only one outcome domain and no head-to-head comparison of measures was performed, these findings should be regarded as hypothesis-generating. We propose that outcome measures may need to be tailored to disease background and age, a hypothesis that warrants testing in prospective studies capturing both objective and subjective endpoints across all patient groups. Full article

Lead-free polymer composites containing high-atomic-number fillers are promising alternatives to conventional lead shielding for nuclear medicine applications. In this study, Bi₂O₃-, WO₃-, and hybrid Bi₂O₃/WO₃ nanoparticle-filled epoxy resin composites were fabricated and evaluated for attenuation of the 140 keV photons emitted by technetium-99m (Tc-99m). The synthesized Bi₂O₃ and WO₃ nanoparticles exhibited hydrodynamic diameters of 638.2 ± 11.3 and 404.2 ± 3.2 nm, respectively, with polydispersity indices below 0.30 and zeta potentials of −33.73 ± 0.63 and −32.47 ± 0.75 mV, indicating acceptable dispersion characteristics and colloidal stability. SEM–EDX confirmed successful incorporation of Bi- and W-containing phases into the epoxy matrix, while the XRD and FTIR analyses verified retention of the crystalline metal oxide phases and the principal chemical structure of the cured epoxy network. Tensile testing revealed a composition-dependent strength–ductility relationship, with the Bi₂O₃-filled composite exhibiting the highest tensile strength among the developed formulations and the hybrid composite showing the greatest elongation at break. XCOM and Phy-X/PSD simulations demonstrated that increasing high-Z filler content enhanced the mass and linear attenuation coefficients and reduced the half-value layer, tenth-value layer, and mean free path. Experimental shielding performance was evaluated using Hp(10) measurements with optically stimulated luminescence dosimeters positioned on an anthropomorphic thorax phantom under a fixed Tc-99m exposure geometry. The transmitted dose decreased with increasing filler loading, and nanoparticle-filled formulations generally outperformed the corresponding conventional-particle composites. The hybrid 75:25 Bi₂O₃/WO₃ NP composite exhibited the lowest mean Hp(10) value of 0.016 µSv, corresponding to a 50% reduction relative to the lead reference under the investigated geometry. The combined structural, mechanical, computational, and dosimetric results demonstrate that hybrid filler design enables simultaneous optimization of attenuation efficiency and mechanical tolerance. These findings identify the Bi-rich hybrid epoxy composite as a promising lead-free material for customized shielding components, including vial holders, syringe-shield housings, protective panels, and workstation accessories used during Tc-99m handling in nuclear medicine. Full article

Barbecue (Moo Kratha) restaurants are prevalent in Chiang Mai City, Thailand. However, their PM_2.5-bound polycyclic aromatic hydrocarbon (PAH) emissions, compounded by the region’s severe seasonal smoke haze, remain poorly characterized. This study investigated the chemical composition and carcinogenic risk of PM_2.5-bound PAHs in this present environment. Ten PM_2.5 samples were collected from ten charcoal Moo Kratha restaurants during peak evening hours in February 2026 (early dry season) using a portable air sampler operated as a fixed-location (area) sampler positioned at the customer dining table (2 L min⁻¹, 180 min) on quartz fiber filters, and the 16 US EPA priority PAHs were analyzed by GC-MS. Carcinogenic risk was assessed using benzo[a]pyrene toxicity equivalent (TEQ_BaP) concentrations and incremental lifetime cancer risk (ILCR) for adult and child customers (diners) via the inhalation pathway. The mean concentrations of PM_2.5 and total PAHs were 87.64 µg m⁻³ and 132.74 ng m⁻³, respectively, with carcinogenic PAHs contributing 52.3%; the mean TEQBaP of 15.34 ng m⁻³ provides an internal index of the carcinogenic potency of the PAH mixture. The mean inhalation ILCR for a frequent diner was 2.82 × 10⁻⁵ for adults and 2.12 × 10⁻⁵ for children, rising to 6.16 × 10⁻⁵ and 4.62 × 10⁻⁵, respectively, at the most contaminated site; even an occasional (monthly) diner exceeded the 10⁻⁶ negligible threshold. These findings indicate that charcoal Moo Kratha restaurants are distinct, persistent sources of carcinogenic PAHs that place diners within the upper part of the tolerable cancer-risk range; worker exposure is expected to be higher but was not quantified here, underlining the need for ventilation and occupational-health strategies. Full article

Terrestrial and amphibious plants frequently encounter severe oxygen deficiency in waterlogged environments. While the impacts of nutrient and water availability on root development are well documented, how underground oxygen status drives the spatial configuration of root systems remains poorly understood. In the present study, we used a custom hydroponic system to impose three dissolved oxygen treatments corresponding to 5%, 50%, and 100% air saturation and investigated the spatial rooting responses of Alternanthera philoxeroides. Our results demonstrated that low oxygen levels significantly restricted overall plant growth, reducing total root number, total length, and biomass allocation to the root system. However, under hypoxic conditions, plants actively altered their spatial rooting patterns by producing more roots at the top solution layers and fewer roots in the bottom layers, a spatial stratification that was more pronounced under 5% than 50% air saturation. Specifically, low dissolved oxygen availability was associated with an asymmetrical distribution of root traits, with greater root number, length, surface area, volume, and fork number on nodes closer to the solution surface than on deeper nodes. Conversely, well-oxygenated conditions (100% air saturation) promoted a more uniform root trait distribution across all vertical layers. These findings reveal a dissolved oxygen-related spatial rooting pattern, demonstrating that A. philoxeroides actively modulates its root architectural traits as a primary strategy to maximize oxygen acquisition in hypoxic environments, rather than relying solely on physiological tolerance. Full article

Railway logistics terminals are crucial nodes in the national logistics system. Prior to the market-oriented reform of railway logistics, the warehousing operations at these stations primarily focused on temporary storage services before and after shipment, making it difficult to provide customers with integrated warehousing and transportation logistics services. With the advancement of railway marketization reforms, railway logistics terminals have gradually begun to offer socialized warehousing services, acquiring the capability to provide integrated warehousing and transportation services. In response to market development needs and the requirements for green development in railway logistics, an optimization design model for obtaining green railway logistics solutions is established, considering factors such as carbon emission costs, integrated warehousing and transportation logistics service costs, fuzzy constraints on logistics network capability, transportation time windows and the customer’s risk tolerance level. The model takes minimizing carbon emission costs and railway logistics service costs as dual-objective functions and uses a standardized weighting method to convert the dual-objective functions into a single-objective function for solving using triangular fuzzy numbers to characterize the ability constraints of network nodes, making the model more realistic. This model aims to minimize these costs and assesses the impact of factors such as changes in delivery time limits, shipment quantity, shipment batches, the superposition of multiple goods batches and customer preferences on the railway logistics solution for different scenarios. Research indicates that reasonably designing delivery time limits and aligning shipment times with railway transportation time windows can effectively reduce carbon emissions and logistics costs, and the risk tolerance level has a significant impact on the reliability of railway logistics solutions. Full article

Existing PLC security solutions face a fundamental conflict between stringent real-time requirements and robust protection: traditional IT security mechanisms (e.g., encryption, authentication) introduce unacceptable latency, while software-based redundancy schemes operate at millisecond scale and remain vulnerable to common-cause failures. To bridge this gap, this study proposes MimicPLC v1.0, a dynamic defense mechanism based on a heterogeneous multi-core architecture that integrates threat perception, dynamic fault tolerance, and rapid recovery within a single chip, thereby reconciling real-time determinism with proactive security in industrial control systems. The architecture integrates three distinct CPU cores (MIPS, ARM, and RISC-V) within a single system-on-chip (ESC0830), coordinated by a dedicated hardware-based mimic scheduling subsystem. This subsystem performs real-time, loosely coupled, transaction-level consistency checks on the AHB-Lite bus operations of the heterogeneous processors, achieving nanosecond-scale arbitration latency for threat detection. We evaluate the proposed design using an industrial-strength testbed, incorporating a custom development board and the Synopsys Verdi simulation environment, under critical attack scenarios including Denial-of-Service (DoS), replay, code injection, and parameter overwrite attacks. The system maintains continuous operation through adaptive redundancy, demonstrating attack perception within 73 clock cycles and leveraging instruction-set asymmetry for effective threat containment. Rigorous validation, including 100 consecutive parameter override attacks, confirms a 100% interception rate within our tested attack scenarios, with zero false positives observed. The design complies with the IEC 61131-3 real-time standard, exhibiting a worst-case recovery duration of 9.3 ms and a 95% confidence interval for recovery latency of [4.0354, 4.0363] ms. This work pioneers a paradigm of rapid-detection endogenous security with nanosecond-scale arbitration for next-generation industrial control systems. Full article

This study presents the prototype manufacturing and experimental validation of a 1 kW, 750 rpm three-phase outer-rotor permanent magnet-assisted synchronous reluctance motor (PMASynRM) designed for in-wheel electric vehicle applications. The work is based on a previously reported electromagnetic design and finite element method (FEM)-based optimization framework and focuses on the physical implementation and experimental evaluation of the proposed motor. The prototype was manufactured using M470-50A grade electrical steel laminations and arc-shaped N35H NdFeB permanent magnets embedded within a three-barrier transversally laminated anisotropic rotor structure. A custom-built experimental test bench consisting of the PMASynRM prototype, a PMSM generator with a controllable resistive load bank, a torque transducer, and a precision power analyzer was developed to evaluate motor performance under controlled operating conditions. Experimental investigations were carried out under four steady-state load conditions—no-load, 13 Nm, 20 Nm, and 26 Nm—as well as during dynamic stepwise load transitions representative of in-wheel drive operation. The measured results show good agreement with FEM predictions, with a maximum efficiency of 90.55% at nominal load and efficiency values remaining above 87% under overload conditions up to 26 Nm. Minor differences between simulation and experimental results are mainly associated with mechanical friction, bearing losses, and manufacturing tolerances that are not fully captured in the numerical model. The study provides experimental validation of an outer-rotor PMASynRM prototype under multi-load steady-state and dynamic operating conditions for in-wheel electric vehicle applications. Full article

We propose a dual-aperture, simultaneous-polarization super-resolution imaging system that combines a total internal reflection optical architecture with a digital micromirror device (DMD) for broadband, high-resolution imaging. The system captures multiple polarization states simultaneously with a single detector and offers a compact, lightweight design. Using reflective Wassermann–Wolf differential equations and Seidel aberration theory, we establish astigmatism-correction boundary conditions and apply iterative optimization to jointly correct spherical aberration, coma, astigmatism, and distortion. Because distortion critically affects super-resolution reconstruction by causing mirror–pixel misregistration, we further introduce a custom merit function to tightly constrain chief-ray positions for each sub-aperture and field point on intermediate and final image planes, effectively suppressing distortion. The final design achieves F/2.5, grid distortion below ±0.5%, and near-diffraction-limited performance in all polarization channels. Tolerance analysis of the four sub-apertures confirms that imaging requirements are satisfied, demonstrating robust high-resolution polarization imaging across multiple polarization states. Full article

Background: Obstructive sleep apnea syndrome (OSAS) is a prevalent sleep-related breathing disorder associated with significant systemic complications and reduced quality of life. Mandibular advancement devices (MADs) represent an established alternative therapy for patients who cannot tolerate continuous positive airway pressure (CPAP). However, concerns remain regarding their potential effects on temporomandibular disorders (TMD). Materials and Methods: This retrospective exploratory study analyzed clinical records of 26 patients (mean age 55.4 ± 5.8 years) with polysomnography-confirmed OSAS and baseline TMD-related symptoms treated with a custom-made monobloc MAD. Clinical parameters were evaluated at baseline (T0) and after approximately 6 months of therapy (T1). Outcomes included apnea–hypopnea index (AHI), Epworth Sleepiness Scale (ESS), Fonseca Anamnestic Index, and health-related quality of life assessed using the SF-36 questionnaire. Repeated measures ANOVA and linear regression analyses were performed. Results: After six months of MAD therapy, a significant reduction in AHI was observed (30 ± 13.76 vs. 10.87 ± 3.9; p < 0.00001). Daytime sleepiness significantly decreased (ESS: 9.31 ± 3.53 vs. 3.38 ± 1.77; p < 0.00001). TMD symptom severity also decreased significantly according to the Fonseca Index (33.85 ± 17.74 vs. 10.00 ± 8.94; p < 0.00001). Quality of life scores improved significantly (SF-36: 41.15 ± 9.52 vs. 65.38 ± 5.82; p < 0.00001). Linear regression analysis showed no significant association between changes in AHI and changes in TMD symptoms, ESS scores, or quality of life. Conclusions: Within the limitations of this retrospective study, MAD therapy was not associated with symptom aggravation of temporomandibular disorders in patients with pre-existing TMD symptoms. Significant improvements in respiratory parameters, daytime sleepiness, and quality of life were observed after six months of therapy. Full article

Multi-agent systems constitute a well-known paradigm to develop complex systems thanks to their ability to process dynamic situations. One of the mechanisms used to ensure dynamic responses is reorganization. It allows agents to dynamically adjust their roles and interactions in response to changes in the environment. Although reorganization improves system flexibility and fault tolerance, its impact on performance efficiency remains poorly explored. This paper presents an empirical study that investigates the effect of reorganization on MAS efficiency by defining and applying a set of customized performance metrics based on the ISO/IEC 25010 standard. The proposed metrics are evaluated based on two versions of RoboCup soccer simulation: one with reorganization mechanisms and another without. Testing the two versions across different scenarios shows that reorganization introduces significant costs, particularly in terms of memory usage (more than double), but contributes to a more balanced distribution of execution time and better collective agent behavior. These results provide valuable insights for the development of efficient multi-agent applications. Full article

Objective: Rapid vertical manoeuvres and intermittent vibration in autonomous electric vertical take-off and landing (eVTOL) aircraft can provoke pronounced psychological anxiety in passengers. To address this, we propose a closed-loop adaptive system that integrates an in-ear wearable sensor with dynamic regulation of the cabin microenvironment, enabling real-time monitoring of each passenger’s autonomic state and delivering individualised mitigation through a continuous sense–analyse–intervene–feedback loop. Methods: The system is built around a pair of custom in-ear modules that integrate dual-wavelength photoplethysmography (PPG; 525 nm green and 940 nm infrared), galvanic skin response (GSR), and a six-axis inertial measurement unit (IMU) sampled at 200 Hz. To suppress the 20–80 Hz vibration generated by the distributed electric propulsion system, a compliant silicone damping sleeve attenuates high-frequency components at the hardware level, while a Kalman filter fuses the IMU and PPG streams and an adaptive notch filter removes residual rotor harmonics. The pipeline raises the heart-rate-variability (HRV) signal-to-noise ratio (SNR) to 24.1 dB, with a Pearson correlation of 0.96 against a medical-grade chest strap. A hybrid CNN–LSTM network—two convolutional layers (32 filters each) followed by two LSTM layers (128 hidden units)—predicts impending anxiety from HRV time-domain features (RMSSD, pNN50) and frequency-domain features (LF/HF ratio), triggering intervention 8.2 s in advance on average. According to the predicted anxiety level (mild/moderate/severe), a fuzzy controller modulates transcutaneous auricular vagus nerve stimulation (1–5 mA), the binaural-beat frequency (4–8 Hz, theta band), and the cabin lighting colour temperature (2700–6500 K) in real time. The intervention parameters are continuously refined by SPSA-based stochastic optimisation of the HRV recovery rate (step size 0.01; updated every 30 s). Results: In a randomised controlled experiment conducted in a simulated flight environment (N = 50; aged 22–45 years; 1:1 sex ratio), the active group reached physiological recovery in 52.3 s on average, compared with 98.6 s for the sham-controlled group—a 47% reduction (Cohen’s d = 1.24, p < 0.001). User acceptance reached 94%. Conclusions: The proposed in-ear platform enables closed-loop adaptive regulation of anxiety in the eVTOL cabin and overcomes the limitations of conventional passive mitigation strategies. By combining vibration-tolerant physiological sensing with multimodal environmental control, the work offers a practical pathway for improving passenger experience in urban air mobility and provides a useful reference for human-factors standards governing autonomous aircraft. Full article