Search Results (140)

The microstructure and mechanical behavior during 100 °C warm rolling of the high-Zn-content Al₈₀Zn₁₄Li₂Mg₂Cu₂ alloy were investigated. The alloy plate was warm-rolled to reductions of 40%, 60%, and 80%. Hardness and tensile strength decreased continuously with increased rolling up to 60%, demonstrating work softening, followed by a slight increase at 80% reduction, indicating work hardening. Systematic characterization revealed that this non-monotonic mechanical response arises from a competition between particle-stimulated nucleation (PSN)-assisted recrystallization and dislocation-driven hardening. The multi-scale intermetallic particles in this alloy play a dual role: coarse Al₅CuLi₃ particles generate high-strain particle deformation zones (PDZs) that serve as potent PSN sites, while fine nano particles pin the recrystallized grain boundaries and restrict their growth. The unusually low PSN activation temperature is attributed to the synergistic effects of the high PDZ storage energy and the progressive subgrain rotation mechanism within the PDZ. The ability to control PSN via micro- and nano-scale intermetallics presents a viable pathway for achieving grain refinement in Al-based alloys and enhancing the machinability of high-Zn-content Al alloys. Full article

Physically unclonable functions (PUFs) are critical security primitives used in authentication and cryptographic key generation. Among these, structural color-based PUFs offer distinct advantages, including fade resistance and the ability to conceal multi-dimensional information. However, current fabrication methods rely heavily on wet processes and laser ablation. Consequently, there is a significant need for flexible PUF labels capable of being produced through a facile and dry process. Here, we present stress-relief modulated photonic crystal PUF labels designed for multi-level dynamic encryption. We achieve random patterning of nanograting-based photonic crystals by leveraging curved pinning edge-induced interruptions and the uncontrolled bulking of the polymeric elastomer due to the uneven adhesion force from the tape. Using artificial intelligence-based deep learning algorithms, we authenticate the labels by extracting structural color, brightness, and saturation, which are determined by the grating periodicity, depth, and orderliness of each pixel. Furthermore, we integrated these photonic crystal patterns with dynamically modulated optical erasure to extend encryption capacity from the spatial to the temporal dimension. We anticipate this approach will enable advanced wearable anti-counterfeiting labels and multi-level digital encryption systems. Full article

Friction braking is the most spread braking system in vehicles, where the morphologies of the disc and the braking pads are essential to ensure that friction reduces rotation speed efficiently. However, modern braking systems are submitted to a complex balance between functionalities: braking ability, resistance to wear, and limited noise emission, i.e., squealing. This article studies the evolution of the morphology of a braking pad in a pin-on-disc configuration to further understand its influence over surface functionalities. Data collected from a pin-on-disc tribometer, and topographies are coupled to perform a multiscale and multiphysics analysis of the braking pad surface. Relevancy of roughness parameters regarding braking ability, surface wear, pad temperature and noise emission is evaluated with a bootstrap-based relevancy analysis. Relevant scales of the pad morphological structures are identified for surface wear (446 µm), braking ability (19.5 µm), pad temperature (2717 and 446 µm) and squealing frequency (1720 and 15.7 µm). Correlations between test bench data and roughness parameters highlighted the role of wear plateaus on the braking pad surface. These plateaus are formed by the damaged surface peaks during braking or by compaction of the third body trapped across the braking pad surface. Full article

The paper presents results of a degradation analysis of polyamide 12 reinforced with carbon fibers used for additive manufacturing of cycloidal gear. Both FEM simulation and a fatigue test indicated the ability of the material to withstand loads during the work of cycloidal transmission. However, a run-to-failure (RTF) test revealed critical failure after 10⁵ cycles, with displacement and damage of the material in the area close to bearing instead of expected areas of teeth being in friction with pins. Acceleration analysis with time synchronous averaging (TSA) confirmed rapid degradation of the material’s strength at the end of the RTF test. It was found that the PA12 cycloidal gear damage was a result of fatigue accelerated by the temperature increase under the cyclic loads that took place during the RTF test. In particular, displacement of 0.2 mm did not appear in the specimens tested at 27 °C even after 10⁵ cycles, while at 140 °C this value was reached almost immediately. At 70 °C and 90 °C, plastic deformation of 0.2 mm was reached after 30,000 and 5000 cycles, respectively. The finding can be used in a predictive maintenance system of such cycloidal transmission with 3D-printed polymer gears. Full article

Rare-earth barium copper oxide (REBCO) high-temperature superconductors, owing to their ability to maintain high critical current density (J_c) under liquid-nitrogen-temperature and high-magnetic-field conditions, are widely regarded as one of the most promising material systems among all superconductors. This review systematically summarizes fabrication strategies for REBCO coated conductors, with a focus on pulsed laser deposition (PLD) for achieving high-quality epitaxial growth with precise composition control. To enhance in-field performance, strategies for introducing artificial pinning centers (APCs) are examined, including rare-earth element doping, substrate surface decoration, and nanoscale secondary phase incorporation. The mechanisms of vortex pinning from different dimensional defects and their synergistic effects are compared. Finally, we suggest potential future directions aimed at further enhancing the superconducting properties. Full article

Periodontal disease (PD) is one of the most widespread oral inflammatory diseases in dogs, with the potential to cause systemic consequences. The purpose of this study was to evaluate the inhibitory potential of yeast-derived postbiotics and probiotic bacterial strains by using a previously developed in vitro biofilm model mimicking canine PD-associated biofilm including five bacterial species: Neisseria zoodegmatis, Corynebacterium canis, Porphyromonas cangingivalis, Peptostreptococcus canis, and Enterococcus faecalis. After we confirmed the presence of these five bacterial species by employing Fluorescence In Situ Hybridization, the biofilm inhibitory and eradication activity of 11 yeast-derived postbiotics and probiotic bacterial strains, as well as selected dual biotic combinations, against the polymicrobial biofilm were determined using a modified version of the Calgary Biofilm Pin Lid Device and the crystal violet method; additionally, hemolytic activity was evaluated using canine red blood cells. The results show that the inhibitory activity against the polymicrobial PD biofilm ranged from 0% to 22.55%, and eradication ability varied between 0% and 17.28%; however, when combined, the biotics achieved a maximum inhibition rate of 71%. Probiotic strain BC-05 exhibited the lowest in vitro hemolytic activity. Overall, based on the results, four yeast-derived postbiotics and one probiotic bacterial strain were selected as promising candidates for further evaluation, aiming at in vivo application. Full article

Anomaly detection of catenary support components (CSCs) is an important component in railway condition monitoring systems. However, because the abnormal features of CSCs loosening are not obvious, and the current CNN models and visual Transformer models have problems such as limited remote modeling capabilities and secondary computational complexity, it is difficult for existing deep learning anomaly detection methods to effectively exert their performance. The state space model (SSM) represented by Mamba is not only good at long-range modeling, but also maintains linear computational complexity. In this paper, using the state space model (SSM), we proposed a new visual state space reconstruction network (VSM-UNet) for the detection of CSC loosening anomalies. First, based on the structure of UNet, a visual state space block (VSS block) is introduced to capture extensive contextual information and multi-scale features, and an asymmetric encoder–decoder structure is constructed through patch merging operations and patch expanding operations. Secondly, the CBAM attention mechanism is introduced between the encoder–decoder structure to enhance the model’s ability to focus on key abnormal features. Finally, a stable abnormality score calculation module is designed using MLP to evaluate the degree of abnormality of components. The experiment shows that the VSM-UNet model, learning strategy and anomaly score calculation method proposed in this article are effective and reasonable, and have certain advantages. Specifically, the proposed method framework can achieve an AUROC of 0.986 and an FPS of 26.56 in the anomaly detection task of looseness on positioning clamp nuts, U-shaped hoop nuts, and cotton pins. Therefore, the method proposed in this article can be effectively applied to the detection of CSCs abnormalities. Full article

Many Time-Sensitive Networking (TSN) workloads require deterministic service across heterogeneous links, yet commodity WLANs are contention-based. Although IEEE 802.11be introduced Restricted Target Wake Time (r-TWT) for prioritized access, its ability to robustly guarantee determinism in mixed deployments with legacy devices remains unverified. We propose a standards-aligned scheme that composes r-TWT, Quiet Time Period (QTP), and an optional Randomized Enqueue (RE) policy. These three mechanisms act in concert to protect the Scheduled Traffic (ST) service period (SP) while minimizing the impact on Non-Scheduled Traffic (NST). To analyze how the proposed scheme impacts existing WLANs, we focus the analysis on how the scheme reshapes the contention period (CP)—where opportunistic capacity is realized—by modeling SP/CP timing with renewal theory and embedding it into an EDCA Markov chain. Simulation results confirm that the proposed scheme protects ST determinism: ST throughput remains pinned to the ceiling with zero observed outage and bounded delay across a wide range of station counts. The proposed scheme minimizes NST throughput degradation in the system-peak throughput range (8–12 stations). Full article

In this paper, we present an extremely compact eleven-state microwave filter with four concentric split-ring resonators (SRRs). Reconfigurability is achieved by switching off either single or multiple SRRs, thereby obtaining different triple-band, dual-band, and single-band configurations from the initial quad-band topology. Switches are placed on the vertical branches of SRRs in order to minimize the additional insertion loss. As switching elements, we first use traditional RF switches—PIN diodes—and then examine the integration of non-volatile RF switches—memristors—into filter design. Memristors’ ability to remember previous electrical states makes them a main building block for designing circuits that are both energy-efficient and adaptive, opening a new era in electronics and artificial intelligence. As RF memristors are not commercially available, PIN diodes are used for experimental filter verification. Afterwards, we compare the filter characteristics realized with PIN diodes and memristors to present capabilities of memristor technology. Memristors require no bias, and their parasitic effects are modeled with low resistance for the ON state and low capacitance for the OFF state. Measured performances of all obtained configurations are in good agreement with the simulations. The filter footprint area is 26 mm × 29 mm on DiClad substrate. Full article

This work presents a high-fidelity simulation of the Peach Bottom turbine trip (PBTT) benchmark using the Virtual Environment for Reactor Applications (VERA), a multiphysics reactor modeling tool developed by the U.S. Department of Energy’s Consortium for Advanced Simulation of Light Water Reactors energy innovation hub. The PBTT benchmark, based on a 1977 transient event at the end of cycle 2 in a General Electric Type-4 boiling water reactor (BWR), is a critical test case for validating core physics models with thermal feedback during rapid reactivity events. VERA was employed to perform end-to-end, pin-resolved simulations from conditions at the beginning of cycle 1 through the turbine-trip transient, incorporating detailed neutron transport, fuel depletion, and subchannel thermal hydraulics. The simulation reproduced key benchmark observables with high accuracy: the peak power excursion occurred at 0.75 s, matching the scram time and closely aligning with the benchmark average of 0.742 s; the simulated maximum power spike was approximately 7600 MW, which is within 3% of the benchmark average of 7400 MW; and void-collapse dynamics were consistent with benchmark expectations. Reactivity predictions during cycles 1 and 2 remained within 1500 pcm and 400 pcm of criticality, respectively. These results confirm VERA’s ability to model complex coupled neutronic and thermal hydraulic behavior in a BWR turbine-trip transient, which will support its use in future studies of modeling dryout, fuel performance, and uncertainty quantification for transients of this type. Full article

This study investigates the friction stir joining of AA6082-T6 aluminum alloy and Noryl GFN2 polymer in a buttstrap configuration, targeting the development of lightweight cylindrical-shaped structures where the polymer provides thermal, chemical, and electrical insulation, while the aluminum ensures mechanical integrity. A parametric analysis was carried out to assess the ability to produce friction stir buttstrap composite panels in a single processing step and assess the resulting tensile and flexural behavior. To that end, travel and rotating speeds ranging from 2150 to 2250 rpm, and 100 to 140 mm/min, respectively, were employed while keeping plunge depth and the tilt angle constant. A total of nine composite joints were successfully produced and subsequently subjected to both tensile and four-point bending tests. The tensile and flexural strength results ranged from 80 to 139 MPa, and 39 to 47 MPa, respectively. Moreover, the microstructural examination revealed that all joints exhibited a defect within the joining region and its size and shape had a significant effect on tensile strength, whereas the flexural strength was less affected with more uniform results. The joining region was also characterized by a decrease in hardness, particularly in the pin-affected region on the aluminum end of the joint, exhibiting a W-shaped pattern. Contrarily, on the polymeric end of the joining region, no significant change in hardness was observed. Full article

The incorporation of multi-material design (MMD) to achieve lightweight vehicles requires Friction Stir Spot Welding (FSSW) to join steel with aluminum, magnesium, or composites. This study investigates the mechanisms, challenges, and performance of FSSW in MMD based on the information available in the literature. It also explores the effect of FSSW tool geometries and design on the spot weld formation and mechanical strength. Larger shoulder and pin diameters increase heat generation during welding. A concave shoulder profile produces a stronger weld compared to flat and convex profiles due to its ability to trap materials and transfer materials to the sheet interface efficiently for the development of a sound weld. Grooves such as Fibonacci and involute, and threads on P-FSSW and R-FSSW tools, also contribute to effective material flow during welding, hence assisting in heat generation. This review also provides recommendations on tool design for FSSW, P-FSSW, and R-FSSW. Full article

This paper proposes a structural silicon heterojunction photosensitive element with a simple form, low manufacturing cost, and efficient performance, which has a high-intensity photoelectric effect and a high frequency range of use. It can be applied as microwave switches to active frequency selective surfaces (AFSSs) to replace PIN diodes. Meanwhile, we explore the crucial role of pentacene/silicon heterojunction in the photoelectric conversion process. It is found that due to the inherent photovoltaic effect and the built-in electric field interaction between the two materials, the insertion loss of the heterojunction formed is reduced to 4.5 dB, which is 2.5 dB lower than that of the high-resistivity silicon wafer. In order to further reduce the insertion loss, the surface of the silicon wafer is etched and then heterojunction is prepared, which can further reduce insertion loss to within 2.5 dB, and the bandwidth difference between the presence and absence of pump excitation exceeds 10 dB extends to 12 GHz, indicating that the light collecting ability of structural silicon significantly enhances its photoelectric effect. The research results demonstrate the potential of using structural silicon heterojunctions in photoelectric devices, providing new technology for high-performance microwave switches and implementing optically controlled FSSs. Full article

Children with onco-hematological diseases require intensive medical treatments that can affect various aspects of their development. In addition to the disease itself, what influences the course of development most are the neurotoxic effects of therapies and frequent hospitalizations, especially if they occur in the first three years of the child’s life. Among these challenges there is the potential for language delay, a condition that can impact their communication abilities and overall development. Background/Objectives: The aim of this study is to examine communicative and linguistic development in a small group of young children diagnosed with different forms of leukemia, rhabdomyosarcoma, and CNS tumors, recruited through the Hematology–Oncology Clinic of the Department of Child and Woman Health (University of Padova). Methods: Child direct (Griffiths III, PinG, PCGO) and parent indirect assessments (PVB, ABAS-II, ASCB) were provided. Results: Griffiths communication subscale scores in children were mainly below average (55.6%), and 44.4% attested at the clinical level in ABAS-II, with the ability to understand being significantly higher than the production of words. However, the two levels of assertiveness–responsiveness obtained balance in 66.7% of cases, and using the Griffiths personal subscale, only 22.2% of children attested below average. Conclusions: Understanding and addressing children’s communication needs is crucial to improve the quality of life of these young patients and foster optimal communicative and linguistic development despite the obstacles they face in order to implement interventions designed specifically for this type of population and their respective families, if necessary. Full article

Background: Increasing evidence shows that HCY plays an important role in stress-induced cognitive dysfunction, and HCY significantly promotes the decline of cognitive function. Stress has been reported to cause elevated HCY in the hippocampus of mice. Cognitive flexibility refers to the ability of individuals to quickly adjust their neurobehavioral strategies to different situations or to solve different tasks. Aims: This study aims to explore the role of HCY in the impairment of cognitive flexibility induced by stress and its possible regulatory mechanism. Methods and Results: First, we examined changes in the protein and mRNA levels of the cognitive flexibility effector molecule, PIN1, during stress in mice. The results show that stress can cause a decline in cognitive flexibility in mice and lead to an increase in PIN1. Moreover, through the use of in vitro experiments, we found that HCY could induce an increase in PIN1 expression in neurons. Further in vivo experiments were used to investigate the effect of VitB on HCY and PIN1 and evaluated the therapeutic effect of VitB on stress-induced impairment of cognitive flexibility. The results show that VitB decreased the levels of HCY in plasma and the hippocampus, alleviated the stress-induced impairment of cognitive flexibility, and reduced the expression of PIN1. Conclusions: These results suggest that the impairment of cognitive flexibility induced by stress can be inhibited by regulating the content of HCY. Collectively, our findings highlight therapeutic strategies aimed at improving HCY treatment for impairments in cognitive flexibility. Full article