Search Results (451)

Solid oxide fuel cells (SOFCs) are a promising near-zero-emission propulsion source for Northern Sea Route (NSR) vessels, but their yttria-stabilized zirconia (YSZ) electrolyte and Ni-cermet anode are susceptible to thermomechanical degradation under repetitive start–stop thermal cycling. We develop a hierarchical Bayesian competing-risk framework built on a dual degradation model that decomposes area-specific resistance (ASR) growth into cycle-induced fatigue and time-dependent electrochemical aging and apply it across six NSR duty-cycle scenarios spanning f = 1–27 cycles/month. Posterior inference via the No-U-Turn Sampler (NUTS) yields 17 estimated parameters meeting standard convergence criteria (R̂ ≤ 1.01, ESS_bulk ≥ 479, zero divergent transitions). The analysis identifies a failure-mode transition at f ≈ 3–6 cycles/month: high-frequency routes are crack-dominated (S1a: 10/15 cells fail by crack within the 600-cycle window with 5/15 right-censored), whereas low-frequency routes are ASR-dominated (S3b: 100% ASR). Global sensitivity analysis indicates the time-dependent rate coefficient k_time as the primary remaining-useful-life driver (S_T = 0.37–0.46). Cycle-based maintenance thresholds span 160 cycles (S3b) to ≥600 cycles (S2b), bracketed by S1a (270 cycles, 10.0 months, crack-dominant) and S3a (480 cycles, 160 months, transition regime); qualitative consistency with published experimental data supports physical plausibility. Full article

Background/Objectives: Genetic testing in Human Epidermal Growth Factor Receptor 2-negative (HER2−) metastatic breast cancer (mBC) is necessary to enable optimal treatment choices including poly(ADP-ribose)polymerase inhibitors (PARPis). The present study evaluated the implementation of genetic testing in a real-world setting to reveal and subsequently allow targeting of potential inadequacies and risk factors for low testing frequency. Methods: We performed a retrospective analysis including HER2− mBC patients treated at a single academic center starting from 10 April 2019 (date of European Medicines Agency (EMA) approval of Olaparib for germline breast cancer gene mutant (gBRCAm) HER2− mBC) to 7 September 2021. The primary objective of the study was to evaluate the rate of HER2− mBC patients that were recommended to undergo genetic testing by the multidisciplinary tumor board (MTB). The secondary objective was to identify factors that were associated with a higher likelihood of having undergone genetic testing. Results: In total, 47.6% (109 of 229) of HER2− mBC patients had been recommended to undergo genetic testing by the MTB. Of these informed patients, 89.0% (97 of 109) underwent genetic testing, of which 11.6% (11 of 95) had a germline BRCA mutation (gBRCAmut) and were eligible for PARPi treatment. In multivariate analysis, younger age (p-value: 0.0007), hormone receptor positive (HR+)/HER2− subtype (p-value < 0.0001) and positive family history for breast and ovarian cancer (p-value: 0.0001) were significantly associated with the performance of genetic counseling. Conclusions: The present study demonstrated low genetic counseling rates of HER2− mBC patients, especially in individuals without specific risk factors for hereditary breast cancer. Informed patients showed a high willingness to undergo genetic testing. Genetic testing revealed targetable mutations in over 10% of tested patients. Full article

Background: Birth asphyxia is a leading cause of neonatal mortality. More than half of these deaths are due to low-quality care. Objectives: To describe the frequency, sequence, timing, and duration of interventions after birth and newborn outcomes. Methods: This prospective observational study in rural Tanzania included newborns ≥28 weeks gestation. Trained research assistants observed and recorded all deliveries and resuscitations 24 h a day, 7 days a week, logging interventions in real time using the Liveborn Observation app. Results: Of 2564 newborns born, 2431 (94.9%) were enrolled in the study. Macerated stillbirth (n = 52), newborns with no parental consent (n = 67) or incomplete Liveborn data (n = 14) were excluded. Additionally, 2193/2431 (90.2%) newborns did not receive bag-mask ventilation (BMV), and 1755/2431 (72.2%) started breathing before 30 s from birth at median (quartiles) 6 (3, 13) s, 438/2431 (18.0%) started breathing beyond 30 s at 49 (38, 67) s. Moreover, 238/2431 (9.8%) received BMV at 82 (54, 120) s after birth, 1/3 within the first min. Finally, 159/238 (66.8%) were suctioned for 26 (17, 40) s. The first suction sequence was initiated at 44 (24, 78) s after birth. In 24/238 (10.1%) newborns, BMV continued for more than 10 min, with an increased risk of dying within 24 h (RR = 4.26, 95% CI; 1.3–10.0, p = 0.016) and seven days (RR = 8.14, 95% CI; 3.5–17.6, p < 0.001) compared to those ventilated for less than 10 min. Conclusions: Almost 10% of newborns received BMV at birth, but only one-third were ventilated within the first recommended minute. Excessive use of suctioning likely delayed the start of BMV, and prolonged ventilation beyond 10 min was associated with higher mortality. Full article

With the rapid development of electric Vertical Take-Off and Landing (eVTOL) aircraft for urban air mobility, ensuring safe operation in complex low-altitude environments remains a major challenge. In particular, interactions with non-cooperative airspace users introduce uncertainties that are difficult to fully handle with current autonomous systems. To better understand these risks, a Monte Carlo simulation framework is developed to model random encounters between an eVTOL and uncontrolled unmanned aerial vehicles. The results show a relatively low collision probability of approximately 0.18%. However, a large proportion of encounters fall within an intermediate separation range of 100–200 m, indicating a high-frequency conflict region that still requires continuous monitoring and decision-making. Based on these observations, Fault Tree Analysis (FTA) is further applied to evaluate system-level safety under different operational architectures, incorporating revised assumptions on human reliability and system interactions. The results suggest that the inclusion of human pilots can contribute to reducing the probability of catastrophic failure compared with fully autonomous configurations, particularly in uncertain and non-cooperative scenarios. These findings suggest that, although full autonomy is a long-term goal, current intelligent systems still face limitations in dealing with uncertain and non-cooperative scenarios in urban airspace. In such situations, human operators can provide additional situational awareness and flexible decision-making, improving overall system robustness. Overall, a phased transition toward full autonomy, starting from a human–machine collaborative approach, appears to be a practical path to ensure safety, support certification, and enable the deployment of eVTOL systems. Full article

Background: Preparing patients for oncological therapy requires the elimination of foci of infection in accordance with Multinational Association of Supportive Care in Cancer/International Society of Oral Oncology (MASCC/ISOO) guidelines. Complications of dental caries, such as abscesses, can lead to sepsis. In Poland, the pre-oncologic dental treatment of patients with hematopoietic disorders does not yet meet MASCC/ISOO standards; however, an inventory of the current status of dental care for these patients is ongoing. The aim of this study was to investigate the frequency of dental caries and to define the local caries risk factors in adult patients prior to Hematopoietic Stem Cell Transplantation (HSCT) as a part of anticancer therapy. Additionally, the time available for dental treatment was assessed. Methods: A total of 302 patients were examined. Dental status was determined based on the number of decayed, missing and filled teeth and on treatment needs. Local caries risk factors, such as poor dietary habits, insufficient oral hygiene, and symptoms of reduced salivary flow, were examined. The diet was assessed using a questionnaire; tooth cleaning efficiency was assessed as a percentage of dental surfaces with biofilm. Symptoms of reduced salivary flow were determined by subjective and clinical signs of low salivary secretion. Results: Active (progressive) dental caries was diagnosed in 85.2% of patients. Insufficient oral hygiene had been found in 71.52% of those examined. Symptoms of hyposalivation were present in 85% of patients. In 31% of cases, time available for dental treatment prior to HSCT was too short. Conclusions: Tooth decay, the presence of caries risk factors, and insufficient time for oral treatment in patients submitted to HSCT represent a serious clinical problem. There is a clear need to establish comprehensive oral health protocols aimed at providing patients with appropriate, urgent dental care. Furthermore, coordination between oncologists and dentists in Poland must be improved. Currently patients are rarely referred to a dentist before starting anticancer therapy; those scheduled to hematopoietic stem cell transplantation, usually see a dentist too late. Full article

The residual sub-millimeter metal particles in gas-insulated metal enclosed switchgear (GIS) and gas-insulated transmission lines (GILs) are significant factors that trigger insulation failures. During actual operation, these particles not only endure the action of alternating electric fields but also are continuously stimulated by mechanical vibrations. Current research mostly focuses on the behavior of millimeter-sized particles under a single physical field, lacking in-depth understanding of the jumping characteristics of sub-millimeter-scale particles under the combined action of alternating electric fields and mechanical vibrations. This paper has built a collaborative action test platform and constructed a spherical-bowl-shaped electrode defect model. It systematically studied the jumping behavior, motion evolution, and local discharge characteristics of 20-mesh and 40-mesh irregular aluminum particles under the combined action of different voltages (0–7 kV) and mechanical vibrations (amplitude 0.01–0.1 mm, frequency 10–100 Hz). The results show that mechanical vibrations provide initial kinetic energy for the particles, significantly reducing the threshold for jumping, and are the key initiating factor in the collaborative action; in the low-voltage stage, vibration dominates the jumping behavior, while in the high-voltage stage, the electric field dominates the motion evolution; and under dual stimulation, the jumping area of the particles is wider and the motion forms are more diverse (such as flying-flying motion, vertical state, pile-up excitation, etc.), and the starting voltage of discharge is significantly reduced, the discharge repetition rate increases with the increase in vibration intensity and voltage, and is closely related to the particle size. This paper reveals the uniqueness of particle motion and discharge under the collaborative action, providing a theoretical basis for the assessment of multi-physical field states and fault prediction of GIS/GIL. Full article

With the increasing penetration of wind and solar renewable energy into modern power systems, grids exhibit ‘dual-high’ (i.e., a high proportion of both renewable energy and power electronic devices) and ‘dual-low’ (i.e., low equivalent rotational inertia and low short-circuit capacity) structural characteristics. This leads to critical challenges, notably insufficient short-circuit capacity, declining voltage and frequency stability, and weakened system damping. To address the stability requirements of new power systems, this study proposes and systematically investigates a variable-speed synchronous condenser based on AC excitation technology. The research encompasses the operational principles, starting mechanisms, and control strategies of the device, with a particular focus on analyzing its stator-flux-oriented vector control method and active–reactive power decoupling regulation mechanism. By independently adjusting the frequency, amplitude, and phase of the AC excitation on the rotor side, the system achieves a millisecond-level dynamic reactive power response, rapid frequency support, and self-starting capability without the need for external starting devices. To validate the effectiveness of the theoretical analysis and engineering practicality, this study presents grid-connected operational tests using a 3600 kVar engineering prototype at a wind farm. The test results demonstrate that the variable-speed synchronous condenser performs excellently in speed regulation, dynamic reactive power response, and primary frequency modulation. It effectively provides short-circuit capacity, enhances system damping, and significantly improves the voltage and frequency stability of power grids with high penetration of renewable energy. This study offers innovative technical pathways and empirical evidence for constructing a stability support system that meets the developmental needs of new power systems. It holds significant theoretical value and engineering guidance for promoting the smooth transition of power grids from synchronous machine-dominated to power electronics-based architectures. Full article

Rising energy costs and strict CO₂ traceability regulations create demand for monitoring energy and CO₂ emissions in manufacturing. This paper presents a framework for modelling component-wise energy models with deployable accuracy. In many factories, power metres log data at a sampling rate of 1–2 Hz, so short start-up peaks of components are underestimated. Manufacturers want to exploit this information to support operational decisions, such as peak shaving and optimising energy contract costs. To enable data-driven decisions with limited measurement infrastructure, energy models must extrapolate component behaviour from sparse data. The framework is based on power measurements in accordance with ISO 14955-3, ensuring that the load characteristics required for subsequent modelling are known. The measurements are then segmented, and regressions are fitted for each segment. As a case study considering the mist extractors of two different machine tools, the proposed segmentation achieved determination coefficients (R²) of up to 0.94 in the complex ramp-up phase. The resulting models are compact, interpretable, and suited for energy monitoring on edge devices. The contribution is a reproducible framework for delivering peak-aware, component-level energy models from low-frequency industrial power metre data. Full article

To address the coupled challenges of renewable power volatility, high operating cost, and electrolyzer degradation in grid-connected wind–PV hydrogen production systems, this paper proposes a hierarchical day-ahead scheduling strategy under time-of-use (TOU) electricity prices. The upper layer performs price-responsive economic dispatch to coordinate renewable utilization, battery operation, grid transactions, and aggregate hydrogen-production power with the objective of minimizing lifecycle operating cost. The lower layer introduces a health-aware non-uniform rotation mechanism to allocate the aggregate power command among electrolyzer units, thereby reducing fluctuation exposure and balancing lifetime consumption across the array. Practical constraints, including multi-state electrolyzer operation, unit-commitment logic, battery state-of-charge dynamics, hydrogen storage limits, and system power balance, are explicitly considered. A case study of a wind–PV hydrogen production project in Northern China shows that the proposed strategy shifts electricity purchases to valley-price periods and promotes electricity export during peak-price periods. Compared with the benchmark strategy, hydrogen production during low wind–PV generation periods increases from 342,000 to 381,000 Nm³, the share of fluctuating operating time decreases from 62.5% to 12.5%, and the average daily start–stop frequency declines from 8.0 to 4.8. Consequently, the degradation penalty is reduced by about 40%, and lifecycle operating cost decreases by 27.3%. Full article

The automotive augmented reality head-up display (AR-HUD) system projects critical driving information directly into the driver’s line of sight, enhancing driving safety, user experience, and navigation efficiency. However, due to the intrinsic asymmetry of vehicle windshields, existing optical configurations are difficult to use as effective design starting points. The asymmetric transmission region of the windshield causes the AR-HUD optical system to deviate significantly from the YOZ plane, increasing the complexity of system design and optimization. To address these challenges, this paper proposes an automated design method for automotive AR-HUD optical systems. Given the windshield geometry and system design specifications, a normal-guided iterative construction method is first employed to generate a high-performance initial optical structure with low distortion. Subsequently, differentiable ray tracing combined with optimization algorithms is employed to further improve system performance. Based on the proposed method, an AR-HUD optical system with a 130 mm × 50 mm eye-box and a 13° × 4° field of view was designed. The design results indicate that the maximum optical distortion is 0.51%. At five sampled eye positions within the eye-box, the MTF exceeds 0.5 at the spatial frequency of 6 lp/mm, and the dynamic distortion remains below 5.36′. Finally, a complete experimental prototype was established, and the experimental results verified the feasibility and effectiveness of the proposed automated design method. Full article

This study addresses the low operational efficiency and high energy storage cost of wind–solar hybrid energy storage systems due to the strong volatility and intermittency of wind and photovoltaic power. Instead, the authors propose a dual-layer optimization model based on convolutional neural network–long short-term memory–attention mechanism (CNN-LSTM-AM) forecasting. First, a CNN-LSTM-AM forecasting model is constructed based on convolutional neural networks and long short-term memory networks. Then, the model is applied to wind and solar power forecasting to dynamically optimize the output power ratio of renewable sources and batteries based on predicted power, thereby reducing the start–stop frequency of compressed air energy storage (CAES) and improving operational efficiency. For lower-layer optimization, a weight evaluation model based on AHP is constructed and subsequently used to optimize the capacity configuration of the hybrid energy storage system to achieve overall system optimality. Case studies indicate that after upper-layer optimization, the number of CAES start–stop cycles decreases from 25 to 17, and further declines to 14 after optimization of the lower-layer capacity configuration, while the energy storage cost is reduced by 5.43% and the curtailment rate decreases by 0.15%. This validates the effectiveness of the proposed model in improving the economic performance and stability of renewable hybrid energy storage systems. Full article

This paper presents a novel dual-mode memristor-based ring oscillator designed for energy-efficient, wireless biomedical signal conditioning systems. The proposed architecture leverages a compact DTMOS memristor emulator, consisting of only two transistors and one capacitor, to replace the conventional NMOS pull-down devices in a three-stage PMOS ring oscillator. This integration enables two distinct operating modes within a single compact core: a fixed-frequency mode for stable clock generation and carrier synthesis, and a programmable chirp mode for frequency-modulated signal generation. The fixed-frequency mode achieves continuous tuning from 3.142 GHz to 4.017 GHz via varactor control, with an ultra-low power consumption of only 111 µW at 4.017 GHz. The chirp mode generates linear frequency sweeps starting from 0.8 GHz, with the sweep range independently controllable through the state capacitor value and the pulse width of the control signal (SW_Chirp). Designed in a standard 0.18 µm CMOS process, the oscillator exhibits a low phase noise of −87.82 dBc/Hz at a 1 MHz offset for the three-stage configuration, improving to −94.3 dBc/Hz for the five-stage design. The overall frequency coverage spans 0.8–4.017 GHz, representing a 133.6% fractional range. The calculated figure of merit (FoM) is −169.45 dBc/Hz. Experimental validation using a discrete CD4007 prototype confirms the oscillation principle, while comprehensive simulations demonstrate robust performance across process corners and temperature variations. With its zero-static-power memristor core, wide tunability, and dual-mode reconfigurability, the proposed oscillator is ideally suited for multi-standard wireless biomedical applications, including implantable telemetry, neural stimulation, ultra-wideband (UWB) transmitters, and non-contact vital sign monitoring. Full article

Accurate reproduction of deterministic gusts in wind tunnels is essential for studying unsteady aerodynamics and aeroelastic response in aircraft, uninhabited aerial vehicles, and wind turbines. This work presents the design, experimental characterization, and numerical modelling of a low-speed gust generator based on oscillating vanes, capable of producing high-amplitude gusts in strongly unsteady flow regimes. Cross-flow hot-wire measurements are combined with time-accurate computational fluid dynamics simulations to analyze gust formation and propagation. Classical ‘1-cos’ gusts are shown to exhibit pronounced negative velocity peaks associated with start–stop vortex shedding. A modified vane motion protocol is proposed that significantly reduces the negative peak factor while preserving a substantial gust ratio over a wide range of reduced frequencies. Measurements are supplemented with computational fluid dynamics (CFD) simulations. The CFD study included 2D and 3D URANS as well as higher fidelity DES simulations. Flow-field analysis reveals that secondary variations in gust angle arise from nonlinear interactions between vortices shed by adjacent vanes and are influenced by wind-tunnel confinement. The results provide physical insight into the limitations of oscillating-vane gust generators and guidance for the design of high-fidelity gust-generation systems. Full article

Colloidal PbSe quantum dots are promising candidates as saturable absorbers for ultrafast fiber lasers, but their performance is often limited by surface-related defects and chemical instability, leading to aggregation under optical pumping. In this study, we present a freestanding PbSe/PbS quantum dot-polystyrene composite saturable absorber film, with PbS overcoating on PbSe to enhance surface passivation and oxidation resistance. The composite exhibits a saturation intensity of 5.76 kW·cm⁻², a modulation depth of 33%, and an optical damage threshold of 13.6 mJ·cm⁻². When integrated into a bidirectionally pumped erbium-doped fiber laser in the anomalous-dispersion regime, the device demonstrates self-starting soliton mode locking at an ultralow pump threshold of 6 mW, generating 1.06 ps pulses with a radio-frequency signal-to-noise ratio of approximately 65 dB. The spectra remain stable over an 8-month period, showing excellent environmental and operational durability. These findings confirm that PbSe/PbS quantum dots in a polymer matrix offer a robust, low-threshold saturable absorber platform for ultrafast fiber lasers. Full article

Efficient internalization of chemical entities into cells across the plasma membrane barrier is crucial for most biomedical applications. Among the physical factors that can enhance the delivery of active substances, the electric field plays an important role. In our experiments, electron paramagnetic resonance (EPR) spectroscopy was used to monitor the process of electric field-assisted endocytosis of a spin probe TEMPO (2,2,6,6-tetramethylpiperidine 1-oxyl) into yeast cells (Saccharomyces cerevisiae). It was found that a long train of low-amplitude voltage pulses (0.5–20 V_pp) can affect the uptake of nitroxide by cells. In addition to the pulse amplitude, the key parameters influencing the internalization process are: frequency, duty cycle and time of exposure to the electric field. The sodium chloride content in the medium in which the cells are suspended is also of great importance. For higher salt concentrations, starting from 3.5% w/w, a significant decrease in cell survival was observed after exposure to an electrical stimulus, which also translated into a decreasing spin probe uptake. Our studies confirm the usefulness of EPR spectroscopy in the study of internalization processes and show that the parameters of electric field pulses and the environmental salinity have a significant impact on the course of electroendocytosis. Full article