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In recent years, the demand and requirement for renewable energy have significantly increased due to concerns regarding energy security and the climate crisis. This has led to a significant focus on wind power generation. As the deployment of wind turbines continues to rise, there is a growing need to assess their lifespan and improve their stability. Access to accurate load data is crucial for enhancing safety and conducting remaining life assessments of wind turbines. However, maintaining and ensuring the reliability of measurement systems for long-term load data accumulation, stability assessments, and residual life evaluations can be challenging. As a result, numerous studies have been conducted on load prediction for wind turbines. However, existing load prediction models based on 10 min statistical data cannot adequately capture the short-term load variations experienced by wind turbines. Therefore, it is essential to develop models capable of predicting load with a high temporal resolution to enhance reliability, especially with the increasing scale and development of floating wind turbines. In this paper, we developed prediction models with a 50 Hz resolution for the bending strain at the tower bottom of offshore wind turbines by combining SCADA data and acceleration data using machine learning techniques and analyzed the results. The load prediction models demonstrated high accuracy, with a mean absolute percentage error below 4%. [ABSTRACT FROM AUTHOR]

We report Chern insulating phases emerging from a single layer of layered chalcogenide CrSiTe3, a transition metal trichacogenides (TMTC) material, in the presence of charge doping. Due to strong hybridization with Te p orbitals, the spin-orbit coupling effect opens a finite band gap, leading to a nontrivial topology of the Cr eg conduction band manifold with higher Chern numbers. Our calculations show that quantum anomalous Hall effects can be realized by adding one electron in a formula unit cell of Cr2Si2Te6, equivalent to electron doping by 2.36 × 1014 cm−2 carrier density. Furthermore, the doping-induced anomalous Hall conductivity can be controlled by an external magnetic field via spin-orientation-dependent tuning of the spin-orbit coupling. In addition, we find distinct quantum anomalous Hall phases employing tight-binding model analysis, suggesting that CrSiTe3 can be a fascinating platform to realize Chern insulating systems with higher Chern numbers. [ABSTRACT FROM AUTHOR]

Kagome metal–organic frameworks (MOFs) are considered a new class of materials that can host two-dimensional (2D) magnetism and correlated electron phenomena such as superconductivity and quantum anomalous Hall effect. Despite its potential for spintronics applications and others, the systematic understanding between the electronic structure and magnetic properties of kagome MOFs is still missing. This work determines the crystal structure, magnetic ground states, and anisotropy of a series of transition metal atoms and ligands from first-principles calculations. We reveal that the coexistence of covalent and ionic bonding characters of 3d orbitals is a distinctive feature of the 2D kagome MOFs. Furthermore, we demonstrate that the occupancies of active bands near the Fermi level are responsible for different superexchange mechanisms: the partially filled bands with empty for V and Co MOFs lead to antiferromagnetic ordering, and the partially filled bands with full for Mn, Fe, and Co MOFs lead to ferromagnetic ordering between transition metal ions. It is pointed out that the bands are formed through dpπ-hybridization between the transition metal dyz, dzx and ligand pz orbitals in the square planar coordination of metal atoms. This mechanism provides valuable insights into understanding magnetism in 2D kagome MOFs. [ABSTRACT FROM AUTHOR]

Predicting the risk of cardiovascular disease is the key to primary prevention. Machine learning has attracted attention in analyzing increasingly large, complex healthcare data. We assessed discrimination and calibration of pre-existing cardiovascular risk prediction models and developed machine learning-based prediction algorithms. This study included 222,998 Korean adults aged 40–79 years, naïve to lipid-lowering therapy, had no history of cardiovascular disease. Pre-existing models showed moderate to good discrimination in predicting future cardiovascular events (C-statistics 0.70–0.80). Pooled cohort equation (PCE) specifically showed C-statistics of 0.738. Among other machine learning models such as logistic regression, treebag, random forest, and adaboost, the neural network model showed the greatest C-statistic (0.751), which was significantly higher than that for PCE. It also showed improved agreement between the predicted risk and observed outcomes (Hosmer–Lemeshow χ2 = 86.1, P < 0.001) than PCE for whites did (Hosmer–Lemeshow χ2 = 171.1, P < 0.001). Similar improvements were observed for Framingham risk score, systematic coronary risk evaluation, and QRISK3. This study demonstrated that machine learning-based algorithms could improve performance in cardiovascular risk prediction over contemporary cardiovascular risk models in statin-naïve healthy Korean adults without cardiovascular disease. The model can be easily adopted for risk assessment and clinical decision making. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine the feasibility of the Smart dynamometer as a rehabilitation exercise device in a daily care by comparing with the existing medical devices. We used and analyzed clinical and measurement data of breast cancer survivors who have used Smart dynamometer during their rehabilitation after breast cancer surgery. The Smart dynamometer was compared with the two existing devices of Takei dynamometer and surface electromyography (sEMG) that were used in routine care, respectively. Three key components of the rehabilitation exercise devices were analyzed to validate the feasibility of the Smart dynamometer: grip strength, reaction time, and grip endurance time. Pearson's correlation analysis was performed to compare the statistical significance between the devices. The data of 12 and 15 female breast cancer patients were analyzed for comparing the Smart dynamometer with Takei dynamometer and sEMG, respectively. There was a very weak correlation between the maximum values from the Takei and the Smart dynamometers in the affected and non-affected arms of breast cancer patients (r = 0.5321, 0.4733). Comparisons of 3 features between the Smart dynamometer and sEMG showed that there were strong positive correlations for both reaction time and endurance time in the affected and non-affected arms (r > 0.9). The feasibility of the Smart dynamometer for the possible use in a daily rehabilitation exercise was partially verified. Moreover, since the Smart dynamometer was highly correlated with time-related variables, it was important and significant to measure both grip strength and time-related information. [ABSTRACT FROM AUTHOR]

We investigate the electronic and magnetic structures of two-dimensional transition metal tri-chalcogenide CrSiTe3 and CrGeTe3 materials by carrying out first-principles calculations. The single-layer CrSiTe3 and CrGeTe3 are found to be a ferromagnetic insulator, where the presence of the strong dpσ-hybridization of Cr eg-Te p plays a crucial role for the ferromagnetic coupling between Cr ions. We observe that the bandgaps and the interlayer magnetic order vary notably depending on the magnitude of on-site Coulomb interaction U for Cr d electrons. The bandgaps are formed between the Cr eg conduction bands and the Te p valence bands for both CrSiTe3 and CrGeTe3 in the majority-spin channel. The dominant Te p antibonding character in the valence bands just below the Fermi level is related to the decrease of the bandgap for the increase of U. We elucidate the energy band diagram, which may serve to understand the electronic and magnetic properties of the ABX3-type transition metal tri-chalcogenides in general. [ABSTRACT FROM AUTHOR]

Sintering additives for BiZnNbO (BZN) ceramic have been studied to facilitate use of BZN as a material for embedded decoupling capacitors in high-density multilayered low-temperature cofired ceramic (LTCC) modules for mobile communication systems and three-dimensional printing modules. Among the additives studied, a CuO/VO mixture was the most promising for cofiring BZN ceramic with a commercial low-permittivity ( ε) LTCC sheet (MLS-22; NEG Co., Japan) and Ag electrode. BZN codoped with 0.5 wt.% CuO/VO was successfully densified at 860°C by reactive liquid-phase sintering, and the resulting dielectric properties were acceptable for use of the CuO/VO-codoped BZN for embedded capacitors in LTCC modules. The room-temperature permittivity ( ε) of the CuO/VO-codoped BZN was 148 at 1 MHz, and the capacitance thermal stability was ±1.3% within the temperature range of −55°C to 125°C. The physical and chemical compatibilities of the CuO/VO-codoped BZN with heterogeneous layers (low- ε LTCC layer and Ag electrode layer) in LTCC modules were also examined. A cofiring test of the doped BZN ceramic with MLS-22 LTCC sheet revealed that thickness control of the two heterogeneous layers was a key factor to avoid crack formation during cofiring. The optimum thickness ratio of doped BZN to MLS-22 layers was less than 0.25:1. A chemical compatibility test revealed no severe reaction between the doped BZN/MLS-22 and doped BZN/Ag layers. [ABSTRACT FROM AUTHOR]

We have grown SrTiO3 thin films by rf-sputtering and studied its photoluminescence (PL) property after postannealing treatments. While the as-grown film does not show any PL signal, visible frequency PL emissions are induced by high temperature (T>550 °C) annealing. When subsequent low-T (50 °C) and long term (>8 months) annealing was made, the PL-spectra evolved into another pattern in which four distinct luminescence peaks appear simultaneously at λ=1.8, 2.2, 2.7, and 3.1 eV. We propose that these remarkable room temperature PL effects are due to both metastable and energetically stabilized defect states formed inside the band gap. [ABSTRACT FROM AUTHOR]

Based on first-principles density-functional theory (DFT) calculations, we report that the transition-metal bis-dithiolene, M3C12S12 (M = Mn and Fe), complexes can be a two-dimensional (2D) ferromagnetic insulator with nontrivial Chern number. Among various synthetic pathways leading to metal bis-dithiolenes, the simplest choice of ligand, Benzene-hexathiol, connecting metal cations to form a Kagome lattice is studied following the experimental report of time-reversal symmetric isostructural compound Ni3C12S12. We show sulfur and carbon-based ligands play the key role in making the complexes topologically nontrivial. An unusual topological quantum phase transition induced by the on-site Coulomb interaction brings a nearly flat band with a nonzero Chern number as the highest occupied band. With this analysis we explain the electronic structure of the class M3C12S12 and predict the existence of nearly flat band with nonzero Chern number and it can be a fractional Chern insulator candidate with carrier doping. [ABSTRACT FROM AUTHOR]