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As the core component of the wind turbine generation gearbox, the gear-rotor-bearing transmission system typically operates in harsh environments, inevitably leading to the occurrence of composite faults in the system, which exacerbates system vibration. Therefore, it is necessary to study the vibration characteristics of wind turbine helical gear-rotor-bearing transmission systems with composite faults. This paper uses an improved energy method to calculate the theoretical time-varying mesh stiffness of a helical gear with a root crack failure. On the premise of considering the time-varying meshing stiffness of the faulty helical gear, the gear eccentric fault, and the nonlinear support force of the faulty bearing, a multi-degree-of-freedom helical gear-rotor-bearing transmission system with compound faults was established by using the lumped parameter method. The dynamic model of the system was solved based on the Runge–Kutta method, and the vibration response of the system under healthy conditions, single faults with gear eccentricity, single faults with tooth root cracks, and coupled bearing composite faults were simulated and analyzed. The results show that the simulation results based on KISSsoft software 2018 version verify the effectiveness of the improved energy method; the existence of single faults and composite faults will cause the fault characteristics in the time domain and frequency domain responses. In this paper, the influence of a single fault and a complex fault on the time domain and frequency domain of the system is mainly discovered through the fault study of the helical rotor-bearing system, and the influence of the fault degree on the vibration of the gear motion system is discussed. The greater the degree of the fault, the more vibration of the system occurs; accordingly, when the system is under the coupling of tooth root crack and bearing fault, there is a significant difference compared with the healthy system and the single fault system. The system vibration has obvious time domain and frequency domain signal characteristics, including periodic pulse impacts caused by gear faults and time domain impact caused by bearing. The fault characteristic frequencies can also be found in the frequency domain. In this paper, the fault study of a helical gear of wind turbine generation provides a reference for the theoretical analysis of the vibration characteristics of the helical gear-rotor-bearing system under various fault conditions, lays a solid foundation for the simulation and subsequent diagnosis of the composite fault signal of the system, and provides help for the fault diagnosis of wind turbine gearboxes in the future. [ABSTRACT FROM AUTHOR]

To characterize focal biomechanical alterations in subclinical keratoconus (SKC) using motion-tracking (MT) Brillouin microscopy and evaluate the ability of MT Brillouin metrics to differentiate eyes with SKC from normal control eyes. Prospective cross-sectional study. Thirty eyes from 30 patients were evaluated, including 15 eyes from 15 bilaterally normal patients and 15 eyes with SKC from 15 patients. All patients underwent Scheimpflug tomography and MT Brillouin microscopy using a custom-built device. Mean and minimum MT Brillouin values within the anterior plateau region and anterior 150 μm were generated. Scheimpflug metrics evaluated included inferior–superior (IS) value, maximum keratometry (K max), thinnest corneal thickness, asymmetry indices, Belin/Ambrosio display total deviation, and Ambrosio relational thickness. Receiver operating characteristic (ROC) curves were generated for all Scheimpflug and MT Brillouin metrics evaluated to determine the area under the ROC curve (AUC), sensitivity, and specificity for each variable. Discriminative performance based on AUC, sensitivity, and specificity. No significant differences were found between groups for age, sex, manifest refraction spherical equivalent, corrected distance visual acuity, K max , or KISA% index. Among Scheimpflug metrics, significant differences were found between groups for thinnest corneal thickness (556 μm vs. 522 μm; P < 0.001), IS value (0.29 diopter [D] vs. 1.05 D; P < 0.001), index of vertical asymmetry (IVA; 0.10 vs. 0.19; P < 0.001), and keratoconus index (1.01 vs. 1.05; P < 0.001), and no significant differences were found for any other Scheimpflug metric. Among MT Brillouin metrics, clear differences were found between control eyes and eyes with SKC for mean plateau (5.71 GHz vs. 5.68 GHz; P < 0.0001), minimum plateau (5.69 GHz vs. 5.65 GHz; P < 0.0001), mean anterior 150 μm (5.72 GHz vs. 5.68 GHz; P < 0.0001), and minimum anterior 150 μm (5.70 GHz vs. 5.66 GHz; P < 0.001). All MT Brillouin plateau and anterior 150 μm mean and minimum metrics fully differentiated groups (AUC, 1.0 for each), whereas the best performing Scheimpflug metrics were keratoconus index (AUC, 0.91), IS value (AUC, 0.89), and IVA (AUC, 0.88). Motion-tracking Brillouin microscopy metrics effectively characterize focal corneal biomechanical alterations in eyes with SKC and clearly differentiated these eyes from control eyes, including eyes that were not differentiated accurately using Scheimpflug metrics. Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article. [ABSTRACT FROM AUTHOR]

• Highly graphitized B,N-GQDs were prepared after pyrolysis of 3-APBA at high temperature. • Portable sensor based on B,N-GQD realized colorimetry and portable dual-mode detection. • This detection method has better universality and multi-functional application. In this investigation, blue-emitting graphene quantum dots (B,N-GQDs) were synthesized via a single-step hydrothermal method in an ethanol/water mixture utilizing 3-APBA as the nitrogen and boron sources. These B,N-GQDs showcased a highly graphitized structure, complemented by surface-functionalized boronic acid and amino groups that bestowed upon them remarkable optical attributes and water solubility. Leveraging the interplay of internal filtering and dynamic quenching effects, the sensor demonstrated remarkable selectivity and sensitivity in detecting caffeic acid (CA) within the range of 0–840 μM, achieving a limit of detection (LOD) of 0.63 μM. Moreover, the fluorescent gel microspheres engineered with B,N-GQDs exhibited robust CA sensing capabilities and portability. As such, the application potential of B,N-GQDs expands to encompass drug metabolism monitoring, alongside the assessment of food and environmental safety. [ABSTRACT FROM AUTHOR]

Increase of soil inorganic C (SIC) and total C stocks at 0–60 cm because of organic fertilization. Combination of humic acid and manure as organic fertilizers increases SIC stocks due to direct increase in the concentration of dissolved calcium ions and enzymatic activities and indirectly via decreasing the concentration of dissolved chloride. [Display omitted] • Organic amendments decreased dissolved Cl− content and increased enzyme activity. • Humic acid plus manure increased soil inorganic carbon (SIC) stock at 0–60 cm. • Higher dissolved Ca2+ and β-xylosidase activity directly increased SIC. • Decreased dissolved Cl− indirectly increased SIC through increased soil organic C. Organic amendments are effective in promoting salt leaching, improving availability of nutrients and increasing crop yield in saline soils. However, the effects of the combined application of organic amendments on soil inorganic carbon (SIC) content and its driving mechanisms are unknown. We examined how changes in soil biochemical properties including moisture content, pH value, dissolved ions, soil organic C (SOC), dissolved organic C (DOC), microbial biomass C (MBC), and activities of C- and N-related enzyme due to applying (i) only mineral fertilizers (control; Ctrl) or mineral fertilization in combination with (ii) manure (M); (iii) biofertilizer plus manure (B+M); and (iv) humic acid plus manure (HA+M) modify SIC pool over three years. Organic amendments increased the content of Ca2+ and HCO 3 – ions, but significantly decreased Na+, Cl−, and SO 4 2− at 0–60 cm soil layers compared to Ctrl. Furthermore, the activities of β-glucosidase (BG), Xylanase (BX), Cellobiosidase (CE), and β-1,4-N-Acetyl-glucosaminidase (NAG) increased at 0–40 cm soil. Partial least squares path model manifested that organic amendment directly accumulated SIC content by increasing Ca2+ content and the activities of BX and NAG. Additionally, the decrease of Cl− contents under organic amendments favored the increase of MBC and SOC content, which further increased SIC content. Generally, the effects of HA+M were greater than other fertilization managements, which increased the stocks of SIC and total C at 0–60 cm soils by 27 Mg ha−1 and 47 Mg ha−1, respectively. Furthermore, the effect of organic amendments on SIC content is more pronounced below the first 20 cm. Thus, the application of organic amendments is recommended as an appropriate measure to not only improve soil condition for plant growth and SOC accumulation but also to store C as SIC at deeper depths. [ABSTRACT FROM AUTHOR]

Generally, Graph convolution network (GCN) utilizes the graph convolution operators and the softmax to extract the deep representation and make the prediction, respectively. Although GCN successfully represents the connectivity relationship among the nodes by aggregating the information on the graph, the softmax-based decision layer may result in suboptimal performance in semi-supervised learning with less label support due to ignoring the inner distribution of the graph nodes. Besides, the gradient descent will take thousands of interaction for optimization. To address the referred issues, we propose a novel graph deep model with a non-gradient decision layer for graph mining. Firstly, manifold learning is unified with label local-structure preservation to capture the topological information and make accurate predictions with limited label support. Moreover, it is theoretically proven to have analytical solutions and acts as a non-gradient decision layer in graph convolution networks. Particularly, a joint optimization method is designed for this graph model, which extremely accelerates the convergence of the model. Finally, extensive experiments show that the proposed model has achieved excellent performance compared to the current models. [Display omitted] • Unifying the orthogonal manifold with label local-structure preservation to mine the topological information of the deep embeddings and make more accurate predictions, the novel non-gradient graph decision layer is put forward. • With the assistance of the designed theorems, the non-gradient graph decision layer can be solved with an elegant analytical solution theoretically. • By embedding the analytical solution into the gradient descent, a joint optimization strategy is designed to jointly optimize the graph convolution network and the proposed non-gradient decision layer. [ABSTRACT FROM AUTHOR]

• Excitability of CSH guided waves in steel pipes was studied; • Offset of operating ranges of few-cycle PPM EMATs was identified; • Cause and effects of the offset problem were further analyzed; • Excitability affects the excitation efficiency of CSH guided waves; • It is necessary to pay more attention to the excitability. Circumferential Shear Horizontal (CSH) guided waves provide an effective method for detecting defects like axial cracks and corrosion in pipes. Periodic Permanent Magnet Electromagnetic Acoustic Transducers (PPM EMATs) are typically used to generate CSH guided waves. However, there is an offset problem to which little attention has been paid. The offset problem refers to the offset of the center (position of maximum energy) of the operating region caused by the variation in the peak frequency of the spatial spectra of PPM with 2 or fewer cycles. Furthermore, the excitability of guided waves is one of the factors that needs to be considered when selecting the excitation parameters of EMATs, but there are still some studies that have not sufficiently addressed this issue. In this paper, the offset problem and the excitability of CSH guided waves were investigated. Firstly, by obtaining the operating regions corresponding to PPM with different cycles, the cause and influences of the offset problem were studied. The results show that the offset in the peak frequency of the spatial spectrum of PPM is the fundamental reason causing the offset problem, and it not only leads to incorrect prediction of the excitation efficiency of guided waves but also affects the selection of the excitation parameters of EMATs. Secondly, finite element simulations and experiments were performed to assess the influence of the excitability on the excitation efficiency of the CSH0 and CSH1 modes in pipes. By analyzing the simulation and experimental results of 2-cycle PPM, as well as the simulation results for PPM with 1 to 5 cycles, the impact of the excitability on the CSH1 mode was confirmed from two perspectives. The final conclusion indicates that an accurate prediction of the amplitudes of CSH guided waves with different modes is only possible through a comprehensively consideration of the operating region of EMAT and the excitability of guided waves. [ABSTRACT FROM AUTHOR]

Vapor-liquid equilibrium (VLE) is a family of first-principled thermodynamic models for transcritical multiphase flows, which can accurately capture the phase transitions at high-pressure conditions that are difficult to deal with using other models. However, VLE-based computational fluid dynamics (CFD) simulation is computationally very expensive for multi-component systems, which severely limits its applications to real-world systems. In this work, we developed a new ISAT-VLE method based on the in situ adaptive tabulation (ISAT) method to improve the computational efficiency of VLE-based CFD simulation with reduced memory usage. We developed several ISAT-VLE solvers for both fully conservative (FC) and double flux (DF) schemes. New methods are proposed to delete redundant records in the ISAT-VLE table and the ISAT-VLE method performance is further improved. To improve the convergence of the VLE solvers, a modified initial guess for equilibrium constant is also introduced. Simulations of high-pressure transcritical two-phase temporal mixing layers and shock-droplet interaction were conducted using the ISAT-VLE CFD solvers. The simulation results show that the new method obtains a speed-up factor approximately from 10 to 60 and the ISAT errors can be controlled within 1%. The shock-droplet interaction results show that the DF scheme can achieve a higher speed-up factor than the FC scheme. The two sets of simulations exhibit the phase separation at high-pressure conditions. It was found that even at supercritical pressures with respect to each component, the droplet surface could still be in a subcritical two-phase state, because the mixture critical pressure is often significantly higher than each component and hence triggers phase separation. In addition, a shock wave could partially or completely convert the droplet surface from a subcritical two-phase state to a single-phase state by raising temperature and pressure. • An in situ adaptive tabulation (ISAT) is developed to accelerate the calculation of vapor-liquid equilibrium (VLE) by 10-60 times with <1% error. • The isoenergetic/isobaric-isochoric VLE solvers are accelerated using the ISAT-VLE method for the fully conservative/double flux schemes. • To enhance the speed and precision of the ISAT-VLE method, analytical Jacobian matrices are derived and implemented for three VLE flash solvers. • The initial guess of equilibrium constant K i is improved to enhance the overall stability and robustness of the VLE algorithm. • At high pressures, the subcritical two-phase droplet interface could be partially or completely driven into the single-phase region by shocks. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mixed sowing of Feed rape and Vicia villosa improved soil multifunctionality. • Reducing nitrogen fertilizer with returning green manure will not reduce soil multifunctionality. • Enzyme activities were the main predictors of soil multifunctionality. • Spring wheat yield was significantly correlated with soil multifunctionality. Soil multifunctionality (SMF) and crop production of continuous green manure returning is crucial for sustainable agricultural development. Multiple cropping of green manure after wheat harvest is a typical planting pattern in the Hetao Irrigation District, and maybe substitute nitrogen (N) fertilizer. However, information is scarce about how the green manure affected SMF and crop production under limited nitrogen inputs. A 7-year field experiment was conducted to investigate the effects of green manure types (Feed rape (FR), Vicia villosa (VV), Feed rape, and Vicia villosa mixed sowing (FR + VV)) on soil properties, enzyme activities, SMF, and rotated wheat yield under different N application rates (150 kg N ha−1, N150; no nitrogen, N0). The results showed that FR and FR + VV increased soil active carbon (C) and N fractions by 4.0 %-499.3 % and 11.3 %-147.8 % compared to VV, respectively. Enzyme activities with FR + VV were significantly increased by 13.7 %-82.9 % compared to FR and VV. SMF and CCI (carbon cycling index) were significantly affected by N fertilizer and green manure types, with N0 higher than N150 by two times and FR + VV higher than FR by 1.4–4.3 times and VV by 1.0–6.6 times in 0–20 cm soil layer. Spring wheat yield was significantly affected by N fertilizer and green manure types, with N0 significantly higher than N150 by 5.8 % and FR and FR + VV higher than VV by 8.0 % and 12.5 % under N150, respectively. Partial least squares path model detected that returning of multiple green manure had a significant positive and indirect effect on SMF through enhancing soil enzyme activities, and ultimately contribute to the improvement in wheat yield. In conclusion, the mixed sowing of FR and VV increased soil active C and N fractions and associated enzyme activities, and has the potential to improve the SMF and rotated wheat yield, thereby providing an effective approach to reduce N fertilizer. [ABSTRACT FROM AUTHOR]

The increasing demand for ecosystem services in regional development has presented significant challenges to environmental sustainability. To alleviate environmental pressure, it is crucial to employ the provincial ecological footprint to gauge regional ecological pressure and research the determinants that contribute to reducing environmental pressure. This underscores the significance of examining and addressing the intricate relationships between ecological resources and regional development. While prior studies often focus on national data, provincial ecological footprints have been relatively ignored. Moreover, scant research exists on the influence of variables such as resource rents and industrial structures. This study employs the ecological footprint model to assess the per capita ecological footprint of Chinese provinces from 1990 to 2020, intending to gauge escalating ecological pressures and pinpoint their drivers. We use spatial panel data analysis to investigate the association among economic growth, natural resource rents, industrial structures and ecological footprint. Leveraging spatial weight matrices, we detected provincial footprint spatial autocorrelation and further analyzed it using the spatial Durbin model. Results underscore that economic growth profoundly shapes the ecological footprint, but an explicit Environmental Kuznets Curve remains elusive. Both natural resource rents and industrial shifts considerably influence the ecological footprint. Distinguishing from earlier non-spatial studies, our research merges spatial panel data analysis, emphasizing the regulatory role of juxtaposing natural resource rents with industrial structure adjustment can decrease the impact of economic growth on the ecological footprint. Advocating robust policies that favor renewables over non-renewables is pivotal, emphasizing the imperative for rigorous environmental standards in sectors shifting to renewables. [ABSTRACT FROM AUTHOR]

Maintaining wound moisture and monitoring of infection are crucial aspects of chronic wound treatment. The development of a pH-sensitive functional hydrogel dressing is an effective approach to monitor, protect, and facilitate wound healing. In this study, beet red pigment extract (BRPE) served as a native and efficient pH indicator by being grafted into silane-modified bacterial nanocellulose (BNC) to prepare a pH-sensitive wound hydrogel dressing (S-g-BNC/BRPE). FTIR confirmed the successful grafting of BRPE into the BNC matrix. The S-g-BNC/BRPE showed superior mechanical properties (0.25 MPa), swelling rate (1251 % on average), and hydrophilic properties (contact angle 21.83°). The composite exhibited a notable color change as the pH changed between 4.0 and 9.0. It appeared purple-red when the pH ranged from 4.0 to 6.0, and appeared light pink at pH 7.0 and 7.4, and appeared ginger-yellow at pH 8.0 and 9.0. Subsequently, the antioxidant activity and cytotoxicity of the composite was evaluated, its DPPH·, ABTS+, ·OH scavenging rates were 32.33 %, 19.31 %, and 30.06 %, respectively, and the cytotoxicity test clearly demonstrated the safety of the dressing. The antioxidant hydrogel dressing, fabricated with a cost-effective and easy method, not only showed excellent biocompatibility and dressing performance but could also indicated the wound state based on pH changes. • The S-g-BNC/BRPE hydrogel showed significant color changes in the pH range associated with chronic or infected wounds. • The S-g-BNC/BRPE hydrogel exhibited superior mechanical properties and hydrophilic properties than unmodified BNC. • The S-g-BNC/BRPE hydrogel showed excellent biocompatibility and certain antioxidant activity. [ABSTRACT FROM AUTHOR]

Potassium ferricyanide (K 4 [Fe(CN) 6 ]) as anti-caking agent plays an important role in avoiding the formation of chunks for fine particulate solids. However, inappropriate and excessive addition and decomposition of K 4 [Fe(CN) 6 ] are detrimental to physical health. At present, appropriate strategies for convenient and accurate analysis of K 4 [Fe(CN) 6 ] in table salt and pickled food are desirable. Herein, an efficient "ON-OFF-ON" fluorescent sensor based on chiral carbon dots was prepared by a simple one-step hydrothermal method. The chiral CDs with L-Tryptophan and D-Tryptophan as chiral source were named as L-CDs and D-CDs. Notably, the bright fluorescence of L/D-CDs could be effectively quenched by K 4 [Fe(CN) 6 ] through dynamic quenching mechanism. This fluorescent sensor achieved excellent sensitive and selective detection of K 4 [Fe(CN) 6 ] with a limit of detection (LOD) of 25.0 ng·mL−1. In addition, the L/D-CDs could be applied not only for selective fluorescent recognition of K 4 [Fe(CN) 6 ] by the methods of portable filter paper and hydrogels, but also as fluorescent dye for repeated message encryption and decryption. [Display omitted] • An efficient "ON-OFF-ON" fluorescent sensor based on chiral carbon dots was prepared. • This method has high sensitivity and excellent selectivity for detecting K 4 [Fe(CN) 6 ]. • The detection limit is much lower than those of other methods. • The L-CDs have been successfully applied to solid state sensors and multiple information encryption. Potassium ferricyanide (K 4 [Fe(CN) 6 ]) as anti-caking agent plays an important role in avoiding the formation of chunks for fine particulate solids. However, inappropriate and excessive addition and decomposition of K 4 [Fe(CN) 6 ] are detrimental to physical health. At present, appropriate strategies for convenient and accurate analysis of K 4 [Fe(CN) 6 ] in table salt and pickled food are desirable. Herein, an efficient "ON-OFF-ON" fluorescent sensor based on chiral carbon dots was prepared by a simple one-step hydrothermal method. The chiral CDs with L-Tryptophan and D-Tryptophan as chiral source were named as L-CDs and D-CDs. Notably, the bright fluorescence of L/D-CDs could be effectively quenched by K 4 [Fe(CN) 6 ] through dynamic quenching mechanism. This fluorescent sensor achieved excellent sensitive and selective detection of K 4 [Fe(CN) 6 ] with a limit of detection (LOD) of 25.0 ng·mL−1. In addition, the L/D-CDs could be applied not only for selective fluorescent recognition of K 4 [Fe(CN) 6 ] by the methods of portable filter paper and hydrogels, but also as fluorescent dye for repeated message encryption and decryption. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel yellow emission Y-CDs were prepared by a hydrothermal method using DHTA. • The Y-CDs as a sensitive sensor could detect Fe3+ and biothiols by dual signals. • This sensor was utilized to sense biothiols in actual samples and living cells. • The Y-CDs were applied for message encryption as solid sensor to detect analytes. The different levels of biothiols in cells can not only screen cancer cells but also play a selective role in killing cancer cells. Therefore, accurate monitoring of biothiol in cancer cells is of great research significance. Herein, novel yellow emission CDs (Y-CDs) were prepared by a simple hydrothermal method using 2, 5-dihydroxyterephthalic acid (DHTA) as precursors. The Y-CDs as a highly efficient dual-mode sensor could detect Fe3+ and biothiols by colorimetric and fluorescence signals. Especially, with the addition of L-Cysteine, the quenched fluorescence could be quickly restored within 2 min and the detection limit was as low as 31.65 nM. Additionally, this sensor was utilized to sense biothiols in actual samples and living cells due to its eminent biocompatibility. Finally, the Y-CDs were successfully applied not only as fluorescent ink for message encryption but also as a portable solid hydrogels sensor for the detection of Fe3+ and biothiols. Therefore, these results suggested that Y-CDs could serve as a promising sensor for Fe3+ and biothiol detection in early cancer screening. [ABSTRACT FROM AUTHOR]