Enhanced Feature Extraction Network Based on Acoustic Signal Feature Learning for Bearing Fault Diagnosis.

The method of acoustic radiation signal detection not only enables contactless measurement but also provides comprehensive state information during equipment operation. This paper proposes an enhanced feature extraction network (EFEN) for fault diagnosis of rolling bearings based on acoustic signal feature learning. The EFEN network comprises four main components: the data preprocessing module, the information feature selection module (IFSM), the channel attention mechanism module (CAMM), and the convolutional neural network module (CNNM). Firstly, the one-dimensional acoustic signal is transformed into a two-dimensional grayscale image. Then, IFSM utilizes three different-sized convolution filters to process input image data and fuse and assign weights to feature information that can attenuate noise while highlighting effective fault information. Next, a channel attention mechanism module is introduced to assign weights to each channel. Finally, the convolutional neural network (CNN) fault diagnosis module is employed for accurate classification of rolling bearing faults. Experimental results demonstrate that the EFEN network achieves high accuracy in fault diagnosis and effectively detects rolling bearing faults based on acoustic signals. The proposed method achieves an accuracy of 98.52%, surpassing other methods in terms of performance. In comparative analysis of antinoise experiments, the average accuracy remains remarkably high at 96.62%, accompanied by a significantly reduced average iteration time of only 0.25 s. Furthermore, comparative analysis confirms that the proposed algorithm exhibits excellent accuracy and resistance against noise.

Effect of rainfall-runoff process on sources and transformations of nitrate using a combined approach of dual isotopes, hydrochemical and Bayesian model in the Dagang River basin.

The control of agricultural nitrogen through inflow rivers is crucial for lake aquatic environment conservation, while nitrate is the main form of non-point source pollution of agricultural nitrogen in watersheds. Therefore, understanding the nitrate sources and transformation in the intensive-agricultural region was particularly concerned. Nitrate sources and transformation varied largely during some crucial periods or events. However, low-resolution sampling campaigns increased some uncertainties due to without considering the effect of key driving factors for identifying nitrate transformations and sources. In our study, high-frequency sampling and analysis of nitrogen and oxygen isotope, hydrochemical and Bayesian model was conducted at the Dagang River to capture nitrate sources and transformations and identify its response to rainfall-runoff process at the event scale. In addition, the N cycle process was refined by comparing the variation and relationship of water quality factors and isotopes before, during, and after rainfall. We found that nitrate and major ions derived from similar agricultural activities caused by anthropogenic factors, such as domestic sewage from rural residents and livestock waste, through field survey and principal component analysis. The δ15N-NO3- and δ18O-NO3- in Dagang River ranged from +0.05‰ to +9.94‰ and + 1.49‰ to +11.64‰, respectively. The spatio-temporal variations of nitrate isotopes and hydrochemical compositions of river water suggested that nitrification was the dominant nitrate transformation process although the mixing effect occurred in some periods, especially during, and after the rainfall. The relationship between NO3-/Cl- and Cl- ratios suggested the occurrence of denitrification in downstream of the river basin after the rainfall. The results of Bayesian model showed that livestock manure and groundwater contributed to the most (66.4 ± 31.9%) nitrate, which indicated the necessity to establish its regulatory policy to avoid the overuse of livestock manure and groundwater in Dagang River. This study benefit for developing concrete and legible management and conservation strategies for decreasing the effect of anthropogenic nitrogen loading on lake eutrophication.

Research on the geochemical background values and evolution rules of lake sediments for heavy metals and nutrients in the Eastern China Plain from 1937 to 2017.

For the first time, background quality guidelines have been developed for lake sediments along the Yangtze River. Evolution Rules of watershed environment in Eastern China were analyzed in 1937-2017. These methods of 137Cs and 210Pb radionuclide, 75% cumulative frequency, and background method were applied to calculate the sediment geochemical backgrounds (GB). The average GB values of Cu, Zn, Cd, Pb, Cr, total carbon (TC), total nitrogen (TN) and total phosphorus (TP) are 45.14 mg/kg, 86.99 mg/kg, 0.29 mg/kg, 33.71 mg/kg, 110.90 mg/kg, 17.20 mg/g, 1.60 mg/g, and 665.78 mg/kg, respectively. The radionuclide methods indicated that the sediment rate of 34 cm corresponding to 1963 is 0.63 cm yr-1. The risk and accumulation of the sediment metals and nutrients in Yangtze Plain were uncontaminated levels before 1960, raised since 1980, and increased significantly in 2000. The Cd, TC, and TN in lake sediment were at low to moderate pollution, and few lakes are at high pollution. Sediment background values of the plain are different from soil background values in China and Consensus-Based Sediment Quality Guidelines in Europe/America. Results of sediment quality guidelines provide an important guidance for pollution prevention, environmental management, and risk assessment, especially the formulation of environmental laws.

Characteristics and drivers of daily nitrogen and phosphorus losses from rice-rapeseed rotation systems in the middle reaches of the Yangtze River.

Crop production systems involving the use of high rates of fertilizer application caused significant losses of nitrogen (N) and phosphorus (P) to the environment, resulting in air pollution and water body eutrophication. Quantitating N and P losses and its drivers in crop production systems was critical for optimizing water and fertilizer management measures to mitigate the nutrient losses. However, N and P losses estimation remains highly uncertain in the field at event scale. We here quantify daily N and P losses and its drivers (daily N and P water input, N and P uptake, N and P water surplus, water loss, etc.) in rice-rapeseed growing systems by high-frequency field experiments at event scale in Central China. Results revealed that there were significant trade-off relationships between daily uptake and surplus for N and P during the whole growing stages both for rice and rapeseed. Although it was not significantly related in heading to mature stage for rapeseed, synergies between daily input or surplus and loss were found for N. Redundancy analysis revealed that water input and leaching loss contributed most for N and P loss in rice and rapeseed. The nutrient losses in easier stages should be reduced by postponing the base fertilizer and making it in line with the crop uptake. The study enhanced our knowledge of N and P losses mechanism for crop production systems and provided a scientific basis for optimization of water and fertilizer managements and N and P loss estimation models.

Robust revascularization, despite impaired VEGF production, after meniscus allograft transplantation in rabbits.

BACKGROUND: Little is known about vascularization restoration and vascular circulation after allogenic graft transplantation, which are both important prerequisites for optimal use of allograft meniscus transplantation. PURPOSE: To study vascularization restoration through autograft and allograft meniscus models in Oryctolagus cuniculus. STUDY DESIGN: Controlled laboratory study. METHODS: Forty-eight rabbits at mature bone age were randomized to receive either an autograft or allograft after the meniscus of the left knee was completely resected. Vascularization, blood circulation, histological characteristics of the grafted meniscus and surrounding tissues, and vascular endothelial growth factor (VEGF) expression in the meniscus were assessed at 4, 8, and 12 weeks after allograft or autologous transplantation. RESULTS: The grafted meniscus was in good condition and was well connected to the surrounding joint capsule, and no obvious damage of the joint cartilage at the tibial plateau was observed. Even though the revascularization pattern was similar in the 2 groups, the meniscus body showed vessel growth mainly at the adhesion margin for less than one-third of the meniscus transverse diameter, and no significant vascular distribution was found at the free margin. Blood circulation peaked after 8 weeks at the anterior and posterior horns and declined thereafter. This was mimicked by VEGF expression, which showed a progressive decrease with time, even though the vascular endothelial cells gradually increased over time. There were no statistical differences in the various assessments between the allograft and autograft groups. CONCLUSION: At 12 weeks after meniscus allografting, the vascular circulation had almost recovered and gradual reconstruction of cells and fibers had begun, mimicking similar observations in the autograft group. CLINICAL RELEVANCE: Our data provide test reference for clinical rehabilitation after meniscus autograft.