Railway Polygonized Wheel Detection Based on Numerical Time-Frequency Analysis of Axle-Box Acceleration

The increasing need for repairs of polygonized wheels on high-speed railways in China is becoming problematic. At high speeds, polygonized wheels cause abnormal vibrations at the wheel-rail interface that can be detected via axle-box accelerations. To investigate the quantitative relationship between axle-box acceleration and wheel polygonization in both the time and frequency domains and under high-speed conditions, a dynamics model was developed to simulate the vehicle-track coupling system and that considers both wheel and track flexibility. The calculated axle-box accelerations were analyzed by using the improved ensemble empirical mode decomposition and Wigner-Ville distribution time-frequency method. The numerical results show that the maximum axle-box accelerations and their frequencies are quantitatively related to the harmonic order and out-of-roundness amplitude of polygonized wheels. In addition, measuring the axle-box acceleration enables both the detection of wheel polygonization and the identification of the degree of damage. Document type: Articl

Evaluating the Effect of Wheel Polygons on Dynamic Track Performance in High-Speed Railway Systems Using Co-Simulation Analysis

With increases in train speed and traffic density, problems due to wheel polygons and those caused by wheel–rail impacts will increase accordingly, which will affect train operational safety and passenger ride comfort. This paper investigates the effects of polygonal wheels on the dynamic performance of the track in a high-speed railway system. The wheel–rail interaction forces caused by wheel polygons are determined using a dynamic vehicle–track model, and the results are entered into a slab track finite element model. The influence of the harmonic order and out-of-roundness (OOR) amplitude of wheel polygons on the transient dynamic characteristics of the track(von Mises equivalent stress, displacement, and acceleration) is examined under high-speed conditions. The results indicate that the vibration acceleration and von Mises equivalent stress of the rail increase in proportion to the harmonic order and the OOR amplitude and velocity of a polygonized wheel. The vibration displacement of the rail first increases and then decreases with a change in the harmonic order, and reaches a maximum at the ninth order. The dynamic responses of the concrete slab layer, cement-asphalt layer, and support layer increase linearly with the harmonic order and amplitude of wheel polygons and decrease from top to bottom. Through a combination of numerical simulations and real-time monitoring of rail vibrations, this study provides guidance on potential sensor locations to identify polygonized wheels before they fail

A Sparsity-Promoted Decomposition for Compressed Fault Diagnosis of Roller Bearings

The traditional approaches for condition monitoring of roller bearings are almost always achieved under Shannon sampling theorem conditions, leading to a big-data problem. The compressed sensing (CS) theory provides a new solution to the big-data problem. However, the vibration signals are insufficiently sparse and it is difficult to achieve sparsity using the conventional techniques, which impedes the application of CS theory. Therefore, it is of great significance to promote the sparsity when applying the CS theory to fault diagnosis of roller bearings. To increase the sparsity of vibration signals, a sparsity-promoted method called the tunable Q-factor wavelet transform based on decomposing the analyzed signals into transient impact components and high oscillation components is utilized in this work. The former become sparser than the raw signals with noise eliminated, whereas the latter include noise. Thus, the decomposed transient impact components replace the original signals for analysis. The CS theory is applied to extract the fault features without complete reconstruction, which means that the reconstruction can be completed when the components with interested frequencies are detected and the fault diagnosis can be achieved during the reconstruction procedure. The application cases prove that the CS theory assisted by the tunable Q-factor wavelet transform can successfully extract the fault features from the compressed samples

Crosstalk of cuproptosis-related subtypes, establishment of a prognostic signature, and immune infiltration characteristics in gastric cancer

Background: Cuproptosis is a novel form of cellular demise that occurs through a unique pathway involving lipoylated proteins in the tricarboxylic acid (TCA) cycle and is closely linked to mitochondrial metabolism. Nevertheless, the comprehensive elucidation of the impact of carcinogenesis-associated genes (CRGs) on prognosis, tumor microenvironment (TME), and therapeutic response in patients with gastric cancer (GC) remains unclear. Methods: In total, 1374 GC samples were gathered from three Gene Expression Omnibus (GEO) datasets and The Cancer Genome Atlas database. The samples were then stratified into different subtypes through unsupervised clustering of the 13 CRG profiles. The CRG_score was developed to quantify CRG patterns of individual tumors. Subsequently, we investigated the associations among the various groups and clinicopathological features, immune infiltration features, TME mutation status, and response to immunotherapy. Results: The GC samples were divided into two clusters based on their distinct clinicopathological features, prognosis, and immune characteristics. Using LASSO and Cox regression analyses, 9 genes were identified for constructing a prognostic signature related to cuproptosis. The novel signature displayed outstanding durability and prognostic capability for the overall lifespan of individuals. Additionally, the expression levels of signature genes in GC tissues and adjacent normal tissues were tested by qRT-PCR. Moreover, we developed a remarkably dependable nomogram to enhance the practicality of the CRG_score in clinical settings. High tumor mutation burden, increased microsatellite instability-high, immune activation, along with good survival probability and increased immunoreactivity to immune checkpoint inhibitors, were distinguishing features of low CRG_scores. Conclusions: The findings of this study revealed the possible impacts of CRGs on the TME, clinical and pathological characteristics, and outlook of patients with GC. This signature was strongly linked to the immune response against GC and has the potential to serve as a valuable tool for predicting patient prognosis

Synthesis of amorphous nickel–cobalt–manganese hydroxides for supercapacitor-battery hybrid energy storage system

In this work, amorphous nickel–cobalt–manganese hydroxide (NiCoMn–OH) was hydrothermally synthesized using a mixed solvent strategy and used as positive electrode materials for supercapacitor-battery hybrid energy storage system. The experimental results show that the mixed solvent is indispensable to form the amorphous phase of NiCoMn–OH, which exhibits significantly improved electrochemical activity and rate capability in comparison with the crystalline counterpart because of more grain boundaries and ion diffusion channels in the former phase. A strong synergy between the transition metal ions in the amorphous NiCoMn–OH is found to significantly contribute to the electrochemical activity, rate capability and cycling stability. In addition to battery behavior, the amorphous NiCoMn–OH exhibits pseudocapacitive behavior, which contributes approximately 40% to the total energy storage capacity. The pseudocapacitive property significantly enhances the rate performance. The robust synthesis method described in this paper was also used to fabricate the NiCoMn–OH porous network on Ni foam, which shows a specific capacity close to its theoretical value, indicating a complete utilization of the electroactive material. Furthermore, a supercapacitor-battery hybrid cell fabricated with the amorphous NiCoMn–OH as the positive electrode and reduced graphene oxide (RGO) as the negative electrode exhibits both high-energy and high-power performances with a specific energy of 42.8 Wh kg-1 at a specific power of 749 W kg-1 or a specific energy of 19.9 Wh kg-1 at a specific power of 20.9 kW kg-1

Evaluation of Urban Sustainability Based on Development Structures and Economic Aggregates: A Case Study of Jiaxing, China

Urban sustainability is the comprehensive manifestation of development structures and economic aggregates. The current sustainable evaluation of cities from a single aspect cannot comprehensively reflect urban sustainable development. Based on emergy, this study constructs an assessment method of urban sustainability from development structures and economic aggregates. Jiaxing is the case study explored as the sustainable development model of cities in the Yangtze River Delta (YRD) of China. High sustainability of economic aggregates is found in Jiaxing, which is driven by the growth of green GDP. However, the urban development of Jiaxing primarily depends on the input of ecosystem resources, which hinders the sustainability of development structures within Jiaxing. These findings indicate that economic aggregates drive the development of Jiaxing and that the development structures within Jiaxing are unsustainable, resulting from the low sustainability of the natural subsystem and the economic subsystem. As such, it is proposed that industrial structures, development models, and management policies be adopted within cities in the YRD of China in order to promote sustainable development of cities in the YRD of China. This study, therefore, seeks to provide methodological guidance for urban sustainable evaluation

Evaluation of Urban Sustainability Based on Development Structures and Economic Aggregates: A Case Study of Jiaxing, China

Urban sustainability is the comprehensive manifestation of development structures and economic aggregates. The current sustainable evaluation of cities from a single aspect cannot comprehensively reflect urban sustainable development. Based on emergy, this study constructs an assessment method of urban sustainability from development structures and economic aggregates. Jiaxing is the case study explored as the sustainable development model of cities in the Yangtze River Delta (YRD) of China. High sustainability of economic aggregates is found in Jiaxing, which is driven by the growth of green GDP. However, the urban development of Jiaxing primarily depends on the input of ecosystem resources, which hinders the sustainability of development structures within Jiaxing. These findings indicate that economic aggregates drive the development of Jiaxing and that the development structures within Jiaxing are unsustainable, resulting from the low sustainability of the natural subsystem and the economic subsystem. As such, it is proposed that industrial structures, development models, and management policies be adopted within cities in the YRD of China in order to promote sustainable development of cities in the YRD of China. This study, therefore, seeks to provide methodological guidance for urban sustainable evaluation