The fault diagnosis of gearboxes and bearings in wind turbines is crucial to extend their service life and reduce maintenance costs. This paper proposes a novel fault diagnosis method combining the ...refined generalized composite multi-scale state joint entropy (RGCMSSJE), robust spectral feature selection (RSFS) unsupervised learning framework, and extreme learning machine (ELM). The method enables feature extraction, dimensionality reduction, and pattern recognition to identify the different condition states of gearboxes. In this method, multi-scale average Euclidean divergence is adopted to assist the RGCMSSJE in parameter selection. Then, the RGCMSSJE is utilized to extract multi-scale features from the gearbox vibration signal and construct a high-dimension feature set. The RSFS method is subsequently used to reduce the dimensionality of the RGCMSSJE feature set. Finally, the reduced low-dimensional features are fed into an ELM classifier for fault pattern recognition. The effectiveness of the proposed fault diagnosis method is verified using two experimental datasets, for which the average accuracy reached 99.9% and 99.3%, respectively. The analysis results show that the method can effectively and accurately identify different fault types in wind turbine gearboxes.
With rapid development of lithium ion batteries（LIB） and sodium ion batteries（SIB）, hard carbon（HC） as new anode material has earned much attention. Besides its rich precursor sources and low cost, ...HC has higher Li+storage capacity and better rate performance than graphite for LIB. Furthermore, it is also recognized as the most commercially potential anode material for SIB. However, low initial Coulombic efficiency is a common issue for HC.In addition, it is believed that the specific capacity can be further improved with the clarification of the Li/Na ion storage mechanism. In recent years, many researches on electrochemical mechanism have been conducted with some model assumptions proposed for better understanding the mechanism. This review introduced the structures and preparation approaches of HC as well as its application in LIB and SIB. The advantages, especially in fast charging,coating and other subdivision were discussed, and the different modification strategies such as pore structure design,doping,
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Hollow carbon spheres (HCSs) with large interior cavity and porous shell have emerged as an important class of carbon materials, while exploring novel synthesis methods in terms of ...convenience, controllability and universality remains a challenge. Herein, we develop a self-propelled nanoemulsion assembly of organosilane approach to fabricate monodispersed HCSs. In this approach, volatile oils are severed as self-elimination soft template and organosilane both as carbon precursor and in-situ pore-template. The key to the synthesis is the self-propelled formation of oil-in-water nanoemulsion stabilized by amphipathic hydrolyzed organosilane, which could hydrolyze at the oil-water interface and condense to form the polysilsesquioxane shell. The present approach has good controllability and universality that can be demonstrated by modulating alternative volatile oils, organosilane precursors and dry condition. After carbonization and NaOH treatment, the as-prepared HCSs have uniform particle size of ∼900 nm, large cavity, controllable carbon shell of 80–110 nm, and high surface area up to 2300 m2/g. The unique integration of high-surface-area and well-defined hollow spherical morphology make them a great potential as electrode materials for supercapacitive energy storage and carbon host for lithium sulfur batteries. These findings could inspire more novel methodologies for constructing of high-surface-area yet well-defined nanostructured materials for tackling energy issues.
Delayed gastric emptying is a common non-motor symptom of Parkinson's disease (PD). However, there is currently no objective evaluation and diagnostic method for this condition.
The purpose of this ...study was to evaluate the feasibility of gastric-filling ultrasonography for gastric motility in patients with PD and the relationship between gastric dynamics and gastrointestinal symptoms and motor symptoms of PD.
We performed a case-control study with 38 patients with PD and 34 healthy controls.
All patients underwent a 120-min ultrasonography examination using a 500-ml semi-liquid test meal. We determined the antral contraction amplitude (ACA), the antrum contraction frequency (ACF), the motility index (MI), and the gastric antral cross-sectional area (CSA). We acquired the CSA at six time points: fasting for 12 h (T0), immediately after drinking the semi-liquid test meal (T1); and at 30 (T30), 60 (T60), 90 (T90), and 120 (T120) min. We calculated the gastric emptying rate (GER) at different time points by using the CSA. We compared the GER between the groups and evaluated the correlation between the GER and gastrointestinal symptoms and motor symptoms of PD.
The MI and ACF were significantly lower in the PD group compared with the control group (
< 0.05). The GER at T30 and the ACA showed no significant difference between the groups (
> 0.05). At different time points, the GER was significantly different between the PD and control groups (
< 0.001). There was no significant association between the GER and gastrointestinal symptoms; none of them were risk factors for impaired gastric emptying (odds ratio > 1). The GER was negatively correlated with the severity of PD motor symptoms (
< 0.05).
Patients with PD had significantly delayed gastric emptying, which was negatively correlated with the severity of PD motor symptoms. Measuring gastric emptying by gastric-filling ultrasound had good diagnostic value in clinical screening for delayed gastric motility in patients with PD.
https://www.chictr.org.cn/showproj.html?proj=126304.
Yeast, as a very valuable microbial resource, has a good enzyme system in the body and can adapt to a variety of special environments. Therefore, it plays an important role in the biological ...treatment of wastewater. The classification and basic characteristics of yeast were introduced, and the application of yeast in the field of wastewater treatment such as high concentration organic wastewater, heavy metal ion wastewater and domestic sewage were summarized. With the mature of yeast technology and the development of science and technology, more techniques such as gene engineering and immobilization technology will be used to treat with yeast, so that it will have a wider application prospect in wastewater treatment.
Phosphorus is one of the essential elements needed for the growth and reproduction of any organism. To improve the efficiency of biological phosphorus removal in sewage, it is very important to grasp ...the precise mechanism of biological phosphorus removal. Yeast is a single cell fungus and has a unique advantage in sewage treatment. Recent studies in the different types of yeast have revealed that there is a phosphate-responsive signal transduction (PHO) pathway to regulate phosphate-responsive genes for controlling phosphate absorption. In this review, the metabolic mechanisms and protein-protein interactions associated with the PHO pathway are highlighted firstly, and then several examples about improving the phosphorus removal efficiency of sewage by inducing gene mutation in yeast phosphorus metabolism was introduced. The aim is to provide new ideas for the realization of high-efficiency phosphorus recovery in nature.
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•APANF separator is fabricated by general electrospinning process and functional group grafting.•Li ion distribution can be well regulated due to the nanofiber structures and the ...polar groups on APANF.•APANF separator can simultaneously suppress Li dendrite formation and polysulfides shuttling.
High-energy-density lithium sulfur (Li-S) batteries are suffering several seemingly insurmountable barriers, including lithium dendrite formation and polysulfides shuttling. Functional separator, which bridges anode, electrolyte and cathode together, has the potential to offer a perfect solution to these concerns. Herein, we develop a functional ammoniated polyacrylonitrile (PAN) nanofiber separator (APANF) which can simultaneously inhibit Li dendrite formation and polysulfides shuttling. Branched polyethyleneimine (PEI) are fixed on the electrospun PAN nanofiber mat via a chemical grafting to provide amino groups. Such strongly polar separator can well regulate the uniform Li ions distribution and induce the formation of the Li3N-rich SEI layer, resulting in an interesting 3D spherical and dendrite-free Li deposit pattern. The coulombic efficiency of resulting Li anode can be improved up to 98.8% with a low overpotential of 15 mV. Meanwhile, the separator can also serve as a block for polysulfides shutting due to the strong chemical adsorption capability of PEI, thus facilitating the capacity retention of sulfur cathode. This work provides an easy and scalable alternative to conventional polyolefin separators for solving problems in both anode and cathode of Li-S battery.
•NACEEMD method is proposed to suppress the mode-mixing problem of EEMD.•A new screening criterion is proposed to screen out the effective IMFs.•EPAD algorithm is developed to implement the peak ...statistics-based thresholding.•Explored and expanded the application potential of the proposed denoising algorithm.
This paper proposes an adaptive denoising methodology for noisy signals that employs a novel adaptive complementary ensemble empirical mode decomposition (NACEEMD) and a peak statistics (PS)-based thresholding technique. The key idea in this paper is the peak statistics (PS)-based thresholding technique,which breaks the traditional strategy with respect to selecting more accurate and more adaptive thresholds. The NACEEMD algorithm is proposed to decompose the noisy signal into a series of intrinsic mode functions (IMFs). At the same time, NACEEMD is also used to verify the applicability of the PS-based thresholding technique in different decomposition algorithms. The PS-based threshold is used to remove the noise inherent in noise-dominant IMFs, and the denoised signal is reconstructed by combining the denoised noise-dominant IMFs and the signal-dominant IMFs. This paper uses a various of simulated signals in various noisy environments for experiments, the experimental results indicate that the proposed algorithm outperforms traditional threshold denoising methodologies in terms of signal-to-noise ratio, root mean square error, and percent root distortion. Moreover, through real ECG signal and multi-sensor data fusion experiments, the application of the proposed algorithm in the field of engineering is explored and expanded.
Colloidal dispersion of Nb2O5/reduced graphene oxide nanocomposites as functional coating layer for polysulfide shuttle suppression and lithium anode protection of Li-S battery.
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...•Nb2O5-rGO composite was consisted of homogeneously Nb2O5 nanoparticles.•Colloidal dispersion of Nb2O5-rGO was coated onto the separator for Li-S battery.•Nb2O5-rGO coating layer showed ultrathin thickness and ultralight weight.•Nb2O5-rGO coating layer could suppress lithium polysulfides shuttle.•Nb2O5-rGO coating layer could retard lithium surface corrosion and dendrite growth.
Functional separator, which bridges anode, electrolyte and cathode together, has the potential to offer a good solution for efficient polysulfide diffusion inhibition and anode protection of Li-S battery. Herein, a novel ultra-thin multifunctional separator is prepared by a facile coating of colloidal dispersion of Nb2O5/reduced graphene oxide nanocomposites (rGO) onto porous polypropylene (PP) matrix. Benefiting from the physical blocking effect of rGO layer and chemisorption of Nb2O5, the shuttle of polysulfides has been greatly suppressed. Meanwhile, the rGO layer functioning as a conductive upper current collector can improve the sulfur utilization, while the Nb2O5 with high activity promotes the transformation of sulfur-containing species. With the assistant of Nb2O5-rGO function layer, the sulfur cathode shows significantly improved electrochemical performance with a high specific capacity of 1328 mAh g−1 at 0.2C and 754 mAh g−1 retained after 200 cycles. The sulfur cathode also exhibits excellent rate capability and stable Coulombic efficiency of 91% without the addition of LiNO3 in the electrolyte. Moreover, the presence of thin Nb2O5-rGO layer also prevents the lithium surface corrosion and the dendrite growth in the lithium anode.
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