A novel fault diagnosis approach of gearbox using an embedded sensor fixed gear body

The vibration signals measured from the surface of a gearbox are complex, nonlinear and non-stationary. This paper presents a novel test approach for tooth root crack fault diagnosis of a spur gearbox using an embedded piezoelectric accelerometer. This enhances the ability to extract useful fault information and provide early fault detection in gear transmission systems. The proposed method uses two piezoelectric accelerometers embedded symmetrically on the gear body, which effectively shortens the transmission path of the vibration signals stimulated by a gear fault. The proposed approach is tested by analyzing experimental data from a healthy gear system and systems with cracked gear faults. In order to extract the weak fault information from the experimental data, minimum entropy deconvolution (MED) is first used to eliminate noise from the vibration signals, and then the cyclic autocorrelation function is used to extract the frequency components. The results suggest that the proposed approach can effectively detect 2 mm and 4 mm crack faults, while traditional methods can only detect 4 mm crack faults

Pyrolysis characteristics of waste tire particles in fixed-bed reactor with internals

This study investigated the characteristics of pyrolysis for waste tire particles in the newly developed fixed-bed reactor with internals that are a central gas collection channel mounted inside reactor. And a few metallic plates vertically welded on the internal wall of the reactors and extending to the region closing their central gas collection pipe walls. Experiments were conducted in two laboratory fixed bed reactors with or without the internals. The results shown that employing internals produced more light oil at externally heating temperatures above 700 °C due to the inhibited secondary reactions in the reactor. The oil from the reactor with internals contained more aliphatic hydrocarbons and fewer aromatic hydrocarbons, leading to its higher H/C atomic ratios as for crude petroleum oil. The char yield was relatively stable for two beds and showed the higher heating values (HHVs) of about 23 MJ/kg. The gaseous product of pyrolysis mainly consisted of H2 and CH4, but the use of internals led to less pyrolysis gas through its promotion of oil production. Keywords: Pyrolysis, Waste tire, Fixed bed, Internals, Secondary reaction

A few recent developments in fluidized bed technology applications for fuel conversion

In recent years, the process concepts based on two-stage and dual bed have been widely adopted in developing fuel conversion technologies including pyrolysis, combustion, gasification and catalytic cracking. These provide indeed advantages of, for example, easy operation and control, poly-generation of products, and high efficiency in elimination of undesirable product or pollutants. The so-called micro fluidized bed analyzer (MFBRA) has been newly developed to measure reaction rates at arbitrary temperatures, giving a great support to fundamental research and technology developments for fuel conversion. This report intends to summarize the involved new concepts, major fundamental understandings, pilot test and/or industrial demonstrations of a few newly developed fuel conversion technologies. Concretely, it will report fluidized bed two-stage gasification (FBTSG), dual fluidized bed pyrolysis combustion (DBPC), fluidized bed cracking gasification (FBCG) and MFBRA. The FBTSG technology separates fuel pyrolysis in a FB pyrolyzer and char gasification in a transport bed gasifier. The latter enables high-temperature tar cracking under catalysis of char to enable remarkably low tar content in the produced gas [1]. For fuel with high contents of water and nitrogen, the DBPC technology first removes fuel water and most fuel volatile in a pyrolyzer. This, on the one hand, ensures stable combustion of the fuel, and on the other hand facilitates NOx reduction by char and pyrolysis gas [2]. The FBCG technology separates the catalytic cracking of heavy feedstock for liquid and the gasification of char, the cokes formed on the catalyst surface, to produce syngas and also to regenerate the catalyst. By using micro fluidized bed, the MFBRA is newly developed to enable the on-line pulse feeding and rapid heating of particle reactant. It effectively suppresses the interfacial diffusion limitation and minimizes the intra-particle diffusion [3]. Thus, MFBRA provides isothermal reaction analysis in comparison with that in TGA based on programmed heating. REFERENCES 1. X. Zeng, et al. Pilot verification of a low-tar two-stage coal gasification process with a FB pyrolyzer and fixed bed gasifier. Applied Energy, 115, 9–16, 2014. 2. P. Dagaut, et al. Experiments and kinetic modeling study of NO-reburning by gases from biomass pyrolysis in a JSR. Energy & Fuels, 17(3), 608-613, 2003. 3. J. Yu, et al. Kinetics and mechanism of solid reactions in a micro fluidized bed reactor. AIChE Journal, 56, 2905-2912, 2010

The role of perivascular adipose tissue-secreted adipocytokines in cardiovascular disease

Perivascular adipose tissue and the vessel wall are connected through intricate bidirectional paracrine and vascular secretory signaling pathways. The secretion of inflammatory factors and oxidative products by the vessel wall in the diseased segment has the ability to influence the phenotype of perivascular adipocytes. Additionally, the secretion of adipokines by perivascular adipose tissue exacerbates the inflammatory response in the diseased vessel wall. Therefore, quantitative and qualitative studies of perivascular adipose tissue are of great value in the context of vascular inflammation and may provide a reference for the assessment of cardiovascular ischemic disease

Magnetic metal organic frameworks (MOFs) composite for removal of lead and malachite green in wastewater

We designed and synthesized a magnetic metal organic frameworks (MOFs) composite, Cu-MOFs/FeO as the adsorbent for removal of lead (Pb(II)) and malachite green (MG) in wastewater. This Cu-MOFs/FeO can be easily prepared by in-situ growth of Cu-MOFs with doping FeO nanoparticles. The prepared Cu-MOFs/FeO composite was well characterized by SEM, XRD, and FTIR spectra. The adsorption experiments found that Cu-MOFs/FeO can serve as adsorbent for removal of Pb(II) and MG simultaneously. The adsorption capacities were found to be 113.67 mg/g for MG and 219.00 mg/g for Pb, respectively, which are significantly higher than reported materials. Adsorption isotherm, kinetics and recyclability of Cu-MOFs/FeO for removal of Pb(II) and MG were then studied. Adsorption of Pb(II) and MG exhibited Freundlich adsorption isotherm model, with the adsorption kinetics of available second-order kinetic. Physical adsorption for MG and chemical adsorption for Pb(II) were confirmed by Dubinin-Radushkevich (D-R) isothermal adsorption model. The adsorption of Pb(II) and MG in real water samples were then studied. The FeO/Cu-MOFs was found to be recyclable for removal of Pb(II) and MG, can be explored as the potential adsorbent for waste water treatment

Oxygen Migration in Torrefaction of Eupatorium adenophorum Spreng. and Its Improvement on Fuel Properties

Totrefaction of Eupaturium adenophorum Spreng., a major invasive plant in southeast China, was investigated in a laboratory fixed bed at temperatures of 200-325 degrees C and residence time of 30 min for improving the properties of the biomass as fuel. During torrefaction, a large amount of oxygen was removed from biomass, which made the torrefied biomass more like,coal. Oxygen in torrefaction products was characterized to study the quantity and approach of oxygen migration. In gas products, oxygen existed as CO2 and CO, and-in the liquid product, it existed in forms of H2O and oxygen-containing compounds, such as acids, alcohols, aldehydes, ketones, furans, guaiacols, phenols, and extracts. The oxygen in the solid product presented as oxygen-containing functional groups, of which the proportion of C-OH and C-O-C obviously decreased with the increase in the torrefaction temperature. At low temperatures (200-250 degrees C), oxygen in biomass was transferred to H2O with traces of oxygen migrated to bio-oil. As the torrefaction temperature increased, a growing amount of oxygen in biomass migrated to bio-oil and gas but dehydration still dominated deoxidation. Carbon migration coupled with oxygen migration led to energy loss to decrease the energy yield of the torrefied product or the obtained fuel. From the perspective of deoxidation effectiveness and carbon loss during torrefaction; 250 degrees C was suggested to be the optimal temperature for torrefaction of E. adenophorum Spreng

A Hybrid De-Noising Algorithm for the Gear Transmission System Based on CEEMDAN-PE-TFPF

In order to remove noise and preserve the important features of a signal, a hybrid de-noising algorithm based on Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (CEEMDAN), Permutation Entropy (PE), and Time-Frequency Peak Filtering (TFPF) is proposed. In view of the limitations of the conventional TFPF method regarding the fixed window length problem, CEEMDAN and PE are applied to compensate for this, so that the signal is balanced with respect to both noise suppression and signal fidelity. First, the Intrinsic Mode Functions (IMFs) of the original spectra are obtained using the CEEMDAN algorithm, and the PE value of each IMF is calculated to classify whether the IMF requires filtering, then, for different IMFs, we select different window lengths to filter them using TFPF; finally, the signal is reconstructed as the sum of the filtered and residual IMFs. The filtering results of a simulated and an actual gearbox vibration signal verify that the de-noising results of CEEMDAN-PE-TFPF outperforms other signal de-noising methods, and the proposed method can reveal fault characteristic information effectively

Application of Sample Entropy Based LMD-TFPF De-Noising Algorithm for the Gear Transmission System

This paper investigates an improved noise reduction method and its application on gearbox vibration signal de-noising. A hybrid de-noising algorithm based on local mean decomposition (LMD), sample entropy (SE), and time-frequency peak filtering (TFPF) is proposed. TFPF is a classical filter method in the time-frequency domain. However, there is a contradiction in TFPF, i.e., a good preservation for signal amplitude, but poor random noise reduction results might be obtained by selecting a short window length, whereas a serious attenuation for signal amplitude, but effective random noise reduction might be obtained by selecting a long window length. In order to make a good tradeoff between valid signal amplitude preservation and random noise reduction, LMD and SE are adopted to improve TFPF. Firstly, the original signal is decomposed into PFs by LMD, and the SE value of each product function (PF) is calculated in order to classify the numerous PFs into the useful component, mixed component, and the noise component; then short-window TFPF is employed for the useful component, long-window TFPF is employed for the mixed component, and the noise component is removed; finally, the final signal is obtained after reconstruction. The gearbox vibration signals are employed to verify the proposed algorithm, and the comparison results show that the proposed SE-LMD-TFPF has the best de-noising results compared to traditional wavelet and TFPF method

Feasibility and effectiveness of disinfection of gloves during routine care: a scoping review protocol

Introduction Disinfecting gloves during patient care has potential benefits and risks. In recent years, disinfection of disposable medical gloves for prolonged use has occurred in clinical practice. However, there is limited high-level evidence to know if this practice can prevent nosocomial infections, reduce microbial levels on the glove surface. This concept was researched using a scoping review to explore the feasibility and effectiveness of disinfecting disposable gloves for prolonged use.Methods and analysis The review will be conducted in accordance with the Arksey and O'Malley scoping review methodology framework. From the date of database construction to 10 February 2023, the following 16 electronic databases in English and Chinese will be searched: PubMed, Embase, CINAHL, Web of Science, Cochrane Library, ProQuest, China National Knowledge Infrastructure, Wanfang, SinoMed Database, Google Scholar, Centers for Disease Control and Prevention (CDC), European Centre for Disease Prevention and Control, WHO, China CDC, International Nosocomial Infection Control Consortium and European Medicines Agency Science Medicines Health. The screening and data extraction of the study will be carried out by two reviewers (KL and SH). Differences between the two reviewers will be handled through negotiation. If there are still differences, they will be discussed with a third reviewer. Any study, for example, intervention study or observational study, that provide insights about the disinfection of disposable medical gloves for prolonged use will be included. Data charts will be used to extract relevant data from the included studies. Results will be reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews, to define the scope of evaluation. A narrative summary will be completed to synthesise key research findings and background information on the disinfection of gloved hands.Ethics and dissemination Ethical approval will not be required because only publicly available data will be analysed. The findings from the scoping review will be published in a peer-reviewed journal and presented at scientific meetings. By highlighting the feasibility and effectiveness of the disinfection of gloved hands in the literature, this review will provide direction for future research and clinical guidelines.Trial registration number This scoping review protocol has been registered in the Open Science Framework (registration number: 10.17605/OSF.IO/M4U8N)