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Aiming at the difficulty of extracting fault features of rolling bearings under the influence of strong background noise, a rolling bearing fault diagnosis method based on the fusion of variational mode decomposition (VMD) and convolutional neural network (CNN) is proposed. After decomposing the original variation signal into multiple components, the proposed method employs the Pearson correlation coefficient as the automatic decomposition termination threshold and the optimal modal component selection index; a convolutional neural network is constructed according to bearing fault features and the optimal modal component is used as the input to extract and classify the fault types. The experiments validate that the proposed method can accurately diagnose the rolling bearing faults, which is validated as a new method for rolling bearing fault diagnosis regarding strong background noise.

The SCO2 turbine machines exchange energy through supercritical carbon dioxide. Their impeller has the features of high-temperature and −speed to enhance energy conversion efficiency, but the rotor needs to be cooled to be compatible with bearings and seals. The paper introduces a pivotal parameter optimization of a concentrating solar SCO2 turbine rotor and seeks to control the harmonic response amplitude while preserving the distance between the critical speed and the working speed. The optimization considers several parameters including bearing span, stiffness, effective mass and damping of the bearing hub, and gas film stiffness coefficients of the cooler. The optimization is accomplished using a multi-objective and −scale quantum harmonic oscillator algorithm (mMQHOA) that couples an information interaction algorithm and transfer matrix model. The application of information interaction accelerates the convergence speed of the objective functions. The verification results from the three-dimensional finite element (3D-FE) indicate that the non-dominant design reduces resonance amplitude of the disc by approximately 71.91%, while the critical frequency increases by about 34.33% in the direction away from the operating frequency, and imply a trade-off relationship between harmonic response amplitude and critical speed. It is further reveal that the increased gas film stiffness of cooler in the primary level interval (

We have established a real-time fluorescent quantitative PCR system that can detect wheat crown rot rapidly and accurately quantify fungi, Fusarium species and Fusarium pseudograminearum in the rhizosphere soil of infected wheat through the standard curve produced, with a view to the early stage of wheat Provide help in predicting the occurrence of wheat crown rot.

Supercritical carbon dioxide (SCO2) Brayton cycle microturbine can be used for the next generation of solar power. In order to comprehensively optimize the supporting system and cooling device parameters of Brayton cycle shafting, the concept of chaos interval is introduced by chaotic mapping, and the CIMPSO algorithm is proposed to optimize the multi-objective rotor system model with nonlinear variables.The results show that the resonance amplitude of the optimized model is effectively attenuated, and the critical speed point is far away from the working speed, which shows the robustness of the optimization algorithm. Finally, based on arbitrary several sets of optimization solutions and empirical parameters, the finite element model of shafting is established for simulation, and the results show that the optimized solution has certain guiding significance for the design of the rotor system.The cooling device is designed and simulated by CFD method based on the optimal solution set. Both the inlet boundary conditions of given pressure (1 MPα) and given mass flow rate (0.1 kg/s) numerical calculations were carried out to characterize the cooling performance, for different jet impingement configurations (Hr/din = 0.0125 ∼ 5).Several sets of analyses show the strong effects of the jet-to-target spacing (Hr/din) on the rotor thermal performance at a given diameter (din) of the nozzle. Average temperature (Tc) at the free end of the rotor show that, as jet-to-target distance decreases (0.0125 ≤ Hr/din ≤ 0.33), the heat dissipation efficiency of the cooling device with the given pressure boundary condition tends to decrease, while the conclusion is opposite when the inlet boundary condition is set to the given mass flow rate. And there is an interval for the optimal combination (Hr/din) to promote the cooling efficiency.

Numerical investigation was carried out to study the heat transfer performance for a high-speed rotating cylindrical surface subjected to single row array round jets impingement, under a very small gap spacing. Various parameters that affect heat transfer, such as the fluid density, flow velocity and Nusselt number distributions of the radius clearance were studied based on varied nozzle to target surface spacing H and mass flow rate. It has been found that the fluid density was a dominant factor and the velocity was the secondary factor for the gas jet heat transfer performances. The overall heat transfer was improved with a reduction in the number of nozzles, for given inlet mass flow rate boundary conditions. The decrease of H/di (di, nozzle diameter) may have positive or negative effects on the heat transfer performance from the impingement surface. Reducing the radius gap H, for a certainty, increases the average density of the fluid in the clearance, which is desirable in applications that enhance heat transfer performance. But when the radius gap (H) is small enough, increasing di may have a negative impact on heat transfer.

The non- linear bearing force in the working state of the rolling bearing is deduced and non-linear dynamics equations of a system are established. The system axis path chart,the bifurcation diagram and the Poincare figure are drawn in Matlab and used to analyze the characteristics of the system vibration with the different parameters. The numerical method is used to solve the equations and the displacement values of system vibration are obtained. The results show that the change of the non- linear bearing force will cause the vibration of the system and bifurcation phenomena will appear in the system. The speed,damping and radial force are important parameters that influence the vibration. By choosing reasonable working parameters,the vibration of system can be reduced and the stability of the system can be improved.

For the process of optimizing the process parameters in the process of cutting the hard and brittle materials such as single-crystal SiC by diamond wire saw, the process parameters such as wire saw speed, workpiece feed speed and workpiece rotation speed are the design variables, and the sawing force and surface roughness are the processing targets by orthogonal experimental design. The grey system theory is introduced to optimize the multi-objective cutting process. According to the experimental data, the grey correlation resolution coefficient is determined. The significant relationship between the processing parameters and the target characteristics is analyzed. The optimal combination of process parameters under multi-target conditions is obtained, namely the workpiece feed rate is 0.025mm/min, the wire saw speed is 1.6m/s, and the workpiece rotating speed is 16r/min.

Recently, there has been a growing interest in the biocontrol activity of volatile organic compounds (VOCs) produced by microorganisms. This study specifically focuses on the effects of VOCs produced by the co-culture of Burkholderia vietnamiensis B418 and Trichoderma harzianum T11-W for the control of two phytopathogenic fungi, Botrytis cinerea and Fusarium oxysporum f. sp. cucumerium Owen. The antagonistic activity of VOCs released in mono- and co-culture modes was evaluated by inhibition assays on a Petri dish and in detached fruit experiments, with the co-culture demonstrating significantly higher inhibitory effects on the phytopathogens on both the plates and fruits compared with the mono-cultures. Metabolomic profiles of VOCs were conducted using the solid–liquid microextraction technique, revealing 341 compounds with significant changes in their production during the co-culture. Among these compounds, linalool, dimethyl trisulfide, dimethyl disulfide, geranylacetone, 2-phenylethanol, and acetophenone were identified as having strong antagonistic activity through a standard inhibition assay. These key compounds were found to be related to the improved inhibitory effect of the B418 and T11-W co-culture. Overall, the results suggest that VOCs produced by the co-culture of B. vietnamiensis B418 and T. harzianum T11-W possess great potential in biological control. [ABSTRACT FROM AUTHOR]

V2O5, as a potential cathode material for lithium-ion batteries (LIBs), is limited by poor activity and structural stability. Herein, a series of 3D shuttle V2O5 materials are obtained by a simple solvothermal method combined with subsequent calcination. When the calcination temperature was set to 600°C, the obtained V2O5 porous material (V-MOFs-600) had the largest specific surface area and pore volume, which conferred more Li+ embedding sites and thus accelerated Li+ embedding/de-embedding. Based on this, paired with a lithium anode, the V-MOFs-600 cathode exhibits excellent lithium storage performance parameters of 162.1 mAh·g-1 at 1A·g-1 and 78.3% capacity retention after 200 cycles. These results indicate that the 3D shuttle V2O5 porous nanoelectrode materials assembled from particles are highly promising as long-life, high-rate cathode materials for next-generation LIBs. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the efficiency of the secondary metabolites (SMs) produced by a co-culture of Trichoderma harzianum TW21990 and Burkholderia vietnamiensis B418 in the control of Colletotrichum siamense CM9. A fermentation filtrate of B418 + TW21990 co-culture (BT21) produced a notable increase in the inhibition rate of CM9 compared to those of TW21990 and B418 monocultures, which reached 91.40% and 80.46% on PDA plates and strawberry leaves, respectively. The BT21 fermentation broth exhibited high control efficiency on strawberry root rot of 68.95% in a pot experiment, which was higher than that in the monocultures and fluazinam treatment. In addition, BT21 treatment promoted strawberry root development, improved antioxidative enzyme activities in the leaves and roots, and enhanced the total chlorophyll content of the strawberry leaves. UHPLC-MS/MS analysis of fermentation filtrates was performed to elucidate SM variations, revealing 478 and 795 metabolites in BT21 co-culture in positive and negative ion modes, respectively. The metabolomic profiles suggested abundant SMs with antagonistic capabilities and growth-promoting effects: 3-(propan-2-yl)-octahydropyrrolo [1,2-a]pyrazine-1,4-dione (cyclo(L-Pro-L-Val)), 3-[(4-hydroxyphenyl)methyl]-octahydropyrrolo[1,2-a]pyrazine-1,4-dione (cyclo(L-Pro-L-Tyr)), 3-indoleacetic acid (IAA), 2-hydroxycinnamic acid, 4-aminobutyric acid (GABA), bafilomycin B1, and DL-indole-3-lactic acid (ILA) were significantly enhanced in the co-culture. Overall, this study demonstrates that a co-culture strategy is efficient for inducing bioactive SMs in T. harzianum and B. vietnamiensis, which could be exploited as a novel approach for developing biocontrol consortia. [ABSTRACT FROM AUTHOR]

Space targets move in orbit at a very high speed, so in order to obtain high-quality imaging, high-speed motion compensation (HSMC) and translational motion compensation (TMC) are required. HSMC and TMC are usually adjacent, and the residual error of HSMC will reduce the accuracy of TMC. At the same time, under the condition of low signal-to-noise ratio (SNR), the accuracy of HSMC and TMC will also decrease, which brings challenges to high-quality ISAR imaging. Therefore, this paper proposes a joint ISAR motion compensation algorithm based on entropy minimization under low-SNR conditions. Firstly, the motion of the space target is analyzed, and the echo signal model is obtained. Then, the motion of the space target is modeled as a high-order polynomial, and a parameterized joint compensation model of high-speed motion and translational motion is established. Finally, taking the image entropy after joint motion compensation as the objective function, the red-tailed hawk–Nelder–Mead (RTH-NM) algorithm is used to estimate the target motion parameters, and the joint compensation is carried out. The experimental results of simulation data and real data verify the effectiveness and robustness of the proposed algorithm. [ABSTRACT FROM AUTHOR]

Strawberry anthracnose caused by Colletotrichum spp. has resulted in significant losses in strawberry production worldwide. Strawberry anthracnose occurs mainly at the seedling and early planting stages, and Colletotrichum siamense is the main pathogen in North China, where mycelia, anamorphic nuclei, and conidia produced in the soil are the main sources of infection. The detection of pathogens in soil is crucial for predicting the prevalence of anthracnose. In this study, a visualized loop-mediated isothermal amplification (LAMP) assay and a loop-mediated isothermal amplification method combined with a TaqMan probe (LAMP-TaqMan) assay were developed for the β-tubulin sequence of C. siamense. Both methods can detect Colletotrichum siamense genomic DNA at very low concentrations (104 copies/g) in soil, while both the visualized LAMP and LAMP-TaqMan assays exhibited a detection limit of 50 copies/μL, surpassing the sensitivity of conventional PCR and qPCR techniques, and both methods showed high specificity for C. siamense. The two methods were compared: LAMP-TaqMan exhibited enhanced specificity due to the incorporation of fluorescent molecular beacons, while visualized LAMP solely necessitated uncomplicated incubation at a constant temperature, with the results determined by the color change; therefore, the requirements for the instrument are relatively straightforward and user-friendly. In conclusion, both assays will help monitor populations of C. siamense in China and control strawberry anthracnose in the field. [ABSTRACT FROM AUTHOR]

Terpenoids are structurally diverse natural products that have been widely used in the pharmaceutical, food, and cosmetic industries. Research has shown that fungi produce a variety of terpenoids, yet fungal terpene synthases remain not thoroughly explored. In this study, the tps1 gene, a crucial component of the terpene synthetic pathway, was isolated from Trichoderma atroviride HB20111 through genome mining. The function of this gene in the terpene synthetic pathway was investigated by constructing tps1-gene-deletion- and overexpression-engineered strains and evaluating the expression differences in the tps1 gene at the transcript level. HS-SPME-GC-MS analysis revealed significant variations in terpene metabolites among wild-type, tps1-deleted (Δtps1), and tps1-overexpressed (Otps1) strains; for instance, most sesquiterpene volatile organic compounds (VOCs) were notably reduced or absent in the Δtps1 strain, while nerolidol, β-acorenol, and guaiene were particularly produced by the Otps1 strain. However, both the Δtps1 and Otps1 strains produced new terpene metabolites compared to the wild-type, which indicated that the tps1 gene played an important role in terpene synthesis but was not the only gene involved in T. atroviride HB20111. The TPS1 protein encoded by the tps1 gene could function as a sesquiterpene cyclase through biological information and evolutionary tree analysis. Additionally, fungal inhibition assay and wheat growth promotion assay results suggested that the deletion or overexpression of the tps1 gene had a minimal impact on fungal inhibitory activity, plant growth promotion, and development, as well as stress response. This implies that these activities of T. atroviride HB20111 might result from a combination of multiple metabolites rather than being solely dependent on one specific metabolite. This study offers theoretical guidance for future investigations into the mechanism of terpenoid synthesis and serves as a foundation for related studies on terpenoid metabolic pathways in fungi. [ABSTRACT FROM AUTHOR]

Ni-based coating, as an excellent anti-corrosion material, is widely used in the petroleum field and has become a research hotspot in recent years. With the continuous progress of the petrochemical industry, especially in the carbon capture, utilization, and storage and enhanced oil recovery (CCUS-EOR) systems, Ni-based coatings face significant challenges. Based on the latest research status, this paper describes the influence factors of Ni-based coatings and the applicability of different Ni-based coatings. Research shows that CO2 and H2S are the key factors affecting corrosion. With the increase in CO2 and H2S content in the environment, the corrosion rate of carbon steel will be accelerated. When the CO2 content reaches a certain critical value, further increasing the CO2 content will reduce the corrosion rate. The corrosion mechanism of carbon steel under the combined action of CO2 and H2S was also analyzed. At a high CO2/H2S partial pressure ratio, the corrosion process is dominated by CO2 corrosion, and with the increase in the H2S/CO2 partial pressure ratio, the corrosion process shifts to H2S corrosion control. The application of Ni-P protective coatings in this corrosive environment has been investigated. A surface Ni-P coating is extremely hard, wear-resistant, and corrosion-resistant. It can withstand the corrosion of CO2, high salinity, and other media while preventing electrolyte penetration. It exhibits strong corrosion resistance in NaCl solution and can help prevent scaling. However, in the presence of CO2-H2s, it has been discovered that due to inherent faults in Ni-P, the corrosion phenomenon may be exacerbated by the action of H2S, and its protection ability has to be further investigated. The mechanical properties and corrosion resistance of the coating can be enhanced by adding particles to the coating, and four new coating systems, Ni-Fe-P, Ni-Cu-P, Ni-W-P, and Ni-W-P-nSiO2, were introduced. Finally, the future development focus and prospect of CO2 corrosion protection coatings under harsh conditions are prospected. [ABSTRACT FROM AUTHOR]

BACKGROUND: Quorum sensing inhibitors (QSIs) are an emerging control tool that inhibits the quorum sensing (QS) system of pathogenic bacteria. We aimed to screen for potential QSIs in the metabolites of Trichoderma and to explore their inhibitory mechanisms. RESULTS: We screened a strain of Trichoderma asperellum LN004, which demonstrated the ability to inhibit the color development of Chromobacterium subtsugae CV026, primarily attributed to the presence of emodin as its key QSI component. The quantitative polymerase chain reaction with reverse transcription results showed that after emodin treatment of Pectobacterium carotovorum subsp. carotovorum (Pcc), plant cell wall degrading enzyme‐related synthetic genes were significantly downregulated, and the exogenous enzyme synthesis gene negative regulator (rsmA) was upregulated 3.5‐fold. Docking simulations indicated that emodin could be a potential ligand for ExpI and ExpR proteins because it exhibited stronger competition than the natural ligands in Pcc. In addition, western blotting showed that emodin attenuated the degradation of n‐acylhomoserine lactone on the ExpR protein and protected it. Different concentrations of emodin reduced the activity of pectinase, cellulase, and protease in Pcc by 20.81%–72.21%, 8.38%–52.73%, and 3.57%–47.50%. Lesion size in Chinese cabbages, carrots and cherry tomatoes following Pcc infestation was reduced by 10.02%–68.57%, 40.17%–88.56% and 11.36%–86.17%. CONCLUSION: Emodin from T. asperellum LN004 as a QSI can compete to bind both ExpI and ExpR proteins, interfering with the QS of Pcc and reducing the production of virulence factors. The first molecular mechanism reveals the ability of emodin as a QSI to competitively inhibit two QS proteins simultaneously. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]