The Prediction and Evaluation of Surface Quality during the Milling of Blade-Root Grooves Based on a Long Short-Term Memory Network and Signal Fusion.

The surface quality of milled blade-root grooves in industrial turbine blades significantly influences their mechanical properties. The surface texture reveals the interaction between the tool and the workpiece during the machining process, which plays a key role in determining the surface quality. In addition, there is a significant correlation between acoustic vibration signals and surface texture features. However, current research on surface quality is still relatively limited, and most considers only a single signal. In this paper, 160 sets of industrial field data were collected by multiple sensors to study the surface quality of a blade-root groove. A surface texture feature prediction method based on acoustic vibration signal fusion is proposed to evaluate the surface quality. Fast Fourier transform (FFT) is used to process the signal, and the clean and smooth features are extracted by combining wavelet denoising and multivariate smoothing denoising. At the same time, based on the gray-level co-occurrence matrix, the surface texture image features of different angles of the blade-root groove are extracted to describe the texture features. The fused acoustic vibration signal features are input, and the texture features are output to establish a texture feature prediction model. After predicting the texture features, the surface quality is evaluated by setting a threshold value. The threshold is selected based on all sample data, and the final judgment accuracy is 90%.

Wettability-Oriented Laser Microgrooving Process on Cemented Carbide Surface.

Surface micro-texture has been shown to enhance wettability and reduce wear on cutting tools. However, there is limited research on how laser parameters impact the dimensional accuracy of surface texture and its wettability. This study focuses on producing arrayed groove textures on WC/Co cemented carbide surfaces using Nd: YAG laser, evaluating the effect of the laser parameters on surface topography and texture accuracy through microscopic observation and simulation. The results indicate that, with laser parameters such as a number of passes less than 5, approximately 16 W power, scanning speed of 100-150 mm/s, and pulse frequency of 30 kHz, the error between the groove width and laser spot diameter was 4.7%. Additionally, the study explores the impact of the groove texture on surface wettability using the solid droplet method and XPS analysis. Comparative experiments reveal that increased surface roughness enhanced oleophobicity, with surfaces exhibiting high texture accuracy and integrity showing improved oleophobic and spreading properties. Thus, the precise regulation of laser processes is crucial for maintaining surface texture integrity and enhancing surface wettability.

Z-scheme CoAl-layereddoublehydroxide/indium vanadate heterojunction for enhanced and highly selective photocatalytic reduction of carbon dioxide to carbon monoxide.

Development of efficient photocatalysts is essential for carbon dioxide (CO2) photocatalytic reduction. In this study, Z-scheme CoAl-layered double hydroxide (LDH)/indium vanadate (InVO4) heterojunction photocatalysts were synthesized using hydrothermal method, and their performance toward CO2 reduction and mechanism were determined. Results of characterizations showed that the CoAl-LDH/InVO4-30 exhibited desired morphology, the most efficient photogenerated carriers separation and charge transfer, and the highest photocurrent response. X-ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR) manifested that charge transfer of the CoAl-LDH/InVO4 conformed to Z-scheme mechanism. The CoAl-LDH/InVO4-30 exhibited the highest carbon monoxide (CO) yield of 174.4 µmol g-1 within 2 h of reaction, which was 2.46 and 9.79 times of pure CoAl-LDH and InVO4, respectively. The CO selectivity was up to nearly 100%. Moreover, in-situ fourier transform infrared spectroscopy (ISFT-IR) demonstrated that bicarbonate (HCO3*) and carboxylate (COOH*) were the main intermediates during the CO2 reduction process, and possible CO2 reduction pathways were proposed. This work provides a reference for construction of Z-scheme LDH-based heterojunctions for efficient CO2 photoreduction.

Visible light driven antibiotics degradation using S-scheme Bi2WO6/CoIn2S4 heterojunction: Mechanism, degradation pathways and toxicity assessment.

S-scheme heterojunction photocatalysts with strong redox ability and excellent photocatalytic activity are highly desired for photocatalytic degradation of pollutants. Herein, S-scheme Bi2WO6/CoIn2S4 heterojunctions were synthesized using hydrothermal method. The photo-induced carriers transfer mechanism of the S-scheme Bi2WO6/CoIn2S4 heterojunction was clarified by band structure analysis, ultraviolet photoelectron spectrometer (UPS), electron spin resonance (ESR) and radical trapping experiments. Significant enhance of light absortion, and more efficient carriers separation were observed from the Bi2WO6/CoIn2S4 with CoIn2S4 nanoclusters growing on the surface of petal-like Bi2WO6 nanosheets. TC degradation efficiency of 90% was achieved by Bi2WO6/CoIn2S4 (15:1) within 3 h of irradiation, and ·O2-and ·OH radicals were dominated contributors. Possible decomposition pathways of TC were proposed, and ECOSAR analysis showed that most of the intermediates exhibited lower ecotoxicity than TC. This work provides reference on the constructing ternary-metal-sulfides-based S-scheme heterojunctions for improving photocatalytic performance.

Step-doped disulfide vacancies and functional groups synergistically enhance photocatalytic activity of S-scheme Cu3SnS4/L-BiOBr towards ciprofloxacin degradation.

Development of efficient photocatalysts for efficient recalcitrant organic pollutants degradation is of great significance. Herein, the step-doped disulfide vacancies S-scheme Cu3SnS4/L-BiOBr (CTS/L-BiOBr) heterojunction photocatalyst was prepared for ciprofloxacin (CIP) degradation. X-ray photoelectron spectroscopy (XPS) analysis, ultraviolet photo-electron spectroscopy (UPS) analysis, band structure and dominant radicals' identification together verified that the transfer of photogenerated carriers conformed to the S-scheme mechanism. Benefited from the interfacial electric field (IEF) of the S-scheme heterojunction and incorporation of L-cysteine with introducing S-vacancies and surface functional groups (-NH2, -COO-), photogenerated charges generation and separation of the CTS/L-BiOBr(10) were greatly improved. With ·OH and h+ as dominant reactive species, CIP removal reached 93% using CTS/L-BiOBr(10) within 180 min of visible light irradiation, which was 3.5 times and 2.6 times of pristine Cu3SnS4 and L-BiOBr, respectively. Moreover, possible CIP degradation pathways were proposed and the degradation intermediates ecotoxicity were evaluated. This study could provide reference for designing efficient S-scheme photocatalysts for recalcitrant wastewater treatment.

Synchronous removal of tetracycline and copper (II) over Z­scheme BiVO4/rGO/g-C3N4 photocatalyst under visible-light irradiation.

The combined pollution of heavy metals and organic pollutants in water body has become one of vital environmental issues. Herein, a series of BiVO4/rGO/g-C3N4 nanocomposites were synthesized for concurrent removals of organic pollutant and heavy metal. Results showed that using the optimized photocatalyst BiVO4/rGO/g-C3N4-28, tetracycline (TC) removal of 87.3% and copper (Cu (II)) removal of 90.6% were achieved under visible-light irradiation within 3 h, respectively; much higher than those using BiVO4 and g-C3N4. More importantly, synergistic effect of TC and Cu (II) removals occurred on the surface of BiVO4/rGO/g-C3N4 in the TC-Cu (II) coexistence condition. Additionally, the ·OH and ·O2- were the most important active species for TC oxidation, while photogenerated electrons were the most responsible for Cu (II) reduction. Results of various characterizations and electron spin resonance test demonstrated that BiVO4/rGO/g-C3N4 was a Z-scheme photocatalyst. Based on the identified intermediates, possible degradation pathways and mechanisms for photocatalytic degradation of TC were proposed. This study advances the development and mechanism of photocatalysts for collaborative removal of pollutants.

Hydroxyl radical and carbonate radical facilitate chlortetracycline degradation in the bio-photoelectrochemical system with a bioanode and a Bi2O3/CuO photocathode using bicarbonate buffer.

The single-chamber bio-photoelectrochemical system (BPES) with a bioanode and a Bi2O3/CuO photocathode is developed for chlortetracycline (CTC) degradation under simulated solar irradiation, using phosphate buffer solution (PBS) or NaHCO3 as buffer solution. The optimized Bi2O3/CuO photocathode possesses rich vacancies, great photoresponse capability, and exhibits great photocatalytic activity toward CTC degradation due to its Z-scheme structure. Electron spin-resonance spectroscopy (ESR) and reactive species trapping experiments reveal that superoxide radicals/hydroxyl radicals are both the main radicals contributing to CTC degradation. Moreover, carbonate radical plays a more effective role toward CTC degradation, resulting in 40% improvement for CTC degradation in the BPES within 2 h. Higher current density (maximum of 137.6 A m-2) and more negative cathode potential are obtained from the illuminated BPES with NaHCO3 buffer. Possible mechanism and pathways of CTC degradation are proposed. This study contributes to the development of BPESs for antibiotics degradation.