Weld Seam Tracking and Detection Robot Based on Artificial Intelligence Technology.

The regular detection of weld seams in large-scale special equipment is crucial for improving safety and efficiency, and this can be achieved effectively through the use of weld seam tracking and detection robots. In this study, a wall-climbing robot with integrated seam tracking and detection was designed, and the wall climbing function was realized via a permanent magnet array and a Mecanum wheel. The function of weld seam tracking and detection was realized using a DeepLabv3+ semantic segmentation model. Several optimizations were implemented to enhance the deployment of the DeepLabv3+ semantic segmentation model on embedded devices. Mobilenetv2 was used to replace the feature extraction network of the original model, and the convolutional block attention module attention mechanism was introduced into the encoder module. All traditional 3×3 convolutions were substituted with depthwise separable dilated convolutions. Subsequently, the welding path was fitted using the least squares method based on the segmentation results. The experimental results showed that the volume of the improved model was reduced by 92.9%, only being 21.8 Mb. The average precision reached 98.5%, surpassing the original model by 1.4%. The reasoning speed was accelerated to 21 frames/s, satisfying the real-time requirements of industrial detection. The detection robot successfully realizes the autonomous identification and tracking of weld seams. This study remarkably contributes to the development of automatic and intelligent weld seam detection technologies.

Enhanced Photocatalytic Activity of Directly Assembled Fe2O3/Gd2O3@TiO2-Based Nanosheets.

TiO2-based nanosheets (TNSs) modified with surface-enriched Fe2O3 and Gd2O3 nanoparticles (NPs) have been synthesized via a direct interfacial assembly strategy. The TNSs with a unique two-dimensional structure are favorable for supporting Fe2O3 and Gd2O3 NPs for photocatalytic applications. The prepared samples were characterized using scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), Raman spectroscopy (Raman), BET, X-ray photoelectron spectroscopy (XPS), UV-Vis diffuse reflectance spectra (DRS), photoluminescence (PL) spectroscopy and the surface photocurrent (SPC) technique. The photocatalysts exhibited large specific surface area (160-260 m²/g). The co-modification with Fe2O3 and Gd2O3 NPs influenced the crystallinity and surface area of the TNSs, and improved visible-light absorption. Surface photocurrent and PL studies revealed that the photogenerated charge carrier separation efficiency could be improved by an appropriate amount of NPs. The optimized nanostructure exhibited photocatalytic efficiency for rhodamine B (RhB) degradation and H2 production is 5.66-fold and 2.99-fold respectively than those of TNSs under visible-light irradiation. The enhancement is attributed to the combined effect of Gd2O3 and Fe2O3 NPs in the Fe2O3/Gd2O3@TNSs composites. The simultaneous use of two different types of NPs led to a fast separation and slow recombination of photoinduced electron-hole pairs. A mechanism is proposed to explain the enhanced visible-light photocatalytic activity.

A surfactant-free solvothermal synthesis of Cu2O microcrystals and their photocatalytic activity.

The Cu2O octahedral microcrystals have been successfully fabricated by a surfactant-free solvothermal approach. The morphology and structure of the as-prepared sample were characterized by scanning electron microscopy, X-ray powder diffraction and UV-Vis spectroscopy. It was found that the structure and morphology of Cu2O microcrystals were strongly affected by synthesis time and temperature. Based on the time-dependent experiment, the possible formation mechanism of Cu2O octahedral microcrystals was proposed. The photocatalytic activities of as-prepared Cu2O samples were also evaluated for degradation of methyl orange under visible-light irradiation. The results showed that the Cu2O synthesized at 180 °C for 4 h had a better photocatalytic performance due to its high percentage of exposed (111) crystal facet and the lowest band gap energy.

Recent Advances and Insights in Designing ZnxCd1-xS-Based Photocatalysts for Hydrogen Production and Synergistic Selective Oxidation to Value-Added Chemical Production.

Combining the hydrogen (H2) extraction process and organic oxidation synthesis in photooxidation-reduction reactions mediated by semiconductors is a desirable strategy because rich chemicals are evolved as byproducts along with hydrogen in trifling conditions upon irradiation, which is the only effort. The bifunctional photocatalytic strategy facilitates the feasible formation of a C═O/C─C bond from a large number of compounds containing a X-H (X = C, O) bond; therefore, the production of H2 can be easily realized without support from third agents like chemical substances, thus providing an eco-friendly and appealing organic synthesis strategy. Among the widely studied semiconductor nanomaterials, ZnxCd1-xS has been continuously studied and explored by researchers over the years, and it has attracted much consideration owing to its unique advantages such as adjustable band edge position, rich elemental composition, excellent photoelectric properties, and ability to respond to visible light. Therefore, nanostructures based on ZnxCd1-xS have been widely studied as a feasible way to efficiently prepare hydrogen energy and selectively oxidize it into high-value fine chemicals. In this Review, first, the crystal and energy band structures of ZnxCd1-xS, the model of twin nanocrystals, the photogenerated charge separation mechanism of the ZB-WZ-ZB homojunction with crisscross bands, and the Volmer-Weber growth mechanism of ZnxCd1-xS are described. Second, the morphology, structure, modification, synthesis, and vacancy engineering of ZnxCd1-xS are surveyed, summarized, and discussed. Then, the research progress in ZnxCd1-xS-based photocatalysis in photocatalytic hydrogen extraction (PHE) technology, the mechanism of PHE, organic substance (benzyl alcohol, methanol, etc.) dehydrogenation, the factors affecting the efficiency of photocatalytic discerning oxidation of organic derivatives, and selective C-H activation and C-C coupling for synergistic efficient dehydrogenation of photocatalysts are described. Conclusively, the challenges in the applicability of ZnxCd1-xS-based photocatalysts are addressed for further research development along this line.

Morphological Control of Supported ZnO Nanosheet Arrays and Their Application in Photodegradation of Organic Pollutants.

Supported nanostructured photocatalysis is considered to be a sustainable and promising method for water pollution photodegradation applications due to its fascinating features, including a high surface area, stability against aggregation, and easy handling and recovery. However, the preparation and morphological control of the supported nanostructured photocatalyst remains a challenge. Herein, a one-step hydrothermal method is proposed to fabricate the supported vertically aligned ZnO nanosheet arrays based on aluminum foil. The morphologically controlled growth of the supported ZnO nanosheet arrays on a large scale was achieved, and the effects of hydrothermal temperature on morphologic, structural, optical, and photocatalytic properties were observed. The results reveal that the surface area and thickness of the nanosheet increase simultaneously with the increase in the hydrothermal temperature. The increase in the surface area enhances the photocatalytic activity by providing more active sites, while the increase in the thickness reduces the charge transfer and thus decreases the photocatalytic activity. The influence competition between the area increasing and thickness increasing of the ZnO nanosheet results in the nonlinear dependence between photocatalytic activity and hydrothermal temperature. By optimizing the hydrothermal growth temperature, as fabricated and supported ZnO nanosheet arrays grown at 110 °C have struck a balance between the increase in surface area and thickness, it exhibits efficient photodegradation, facile fabrication, high recyclability, and improved durability. The RhB photodegradation efficiency of optimized and grown ZnO nanosheet arrays increased by more than four times that of the unoptimized structure. With 10 cm2 of as-fabricated ZnO nanosheet arrays, the degradation ratio of 10 mg/L MO, MB, OFL, and NOR was 85%, 51%, 58%, and 71% under UV irradiation (365 nm, 20 mW/cm2) for 60 min. All the target pollutant solutions were almost completely degraded under UV irradiation for 180 min. This work offers a facile way for the fabrication and morphological control of the supported nanostructured photocatalyst with excellent photodegradation properties and has significant implications in the practical application of the supported nanostructured photocatalyst for water pollution photodegradation.

Preparation and novel photoluminescence properties of the self-supporting nanoporous InP thin films.

Self-supporting nanoporous InP membranes are prepared by electrochemical etching, and are then first transferred to highly reflective (> 96%) mesoporous GaN (MP-GaN) distributed Bragg reflector (DBR) or quartz substrate. By the modulation of bandgap, the nanoporous InP samples show a strong photoluminescence (PL) peak at 541.2 nm due to the quantum size effect of the nanoporous InP structure. Compared to the nanoporous InP membrane with quartz substrate, the nanoporous membrane transferred to DBR shows a twofold enhancement in PL intensity owing to the high light reflection effect of bottom DBR.

Enhanced visible light photodegradation activity of RhB/MB from aqueous solution using nanosized novel Fe-Cd co-modified ZnO.

A series of novel Fe-Cd co-doped ZnO nanoparticle based photocatalysts are successfully synthesized by sol-gel route and characterized using scanning electron microscopy (SEM), energy dispersive X-ray emission (EDX), transmission electron microscopy (TEM), X-ray diffraction (XRD), UV-Vis spectroscopy, X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller (BET) techniques. The photocatalytic activity of ZnO nanoparticles doped with various atomic weight fraction of Fe and Cd has been investigated under visible light irradiation using the Methylene Blue and Rhodamine B dye in aqueous solution. The FeCd (2%):ZnO (ZFC-1) exhibit the highest photocatalytic activity in terms of rate constant as KMB = 0.01153 min-1 and KRhB = 0.00916 min-1). Further, the re-usability of the ZFC-1 photocatalyst is studied which confirms that it can be reused up to five times with nearly negligible loss of the photocatalytic efficiency. Moreover, the role of photoactive species investigated using a radical scavenger technique. The present investigations show that the doping concentration plays significant role in photocatalytic performance. The visible light absorption shown by Fe-Cd co-doped ZnO nanoparticles is much higher than that of undoped body probably due to co-doping, and the charge carrier recombination is decreased effectively which yields a higher photocatalytic performance. The mechanism for the enhancement of photocatalytic activity under visible light irradiation is also proposed.

Solvothermal-assisted synthesis of self-assembling TiO2 nanorods on large graphitic carbon nitride sheets with their anti-recombination in the photocatalytic removal of Cr(vi) and rhodamine B under visible light irradiation.

TiO2-based nanorods (TNRs) were self-assembled on large graphitic carbon nitride (g-C3N4) sheets via the solvothermal-assisted route. The results demonstrated that the effective anchoring of TNRs (a side length of ca. 200-300 nm) was highly dispersed on the surface of whole g-C3N4 sheets. The shift in the Ti 2p XPS core level spectrum indicated an increase in the net positive charge of the Ti ions, ensuring the formation of an interface between TNRs and g-C3N4. The charge transferred from g-C3N4 sheets to TNRs effectively prevented the recombination of excited charges, which is consistent with the significant quenching of PL. The extent of visible-light-sensitive photocatalytic (PC) activity was evaluated by the removal of potassium dichromate (Cr(vi)) or the degradation of rhodamine B (RhB). The photocatalytic removal of Cr(vi) using RhB was effectively improved. The synergistic effect between the removal of Cr(vi) and degradation of RhB was revealed by multiple utilization of TNRs/g-C3N4 for PC activity. The effective suppression of the recombination of photo-induced charges and the absorption of RhB was responsible for the enhancement in the PC activity. An alternate mechanism for enhanced visible-light photocatalytic activity was also considered.